| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Andrii Nakryiko | 30881 | 46.93% | 238 | 39.08% |
| Martin KaFai Lau | 11895 | 18.08% | 15 | 2.46% |
| Alexei Starovoitov | 3290 | 5.00% | 33 | 5.42% |
| Jiri Olsa | 2197 | 3.34% | 14 | 2.30% |
| Wang Nan | 1827 | 2.78% | 32 | 5.25% |
| Daniel Müller | 1280 | 1.95% | 9 | 1.48% |
| Yonghong Song | 1146 | 1.74% | 19 | 3.12% |
| Daniel Borkmann | 1119 | 1.70% | 10 | 1.64% |
| Kumar Kartikeya Dwivedi | 964 | 1.46% | 10 | 1.64% |
| Toke Höiland-Jörgensen | 793 | 1.21% | 14 | 2.30% |
| Hengqi Chen | 708 | 1.08% | 10 | 1.64% |
| JackieLiu | 699 | 1.06% | 2 | 0.33% |
| Kui-Feng Lee | 685 | 1.04% | 4 | 0.66% |
| Alan Maguire | 645 | 0.98% | 7 | 1.15% |
| JP Kobryn | 608 | 0.92% | 3 | 0.49% |
| Delyan Kratunov | 515 | 0.78% | 3 | 0.49% |
| Stanislav Fomichev | 457 | 0.69% | 12 | 1.97% |
| Hao Luo | 405 | 0.62% | 4 | 0.66% |
| KP Singh | 372 | 0.57% | 3 | 0.49% |
| Rafael David Tinoco | 334 | 0.51% | 2 | 0.33% |
| Martynas Pumputis | 333 | 0.51% | 3 | 0.49% |
| Ilya Leoshkevich | 312 | 0.47% | 4 | 0.66% |
| Jakub Kiciński | 268 | 0.41% | 14 | 2.30% |
| Andrey Ignatov | 256 | 0.39% | 17 | 2.79% |
| YiFei Zhu | 255 | 0.39% | 1 | 0.16% |
| Florian Westphal | 252 | 0.38% | 3 | 0.49% |
| Eelco Chaudron | 250 | 0.38% | 3 | 0.49% |
| Menglong Dong | 241 | 0.37% | 2 | 0.33% |
| Joe Stringer | 200 | 0.30% | 9 | 1.48% |
| Joanne Koong | 157 | 0.24% | 1 | 0.16% |
| Hechao Li | 154 | 0.23% | 1 | 0.16% |
| Mauricio Vásquez | 134 | 0.20% | 2 | 0.33% |
| Dave Marchevsky | 124 | 0.19% | 2 | 0.33% |
| Jon Doron | 115 | 0.17% | 3 | 0.49% |
| Wang Yufen | 114 | 0.17% | 1 | 0.16% |
| Shuyi Cheng | 111 | 0.17% | 3 | 0.49% |
| Stijn Tintel | 102 | 0.15% | 1 | 0.16% |
| Taeung Song | 87 | 0.13% | 1 | 0.16% |
| Daan De Meyer | 85 | 0.13% | 1 | 0.16% |
| Hou Tao | 80 | 0.12% | 1 | 0.16% |
| Lorenzo Bianconi | 78 | 0.12% | 2 | 0.33% |
| Thomas Richter | 77 | 0.12% | 1 | 0.16% |
| Chuang Wang | 76 | 0.12% | 2 | 0.33% |
| Kefeng Wang | 66 | 0.10% | 1 | 0.16% |
| Shung-Hsi Yu | 64 | 0.10% | 3 | 0.49% |
| Hangbin Liu | 61 | 0.09% | 4 | 0.66% |
| Song Liu | 61 | 0.09% | 2 | 0.33% |
| Nikita V. Shirokov | 61 | 0.09% | 1 | 0.16% |
| Roman Gushchin | 60 | 0.09% | 2 | 0.33% |
| Jakub Sitnicki | 57 | 0.09% | 3 | 0.49% |
| Liu Pan | 56 | 0.09% | 1 | 0.16% |
| John Fastabend | 55 | 0.08% | 5 | 0.82% |
| David Vernet | 52 | 0.08% | 3 | 0.49% |
| Quentin Monnet | 51 | 0.08% | 5 | 0.82% |
| Grant Seltzer | 44 | 0.07% | 2 | 0.33% |
| Anquan Wu | 44 | 0.07% | 1 | 0.16% |
| Daniel Xu | 41 | 0.06% | 1 | 0.16% |
| Arnaldo Carvalho de Melo | 31 | 0.05% | 8 | 1.31% |
| Andrei Matei | 28 | 0.04% | 1 | 0.16% |
| Eric Leblond | 25 | 0.04% | 1 | 0.16% |
| Evgeniy Litvinenko | 18 | 0.03% | 1 | 0.16% |
| Andrea Terzolo | 18 | 0.03% | 1 | 0.16% |
| Jesper Dangaard Brouer | 17 | 0.03% | 2 | 0.33% |
| Qiang Wang | 16 | 0.02% | 2 | 0.33% |
| James Hilliard | 15 | 0.02% | 1 | 0.16% |
| Jonathan Edwards | 15 | 0.02% | 1 | 0.16% |
| Maciej Fijalkowski | 15 | 0.02% | 1 | 0.16% |
| Takshak Chahande | 14 | 0.02% | 1 | 0.16% |
| Kenny Yu | 14 | 0.02% | 1 | 0.16% |
| Yuntao Wang | 12 | 0.02% | 2 | 0.33% |
| Yafang Shao | 10 | 0.02% | 1 | 0.16% |
| David Beckett | 9 | 0.01% | 1 | 0.16% |
| Kuniyuki Iwashima | 9 | 0.01% | 1 | 0.16% |
| Prashant Bhole | 8 | 0.01% | 1 | 0.16% |
| Ian Rogers | 8 | 0.01% | 1 | 0.16% |
| Tony Ambardar | 8 | 0.01% | 1 | 0.16% |
| Brendan Jackman | 7 | 0.01% | 1 | 0.16% |
| Craig Gallek | 6 | 0.01% | 2 | 0.33% |
| Eduard Zingerman | 6 | 0.01% | 1 | 0.16% |
| Namhyung Kim | 6 | 0.01% | 1 | 0.16% |
| Roberto Sassu | 5 | 0.01% | 1 | 0.16% |
| Kang Minchul | 4 | 0.01% | 1 | 0.16% |
| Florent Revest | 4 | 0.01% | 1 | 0.16% |
| Petar Penkov | 4 | 0.01% | 1 | 0.16% |
| Khem Raj | 3 | 0.00% | 1 | 0.16% |
| Christy Lee | 3 | 0.00% | 1 | 0.16% |
| Jiong Wang | 3 | 0.00% | 1 | 0.16% |
| Xu Wang | 2 | 0.00% | 2 | 0.33% |
| Ludovic L'Hours | 2 | 0.00% | 1 | 0.16% |
| Marco Vedovati | 2 | 0.00% | 1 | 0.16% |
| Colin Ian King | 1 | 0.00% | 1 | 0.16% |
| Runqing Yang | 1 | 0.00% | 1 | 0.16% |
| David Ahern | 1 | 0.00% | 1 | 0.16% |
| Gustavo A. R. Silva | 1 | 0.00% | 1 | 0.16% |
| Julia Lawall | 1 | 0.00% | 1 | 0.16% |
| Hui Wang | 1 | 0.00% | 1 | 0.16% |
| Alexey Dobriyan | 1 | 0.00% | 1 | 0.16% |
| Pu Lehui | 1 | 0.00% | 1 | 0.16% |
| Total | 65809 | 609 |
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) /* * Common eBPF ELF object loading operations. * * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org> * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> * Copyright (C) 2015 Huawei Inc. * Copyright (C) 2017 Nicira, Inc. * Copyright (C) 2019 Isovalent, Inc. */ #ifndef _GNU_SOURCE #define _GNU_SOURCE #endif #include <stdlib.h> #include <stdio.h> #include <stdarg.h> #include <libgen.h> #include <inttypes.h> #include <limits.h> #include <string.h> #include <unistd.h> #include <endian.h> #include <fcntl.h> #include <errno.h> #include <ctype.h> #include <asm/unistd.h> #include <linux/err.h> #include <linux/kernel.h> #include <linux/bpf.h> #include <linux/btf.h> #include <linux/filter.h> #include <linux/limits.h> #include <linux/perf_event.h> #include <linux/ring_buffer.h> #include <sys/epoll.h> #include <sys/ioctl.h> #include <sys/mman.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/vfs.h> #include <sys/utsname.h> #include <sys/resource.h> #include <libelf.h> #include <gelf.h> #include <zlib.h> #include "libbpf.h" #include "bpf.h" #include "btf.h" #include "str_error.h" #include "libbpf_internal.h" #include "hashmap.h" #include "bpf_gen_internal.h" #include "zip.h" #ifndef BPF_FS_MAGIC #define BPF_FS_MAGIC 0xcafe4a11 #endif #define BPF_INSN_SZ (sizeof(struct bpf_insn)) /* vsprintf() in __base_pr() uses nonliteral format string. It may break * compilation if user enables corresponding warning. Disable it explicitly. */ #pragma GCC diagnostic ignored "-Wformat-nonliteral" #define __printf(a, b) __attribute__((format(printf, a, b))) static struct bpf_map *bpf_object__add_map(struct bpf_object *obj); static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog); static const char * const attach_type_name[] = { [BPF_CGROUP_INET_INGRESS] = "cgroup_inet_ingress", [BPF_CGROUP_INET_EGRESS] = "cgroup_inet_egress", [BPF_CGROUP_INET_SOCK_CREATE] = "cgroup_inet_sock_create", [BPF_CGROUP_INET_SOCK_RELEASE] = "cgroup_inet_sock_release", [BPF_CGROUP_SOCK_OPS] = "cgroup_sock_ops", [BPF_CGROUP_DEVICE] = "cgroup_device", [BPF_CGROUP_INET4_BIND] = "cgroup_inet4_bind", [BPF_CGROUP_INET6_BIND] = "cgroup_inet6_bind", [BPF_CGROUP_INET4_CONNECT] = "cgroup_inet4_connect", [BPF_CGROUP_INET6_CONNECT] = "cgroup_inet6_connect", [BPF_CGROUP_UNIX_CONNECT] = "cgroup_unix_connect", [BPF_CGROUP_INET4_POST_BIND] = "cgroup_inet4_post_bind", [BPF_CGROUP_INET6_POST_BIND] = "cgroup_inet6_post_bind", [BPF_CGROUP_INET4_GETPEERNAME] = "cgroup_inet4_getpeername", [BPF_CGROUP_INET6_GETPEERNAME] = "cgroup_inet6_getpeername", [BPF_CGROUP_UNIX_GETPEERNAME] = "cgroup_unix_getpeername", [BPF_CGROUP_INET4_GETSOCKNAME] = "cgroup_inet4_getsockname", [BPF_CGROUP_INET6_GETSOCKNAME] = "cgroup_inet6_getsockname", [BPF_CGROUP_UNIX_GETSOCKNAME] = "cgroup_unix_getsockname", [BPF_CGROUP_UDP4_SENDMSG] = "cgroup_udp4_sendmsg", [BPF_CGROUP_UDP6_SENDMSG] = "cgroup_udp6_sendmsg", [BPF_CGROUP_UNIX_SENDMSG] = "cgroup_unix_sendmsg", [BPF_CGROUP_SYSCTL] = "cgroup_sysctl", [BPF_CGROUP_UDP4_RECVMSG] = "cgroup_udp4_recvmsg", [BPF_CGROUP_UDP6_RECVMSG] = "cgroup_udp6_recvmsg", [BPF_CGROUP_UNIX_RECVMSG] = "cgroup_unix_recvmsg", [BPF_CGROUP_GETSOCKOPT] = "cgroup_getsockopt", [BPF_CGROUP_SETSOCKOPT] = "cgroup_setsockopt", [BPF_SK_SKB_STREAM_PARSER] = "sk_skb_stream_parser", [BPF_SK_SKB_STREAM_VERDICT] = "sk_skb_stream_verdict", [BPF_SK_SKB_VERDICT] = "sk_skb_verdict", [BPF_SK_MSG_VERDICT] = "sk_msg_verdict", [BPF_LIRC_MODE2] = "lirc_mode2", [BPF_FLOW_DISSECTOR] = "flow_dissector", [BPF_TRACE_RAW_TP] = "trace_raw_tp", [BPF_TRACE_FENTRY] = "trace_fentry", [BPF_TRACE_FEXIT] = "trace_fexit", [BPF_MODIFY_RETURN] = "modify_return", [BPF_LSM_MAC] = "lsm_mac", [BPF_LSM_CGROUP] = "lsm_cgroup", [BPF_SK_LOOKUP] = "sk_lookup", [BPF_TRACE_ITER] = "trace_iter", [BPF_XDP_DEVMAP] = "xdp_devmap", [BPF_XDP_CPUMAP] = "xdp_cpumap", [BPF_XDP] = "xdp", [BPF_SK_REUSEPORT_SELECT] = "sk_reuseport_select", [BPF_SK_REUSEPORT_SELECT_OR_MIGRATE] = "sk_reuseport_select_or_migrate", [BPF_PERF_EVENT] = "perf_event", [BPF_TRACE_KPROBE_MULTI] = "trace_kprobe_multi", [BPF_STRUCT_OPS] = "struct_ops", [BPF_NETFILTER] = "netfilter", [BPF_TCX_INGRESS] = "tcx_ingress", [BPF_TCX_EGRESS] = "tcx_egress", [BPF_TRACE_UPROBE_MULTI] = "trace_uprobe_multi", [BPF_NETKIT_PRIMARY] = "netkit_primary", [BPF_NETKIT_PEER] = "netkit_peer", }; static const char * const link_type_name[] = { [BPF_LINK_TYPE_UNSPEC] = "unspec", [BPF_LINK_TYPE_RAW_TRACEPOINT] = "raw_tracepoint", [BPF_LINK_TYPE_TRACING] = "tracing", [BPF_LINK_TYPE_CGROUP] = "cgroup", [BPF_LINK_TYPE_ITER] = "iter", [BPF_LINK_TYPE_NETNS] = "netns", [BPF_LINK_TYPE_XDP] = "xdp", [BPF_LINK_TYPE_PERF_EVENT] = "perf_event", [BPF_LINK_TYPE_KPROBE_MULTI] = "kprobe_multi", [BPF_LINK_TYPE_STRUCT_OPS] = "struct_ops", [BPF_LINK_TYPE_NETFILTER] = "netfilter", [BPF_LINK_TYPE_TCX] = "tcx", [BPF_LINK_TYPE_UPROBE_MULTI] = "uprobe_multi", [BPF_LINK_TYPE_NETKIT] = "netkit", }; static const char * const map_type_name[] = { [BPF_MAP_TYPE_UNSPEC] = "unspec", [BPF_MAP_TYPE_HASH] = "hash", [BPF_MAP_TYPE_ARRAY] = "array", [BPF_MAP_TYPE_PROG_ARRAY] = "prog_array", [BPF_MAP_TYPE_PERF_EVENT_ARRAY] = "perf_event_array", [BPF_MAP_TYPE_PERCPU_HASH] = "percpu_hash", [BPF_MAP_TYPE_PERCPU_ARRAY] = "percpu_array", [BPF_MAP_TYPE_STACK_TRACE] = "stack_trace", [BPF_MAP_TYPE_CGROUP_ARRAY] = "cgroup_array", [BPF_MAP_TYPE_LRU_HASH] = "lru_hash", [BPF_MAP_TYPE_LRU_PERCPU_HASH] = "lru_percpu_hash", [BPF_MAP_TYPE_LPM_TRIE] = "lpm_trie", [BPF_MAP_TYPE_ARRAY_OF_MAPS] = "array_of_maps", [BPF_MAP_TYPE_HASH_OF_MAPS] = "hash_of_maps", [BPF_MAP_TYPE_DEVMAP] = "devmap", [BPF_MAP_TYPE_DEVMAP_HASH] = "devmap_hash", [BPF_MAP_TYPE_SOCKMAP] = "sockmap", [BPF_MAP_TYPE_CPUMAP] = "cpumap", [BPF_MAP_TYPE_XSKMAP] = "xskmap", [BPF_MAP_TYPE_SOCKHASH] = "sockhash", [BPF_MAP_TYPE_CGROUP_STORAGE] = "cgroup_storage", [BPF_MAP_TYPE_REUSEPORT_SOCKARRAY] = "reuseport_sockarray", [BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE] = "percpu_cgroup_storage", [BPF_MAP_TYPE_QUEUE] = "queue", [BPF_MAP_TYPE_STACK] = "stack", [BPF_MAP_TYPE_SK_STORAGE] = "sk_storage", [BPF_MAP_TYPE_STRUCT_OPS] = "struct_ops", [BPF_MAP_TYPE_RINGBUF] = "ringbuf", [BPF_MAP_TYPE_INODE_STORAGE] = "inode_storage", [BPF_MAP_TYPE_TASK_STORAGE] = "task_storage", [BPF_MAP_TYPE_BLOOM_FILTER] = "bloom_filter", [BPF_MAP_TYPE_USER_RINGBUF] = "user_ringbuf", [BPF_MAP_TYPE_CGRP_STORAGE] = "cgrp_storage", }; static const char * const prog_type_name[] = { [BPF_PROG_TYPE_UNSPEC] = "unspec", [BPF_PROG_TYPE_SOCKET_FILTER] = "socket_filter", [BPF_PROG_TYPE_KPROBE] = "kprobe", [BPF_PROG_TYPE_SCHED_CLS] = "sched_cls", [BPF_PROG_TYPE_SCHED_ACT] = "sched_act", [BPF_PROG_TYPE_TRACEPOINT] = "tracepoint", [BPF_PROG_TYPE_XDP] = "xdp", [BPF_PROG_TYPE_PERF_EVENT] = "perf_event", [BPF_PROG_TYPE_CGROUP_SKB] = "cgroup_skb", [BPF_PROG_TYPE_CGROUP_SOCK] = "cgroup_sock", [BPF_PROG_TYPE_LWT_IN] = "lwt_in", [BPF_PROG_TYPE_LWT_OUT] = "lwt_out", [BPF_PROG_TYPE_LWT_XMIT] = "lwt_xmit", [BPF_PROG_TYPE_SOCK_OPS] = "sock_ops", [BPF_PROG_TYPE_SK_SKB] = "sk_skb", [BPF_PROG_TYPE_CGROUP_DEVICE] = "cgroup_device", [BPF_PROG_TYPE_SK_MSG] = "sk_msg", [BPF_PROG_TYPE_RAW_TRACEPOINT] = "raw_tracepoint", [BPF_PROG_TYPE_CGROUP_SOCK_ADDR] = "cgroup_sock_addr", [BPF_PROG_TYPE_LWT_SEG6LOCAL] = "lwt_seg6local", [BPF_PROG_TYPE_LIRC_MODE2] = "lirc_mode2", [BPF_PROG_TYPE_SK_REUSEPORT] = "sk_reuseport", [BPF_PROG_TYPE_FLOW_DISSECTOR] = "flow_dissector", [BPF_PROG_TYPE_CGROUP_SYSCTL] = "cgroup_sysctl", [BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE] = "raw_tracepoint_writable", [BPF_PROG_TYPE_CGROUP_SOCKOPT] = "cgroup_sockopt", [BPF_PROG_TYPE_TRACING] = "tracing", [BPF_PROG_TYPE_STRUCT_OPS] = "struct_ops", [BPF_PROG_TYPE_EXT] = "ext", [BPF_PROG_TYPE_LSM] = "lsm", [BPF_PROG_TYPE_SK_LOOKUP] = "sk_lookup", [BPF_PROG_TYPE_SYSCALL] = "syscall", [BPF_PROG_TYPE_NETFILTER] = "netfilter", }; static int __base_pr(enum libbpf_print_level level, const char *format, va_list args) { if (level == LIBBPF_DEBUG) return 0; return vfprintf(stderr, format, args); } static libbpf_print_fn_t __libbpf_pr = __base_pr; libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn) { libbpf_print_fn_t old_print_fn; old_print_fn = __atomic_exchange_n(&__libbpf_pr, fn, __ATOMIC_RELAXED); return old_print_fn; } __printf(2, 3) void libbpf_print(enum libbpf_print_level level, const char *format, ...) { va_list args; int old_errno; libbpf_print_fn_t print_fn; print_fn = __atomic_load_n(&__libbpf_pr, __ATOMIC_RELAXED); if (!print_fn) return; old_errno = errno; va_start(args, format); __libbpf_pr(level, format, args); va_end(args); errno = old_errno; } static void pr_perm_msg(int err) { struct rlimit limit; char buf[100]; if (err != -EPERM || geteuid() != 0) return; err = getrlimit(RLIMIT_MEMLOCK, &limit); if (err) return; if (limit.rlim_cur == RLIM_INFINITY) return; if (limit.rlim_cur < 1024) snprintf(buf, sizeof(buf), "%zu bytes", (size_t)limit.rlim_cur); else if (limit.rlim_cur < 1024*1024) snprintf(buf, sizeof(buf), "%.1f KiB", (double)limit.rlim_cur / 1024); else snprintf(buf, sizeof(buf), "%.1f MiB", (double)limit.rlim_cur / (1024*1024)); pr_warn("permission error while running as root; try raising 'ulimit -l'? current value: %s\n", buf); } #define STRERR_BUFSIZE 128 /* Copied from tools/perf/util/util.h */ #ifndef zfree # define zfree(ptr) ({ free(*ptr); *ptr = NULL; }) #endif #ifndef zclose # define zclose(fd) ({ \ int ___err = 0; \ if ((fd) >= 0) \ ___err = close((fd)); \ fd = -1; \ ___err; }) #endif static inline __u64 ptr_to_u64(const void *ptr) { return (__u64) (unsigned long) ptr; } int libbpf_set_strict_mode(enum libbpf_strict_mode mode) { /* as of v1.0 libbpf_set_strict_mode() is a no-op */ return 0; } __u32 libbpf_major_version(void) { return LIBBPF_MAJOR_VERSION; } __u32 libbpf_minor_version(void) { return LIBBPF_MINOR_VERSION; } const char *libbpf_version_string(void) { #define __S(X) #X #define _S(X) __S(X) return "v" _S(LIBBPF_MAJOR_VERSION) "." _S(LIBBPF_MINOR_VERSION); #undef _S #undef __S } enum reloc_type { RELO_LD64, RELO_CALL, RELO_DATA, RELO_EXTERN_LD64, RELO_EXTERN_CALL, RELO_SUBPROG_ADDR, RELO_CORE, }; struct reloc_desc { enum reloc_type type; int insn_idx; union { const struct bpf_core_relo *core_relo; /* used when type == RELO_CORE */ struct { int map_idx; int sym_off; int ext_idx; }; }; }; /* stored as sec_def->cookie for all libbpf-supported SEC()s */ enum sec_def_flags { SEC_NONE = 0, /* expected_attach_type is optional, if kernel doesn't support that */ SEC_EXP_ATTACH_OPT = 1, /* legacy, only used by libbpf_get_type_names() and * libbpf_attach_type_by_name(), not used by libbpf itself at all. * This used to be associated with cgroup (and few other) BPF programs * that were attachable through BPF_PROG_ATTACH command. Pretty * meaningless nowadays, though. */ SEC_ATTACHABLE = 2, SEC_ATTACHABLE_OPT = SEC_ATTACHABLE | SEC_EXP_ATTACH_OPT, /* attachment target is specified through BTF ID in either kernel or * other BPF program's BTF object */ SEC_ATTACH_BTF = 4, /* BPF program type allows sleeping/blocking in kernel */ SEC_SLEEPABLE = 8, /* BPF program support non-linear XDP buffer */ SEC_XDP_FRAGS = 16, /* Setup proper attach type for usdt probes. */ SEC_USDT = 32, }; struct bpf_sec_def { char *sec; enum bpf_prog_type prog_type; enum bpf_attach_type expected_attach_type; long cookie; int handler_id; libbpf_prog_setup_fn_t prog_setup_fn; libbpf_prog_prepare_load_fn_t prog_prepare_load_fn; libbpf_prog_attach_fn_t prog_attach_fn; }; /* * bpf_prog should be a better name but it has been used in * linux/filter.h. */ struct bpf_program { char *name; char *sec_name; size_t sec_idx; const struct bpf_sec_def *sec_def; /* this program's instruction offset (in number of instructions) * within its containing ELF section */ size_t sec_insn_off; /* number of original instructions in ELF section belonging to this * program, not taking into account subprogram instructions possible * appended later during relocation */ size_t sec_insn_cnt; /* Offset (in number of instructions) of the start of instruction * belonging to this BPF program within its containing main BPF * program. For the entry-point (main) BPF program, this is always * zero. For a sub-program, this gets reset before each of main BPF * programs are processed and relocated and is used to determined * whether sub-program was already appended to the main program, and * if yes, at which instruction offset. */ size_t sub_insn_off; /* instructions that belong to BPF program; insns[0] is located at * sec_insn_off instruction within its ELF section in ELF file, so * when mapping ELF file instruction index to the local instruction, * one needs to subtract sec_insn_off; and vice versa. */ struct bpf_insn *insns; /* actual number of instruction in this BPF program's image; for * entry-point BPF programs this includes the size of main program * itself plus all the used sub-programs, appended at the end */ size_t insns_cnt; struct reloc_desc *reloc_desc; int nr_reloc; /* BPF verifier log settings */ char *log_buf; size_t log_size; __u32 log_level; struct bpf_object *obj; int fd; bool autoload; bool autoattach; bool sym_global; bool mark_btf_static; enum bpf_prog_type type; enum bpf_attach_type expected_attach_type; int exception_cb_idx; int prog_ifindex; __u32 attach_btf_obj_fd; __u32 attach_btf_id; __u32 attach_prog_fd; void *func_info; __u32 func_info_rec_size; __u32 func_info_cnt; void *line_info; __u32 line_info_rec_size; __u32 line_info_cnt; __u32 prog_flags; }; struct bpf_struct_ops { const char *tname; const struct btf_type *type; struct bpf_program **progs; __u32 *kern_func_off; /* e.g. struct tcp_congestion_ops in bpf_prog's btf format */ void *data; /* e.g. struct bpf_struct_ops_tcp_congestion_ops in * btf_vmlinux's format. * struct bpf_struct_ops_tcp_congestion_ops { * [... some other kernel fields ...] * struct tcp_congestion_ops data; * } * kern_vdata-size == sizeof(struct bpf_struct_ops_tcp_congestion_ops) * bpf_map__init_kern_struct_ops() will populate the "kern_vdata" * from "data". */ void *kern_vdata; __u32 type_id; }; #define DATA_SEC ".data" #define BSS_SEC ".bss" #define RODATA_SEC ".rodata" #define KCONFIG_SEC ".kconfig" #define KSYMS_SEC ".ksyms" #define STRUCT_OPS_SEC ".struct_ops" #define STRUCT_OPS_LINK_SEC ".struct_ops.link" enum libbpf_map_type { LIBBPF_MAP_UNSPEC, LIBBPF_MAP_DATA, LIBBPF_MAP_BSS, LIBBPF_MAP_RODATA, LIBBPF_MAP_KCONFIG, }; struct bpf_map_def { unsigned int type; unsigned int key_size; unsigned int value_size; unsigned int max_entries; unsigned int map_flags; }; struct bpf_map { struct bpf_object *obj; char *name; /* real_name is defined for special internal maps (.rodata*, * .data*, .bss, .kconfig) and preserves their original ELF section * name. This is important to be able to find corresponding BTF * DATASEC information. */ char *real_name; int fd; int sec_idx; size_t sec_offset; int map_ifindex; int inner_map_fd; struct bpf_map_def def; __u32 numa_node; __u32 btf_var_idx; __u32 btf_key_type_id; __u32 btf_value_type_id; __u32 btf_vmlinux_value_type_id; enum libbpf_map_type libbpf_type; void *mmaped; struct bpf_struct_ops *st_ops; struct bpf_map *inner_map; void **init_slots; int init_slots_sz; char *pin_path; bool pinned; bool reused; bool autocreate; __u64 map_extra; }; enum extern_type { EXT_UNKNOWN, EXT_KCFG, EXT_KSYM, }; enum kcfg_type { KCFG_UNKNOWN, KCFG_CHAR, KCFG_BOOL, KCFG_INT, KCFG_TRISTATE, KCFG_CHAR_ARR, }; struct extern_desc { enum extern_type type; int sym_idx; int btf_id; int sec_btf_id; const char *name; char *essent_name; bool is_set; bool is_weak; union { struct { enum kcfg_type type; int sz; int align; int data_off; bool is_signed; } kcfg; struct { unsigned long long addr; /* target btf_id of the corresponding kernel var. */ int kernel_btf_obj_fd; int kernel_btf_id; /* local btf_id of the ksym extern's type. */ __u32 type_id; /* BTF fd index to be patched in for insn->off, this is * 0 for vmlinux BTF, index in obj->fd_array for module * BTF */ __s16 btf_fd_idx; } ksym; }; }; struct module_btf { struct btf *btf; char *name; __u32 id; int fd; int fd_array_idx; }; enum sec_type { SEC_UNUSED = 0, SEC_RELO, SEC_BSS, SEC_DATA, SEC_RODATA, }; struct elf_sec_desc { enum sec_type sec_type; Elf64_Shdr *shdr; Elf_Data *data; }; struct elf_state { int fd; const void *obj_buf; size_t obj_buf_sz; Elf *elf; Elf64_Ehdr *ehdr; Elf_Data *symbols; Elf_Data *st_ops_data; Elf_Data *st_ops_link_data; size_t shstrndx; /* section index for section name strings */ size_t strtabidx; struct elf_sec_desc *secs; size_t sec_cnt; int btf_maps_shndx; __u32 btf_maps_sec_btf_id; int text_shndx; int symbols_shndx; int st_ops_shndx; int st_ops_link_shndx; }; struct usdt_manager; struct bpf_object { char name[BPF_OBJ_NAME_LEN]; char license[64]; __u32 kern_version; struct bpf_program *programs; size_t nr_programs; struct bpf_map *maps; size_t nr_maps; size_t maps_cap; char *kconfig; struct extern_desc *externs; int nr_extern; int kconfig_map_idx; bool loaded; bool has_subcalls; bool has_rodata; struct bpf_gen *gen_loader; /* Information when doing ELF related work. Only valid if efile.elf is not NULL */ struct elf_state efile; struct btf *btf; struct btf_ext *btf_ext; /* Parse and load BTF vmlinux if any of the programs in the object need * it at load time. */ struct btf *btf_vmlinux; /* Path to the custom BTF to be used for BPF CO-RE relocations as an * override for vmlinux BTF. */ char *btf_custom_path; /* vmlinux BTF override for CO-RE relocations */ struct btf *btf_vmlinux_override; /* Lazily initialized kernel module BTFs */ struct module_btf *btf_modules; bool btf_modules_loaded; size_t btf_module_cnt; size_t btf_module_cap; /* optional log settings passed to BPF_BTF_LOAD and BPF_PROG_LOAD commands */ char *log_buf; size_t log_size; __u32 log_level; int *fd_array; size_t fd_array_cap; size_t fd_array_cnt; struct usdt_manager *usdt_man; char path[]; }; static const char *elf_sym_str(const struct bpf_object *obj, size_t off); static const char *elf_sec_str(const struct bpf_object *obj, size_t off); static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx); static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name); static Elf64_Shdr *elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn); static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn); static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn); static Elf64_Sym *elf_sym_by_idx(const struct bpf_object *obj, size_t idx); static Elf64_Rel *elf_rel_by_idx(Elf_Data *data, size_t idx); void bpf_program__unload(struct bpf_program *prog) { if (!prog) return; zclose(prog->fd); zfree(&prog->func_info); zfree(&prog->line_info); } static void bpf_program__exit(struct bpf_program *prog) { if (!prog) return; bpf_program__unload(prog); zfree(&prog->name); zfree(&prog->sec_name); zfree(&prog->insns); zfree(&prog->reloc_desc); prog->nr_reloc = 0; prog->insns_cnt = 0; prog->sec_idx = -1; } static bool insn_is_subprog_call(const struct bpf_insn *insn) { return BPF_CLASS(insn->code) == BPF_JMP && BPF_OP(insn->code) == BPF_CALL && BPF_SRC(insn->code) == BPF_K && insn->src_reg == BPF_PSEUDO_CALL && insn->dst_reg == 0 && insn->off == 0; } static bool is_call_insn(const struct bpf_insn *insn) { return insn->code == (BPF_JMP | BPF_CALL); } static bool insn_is_pseudo_func(struct bpf_insn *insn) { return is_ldimm64_insn(insn) && insn->src_reg == BPF_PSEUDO_FUNC; } static int bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog, const char *name, size_t sec_idx, const char *sec_name, size_t sec_off, void *insn_data, size_t insn_data_sz) { if (insn_data_sz == 0 || insn_data_sz % BPF_INSN_SZ || sec_off % BPF_INSN_SZ) { pr_warn("sec '%s': corrupted program '%s', offset %zu, size %zu\n", sec_name, name, sec_off, insn_data_sz); return -EINVAL; } memset(prog, 0, sizeof(*prog)); prog->obj = obj; prog->sec_idx = sec_idx; prog->sec_insn_off = sec_off / BPF_INSN_SZ; prog->sec_insn_cnt = insn_data_sz / BPF_INSN_SZ; /* insns_cnt can later be increased by appending used subprograms */ prog->insns_cnt = prog->sec_insn_cnt; prog->type = BPF_PROG_TYPE_UNSPEC; prog->fd = -1; prog->exception_cb_idx = -1; /* libbpf's convention for SEC("?abc...") is that it's just like * SEC("abc...") but the corresponding bpf_program starts out with * autoload set to false. */ if (sec_name[0] == '?') { prog->autoload = false; /* from now on forget there was ? in section name */ sec_name++; } else { prog->autoload = true; } prog->autoattach = true; /* inherit object's log_level */ prog->log_level = obj->log_level; prog->sec_name = strdup(sec_name); if (!prog->sec_name) goto errout; prog->name = strdup(name); if (!prog->name) goto errout; prog->insns = malloc(insn_data_sz); if (!prog->insns) goto errout; memcpy(prog->insns, insn_data, insn_data_sz); return 0; errout: pr_warn("sec '%s': failed to allocate memory for prog '%s'\n", sec_name, name); bpf_program__exit(prog); return -ENOMEM; } static int bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, const char *sec_name, int sec_idx) { Elf_Data *symbols = obj->efile.symbols; struct bpf_program *prog, *progs; void *data = sec_data->d_buf; size_t sec_sz = sec_data->d_size, sec_off, prog_sz, nr_syms; int nr_progs, err, i; const char *name; Elf64_Sym *sym; progs = obj->programs; nr_progs = obj->nr_programs; nr_syms = symbols->d_size / sizeof(Elf64_Sym); for (i = 0; i < nr_syms; i++) { sym = elf_sym_by_idx(obj, i); if (sym->st_shndx != sec_idx) continue; if (ELF64_ST_TYPE(sym->st_info) != STT_FUNC) continue; prog_sz = sym->st_size; sec_off = sym->st_value; name = elf_sym_str(obj, sym->st_name); if (!name) { pr_warn("sec '%s': failed to get symbol name for offset %zu\n", sec_name, sec_off); return -LIBBPF_ERRNO__FORMAT; } if (sec_off + prog_sz > sec_sz) { pr_warn("sec '%s': program at offset %zu crosses section boundary\n", sec_name, sec_off); return -LIBBPF_ERRNO__FORMAT; } if (sec_idx != obj->efile.text_shndx && ELF64_ST_BIND(sym->st_info) == STB_LOCAL) { pr_warn("sec '%s': program '%s' is static and not supported\n", sec_name, name); return -ENOTSUP; } pr_debug("sec '%s': found program '%s' at insn offset %zu (%zu bytes), code size %zu insns (%zu bytes)\n", sec_name, name, sec_off / BPF_INSN_SZ, sec_off, prog_sz / BPF_INSN_SZ, prog_sz); progs = libbpf_reallocarray(progs, nr_progs + 1, sizeof(*progs)); if (!progs) { /* * In this case the original obj->programs * is still valid, so don't need special treat for * bpf_close_object(). */ pr_warn("sec '%s': failed to alloc memory for new program '%s'\n", sec_name, name); return -ENOMEM; } obj->programs = progs; prog = &progs[nr_progs]; err = bpf_object__init_prog(obj, prog, name, sec_idx, sec_name, sec_off, data + sec_off, prog_sz); if (err) return err; if (ELF64_ST_BIND(sym->st_info) != STB_LOCAL) prog->sym_global = true; /* if function is a global/weak symbol, but has restricted * (STV_HIDDEN or STV_INTERNAL) visibility, mark its BTF FUNC * as static to enable more permissive BPF verification mode * with more outside context available to BPF verifier */ if (prog->sym_global && (ELF64_ST_VISIBILITY(sym->st_other) == STV_HIDDEN || ELF64_ST_VISIBILITY(sym->st_other) == STV_INTERNAL)) prog->mark_btf_static = true; nr_progs++; obj->nr_programs = nr_progs; } return 0; } static const struct btf_member * find_member_by_offset(const struct btf_type *t, __u32 bit_offset) { struct btf_member *m; int i; for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) { if (btf_member_bit_offset(t, i) == bit_offset) return m; } return NULL; } static const struct btf_member * find_member_by_name(const struct btf *btf, const struct btf_type *t, const char *name) { struct btf_member *m; int i; for (i = 0, m = btf_members(t); i < btf_vlen(t); i++, m++) { if (!strcmp(btf__name_by_offset(btf, m->name_off), name)) return m; } return NULL; } #define STRUCT_OPS_VALUE_PREFIX "bpf_struct_ops_" static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix, const char *name, __u32 kind); static int find_struct_ops_kern_types(const struct btf *btf, const char *tname, const struct btf_type **type, __u32 *type_id, const struct btf_type **vtype, __u32 *vtype_id, const struct btf_member **data_member) { const struct btf_type *kern_type, *kern_vtype; const struct btf_member *kern_data_member; __s32 kern_vtype_id, kern_type_id; __u32 i; kern_type_id = btf__find_by_name_kind(btf, tname, BTF_KIND_STRUCT); if (kern_type_id < 0) { pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n", tname); return kern_type_id; } kern_type = btf__type_by_id(btf, kern_type_id); /* Find the corresponding "map_value" type that will be used * in map_update(BPF_MAP_TYPE_STRUCT_OPS). For example, * find "struct bpf_struct_ops_tcp_congestion_ops" from the * btf_vmlinux. */ kern_vtype_id = find_btf_by_prefix_kind(btf, STRUCT_OPS_VALUE_PREFIX, tname, BTF_KIND_STRUCT); if (kern_vtype_id < 0) { pr_warn("struct_ops init_kern: struct %s%s is not found in kernel BTF\n", STRUCT_OPS_VALUE_PREFIX, tname); return kern_vtype_id; } kern_vtype = btf__type_by_id(btf, kern_vtype_id); /* Find "struct tcp_congestion_ops" from * struct bpf_struct_ops_tcp_congestion_ops { * [ ... ] * struct tcp_congestion_ops data; * } */ kern_data_member = btf_members(kern_vtype); for (i = 0; i < btf_vlen(kern_vtype); i++, kern_data_member++) { if (kern_data_member->type == kern_type_id) break; } if (i == btf_vlen(kern_vtype)) { pr_warn("struct_ops init_kern: struct %s data is not found in struct %s%s\n", tname, STRUCT_OPS_VALUE_PREFIX, tname); return -EINVAL; } *type = kern_type; *type_id = kern_type_id; *vtype = kern_vtype; *vtype_id = kern_vtype_id; *data_member = kern_data_member; return 0; } static bool bpf_map__is_struct_ops(const struct bpf_map *map) { return map->def.type == BPF_MAP_TYPE_STRUCT_OPS; } /* Init the map's fields that depend on kern_btf */ static int bpf_map__init_kern_struct_ops(struct bpf_map *map, const struct btf *btf, const struct btf *kern_btf) { const struct btf_member *member, *kern_member, *kern_data_member; const struct btf_type *type, *kern_type, *kern_vtype; __u32 i, kern_type_id, kern_vtype_id, kern_data_off; struct bpf_struct_ops *st_ops; void *data, *kern_data; const char *tname; int err; st_ops = map->st_ops; type = st_ops->type; tname = st_ops->tname; err = find_struct_ops_kern_types(kern_btf, tname, &kern_type, &kern_type_id, &kern_vtype, &kern_vtype_id, &kern_data_member); if (err) return err; pr_debug("struct_ops init_kern %s: type_id:%u kern_type_id:%u kern_vtype_id:%u\n", map->name, st_ops->type_id, kern_type_id, kern_vtype_id); map->def.value_size = kern_vtype->size; map->btf_vmlinux_value_type_id = kern_vtype_id; st_ops->kern_vdata = calloc(1, kern_vtype->size); if (!st_ops->kern_vdata) return -ENOMEM; data = st_ops->data; kern_data_off = kern_data_member->offset / 8; kern_data = st_ops->kern_vdata + kern_data_off; member = btf_members(type); for (i = 0; i < btf_vlen(type); i++, member++) { const struct btf_type *mtype, *kern_mtype; __u32 mtype_id, kern_mtype_id; void *mdata, *kern_mdata; __s64 msize, kern_msize; __u32 moff, kern_moff; __u32 kern_member_idx; const char *mname; mname = btf__name_by_offset(btf, member->name_off); kern_member = find_member_by_name(kern_btf, kern_type, mname); if (!kern_member) { pr_warn("struct_ops init_kern %s: Cannot find member %s in kernel BTF\n", map->name, mname); return -ENOTSUP; } kern_member_idx = kern_member - btf_members(kern_type); if (btf_member_bitfield_size(type, i) || btf_member_bitfield_size(kern_type, kern_member_idx)) { pr_warn("struct_ops init_kern %s: bitfield %s is not supported\n", map->name, mname); return -ENOTSUP; } moff = member->offset / 8; kern_moff = kern_member->offset / 8; mdata = data + moff; kern_mdata = kern_data + kern_moff; mtype = skip_mods_and_typedefs(btf, member->type, &mtype_id); kern_mtype = skip_mods_and_typedefs(kern_btf, kern_member->type, &kern_mtype_id); if (BTF_INFO_KIND(mtype->info) != BTF_INFO_KIND(kern_mtype->info)) { pr_warn("struct_ops init_kern %s: Unmatched member type %s %u != %u(kernel)\n", map->name, mname, BTF_INFO_KIND(mtype->info), BTF_INFO_KIND(kern_mtype->info)); return -ENOTSUP; } if (btf_is_ptr(mtype)) { struct bpf_program *prog; prog = st_ops->progs[i]; if (!prog) continue; kern_mtype = skip_mods_and_typedefs(kern_btf, kern_mtype->type, &kern_mtype_id); /* mtype->type must be a func_proto which was * guaranteed in bpf_object__collect_st_ops_relos(), * so only check kern_mtype for func_proto here. */ if (!btf_is_func_proto(kern_mtype)) { pr_warn("struct_ops init_kern %s: kernel member %s is not a func ptr\n", map->name, mname); return -ENOTSUP; } prog->attach_btf_id = kern_type_id; prog->expected_attach_type = kern_member_idx; st_ops->kern_func_off[i] = kern_data_off + kern_moff; pr_debug("struct_ops init_kern %s: func ptr %s is set to prog %s from data(+%u) to kern_data(+%u)\n", map->name, mname, prog->name, moff, kern_moff); continue; } msize = btf__resolve_size(btf, mtype_id); kern_msize = btf__resolve_size(kern_btf, kern_mtype_id); if (msize < 0 || kern_msize < 0 || msize != kern_msize) { pr_warn("struct_ops init_kern %s: Error in size of member %s: %zd != %zd(kernel)\n", map->name, mname, (ssize_t)msize, (ssize_t)kern_msize); return -ENOTSUP; } pr_debug("struct_ops init_kern %s: copy %s %u bytes from data(+%u) to kern_data(+%u)\n", map->name, mname, (unsigned int)msize, moff, kern_moff); memcpy(kern_mdata, mdata, msize); } return 0; } static int bpf_object__init_kern_struct_ops_maps(struct bpf_object *obj) { struct bpf_map *map; size_t i; int err; for (i = 0; i < obj->nr_maps; i++) { map = &obj->maps[i]; if (!bpf_map__is_struct_ops(map)) continue; err = bpf_map__init_kern_struct_ops(map, obj->btf, obj->btf_vmlinux); if (err) return err; } return 0; } static int init_struct_ops_maps(struct bpf_object *obj, const char *sec_name, int shndx, Elf_Data *data, __u32 map_flags) { const struct btf_type *type, *datasec; const struct btf_var_secinfo *vsi; struct bpf_struct_ops *st_ops; const char *tname, *var_name; __s32 type_id, datasec_id; const struct btf *btf; struct bpf_map *map; __u32 i; if (shndx == -1) return 0; btf = obj->btf; datasec_id = btf__find_by_name_kind(btf, sec_name, BTF_KIND_DATASEC); if (datasec_id < 0) { pr_warn("struct_ops init: DATASEC %s not found\n", sec_name); return -EINVAL; } datasec = btf__type_by_id(btf, datasec_id); vsi = btf_var_secinfos(datasec); for (i = 0; i < btf_vlen(datasec); i++, vsi++) { type = btf__type_by_id(obj->btf, vsi->type); var_name = btf__name_by_offset(obj->btf, type->name_off); type_id = btf__resolve_type(obj->btf, vsi->type); if (type_id < 0) { pr_warn("struct_ops init: Cannot resolve var type_id %u in DATASEC %s\n", vsi->type, sec_name); return -EINVAL; } type = btf__type_by_id(obj->btf, type_id); tname = btf__name_by_offset(obj->btf, type->name_off); if (!tname[0]) { pr_warn("struct_ops init: anonymous type is not supported\n"); return -ENOTSUP; } if (!btf_is_struct(type)) { pr_warn("struct_ops init: %s is not a struct\n", tname); return -EINVAL; } map = bpf_object__add_map(obj); if (IS_ERR(map)) return PTR_ERR(map); map->sec_idx = shndx; map->sec_offset = vsi->offset; map->name = strdup(var_name); if (!map->name) return -ENOMEM; map->def.type = BPF_MAP_TYPE_STRUCT_OPS; map->def.key_size = sizeof(int); map->def.value_size = type->size; map->def.max_entries = 1; map->def.map_flags = map_flags; map->st_ops = calloc(1, sizeof(*map->st_ops)); if (!map->st_ops) return -ENOMEM; st_ops = map->st_ops; st_ops->data = malloc(type->size); st_ops->progs = calloc(btf_vlen(type), sizeof(*st_ops->progs)); st_ops->kern_func_off = malloc(btf_vlen(type) * sizeof(*st_ops->kern_func_off)); if (!st_ops->data || !st_ops->progs || !st_ops->kern_func_off) return -ENOMEM; if (vsi->offset + type->size > data->d_size) { pr_warn("struct_ops init: var %s is beyond the end of DATASEC %s\n", var_name, sec_name); return -EINVAL; } memcpy(st_ops->data, data->d_buf + vsi->offset, type->size); st_ops->tname = tname; st_ops->type = type; st_ops->type_id = type_id; pr_debug("struct_ops init: struct %s(type_id=%u) %s found at offset %u\n", tname, type_id, var_name, vsi->offset); } return 0; } static int bpf_object_init_struct_ops(struct bpf_object *obj) { int err; err = init_struct_ops_maps(obj, STRUCT_OPS_SEC, obj->efile.st_ops_shndx, obj->efile.st_ops_data, 0); err = err ?: init_struct_ops_maps(obj, STRUCT_OPS_LINK_SEC, obj->efile.st_ops_link_shndx, obj->efile.st_ops_link_data, BPF_F_LINK); return err; } static struct bpf_object *bpf_object__new(const char *path, const void *obj_buf, size_t obj_buf_sz, const char *obj_name) { struct bpf_object *obj; char *end; obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1); if (!obj) { pr_warn("alloc memory failed for %s\n", path); return ERR_PTR(-ENOMEM); } strcpy(obj->path, path); if (obj_name) { libbpf_strlcpy(obj->name, obj_name, sizeof(obj->name)); } else { /* Using basename() GNU version which doesn't modify arg. */ libbpf_strlcpy(obj->name, basename((void *)path), sizeof(obj->name)); end = strchr(obj->name, '.'); if (end) *end = 0; } obj->efile.fd = -1; /* * Caller of this function should also call * bpf_object__elf_finish() after data collection to return * obj_buf to user. If not, we should duplicate the buffer to * avoid user freeing them before elf finish. */ obj->efile.obj_buf = obj_buf; obj->efile.obj_buf_sz = obj_buf_sz; obj->efile.btf_maps_shndx = -1; obj->efile.st_ops_shndx = -1; obj->efile.st_ops_link_shndx = -1; obj->kconfig_map_idx = -1; obj->kern_version = get_kernel_version(); obj->loaded = false; return obj; } static void bpf_object__elf_finish(struct bpf_object *obj) { if (!obj->efile.elf) return; elf_end(obj->efile.elf); obj->efile.elf = NULL; obj->efile.symbols = NULL; obj->efile.st_ops_data = NULL; obj->efile.st_ops_link_data = NULL; zfree(&obj->efile.secs); obj->efile.sec_cnt = 0; zclose(obj->efile.fd); obj->efile.obj_buf = NULL; obj->efile.obj_buf_sz = 0; } static int bpf_object__elf_init(struct bpf_object *obj) { Elf64_Ehdr *ehdr; int err = 0; Elf *elf; if (obj->efile.elf) { pr_warn("elf: init internal error\n"); return -LIBBPF_ERRNO__LIBELF; } if (obj->efile.obj_buf_sz > 0) { /* obj_buf should have been validated by bpf_object__open_mem(). */ elf = elf_memory((char *)obj->efile.obj_buf, obj->efile.obj_buf_sz); } else { obj->efile.fd = open(obj->path, O_RDONLY | O_CLOEXEC); if (obj->efile.fd < 0) { char errmsg[STRERR_BUFSIZE], *cp; err = -errno; cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); pr_warn("elf: failed to open %s: %s\n", obj->path, cp); return err; } elf = elf_begin(obj->efile.fd, ELF_C_READ_MMAP, NULL); } if (!elf) { pr_warn("elf: failed to open %s as ELF file: %s\n", obj->path, elf_errmsg(-1)); err = -LIBBPF_ERRNO__LIBELF; goto errout; } obj->efile.elf = elf; if (elf_kind(elf) != ELF_K_ELF) { err = -LIBBPF_ERRNO__FORMAT; pr_warn("elf: '%s' is not a proper ELF object\n", obj->path); goto errout; } if (gelf_getclass(elf) != ELFCLASS64) { err = -LIBBPF_ERRNO__FORMAT; pr_warn("elf: '%s' is not a 64-bit ELF object\n", obj->path); goto errout; } obj->efile.ehdr = ehdr = elf64_getehdr(elf); if (!obj->efile.ehdr) { pr_warn("elf: failed to get ELF header from %s: %s\n", obj->path, elf_errmsg(-1)); err = -LIBBPF_ERRNO__FORMAT; goto errout; } if (elf_getshdrstrndx(elf, &obj->efile.shstrndx)) { pr_warn("elf: failed to get section names section index for %s: %s\n", obj->path, elf_errmsg(-1)); err = -LIBBPF_ERRNO__FORMAT; goto errout; } /* ELF is corrupted/truncated, avoid calling elf_strptr. */ if (!elf_rawdata(elf_getscn(elf, obj->efile.shstrndx), NULL)) { pr_warn("elf: failed to get section names strings from %s: %s\n", obj->path, elf_errmsg(-1)); err = -LIBBPF_ERRNO__FORMAT; goto errout; } /* Old LLVM set e_machine to EM_NONE */ if (ehdr->e_type != ET_REL || (ehdr->e_machine && ehdr->e_machine != EM_BPF)) { pr_warn("elf: %s is not a valid eBPF object file\n", obj->path); err = -LIBBPF_ERRNO__FORMAT; goto errout; } return 0; errout: bpf_object__elf_finish(obj); return err; } static int bpf_object__check_endianness(struct bpf_object *obj) { #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ if (obj->efile.ehdr->e_ident[EI_DATA] == ELFDATA2LSB) return 0; #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ if (obj->efile.ehdr->e_ident[EI_DATA] == ELFDATA2MSB) return 0; #else # error "Unrecognized __BYTE_ORDER__" #endif pr_warn("elf: endianness mismatch in %s.\n", obj->path); return -LIBBPF_ERRNO__ENDIAN; } static int bpf_object__init_license(struct bpf_object *obj, void *data, size_t size) { if (!data) { pr_warn("invalid license section in %s\n", obj->path); return -LIBBPF_ERRNO__FORMAT; } /* libbpf_strlcpy() only copies first N - 1 bytes, so size + 1 won't * go over allowed ELF data section buffer */ libbpf_strlcpy(obj->license, data, min(size + 1, sizeof(obj->license))); pr_debug("license of %s is %s\n", obj->path, obj->license); return 0; } static int bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size) { __u32 kver; if (!data || size != sizeof(kver)) { pr_warn("invalid kver section in %s\n", obj->path); return -LIBBPF_ERRNO__FORMAT; } memcpy(&kver, data, sizeof(kver)); obj->kern_version = kver; pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version); return 0; } static bool bpf_map_type__is_map_in_map(enum bpf_map_type type) { if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS || type == BPF_MAP_TYPE_HASH_OF_MAPS) return true; return false; } static int find_elf_sec_sz(const struct bpf_object *obj, const char *name, __u32 *size) { Elf_Data *data; Elf_Scn *scn; if (!name) return -EINVAL; scn = elf_sec_by_name(obj, name); data = elf_sec_data(obj, scn); if (data) { *size = data->d_size; return 0; /* found it */ } return -ENOENT; } static Elf64_Sym *find_elf_var_sym(const struct bpf_object *obj, const char *name) { Elf_Data *symbols = obj->efile.symbols; const char *sname; size_t si; for (si = 0; si < symbols->d_size / sizeof(Elf64_Sym); si++) { Elf64_Sym *sym = elf_sym_by_idx(obj, si); if (ELF64_ST_TYPE(sym->st_info) != STT_OBJECT) continue; if (ELF64_ST_BIND(sym->st_info) != STB_GLOBAL && ELF64_ST_BIND(sym->st_info) != STB_WEAK) continue; sname = elf_sym_str(obj, sym->st_name); if (!sname) { pr_warn("failed to get sym name string for var %s\n", name); return ERR_PTR(-EIO); } if (strcmp(name, sname) == 0) return sym; } return ERR_PTR(-ENOENT); } static struct bpf_map *bpf_object__add_map(struct bpf_object *obj) { struct bpf_map *map; int err; err = libbpf_ensure_mem((void **)&obj->maps, &obj->maps_cap, sizeof(*obj->maps), obj->nr_maps + 1); if (err) return ERR_PTR(err); map = &obj->maps[obj->nr_maps++]; map->obj = obj; map->fd = -1; map->inner_map_fd = -1; map->autocreate = true; return map; } static size_t bpf_map_mmap_sz(unsigned int value_sz, unsigned int max_entries) { const long page_sz = sysconf(_SC_PAGE_SIZE); size_t map_sz; map_sz = (size_t)roundup(value_sz, 8) * max_entries; map_sz = roundup(map_sz, page_sz); return map_sz; } static int bpf_map_mmap_resize(struct bpf_map *map, size_t old_sz, size_t new_sz) { void *mmaped; if (!map->mmaped) return -EINVAL; if (old_sz == new_sz) return 0; mmaped = mmap(NULL, new_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (mmaped == MAP_FAILED) return -errno; memcpy(mmaped, map->mmaped, min(old_sz, new_sz)); munmap(map->mmaped, old_sz); map->mmaped = mmaped; return 0; } static char *internal_map_name(struct bpf_object *obj, const char *real_name) { char map_name[BPF_OBJ_NAME_LEN], *p; int pfx_len, sfx_len = max((size_t)7, strlen(real_name)); /* This is one of the more confusing parts of libbpf for various * reasons, some of which are historical. The original idea for naming * internal names was to include as much of BPF object name prefix as * possible, so that it can be distinguished from similar internal * maps of a different BPF object. * As an example, let's say we have bpf_object named 'my_object_name' * and internal map corresponding to '.rodata' ELF section. The final * map name advertised to user and to the kernel will be * 'my_objec.rodata', taking first 8 characters of object name and * entire 7 characters of '.rodata'. * Somewhat confusingly, if internal map ELF section name is shorter * than 7 characters, e.g., '.bss', we still reserve 7 characters * for the suffix, even though we only have 4 actual characters, and * resulting map will be called 'my_objec.bss', not even using all 15 * characters allowed by the kernel. Oh well, at least the truncated * object name is somewhat consistent in this case. But if the map * name is '.kconfig', we'll still have entirety of '.kconfig' added * (8 chars) and thus will be left with only first 7 characters of the * object name ('my_obje'). Happy guessing, user, that the final map * name will be "my_obje.kconfig". * Now, with libbpf starting to support arbitrarily named .rodata.* * and .data.* data sections, it's possible that ELF section name is * longer than allowed 15 chars, so we now need to be careful to take * only up to 15 first characters of ELF name, taking no BPF object * name characters at all. So '.rodata.abracadabra' will result in * '.rodata.abracad' kernel and user-visible name. * We need to keep this convoluted logic intact for .data, .bss and * .rodata maps, but for new custom .data.custom and .rodata.custom * maps we use their ELF names as is, not prepending bpf_object name * in front. We still need to truncate them to 15 characters for the * kernel. Full name can be recovered for such maps by using DATASEC * BTF type associated with such map's value type, though. */ if (sfx_len >= BPF_OBJ_NAME_LEN) sfx_len = BPF_OBJ_NAME_LEN - 1; /* if there are two or more dots in map name, it's a custom dot map */ if (strchr(real_name + 1, '.') != NULL) pfx_len = 0; else pfx_len = min((size_t)BPF_OBJ_NAME_LEN - sfx_len - 1, strlen(obj->name)); snprintf(map_name, sizeof(map_name), "%.*s%.*s", pfx_len, obj->name, sfx_len, real_name); /* sanitise map name to characters allowed by kernel */ for (p = map_name; *p && p < map_name + sizeof(map_name); p++) if (!isalnum(*p) && *p != '_' && *p != '.') *p = '_'; return strdup(map_name); } static int map_fill_btf_type_info(struct bpf_object *obj, struct bpf_map *map); /* Internal BPF map is mmap()'able only if at least one of corresponding * DATASEC's VARs are to be exposed through BPF skeleton. I.e., it's a GLOBAL * variable and it's not marked as __hidden (which turns it into, effectively, * a STATIC variable). */ static bool map_is_mmapable(struct bpf_object *obj, struct bpf_map *map) { const struct btf_type *t, *vt; struct btf_var_secinfo *vsi; int i, n; if (!map->btf_value_type_id) return false; t = btf__type_by_id(obj->btf, map->btf_value_type_id); if (!btf_is_datasec(t)) return false; vsi = btf_var_secinfos(t); for (i = 0, n = btf_vlen(t); i < n; i++, vsi++) { vt = btf__type_by_id(obj->btf, vsi->type); if (!btf_is_var(vt)) continue; if (btf_var(vt)->linkage != BTF_VAR_STATIC) return true; } return false; } static int bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, const char *real_name, int sec_idx, void *data, size_t data_sz) { struct bpf_map_def *def; struct bpf_map *map; size_t mmap_sz; int err; map = bpf_object__add_map(obj); if (IS_ERR(map)) return PTR_ERR(map); map->libbpf_type = type; map->sec_idx = sec_idx; map->sec_offset = 0; map->real_name = strdup(real_name); map->name = internal_map_name(obj, real_name); if (!map->real_name || !map->name) { zfree(&map->real_name); zfree(&map->name); return -ENOMEM; } def = &map->def; def->type = BPF_MAP_TYPE_ARRAY; def->key_size = sizeof(int); def->value_size = data_sz; def->max_entries = 1; def->map_flags = type == LIBBPF_MAP_RODATA || type == LIBBPF_MAP_KCONFIG ? BPF_F_RDONLY_PROG : 0; /* failures are fine because of maps like .rodata.str1.1 */ (void) map_fill_btf_type_info(obj, map); if (map_is_mmapable(obj, map)) def->map_flags |= BPF_F_MMAPABLE; pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n", map->name, map->sec_idx, map->sec_offset, def->map_flags); mmap_sz = bpf_map_mmap_sz(map->def.value_size, map->def.max_entries); map->mmaped = mmap(NULL, mmap_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (map->mmaped == MAP_FAILED) { err = -errno; map->mmaped = NULL; pr_warn("failed to alloc map '%s' content buffer: %d\n", map->name, err); zfree(&map->real_name); zfree(&map->name); return err; } if (data) memcpy(map->mmaped, data, data_sz); pr_debug("map %td is \"%s\"\n", map - obj->maps, map->name); return 0; } static int bpf_object__init_global_data_maps(struct bpf_object *obj) { struct elf_sec_desc *sec_desc; const char *sec_name; int err = 0, sec_idx; /* * Populate obj->maps with libbpf internal maps. */ for (sec_idx = 1; sec_idx < obj->efile.sec_cnt; sec_idx++) { sec_desc = &obj->efile.secs[sec_idx]; /* Skip recognized sections with size 0. */ if (!sec_desc->data || sec_desc->data->d_size == 0) continue; switch (sec_desc->sec_type) { case SEC_DATA: sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA, sec_name, sec_idx, sec_desc->data->d_buf, sec_desc->data->d_size); break; case SEC_RODATA: obj->has_rodata = true; sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA, sec_name, sec_idx, sec_desc->data->d_buf, sec_desc->data->d_size); break; case SEC_BSS: sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS, sec_name, sec_idx, NULL, sec_desc->data->d_size); break; default: /* skip */ break; } if (err) return err; } return 0; } static struct extern_desc *find_extern_by_name(const struct bpf_object *obj, const void *name) { int i; for (i = 0; i < obj->nr_extern; i++) { if (strcmp(obj->externs[i].name, name) == 0) return &obj->externs[i]; } return NULL; } static int set_kcfg_value_tri(struct extern_desc *ext, void *ext_val, char value) { switch (ext->kcfg.type) { case KCFG_BOOL: if (value == 'm') { pr_warn("extern (kcfg) '%s': value '%c' implies tristate or char type\n", ext->name, value); return -EINVAL; } *(bool *)ext_val = value == 'y' ? true : false; break; case KCFG_TRISTATE: if (value == 'y') *(enum libbpf_tristate *)ext_val = TRI_YES; else if (value == 'm') *(enum libbpf_tristate *)ext_val = TRI_MODULE; else /* value == 'n' */ *(enum libbpf_tristate *)ext_val = TRI_NO; break; case KCFG_CHAR: *(char *)ext_val = value; break; case KCFG_UNKNOWN: case KCFG_INT: case KCFG_CHAR_ARR: default: pr_warn("extern (kcfg) '%s': value '%c' implies bool, tristate, or char type\n", ext->name, value); return -EINVAL; } ext->is_set = true; return 0; } static int set_kcfg_value_str(struct extern_desc *ext, char *ext_val, const char *value) { size_t len; if (ext->kcfg.type != KCFG_CHAR_ARR) { pr_warn("extern (kcfg) '%s': value '%s' implies char array type\n", ext->name, value); return -EINVAL; } len = strlen(value); if (value[len - 1] != '"') { pr_warn("extern (kcfg) '%s': invalid string config '%s'\n", ext->name, value); return -EINVAL; } /* strip quotes */ len -= 2; if (len >= ext->kcfg.sz) { pr_warn("extern (kcfg) '%s': long string '%s' of (%zu bytes) truncated to %d bytes\n", ext->name, value, len, ext->kcfg.sz - 1); len = ext->kcfg.sz - 1; } memcpy(ext_val, value + 1, len); ext_val[len] = '\0'; ext->is_set = true; return 0; } static int parse_u64(const char *value, __u64 *res) { char *value_end; int err; errno = 0; *res = strtoull(value, &value_end, 0); if (errno) { err = -errno; pr_warn("failed to parse '%s' as integer: %d\n", value, err); return err; } if (*value_end) { pr_warn("failed to parse '%s' as integer completely\n", value); return -EINVAL; } return 0; } static bool is_kcfg_value_in_range(const struct extern_desc *ext, __u64 v) { int bit_sz = ext->kcfg.sz * 8; if (ext->kcfg.sz == 8) return true; /* Validate that value stored in u64 fits in integer of `ext->sz` * bytes size without any loss of information. If the target integer * is signed, we rely on the following limits of integer type of * Y bits and subsequent transformation: * * -2^(Y-1) <= X <= 2^(Y-1) - 1 * 0 <= X + 2^(Y-1) <= 2^Y - 1 * 0 <= X + 2^(Y-1) < 2^Y * * For unsigned target integer, check that all the (64 - Y) bits are * zero. */ if (ext->kcfg.is_signed) return v + (1ULL << (bit_sz - 1)) < (1ULL << bit_sz); else return (v >> bit_sz) == 0; } static int set_kcfg_value_num(struct extern_desc *ext, void *ext_val, __u64 value) { if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR && ext->kcfg.type != KCFG_BOOL) { pr_warn("extern (kcfg) '%s': value '%llu' implies integer, char, or boolean type\n", ext->name, (unsigned long long)value); return -EINVAL; } if (ext->kcfg.type == KCFG_BOOL && value > 1) { pr_warn("extern (kcfg) '%s': value '%llu' isn't boolean compatible\n", ext->name, (unsigned long long)value); return -EINVAL; } if (!is_kcfg_value_in_range(ext, value)) { pr_warn("extern (kcfg) '%s': value '%llu' doesn't fit in %d bytes\n", ext->name, (unsigned long long)value, ext->kcfg.sz); return -ERANGE; } switch (ext->kcfg.sz) { case 1: *(__u8 *)ext_val = value; break; case 2: *(__u16 *)ext_val = value; break; case 4: *(__u32 *)ext_val = value; break; case 8: *(__u64 *)ext_val = value; break; default: return -EINVAL; } ext->is_set = true; return 0; } static int bpf_object__process_kconfig_line(struct bpf_object *obj, char *buf, void *data) { struct extern_desc *ext; char *sep, *value; int len, err = 0; void *ext_val; __u64 num; if (!str_has_pfx(buf, "CONFIG_")) return 0; sep = strchr(buf, '='); if (!sep) { pr_warn("failed to parse '%s': no separator\n", buf); return -EINVAL; } /* Trim ending '\n' */ len = strlen(buf); if (buf[len - 1] == '\n') buf[len - 1] = '\0'; /* Split on '=' and ensure that a value is present. */ *sep = '\0'; if (!sep[1]) { *sep = '='; pr_warn("failed to parse '%s': no value\n", buf); return -EINVAL; } ext = find_extern_by_name(obj, buf); if (!ext || ext->is_set) return 0; ext_val = data + ext->kcfg.data_off; value = sep + 1; switch (*value) { case 'y': case 'n': case 'm': err = set_kcfg_value_tri(ext, ext_val, *value); break; case '"': err = set_kcfg_value_str(ext, ext_val, value); break; default: /* assume integer */ err = parse_u64(value, &num); if (err) { pr_warn("extern (kcfg) '%s': value '%s' isn't a valid integer\n", ext->name, value); return err; } if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR) { pr_warn("extern (kcfg) '%s': value '%s' implies integer type\n", ext->name, value); return -EINVAL; } err = set_kcfg_value_num(ext, ext_val, num); break; } if (err) return err; pr_debug("extern (kcfg) '%s': set to %s\n", ext->name, value); return 0; } static int bpf_object__read_kconfig_file(struct bpf_object *obj, void *data) { char buf[PATH_MAX]; struct utsname uts; int len, err = 0; gzFile file; uname(&uts); len = snprintf(buf, PATH_MAX, "/boot/config-%s", uts.release); if (len < 0) return -EINVAL; else if (len >= PATH_MAX) return -ENAMETOOLONG; /* gzopen also accepts uncompressed files. */ file = gzopen(buf, "re"); if (!file) file = gzopen("/proc/config.gz", "re"); if (!file) { pr_warn("failed to open system Kconfig\n"); return -ENOENT; } while (gzgets(file, buf, sizeof(buf))) { err = bpf_object__process_kconfig_line(obj, buf, data); if (err) { pr_warn("error parsing system Kconfig line '%s': %d\n", buf, err); goto out; } } out: gzclose(file); return err; } static int bpf_object__read_kconfig_mem(struct bpf_object *obj, const char *config, void *data) { char buf[PATH_MAX]; int err = 0; FILE *file; file = fmemopen((void *)config, strlen(config), "r"); if (!file) { err = -errno; pr_warn("failed to open in-memory Kconfig: %d\n", err); return err; } while (fgets(buf, sizeof(buf), file)) { err = bpf_object__process_kconfig_line(obj, buf, data); if (err) { pr_warn("error parsing in-memory Kconfig line '%s': %d\n", buf, err); break; } } fclose(file); return err; } static int bpf_object__init_kconfig_map(struct bpf_object *obj) { struct extern_desc *last_ext = NULL, *ext; size_t map_sz; int i, err; for (i = 0; i < obj->nr_extern; i++) { ext = &obj->externs[i]; if (ext->type == EXT_KCFG) last_ext = ext; } if (!last_ext) return 0; map_sz = last_ext->kcfg.data_off + last_ext->kcfg.sz; err = bpf_object__init_internal_map(obj, LIBBPF_MAP_KCONFIG, ".kconfig", obj->efile.symbols_shndx, NULL, map_sz); if (err) return err; obj->kconfig_map_idx = obj->nr_maps - 1; return 0; } const struct btf_type * skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id) { const struct btf_type *t = btf__type_by_id(btf, id); if (res_id) *res_id = id; while (btf_is_mod(t) || btf_is_typedef(t)) { if (res_id) *res_id = t->type; t = btf__type_by_id(btf, t->type); } return t; } static const struct btf_type * resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id) { const struct btf_type *t; t = skip_mods_and_typedefs(btf, id, NULL); if (!btf_is_ptr(t)) return NULL; t = skip_mods_and_typedefs(btf, t->type, res_id); return btf_is_func_proto(t) ? t : NULL; } static const char *__btf_kind_str(__u16 kind) { switch (kind) { case BTF_KIND_UNKN: return "void"; case BTF_KIND_INT: return "int"; case BTF_KIND_PTR: return "ptr"; case BTF_KIND_ARRAY: return "array"; case BTF_KIND_STRUCT: return "struct"; case BTF_KIND_UNION: return "union"; case BTF_KIND_ENUM: return "enum"; case BTF_KIND_FWD: return "fwd"; case BTF_KIND_TYPEDEF: return "typedef"; case BTF_KIND_VOLATILE: return "volatile"; case BTF_KIND_CONST: return "const"; case BTF_KIND_RESTRICT: return "restrict"; case BTF_KIND_FUNC: return "func"; case BTF_KIND_FUNC_PROTO: return "func_proto"; case BTF_KIND_VAR: return "var"; case BTF_KIND_DATASEC: return "datasec"; case BTF_KIND_FLOAT: return "float"; case BTF_KIND_DECL_TAG: return "decl_tag"; case BTF_KIND_TYPE_TAG: return "type_tag"; case BTF_KIND_ENUM64: return "enum64"; default: return "unknown"; } } const char *btf_kind_str(const struct btf_type *t) { return __btf_kind_str(btf_kind(t)); } /* * Fetch integer attribute of BTF map definition. Such attributes are * represented using a pointer to an array, in which dimensionality of array * encodes specified integer value. E.g., int (*type)[BPF_MAP_TYPE_ARRAY]; * encodes `type => BPF_MAP_TYPE_ARRAY` key/value pair completely using BTF * type definition, while using only sizeof(void *) space in ELF data section. */ static bool get_map_field_int(const char *map_name, const struct btf *btf, const struct btf_member *m, __u32 *res) { const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL); const char *name = btf__name_by_offset(btf, m->name_off); const struct btf_array *arr_info; const struct btf_type *arr_t; if (!btf_is_ptr(t)) { pr_warn("map '%s': attr '%s': expected PTR, got %s.\n", map_name, name, btf_kind_str(t)); return false; } arr_t = btf__type_by_id(btf, t->type); if (!arr_t) { pr_warn("map '%s': attr '%s': type [%u] not found.\n", map_name, name, t->type); return false; } if (!btf_is_array(arr_t)) { pr_warn("map '%s': attr '%s': expected ARRAY, got %s.\n", map_name, name, btf_kind_str(arr_t)); return false; } arr_info = btf_array(arr_t); *res = arr_info->nelems; return true; } static int pathname_concat(char *buf, size_t buf_sz, const char *path, const char *name) { int len; len = snprintf(buf, buf_sz, "%s/%s", path, name); if (len < 0) return -EINVAL; if (len >= buf_sz) return -ENAMETOOLONG; return 0; } static int build_map_pin_path(struct bpf_map *map, const char *path) { char buf[PATH_MAX]; int err; if (!path) path = "/sys/fs/bpf"; err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map)); if (err) return err; return bpf_map__set_pin_path(map, buf); } /* should match definition in bpf_helpers.h */ enum libbpf_pin_type { LIBBPF_PIN_NONE, /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */ LIBBPF_PIN_BY_NAME, }; int parse_btf_map_def(const char *map_name, struct btf *btf, const struct btf_type *def_t, bool strict, struct btf_map_def *map_def, struct btf_map_def *inner_def) { const struct btf_type *t; const struct btf_member *m; bool is_inner = inner_def == NULL; int vlen, i; vlen = btf_vlen(def_t); m = btf_members(def_t); for (i = 0; i < vlen; i++, m++) { const char *name = btf__name_by_offset(btf, m->name_off); if (!name) { pr_warn("map '%s': invalid field #%d.\n", map_name, i); return -EINVAL; } if (strcmp(name, "type") == 0) { if (!get_map_field_int(map_name, btf, m, &map_def->map_type)) return -EINVAL; map_def->parts |= MAP_DEF_MAP_TYPE; } else if (strcmp(name, "max_entries") == 0) { if (!get_map_field_int(map_name, btf, m, &map_def->max_entries)) return -EINVAL; map_def->parts |= MAP_DEF_MAX_ENTRIES; } else if (strcmp(name, "map_flags") == 0) { if (!get_map_field_int(map_name, btf, m, &map_def->map_flags)) return -EINVAL; map_def->parts |= MAP_DEF_MAP_FLAGS; } else if (strcmp(name, "numa_node") == 0) { if (!get_map_field_int(map_name, btf, m, &map_def->numa_node)) return -EINVAL; map_def->parts |= MAP_DEF_NUMA_NODE; } else if (strcmp(name, "key_size") == 0) { __u32 sz; if (!get_map_field_int(map_name, btf, m, &sz)) return -EINVAL; if (map_def->key_size && map_def->key_size != sz) { pr_warn("map '%s': conflicting key size %u != %u.\n", map_name, map_def->key_size, sz); return -EINVAL; } map_def->key_size = sz; map_def->parts |= MAP_DEF_KEY_SIZE; } else if (strcmp(name, "key") == 0) { __s64 sz; t = btf__type_by_id(btf, m->type); if (!t) { pr_warn("map '%s': key type [%d] not found.\n", map_name, m->type); return -EINVAL; } if (!btf_is_ptr(t)) { pr_warn("map '%s': key spec is not PTR: %s.\n", map_name, btf_kind_str(t)); return -EINVAL; } sz = btf__resolve_size(btf, t->type); if (sz < 0) { pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n", map_name, t->type, (ssize_t)sz); return sz; } if (map_def->key_size && map_def->key_size != sz) { pr_warn("map '%s': conflicting key size %u != %zd.\n", map_name, map_def->key_size, (ssize_t)sz); return -EINVAL; } map_def->key_size = sz; map_def->key_type_id = t->type; map_def->parts |= MAP_DEF_KEY_SIZE | MAP_DEF_KEY_TYPE; } else if (strcmp(name, "value_size") == 0) { __u32 sz; if (!get_map_field_int(map_name, btf, m, &sz)) return -EINVAL; if (map_def->value_size && map_def->value_size != sz) { pr_warn("map '%s': conflicting value size %u != %u.\n", map_name, map_def->value_size, sz); return -EINVAL; } map_def->value_size = sz; map_def->parts |= MAP_DEF_VALUE_SIZE; } else if (strcmp(name, "value") == 0) { __s64 sz; t = btf__type_by_id(btf, m->type); if (!t) { pr_warn("map '%s': value type [%d] not found.\n", map_name, m->type); return -EINVAL; } if (!btf_is_ptr(t)) { pr_warn("map '%s': value spec is not PTR: %s.\n", map_name, btf_kind_str(t)); return -EINVAL; } sz = btf__resolve_size(btf, t->type); if (sz < 0) { pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n", map_name, t->type, (ssize_t)sz); return sz; } if (map_def->value_size && map_def->value_size != sz) { pr_warn("map '%s': conflicting value size %u != %zd.\n", map_name, map_def->value_size, (ssize_t)sz); return -EINVAL; } map_def->value_size = sz; map_def->value_type_id = t->type; map_def->parts |= MAP_DEF_VALUE_SIZE | MAP_DEF_VALUE_TYPE; } else if (strcmp(name, "values") == 0) { bool is_map_in_map = bpf_map_type__is_map_in_map(map_def->map_type); bool is_prog_array = map_def->map_type == BPF_MAP_TYPE_PROG_ARRAY; const char *desc = is_map_in_map ? "map-in-map inner" : "prog-array value"; char inner_map_name[128]; int err; if (is_inner) { pr_warn("map '%s': multi-level inner maps not supported.\n", map_name); return -ENOTSUP; } if (i != vlen - 1) { pr_warn("map '%s': '%s' member should be last.\n", map_name, name); return -EINVAL; } if (!is_map_in_map && !is_prog_array) { pr_warn("map '%s': should be map-in-map or prog-array.\n", map_name); return -ENOTSUP; } if (map_def->value_size && map_def->value_size != 4) { pr_warn("map '%s': conflicting value size %u != 4.\n", map_name, map_def->value_size); return -EINVAL; } map_def->value_size = 4; t = btf__type_by_id(btf, m->type); if (!t) { pr_warn("map '%s': %s type [%d] not found.\n", map_name, desc, m->type); return -EINVAL; } if (!btf_is_array(t) || btf_array(t)->nelems) { pr_warn("map '%s': %s spec is not a zero-sized array.\n", map_name, desc); return -EINVAL; } t = skip_mods_and_typedefs(btf, btf_array(t)->type, NULL); if (!btf_is_ptr(t)) { pr_warn("map '%s': %s def is of unexpected kind %s.\n", map_name, desc, btf_kind_str(t)); return -EINVAL; } t = skip_mods_and_typedefs(btf, t->type, NULL); if (is_prog_array) { if (!btf_is_func_proto(t)) { pr_warn("map '%s': prog-array value def is of unexpected kind %s.\n", map_name, btf_kind_str(t)); return -EINVAL; } continue; } if (!btf_is_struct(t)) { pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", map_name, btf_kind_str(t)); return -EINVAL; } snprintf(inner_map_name, sizeof(inner_map_name), "%s.inner", map_name); err = parse_btf_map_def(inner_map_name, btf, t, strict, inner_def, NULL); if (err) return err; map_def->parts |= MAP_DEF_INNER_MAP; } else if (strcmp(name, "pinning") == 0) { __u32 val; if (is_inner) { pr_warn("map '%s': inner def can't be pinned.\n", map_name); return -EINVAL; } if (!get_map_field_int(map_name, btf, m, &val)) return -EINVAL; if (val != LIBBPF_PIN_NONE && val != LIBBPF_PIN_BY_NAME) { pr_warn("map '%s': invalid pinning value %u.\n", map_name, val); return -EINVAL; } map_def->pinning = val; map_def->parts |= MAP_DEF_PINNING; } else if (strcmp(name, "map_extra") == 0) { __u32 map_extra; if (!get_map_field_int(map_name, btf, m, &map_extra)) return -EINVAL; map_def->map_extra = map_extra; map_def->parts |= MAP_DEF_MAP_EXTRA; } else { if (strict) { pr_warn("map '%s': unknown field '%s'.\n", map_name, name); return -ENOTSUP; } pr_debug("map '%s': ignoring unknown field '%s'.\n", map_name, name); } } if (map_def->map_type == BPF_MAP_TYPE_UNSPEC) { pr_warn("map '%s': map type isn't specified.\n", map_name); return -EINVAL; } return 0; } static size_t adjust_ringbuf_sz(size_t sz) { __u32 page_sz = sysconf(_SC_PAGE_SIZE); __u32 mul; /* if user forgot to set any size, make sure they see error */ if (sz == 0) return 0; /* Kernel expects BPF_MAP_TYPE_RINGBUF's max_entries to be * a power-of-2 multiple of kernel's page size. If user diligently * satisified these conditions, pass the size through. */ if ((sz % page_sz) == 0 && is_pow_of_2(sz / page_sz)) return sz; /* Otherwise find closest (page_sz * power_of_2) product bigger than * user-set size to satisfy both user size request and kernel * requirements and substitute correct max_entries for map creation. */ for (mul = 1; mul <= UINT_MAX / page_sz; mul <<= 1) { if (mul * page_sz > sz) return mul * page_sz; } /* if it's impossible to satisfy the conditions (i.e., user size is * very close to UINT_MAX but is not a power-of-2 multiple of * page_size) then just return original size and let kernel reject it */ return sz; } static bool map_is_ringbuf(const struct bpf_map *map) { return map->def.type == BPF_MAP_TYPE_RINGBUF || map->def.type == BPF_MAP_TYPE_USER_RINGBUF; } static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def) { map->def.type = def->map_type; map->def.key_size = def->key_size; map->def.value_size = def->value_size; map->def.max_entries = def->max_entries; map->def.map_flags = def->map_flags; map->map_extra = def->map_extra; map->numa_node = def->numa_node; map->btf_key_type_id = def->key_type_id; map->btf_value_type_id = def->value_type_id; /* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */ if (map_is_ringbuf(map)) map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries); if (def->parts & MAP_DEF_MAP_TYPE) pr_debug("map '%s': found type = %u.\n", map->name, def->map_type); if (def->parts & MAP_DEF_KEY_TYPE) pr_debug("map '%s': found key [%u], sz = %u.\n", map->name, def->key_type_id, def->key_size); else if (def->parts & MAP_DEF_KEY_SIZE) pr_debug("map '%s': found key_size = %u.\n", map->name, def->key_size); if (def->parts & MAP_DEF_VALUE_TYPE) pr_debug("map '%s': found value [%u], sz = %u.\n", map->name, def->value_type_id, def->value_size); else if (def->parts & MAP_DEF_VALUE_SIZE) pr_debug("map '%s': found value_size = %u.\n", map->name, def->value_size); if (def->parts & MAP_DEF_MAX_ENTRIES) pr_debug("map '%s': found max_entries = %u.\n", map->name, def->max_entries); if (def->parts & MAP_DEF_MAP_FLAGS) pr_debug("map '%s': found map_flags = 0x%x.\n", map->name, def->map_flags); if (def->parts & MAP_DEF_MAP_EXTRA) pr_debug("map '%s': found map_extra = 0x%llx.\n", map->name, (unsigned long long)def->map_extra); if (def->parts & MAP_DEF_PINNING) pr_debug("map '%s': found pinning = %u.\n", map->name, def->pinning); if (def->parts & MAP_DEF_NUMA_NODE) pr_debug("map '%s': found numa_node = %u.\n", map->name, def->numa_node); if (def->parts & MAP_DEF_INNER_MAP) pr_debug("map '%s': found inner map definition.\n", map->name); } static const char *btf_var_linkage_str(__u32 linkage) { switch (linkage) { case BTF_VAR_STATIC: return "static"; case BTF_VAR_GLOBAL_ALLOCATED: return "global"; case BTF_VAR_GLOBAL_EXTERN: return "extern"; default: return "unknown"; } } static int bpf_object__init_user_btf_map(struct bpf_object *obj, const struct btf_type *sec, int var_idx, int sec_idx, const Elf_Data *data, bool strict, const char *pin_root_path) { struct btf_map_def map_def = {}, inner_def = {}; const struct btf_type *var, *def; const struct btf_var_secinfo *vi; const struct btf_var *var_extra; const char *map_name; struct bpf_map *map; int err; vi = btf_var_secinfos(sec) + var_idx; var = btf__type_by_id(obj->btf, vi->type); var_extra = btf_var(var); map_name = btf__name_by_offset(obj->btf, var->name_off); if (map_name == NULL || map_name[0] == '\0') { pr_warn("map #%d: empty name.\n", var_idx); return -EINVAL; } if ((__u64)vi->offset + vi->size > data->d_size) { pr_warn("map '%s' BTF data is corrupted.\n", map_name); return -EINVAL; } if (!btf_is_var(var)) { pr_warn("map '%s': unexpected var kind %s.\n", map_name, btf_kind_str(var)); return -EINVAL; } if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED) { pr_warn("map '%s': unsupported map linkage %s.\n", map_name, btf_var_linkage_str(var_extra->linkage)); return -EOPNOTSUPP; } def = skip_mods_and_typedefs(obj->btf, var->type, NULL); if (!btf_is_struct(def)) { pr_warn("map '%s': unexpected def kind %s.\n", map_name, btf_kind_str(var)); return -EINVAL; } if (def->size > vi->size) { pr_warn("map '%s': invalid def size.\n", map_name); return -EINVAL; } map = bpf_object__add_map(obj); if (IS_ERR(map)) return PTR_ERR(map); map->name = strdup(map_name); if (!map->name) { pr_warn("map '%s': failed to alloc map name.\n", map_name); return -ENOMEM; } map->libbpf_type = LIBBPF_MAP_UNSPEC; map->def.type = BPF_MAP_TYPE_UNSPEC; map->sec_idx = sec_idx; map->sec_offset = vi->offset; map->btf_var_idx = var_idx; pr_debug("map '%s': at sec_idx %d, offset %zu.\n", map_name, map->sec_idx, map->sec_offset); err = parse_btf_map_def(map->name, obj->btf, def, strict, &map_def, &inner_def); if (err) return err; fill_map_from_def(map, &map_def); if (map_def.pinning == LIBBPF_PIN_BY_NAME) { err = build_map_pin_path(map, pin_root_path); if (err) { pr_warn("map '%s': couldn't build pin path.\n", map->name); return err; } } if (map_def.parts & MAP_DEF_INNER_MAP) { map->inner_map = calloc(1, sizeof(*map->inner_map)); if (!map->inner_map) return -ENOMEM; map->inner_map->fd = -1; map->inner_map->sec_idx = sec_idx; map->inner_map->name = malloc(strlen(map_name) + sizeof(".inner") + 1); if (!map->inner_map->name) return -ENOMEM; sprintf(map->inner_map->name, "%s.inner", map_name); fill_map_from_def(map->inner_map, &inner_def); } err = map_fill_btf_type_info(obj, map); if (err) return err; return 0; } static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict, const char *pin_root_path) { const struct btf_type *sec = NULL; int nr_types, i, vlen, err; const struct btf_type *t; const char *name; Elf_Data *data; Elf_Scn *scn; if (obj->efile.btf_maps_shndx < 0) return 0; scn = elf_sec_by_idx(obj, obj->efile.btf_maps_shndx); data = elf_sec_data(obj, scn); if (!scn || !data) { pr_warn("elf: failed to get %s map definitions for %s\n", MAPS_ELF_SEC, obj->path); return -EINVAL; } nr_types = btf__type_cnt(obj->btf); for (i = 1; i < nr_types; i++) { t = btf__type_by_id(obj->btf, i); if (!btf_is_datasec(t)) continue; name = btf__name_by_offset(obj->btf, t->name_off); if (strcmp(name, MAPS_ELF_SEC) == 0) { sec = t; obj->efile.btf_maps_sec_btf_id = i; break; } } if (!sec) { pr_warn("DATASEC '%s' not found.\n", MAPS_ELF_SEC); return -ENOENT; } vlen = btf_vlen(sec); for (i = 0; i < vlen; i++) { err = bpf_object__init_user_btf_map(obj, sec, i, obj->efile.btf_maps_shndx, data, strict, pin_root_path); if (err) return err; } return 0; } static int bpf_object__init_maps(struct bpf_object *obj, const struct bpf_object_open_opts *opts) { const char *pin_root_path; bool strict; int err = 0; strict = !OPTS_GET(opts, relaxed_maps, false); pin_root_path = OPTS_GET(opts, pin_root_path, NULL); err = bpf_object__init_user_btf_maps(obj, strict, pin_root_path); err = err ?: bpf_object__init_global_data_maps(obj); err = err ?: bpf_object__init_kconfig_map(obj); err = err ?: bpf_object_init_struct_ops(obj); return err; } static bool section_have_execinstr(struct bpf_object *obj, int idx) { Elf64_Shdr *sh; sh = elf_sec_hdr(obj, elf_sec_by_idx(obj, idx)); if (!sh) return false; return sh->sh_flags & SHF_EXECINSTR; } static bool btf_needs_sanitization(struct bpf_object *obj) { bool has_func_global = kernel_supports(obj, FEAT_BTF_GLOBAL_FUNC); bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC); bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT); bool has_func = kernel_supports(obj, FEAT_BTF_FUNC); bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG); bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG); bool has_enum64 = kernel_supports(obj, FEAT_BTF_ENUM64); return !has_func || !has_datasec || !has_func_global || !has_float || !has_decl_tag || !has_type_tag || !has_enum64; } static int bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf) { bool has_func_global = kernel_supports(obj, FEAT_BTF_GLOBAL_FUNC); bool has_datasec = kernel_supports(obj, FEAT_BTF_DATASEC); bool has_float = kernel_supports(obj, FEAT_BTF_FLOAT); bool has_func = kernel_supports(obj, FEAT_BTF_FUNC); bool has_decl_tag = kernel_supports(obj, FEAT_BTF_DECL_TAG); bool has_type_tag = kernel_supports(obj, FEAT_BTF_TYPE_TAG); bool has_enum64 = kernel_supports(obj, FEAT_BTF_ENUM64); int enum64_placeholder_id = 0; struct btf_type *t; int i, j, vlen; for (i = 1; i < btf__type_cnt(btf); i++) { t = (struct btf_type *)btf__type_by_id(btf, i); if ((!has_datasec && btf_is_var(t)) || (!has_decl_tag && btf_is_decl_tag(t))) { /* replace VAR/DECL_TAG with INT */ t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0); /* * using size = 1 is the safest choice, 4 will be too * big and cause kernel BTF validation failure if * original variable took less than 4 bytes */ t->size = 1; *(int *)(t + 1) = BTF_INT_ENC(0, 0, 8); } else if (!has_datasec && btf_is_datasec(t)) { /* replace DATASEC with STRUCT */ const struct btf_var_secinfo *v = btf_var_secinfos(t); struct btf_member *m = btf_members(t); struct btf_type *vt; char *name; name = (char *)btf__name_by_offset(btf, t->name_off); while (*name) { if (*name == '.') *name = '_'; name++; } vlen = btf_vlen(t); t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, vlen); for (j = 0; j < vlen; j++, v++, m++) { /* order of field assignments is important */ m->offset = v->offset * 8; m->type = v->type; /* preserve variable name as member name */ vt = (void *)btf__type_by_id(btf, v->type); m->name_off = vt->name_off; } } else if (!has_func && btf_is_func_proto(t)) { /* replace FUNC_PROTO with ENUM */ vlen = btf_vlen(t); t->info = BTF_INFO_ENC(BTF_KIND_ENUM, 0, vlen); t->size = sizeof(__u32); /* kernel enforced */ } else if (!has_func && btf_is_func(t)) { /* replace FUNC with TYPEDEF */ t->info = BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0); } else if (!has_func_global && btf_is_func(t)) { /* replace BTF_FUNC_GLOBAL with BTF_FUNC_STATIC */ t->info = BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0); } else if (!has_float && btf_is_float(t)) { /* replace FLOAT with an equally-sized empty STRUCT; * since C compilers do not accept e.g. "float" as a * valid struct name, make it anonymous */ t->name_off = 0; t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 0); } else if (!has_type_tag && btf_is_type_tag(t)) { /* replace TYPE_TAG with a CONST */ t->name_off = 0; t->info = BTF_INFO_ENC(BTF_KIND_CONST, 0, 0); } else if (!has_enum64 && btf_is_enum(t)) { /* clear the kflag */ t->info = btf_type_info(btf_kind(t), btf_vlen(t), false); } else if (!has_enum64 && btf_is_enum64(t)) { /* replace ENUM64 with a union */ struct btf_member *m; if (enum64_placeholder_id == 0) { enum64_placeholder_id = btf__add_int(btf, "enum64_placeholder", 1, 0); if (enum64_placeholder_id < 0) return enum64_placeholder_id; t = (struct btf_type *)btf__type_by_id(btf, i); } m = btf_members(t); vlen = btf_vlen(t); t->info = BTF_INFO_ENC(BTF_KIND_UNION, 0, vlen); for (j = 0; j < vlen; j++, m++) { m->type = enum64_placeholder_id; m->offset = 0; } } } return 0; } static bool libbpf_needs_btf(const struct bpf_object *obj) { return obj->efile.btf_maps_shndx >= 0 || obj->efile.st_ops_shndx >= 0 || obj->efile.st_ops_link_shndx >= 0 || obj->nr_extern > 0; } static bool kernel_needs_btf(const struct bpf_object *obj) { return obj->efile.st_ops_shndx >= 0 || obj->efile.st_ops_link_shndx >= 0; } static int bpf_object__init_btf(struct bpf_object *obj, Elf_Data *btf_data, Elf_Data *btf_ext_data) { int err = -ENOENT; if (btf_data) { obj->btf = btf__new(btf_data->d_buf, btf_data->d_size); err = libbpf_get_error(obj->btf); if (err) { obj->btf = NULL; pr_warn("Error loading ELF section %s: %d.\n", BTF_ELF_SEC, err); goto out; } /* enforce 8-byte pointers for BPF-targeted BTFs */ btf__set_pointer_size(obj->btf, 8); } if (btf_ext_data) { struct btf_ext_info *ext_segs[3]; int seg_num, sec_num; if (!obj->btf) { pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n", BTF_EXT_ELF_SEC, BTF_ELF_SEC); goto out; } obj->btf_ext = btf_ext__new(btf_ext_data->d_buf, btf_ext_data->d_size); err = libbpf_get_error(obj->btf_ext); if (err) { pr_warn("Error loading ELF section %s: %d. Ignored and continue.\n", BTF_EXT_ELF_SEC, err); obj->btf_ext = NULL; goto out; } /* setup .BTF.ext to ELF section mapping */ ext_segs[0] = &obj->btf_ext->func_info; ext_segs[1] = &obj->btf_ext->line_info; ext_segs[2] = &obj->btf_ext->core_relo_info; for (seg_num = 0; seg_num < ARRAY_SIZE(ext_segs); seg_num++) { struct btf_ext_info *seg = ext_segs[seg_num]; const struct btf_ext_info_sec *sec; const char *sec_name; Elf_Scn *scn; if (seg->sec_cnt == 0) continue; seg->sec_idxs = calloc(seg->sec_cnt, sizeof(*seg->sec_idxs)); if (!seg->sec_idxs) { err = -ENOMEM; goto out; } sec_num = 0; for_each_btf_ext_sec(seg, sec) { /* preventively increment index to avoid doing * this before every continue below */ sec_num++; sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); if (str_is_empty(sec_name)) continue; scn = elf_sec_by_name(obj, sec_name); if (!scn) continue; seg->sec_idxs[sec_num - 1] = elf_ndxscn(scn); } } } out: if (err && libbpf_needs_btf(obj)) { pr_warn("BTF is required, but is missing or corrupted.\n"); return err; } return 0; } static int compare_vsi_off(const void *_a, const void *_b) { const struct btf_var_secinfo *a = _a; const struct btf_var_secinfo *b = _b; return a->offset - b->offset; } static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf, struct btf_type *t) { __u32 size = 0, i, vars = btf_vlen(t); const char *sec_name = btf__name_by_offset(btf, t->name_off); struct btf_var_secinfo *vsi; bool fixup_offsets = false; int err; if (!sec_name) { pr_debug("No name found in string section for DATASEC kind.\n"); return -ENOENT; } /* Extern-backing datasecs (.ksyms, .kconfig) have their size and * variable offsets set at the previous step. Further, not every * extern BTF VAR has corresponding ELF symbol preserved, so we skip * all fixups altogether for such sections and go straight to sorting * VARs within their DATASEC. */ if (strcmp(sec_name, KCONFIG_SEC) == 0 || strcmp(sec_name, KSYMS_SEC) == 0) goto sort_vars; /* Clang leaves DATASEC size and VAR offsets as zeroes, so we need to * fix this up. But BPF static linker already fixes this up and fills * all the sizes and offsets during static linking. So this step has * to be optional. But the STV_HIDDEN handling is non-optional for any * non-extern DATASEC, so the variable fixup loop below handles both * functions at the same time, paying the cost of BTF VAR <-> ELF * symbol matching just once. */ if (t->size == 0) { err = find_elf_sec_sz(obj, sec_name, &size); if (err || !size) { pr_debug("sec '%s': failed to determine size from ELF: size %u, err %d\n", sec_name, size, err); return -ENOENT; } t->size = size; fixup_offsets = true; } for (i = 0, vsi = btf_var_secinfos(t); i < vars; i++, vsi++) { const struct btf_type *t_var; struct btf_var *var; const char *var_name; Elf64_Sym *sym; t_var = btf__type_by_id(btf, vsi->type); if (!t_var || !btf_is_var(t_var)) { pr_debug("sec '%s': unexpected non-VAR type found\n", sec_name); return -EINVAL; } var = btf_var(t_var); if (var->linkage == BTF_VAR_STATIC || var->linkage == BTF_VAR_GLOBAL_EXTERN) continue; var_name = btf__name_by_offset(btf, t_var->name_off); if (!var_name) { pr_debug("sec '%s': failed to find name of DATASEC's member #%d\n", sec_name, i); return -ENOENT; } sym = find_elf_var_sym(obj, var_name); if (IS_ERR(sym)) { pr_debug("sec '%s': failed to find ELF symbol for VAR '%s'\n", sec_name, var_name); return -ENOENT; } if (fixup_offsets) vsi->offset = sym->st_value; /* if variable is a global/weak symbol, but has restricted * (STV_HIDDEN or STV_INTERNAL) visibility, mark its BTF VAR * as static. This follows similar logic for functions (BPF * subprogs) and influences libbpf's further decisions about * whether to make global data BPF array maps as * BPF_F_MMAPABLE. */ if (ELF64_ST_VISIBILITY(sym->st_other) == STV_HIDDEN || ELF64_ST_VISIBILITY(sym->st_other) == STV_INTERNAL) var->linkage = BTF_VAR_STATIC; } sort_vars: qsort(btf_var_secinfos(t), vars, sizeof(*vsi), compare_vsi_off); return 0; } static int bpf_object_fixup_btf(struct bpf_object *obj) { int i, n, err = 0; if (!obj->btf) return 0; n = btf__type_cnt(obj->btf); for (i = 1; i < n; i++) { struct btf_type *t = btf_type_by_id(obj->btf, i); /* Loader needs to fix up some of the things compiler * couldn't get its hands on while emitting BTF. This * is section size and global variable offset. We use * the info from the ELF itself for this purpose. */ if (btf_is_datasec(t)) { err = btf_fixup_datasec(obj, obj->btf, t); if (err) return err; } } return 0; } static bool prog_needs_vmlinux_btf(struct bpf_program *prog) { if (prog->type == BPF_PROG_TYPE_STRUCT_OPS || prog->type == BPF_PROG_TYPE_LSM) return true; /* BPF_PROG_TYPE_TRACING programs which do not attach to other programs * also need vmlinux BTF */ if (prog->type == BPF_PROG_TYPE_TRACING && !prog->attach_prog_fd) return true; return false; } static bool obj_needs_vmlinux_btf(const struct bpf_object *obj) { struct bpf_program *prog; int i; /* CO-RE relocations need kernel BTF, only when btf_custom_path * is not specified */ if (obj->btf_ext && obj->btf_ext->core_relo_info.len && !obj->btf_custom_path) return true; /* Support for typed ksyms needs kernel BTF */ for (i = 0; i < obj->nr_extern; i++) { const struct extern_desc *ext; ext = &obj->externs[i]; if (ext->type == EXT_KSYM && ext->ksym.type_id) return true; } bpf_object__for_each_program(prog, obj) { if (!prog->autoload) continue; if (prog_needs_vmlinux_btf(prog)) return true; } return false; } static int bpf_object__load_vmlinux_btf(struct bpf_object *obj, bool force) { int err; /* btf_vmlinux could be loaded earlier */ if (obj->btf_vmlinux || obj->gen_loader) return 0; if (!force && !obj_needs_vmlinux_btf(obj)) return 0; obj->btf_vmlinux = btf__load_vmlinux_btf(); err = libbpf_get_error(obj->btf_vmlinux); if (err) { pr_warn("Error loading vmlinux BTF: %d\n", err); obj->btf_vmlinux = NULL; return err; } return 0; } static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) { struct btf *kern_btf = obj->btf; bool btf_mandatory, sanitize; int i, err = 0; if (!obj->btf) return 0; if (!kernel_supports(obj, FEAT_BTF)) { if (kernel_needs_btf(obj)) { err = -EOPNOTSUPP; goto report; } pr_debug("Kernel doesn't support BTF, skipping uploading it.\n"); return 0; } /* Even though some subprogs are global/weak, user might prefer more * permissive BPF verification process that BPF verifier performs for * static functions, taking into account more context from the caller * functions. In such case, they need to mark such subprogs with * __attribute__((visibility("hidden"))) and libbpf will adjust * corresponding FUNC BTF type to be marked as static and trigger more * involved BPF verification process. */ for (i = 0; i < obj->nr_programs; i++) { struct bpf_program *prog = &obj->programs[i]; struct btf_type *t; const char *name; int j, n; if (!prog->mark_btf_static || !prog_is_subprog(obj, prog)) continue; n = btf__type_cnt(obj->btf); for (j = 1; j < n; j++) { t = btf_type_by_id(obj->btf, j); if (!btf_is_func(t) || btf_func_linkage(t) != BTF_FUNC_GLOBAL) continue; name = btf__str_by_offset(obj->btf, t->name_off); if (strcmp(name, prog->name) != 0) continue; t->info = btf_type_info(BTF_KIND_FUNC, BTF_FUNC_STATIC, 0); break; } } if (!kernel_supports(obj, FEAT_BTF_DECL_TAG)) goto skip_exception_cb; for (i = 0; i < obj->nr_programs; i++) { struct bpf_program *prog = &obj->programs[i]; int j, k, n; if (prog_is_subprog(obj, prog)) continue; n = btf__type_cnt(obj->btf); for (j = 1; j < n; j++) { const char *str = "exception_callback:", *name; size_t len = strlen(str); struct btf_type *t; t = btf_type_by_id(obj->btf, j); if (!btf_is_decl_tag(t) || btf_decl_tag(t)->component_idx != -1) continue; name = btf__str_by_offset(obj->btf, t->name_off); if (strncmp(name, str, len)) continue; t = btf_type_by_id(obj->btf, t->type); if (!btf_is_func(t) || btf_func_linkage(t) != BTF_FUNC_GLOBAL) { pr_warn("prog '%s': exception_callback:<value> decl tag not applied to the main program\n", prog->name); return -EINVAL; } if (strcmp(prog->name, btf__str_by_offset(obj->btf, t->name_off))) continue; /* Multiple callbacks are specified for the same prog, * the verifier will eventually return an error for this * case, hence simply skip appending a subprog. */ if (prog->exception_cb_idx >= 0) { prog->exception_cb_idx = -1; break; } name += len; if (str_is_empty(name)) { pr_warn("prog '%s': exception_callback:<value> decl tag contains empty value\n", prog->name); return -EINVAL; } for (k = 0; k < obj->nr_programs; k++) { struct bpf_program *subprog = &obj->programs[k]; if (!prog_is_subprog(obj, subprog)) continue; if (strcmp(name, subprog->name)) continue; /* Enforce non-hidden, as from verifier point of * view it expects global functions, whereas the * mark_btf_static fixes up linkage as static. */ if (!subprog->sym_global || subprog->mark_btf_static) { pr_warn("prog '%s': exception callback %s must be a global non-hidden function\n", prog->name, subprog->name); return -EINVAL; } /* Let's see if we already saw a static exception callback with the same name */ if (prog->exception_cb_idx >= 0) { pr_warn("prog '%s': multiple subprogs with same name as exception callback '%s'\n", prog->name, subprog->name); return -EINVAL; } prog->exception_cb_idx = k; break; } if (prog->exception_cb_idx >= 0) continue; pr_warn("prog '%s': cannot find exception callback '%s'\n", prog->name, name); return -ENOENT; } } skip_exception_cb: sanitize = btf_needs_sanitization(obj); if (sanitize) { const void *raw_data; __u32 sz; /* clone BTF to sanitize a copy and leave the original intact */ raw_data = btf__raw_data(obj->btf, &sz); kern_btf = btf__new(raw_data, sz); err = libbpf_get_error(kern_btf); if (err) return err; /* enforce 8-byte pointers for BPF-targeted BTFs */ btf__set_pointer_size(obj->btf, 8); err = bpf_object__sanitize_btf(obj, kern_btf); if (err) return err; } if (obj->gen_loader) { __u32 raw_size = 0; const void *raw_data = btf__raw_data(kern_btf, &raw_size); if (!raw_data) return -ENOMEM; bpf_gen__load_btf(obj->gen_loader, raw_data, raw_size); /* Pretend to have valid FD to pass various fd >= 0 checks. * This fd == 0 will not be used with any syscall and will be reset to -1 eventually. */ btf__set_fd(kern_btf, 0); } else { /* currently BPF_BTF_LOAD only supports log_level 1 */ err = btf_load_into_kernel(kern_btf, obj->log_buf, obj->log_size, obj->log_level ? 1 : 0); } if (sanitize) { if (!err) { /* move fd to libbpf's BTF */ btf__set_fd(obj->btf, btf__fd(kern_btf)); btf__set_fd(kern_btf, -1); } btf__free(kern_btf); } report: if (err) { btf_mandatory = kernel_needs_btf(obj); pr_warn("Error loading .BTF into kernel: %d. %s\n", err, btf_mandatory ? "BTF is mandatory, can't proceed." : "BTF is optional, ignoring."); if (!btf_mandatory) err = 0; } return err; } static const char *elf_sym_str(const struct bpf_object *obj, size_t off) { const char *name; name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, off); if (!name) { pr_warn("elf: failed to get section name string at offset %zu from %s: %s\n", off, obj->path, elf_errmsg(-1)); return NULL; } return name; } static const char *elf_sec_str(const struct bpf_object *obj, size_t off) { const char *name; name = elf_strptr(obj->efile.elf, obj->efile.shstrndx, off); if (!name) { pr_warn("elf: failed to get section name string at offset %zu from %s: %s\n", off, obj->path, elf_errmsg(-1)); return NULL; } return name; } static Elf_Scn *elf_sec_by_idx(const struct bpf_object *obj, size_t idx) { Elf_Scn *scn; scn = elf_getscn(obj->efile.elf, idx); if (!scn) { pr_warn("elf: failed to get section(%zu) from %s: %s\n", idx, obj->path, elf_errmsg(-1)); return NULL; } return scn; } static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name) { Elf_Scn *scn = NULL; Elf *elf = obj->efile.elf; const char *sec_name; while ((scn = elf_nextscn(elf, scn)) != NULL) { sec_name = elf_sec_name(obj, scn); if (!sec_name) return NULL; if (strcmp(sec_name, name) != 0) continue; return scn; } return NULL; } static Elf64_Shdr *elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn) { Elf64_Shdr *shdr; if (!scn) return NULL; shdr = elf64_getshdr(scn); if (!shdr) { pr_warn("elf: failed to get section(%zu) header from %s: %s\n", elf_ndxscn(scn), obj->path, elf_errmsg(-1)); return NULL; } return shdr; } static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn) { const char *name; Elf64_Shdr *sh; if (!scn) return NULL; sh = elf_sec_hdr(obj, scn); if (!sh) return NULL; name = elf_sec_str(obj, sh->sh_name); if (!name) { pr_warn("elf: failed to get section(%zu) name from %s: %s\n", elf_ndxscn(scn), obj->path, elf_errmsg(-1)); return NULL; } return name; } static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn) { Elf_Data *data; if (!scn) return NULL; data = elf_getdata(scn, 0); if (!data) { pr_warn("elf: failed to get section(%zu) %s data from %s: %s\n", elf_ndxscn(scn), elf_sec_name(obj, scn) ?: "<?>", obj->path, elf_errmsg(-1)); return NULL; } return data; } static Elf64_Sym *elf_sym_by_idx(const struct bpf_object *obj, size_t idx) { if (idx >= obj->efile.symbols->d_size / sizeof(Elf64_Sym)) return NULL; return (Elf64_Sym *)obj->efile.symbols->d_buf + idx; } static Elf64_Rel *elf_rel_by_idx(Elf_Data *data, size_t idx) { if (idx >= data->d_size / sizeof(Elf64_Rel)) return NULL; return (Elf64_Rel *)data->d_buf + idx; } static bool is_sec_name_dwarf(const char *name) { /* approximation, but the actual list is too long */ return str_has_pfx(name, ".debug_"); } static bool ignore_elf_section(Elf64_Shdr *hdr, const char *name) { /* no special handling of .strtab */ if (hdr->sh_type == SHT_STRTAB) return true; /* ignore .llvm_addrsig section as well */ if (hdr->sh_type == SHT_LLVM_ADDRSIG) return true; /* no subprograms will lead to an empty .text section, ignore it */ if (hdr->sh_type == SHT_PROGBITS && hdr->sh_size == 0 && strcmp(name, ".text") == 0) return true; /* DWARF sections */ if (is_sec_name_dwarf(name)) return true; if (str_has_pfx(name, ".rel")) { name += sizeof(".rel") - 1; /* DWARF section relocations */ if (is_sec_name_dwarf(name)) return true; /* .BTF and .BTF.ext don't need relocations */ if (strcmp(name, BTF_ELF_SEC) == 0 || strcmp(name, BTF_EXT_ELF_SEC) == 0) return true; } return false; } static int cmp_progs(const void *_a, const void *_b) { const struct bpf_program *a = _a; const struct bpf_program *b = _b; if (a->sec_idx != b->sec_idx) return a->sec_idx < b->sec_idx ? -1 : 1; /* sec_insn_off can't be the same within the section */ return a->sec_insn_off < b->sec_insn_off ? -1 : 1; } static int bpf_object__elf_collect(struct bpf_object *obj) { struct elf_sec_desc *sec_desc; Elf *elf = obj->efile.elf; Elf_Data *btf_ext_data = NULL; Elf_Data *btf_data = NULL; int idx = 0, err = 0; const char *name; Elf_Data *data; Elf_Scn *scn; Elf64_Shdr *sh; /* ELF section indices are 0-based, but sec #0 is special "invalid" * section. Since section count retrieved by elf_getshdrnum() does * include sec #0, it is already the necessary size of an array to keep * all the sections. */ if (elf_getshdrnum(obj->efile.elf, &obj->efile.sec_cnt)) { pr_warn("elf: failed to get the number of sections for %s: %s\n", obj->path, elf_errmsg(-1)); return -LIBBPF_ERRNO__FORMAT; } obj->efile.secs = calloc(obj->efile.sec_cnt, sizeof(*obj->efile.secs)); if (!obj->efile.secs) return -ENOMEM; /* a bunch of ELF parsing functionality depends on processing symbols, * so do the first pass and find the symbol table */ scn = NULL; while ((scn = elf_nextscn(elf, scn)) != NULL) { sh = elf_sec_hdr(obj, scn); if (!sh) return -LIBBPF_ERRNO__FORMAT; if (sh->sh_type == SHT_SYMTAB) { if (obj->efile.symbols) { pr_warn("elf: multiple symbol tables in %s\n", obj->path); return -LIBBPF_ERRNO__FORMAT; } data = elf_sec_data(obj, scn); if (!data) return -LIBBPF_ERRNO__FORMAT; idx = elf_ndxscn(scn); obj->efile.symbols = data; obj->efile.symbols_shndx = idx; obj->efile.strtabidx = sh->sh_link; } } if (!obj->efile.symbols) { pr_warn("elf: couldn't find symbol table in %s, stripped object file?\n", obj->path); return -ENOENT; } scn = NULL; while ((scn = elf_nextscn(elf, scn)) != NULL) { idx = elf_ndxscn(scn); sec_desc = &obj->efile.secs[idx]; sh = elf_sec_hdr(obj, scn); if (!sh) return -LIBBPF_ERRNO__FORMAT; name = elf_sec_str(obj, sh->sh_name); if (!name) return -LIBBPF_ERRNO__FORMAT; if (ignore_elf_section(sh, name)) continue; data = elf_sec_data(obj, scn); if (!data) return -LIBBPF_ERRNO__FORMAT; pr_debug("elf: section(%d) %s, size %ld, link %d, flags %lx, type=%d\n", idx, name, (unsigned long)data->d_size, (int)sh->sh_link, (unsigned long)sh->sh_flags, (int)sh->sh_type); if (strcmp(name, "license") == 0) { err = bpf_object__init_license(obj, data->d_buf, data->d_size); if (err) return err; } else if (strcmp(name, "version") == 0) { err = bpf_object__init_kversion(obj, data->d_buf, data->d_size); if (err) return err; } else if (strcmp(name, "maps") == 0) { pr_warn("elf: legacy map definitions in 'maps' section are not supported by libbpf v1.0+\n"); return -ENOTSUP; } else if (strcmp(name, MAPS_ELF_SEC) == 0) { obj->efile.btf_maps_shndx = idx; } else if (strcmp(name, BTF_ELF_SEC) == 0) { if (sh->sh_type != SHT_PROGBITS) return -LIBBPF_ERRNO__FORMAT; btf_data = data; } else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) { if (sh->sh_type != SHT_PROGBITS) return -LIBBPF_ERRNO__FORMAT; btf_ext_data = data; } else if (sh->sh_type == SHT_SYMTAB) { /* already processed during the first pass above */ } else if (sh->sh_type == SHT_PROGBITS && data->d_size > 0) { if (sh->sh_flags & SHF_EXECINSTR) { if (strcmp(name, ".text") == 0) obj->efile.text_shndx = idx; err = bpf_object__add_programs(obj, data, name, idx); if (err) return err; } else if (strcmp(name, DATA_SEC) == 0 || str_has_pfx(name, DATA_SEC ".")) { sec_desc->sec_type = SEC_DATA; sec_desc->shdr = sh; sec_desc->data = data; } else if (strcmp(name, RODATA_SEC) == 0 || str_has_pfx(name, RODATA_SEC ".")) { sec_desc->sec_type = SEC_RODATA; sec_desc->shdr = sh; sec_desc->data = data; } else if (strcmp(name, STRUCT_OPS_SEC) == 0) { obj->efile.st_ops_data = data; obj->efile.st_ops_shndx = idx; } else if (strcmp(name, STRUCT_OPS_LINK_SEC) == 0) { obj->efile.st_ops_link_data = data; obj->efile.st_ops_link_shndx = idx; } else { pr_info("elf: skipping unrecognized data section(%d) %s\n", idx, name); } } else if (sh->sh_type == SHT_REL) { int targ_sec_idx = sh->sh_info; /* points to other section */ if (sh->sh_entsize != sizeof(Elf64_Rel) || targ_sec_idx >= obj->efile.sec_cnt) return -LIBBPF_ERRNO__FORMAT; /* Only do relo for section with exec instructions */ if (!section_have_execinstr(obj, targ_sec_idx) && strcmp(name, ".rel" STRUCT_OPS_SEC) && strcmp(name, ".rel" STRUCT_OPS_LINK_SEC) && strcmp(name, ".rel" MAPS_ELF_SEC)) { pr_info("elf: skipping relo section(%d) %s for section(%d) %s\n", idx, name, targ_sec_idx, elf_sec_name(obj, elf_sec_by_idx(obj, targ_sec_idx)) ?: "<?>"); continue; } sec_desc->sec_type = SEC_RELO; sec_desc->shdr = sh; sec_desc->data = data; } else if (sh->sh_type == SHT_NOBITS && (strcmp(name, BSS_SEC) == 0 || str_has_pfx(name, BSS_SEC "."))) { sec_desc->sec_type = SEC_BSS; sec_desc->shdr = sh; sec_desc->data = data; } else { pr_info("elf: skipping section(%d) %s (size %zu)\n", idx, name, (size_t)sh->sh_size); } } if (!obj->efile.strtabidx || obj->efile.strtabidx > idx) { pr_warn("elf: symbol strings section missing or invalid in %s\n", obj->path); return -LIBBPF_ERRNO__FORMAT; } /* sort BPF programs by section name and in-section instruction offset * for faster search */ if (obj->nr_programs) qsort(obj->programs, obj->nr_programs, sizeof(*obj->programs), cmp_progs); return bpf_object__init_btf(obj, btf_data, btf_ext_data); } static bool sym_is_extern(const Elf64_Sym *sym) { int bind = ELF64_ST_BIND(sym->st_info); /* externs are symbols w/ type=NOTYPE, bind=GLOBAL|WEAK, section=UND */ return sym->st_shndx == SHN_UNDEF && (bind == STB_GLOBAL || bind == STB_WEAK) && ELF64_ST_TYPE(sym->st_info) == STT_NOTYPE; } static bool sym_is_subprog(const Elf64_Sym *sym, int text_shndx) { int bind = ELF64_ST_BIND(sym->st_info); int type = ELF64_ST_TYPE(sym->st_info); /* in .text section */ if (sym->st_shndx != text_shndx) return false; /* local function */ if (bind == STB_LOCAL && type == STT_SECTION) return true; /* global function */ return bind == STB_GLOBAL && type == STT_FUNC; } static int find_extern_btf_id(const struct btf *btf, const char *ext_name) { const struct btf_type *t; const char *tname; int i, n; if (!btf) return -ESRCH; n = btf__type_cnt(btf); for (i = 1; i < n; i++) { t = btf__type_by_id(btf, i); if (!btf_is_var(t) && !btf_is_func(t)) continue; tname = btf__name_by_offset(btf, t->name_off); if (strcmp(tname, ext_name)) continue; if (btf_is_var(t) && btf_var(t)->linkage != BTF_VAR_GLOBAL_EXTERN) return -EINVAL; if (btf_is_func(t) && btf_func_linkage(t) != BTF_FUNC_EXTERN) return -EINVAL; return i; } return -ENOENT; } static int find_extern_sec_btf_id(struct btf *btf, int ext_btf_id) { const struct btf_var_secinfo *vs; const struct btf_type *t; int i, j, n; if (!btf) return -ESRCH; n = btf__type_cnt(btf); for (i = 1; i < n; i++) { t = btf__type_by_id(btf, i); if (!btf_is_datasec(t)) continue; vs = btf_var_secinfos(t); for (j = 0; j < btf_vlen(t); j++, vs++) { if (vs->type == ext_btf_id) return i; } } return -ENOENT; } static enum kcfg_type find_kcfg_type(const struct btf *btf, int id, bool *is_signed) { const struct btf_type *t; const char *name; t = skip_mods_and_typedefs(btf, id, NULL); name = btf__name_by_offset(btf, t->name_off); if (is_signed) *is_signed = false; switch (btf_kind(t)) { case BTF_KIND_INT: { int enc = btf_int_encoding(t); if (enc & BTF_INT_BOOL) return t->size == 1 ? KCFG_BOOL : KCFG_UNKNOWN; if (is_signed) *is_signed = enc & BTF_INT_SIGNED; if (t->size == 1) return KCFG_CHAR; if (t->size < 1 || t->size > 8 || (t->size & (t->size - 1))) return KCFG_UNKNOWN; return KCFG_INT; } case BTF_KIND_ENUM: if (t->size != 4) return KCFG_UNKNOWN; if (strcmp(name, "libbpf_tristate")) return KCFG_UNKNOWN; return KCFG_TRISTATE; case BTF_KIND_ENUM64: if (strcmp(name, "libbpf_tristate")) return KCFG_UNKNOWN; return KCFG_TRISTATE; case BTF_KIND_ARRAY: if (btf_array(t)->nelems == 0) return KCFG_UNKNOWN; if (find_kcfg_type(btf, btf_array(t)->type, NULL) != KCFG_CHAR) return KCFG_UNKNOWN; return KCFG_CHAR_ARR; default: return KCFG_UNKNOWN; } } static int cmp_externs(const void *_a, const void *_b) { const struct extern_desc *a = _a; const struct extern_desc *b = _b; if (a->type != b->type) return a->type < b->type ? -1 : 1; if (a->type == EXT_KCFG) { /* descending order by alignment requirements */ if (a->kcfg.align != b->kcfg.align) return a->kcfg.align > b->kcfg.align ? -1 : 1; /* ascending order by size, within same alignment class */ if (a->kcfg.sz != b->kcfg.sz) return a->kcfg.sz < b->kcfg.sz ? -1 : 1; } /* resolve ties by name */ return strcmp(a->name, b->name); } static int find_int_btf_id(const struct btf *btf) { const struct btf_type *t; int i, n; n = btf__type_cnt(btf); for (i = 1; i < n; i++) { t = btf__type_by_id(btf, i); if (btf_is_int(t) && btf_int_bits(t) == 32) return i; } return 0; } static int add_dummy_ksym_var(struct btf *btf) { int i, int_btf_id, sec_btf_id, dummy_var_btf_id; const struct btf_var_secinfo *vs; const struct btf_type *sec; if (!btf) return 0; sec_btf_id = btf__find_by_name_kind(btf, KSYMS_SEC, BTF_KIND_DATASEC); if (sec_btf_id < 0) return 0; sec = btf__type_by_id(btf, sec_btf_id); vs = btf_var_secinfos(sec); for (i = 0; i < btf_vlen(sec); i++, vs++) { const struct btf_type *vt; vt = btf__type_by_id(btf, vs->type); if (btf_is_func(vt)) break; } /* No func in ksyms sec. No need to add dummy var. */ if (i == btf_vlen(sec)) return 0; int_btf_id = find_int_btf_id(btf); dummy_var_btf_id = btf__add_var(btf, "dummy_ksym", BTF_VAR_GLOBAL_ALLOCATED, int_btf_id); if (dummy_var_btf_id < 0) pr_warn("cannot create a dummy_ksym var\n"); return dummy_var_btf_id; } static int bpf_object__collect_externs(struct bpf_object *obj) { struct btf_type *sec, *kcfg_sec = NULL, *ksym_sec = NULL; const struct btf_type *t; struct extern_desc *ext; int i, n, off, dummy_var_btf_id; const char *ext_name, *sec_name; size_t ext_essent_len; Elf_Scn *scn; Elf64_Shdr *sh; if (!obj->efile.symbols) return 0; scn = elf_sec_by_idx(obj, obj->efile.symbols_shndx); sh = elf_sec_hdr(obj, scn); if (!sh || sh->sh_entsize != sizeof(Elf64_Sym)) return -LIBBPF_ERRNO__FORMAT; dummy_var_btf_id = add_dummy_ksym_var(obj->btf); if (dummy_var_btf_id < 0) return dummy_var_btf_id; n = sh->sh_size / sh->sh_entsize; pr_debug("looking for externs among %d symbols...\n", n); for (i = 0; i < n; i++) { Elf64_Sym *sym = elf_sym_by_idx(obj, i); if (!sym) return -LIBBPF_ERRNO__FORMAT; if (!sym_is_extern(sym)) continue; ext_name = elf_sym_str(obj, sym->st_name); if (!ext_name || !ext_name[0]) continue; ext = obj->externs; ext = libbpf_reallocarray(ext, obj->nr_extern + 1, sizeof(*ext)); if (!ext) return -ENOMEM; obj->externs = ext; ext = &ext[obj->nr_extern]; memset(ext, 0, sizeof(*ext)); obj->nr_extern++; ext->btf_id = find_extern_btf_id(obj->btf, ext_name); if (ext->btf_id <= 0) { pr_warn("failed to find BTF for extern '%s': %d\n", ext_name, ext->btf_id); return ext->btf_id; } t = btf__type_by_id(obj->btf, ext->btf_id); ext->name = btf__name_by_offset(obj->btf, t->name_off); ext->sym_idx = i; ext->is_weak = ELF64_ST_BIND(sym->st_info) == STB_WEAK; ext_essent_len = bpf_core_essential_name_len(ext->name); ext->essent_name = NULL; if (ext_essent_len != strlen(ext->name)) { ext->essent_name = strndup(ext->name, ext_essent_len); if (!ext->essent_name) return -ENOMEM; } ext->sec_btf_id = find_extern_sec_btf_id(obj->btf, ext->btf_id); if (ext->sec_btf_id <= 0) { pr_warn("failed to find BTF for extern '%s' [%d] section: %d\n", ext_name, ext->btf_id, ext->sec_btf_id); return ext->sec_btf_id; } sec = (void *)btf__type_by_id(obj->btf, ext->sec_btf_id); sec_name = btf__name_by_offset(obj->btf, sec->name_off); if (strcmp(sec_name, KCONFIG_SEC) == 0) { if (btf_is_func(t)) { pr_warn("extern function %s is unsupported under %s section\n", ext->name, KCONFIG_SEC); return -ENOTSUP; } kcfg_sec = sec; ext->type = EXT_KCFG; ext->kcfg.sz = btf__resolve_size(obj->btf, t->type); if (ext->kcfg.sz <= 0) { pr_warn("failed to resolve size of extern (kcfg) '%s': %d\n", ext_name, ext->kcfg.sz); return ext->kcfg.sz; } ext->kcfg.align = btf__align_of(obj->btf, t->type); if (ext->kcfg.align <= 0) { pr_warn("failed to determine alignment of extern (kcfg) '%s': %d\n", ext_name, ext->kcfg.align); return -EINVAL; } ext->kcfg.type = find_kcfg_type(obj->btf, t->type, &ext->kcfg.is_signed); if (ext->kcfg.type == KCFG_UNKNOWN) { pr_warn("extern (kcfg) '%s': type is unsupported\n", ext_name); return -ENOTSUP; } } else if (strcmp(sec_name, KSYMS_SEC) == 0) { ksym_sec = sec; ext->type = EXT_KSYM; skip_mods_and_typedefs(obj->btf, t->type, &ext->ksym.type_id); } else { pr_warn("unrecognized extern section '%s'\n", sec_name); return -ENOTSUP; } } pr_debug("collected %d externs total\n", obj->nr_extern); if (!obj->nr_extern) return 0; /* sort externs by type, for kcfg ones also by (align, size, name) */ qsort(obj->externs, obj->nr_extern, sizeof(*ext), cmp_externs); /* for .ksyms section, we need to turn all externs into allocated * variables in BTF to pass kernel verification; we do this by * pretending that each extern is a 8-byte variable */ if (ksym_sec) { /* find existing 4-byte integer type in BTF to use for fake * extern variables in DATASEC */ int int_btf_id = find_int_btf_id(obj->btf); /* For extern function, a dummy_var added earlier * will be used to replace the vs->type and * its name string will be used to refill * the missing param's name. */ const struct btf_type *dummy_var; dummy_var = btf__type_by_id(obj->btf, dummy_var_btf_id); for (i = 0; i < obj->nr_extern; i++) { ext = &obj->externs[i]; if (ext->type != EXT_KSYM) continue; pr_debug("extern (ksym) #%d: symbol %d, name %s\n", i, ext->sym_idx, ext->name); } sec = ksym_sec; n = btf_vlen(sec); for (i = 0, off = 0; i < n; i++, off += sizeof(int)) { struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i; struct btf_type *vt; vt = (void *)btf__type_by_id(obj->btf, vs->type); ext_name = btf__name_by_offset(obj->btf, vt->name_off); ext = find_extern_by_name(obj, ext_name); if (!ext) { pr_warn("failed to find extern definition for BTF %s '%s'\n", btf_kind_str(vt), ext_name); return -ESRCH; } if (btf_is_func(vt)) { const struct btf_type *func_proto; struct btf_param *param; int j; func_proto = btf__type_by_id(obj->btf, vt->type); param = btf_params(func_proto); /* Reuse the dummy_var string if the * func proto does not have param name. */ for (j = 0; j < btf_vlen(func_proto); j++) if (param[j].type && !param[j].name_off) param[j].name_off = dummy_var->name_off; vs->type = dummy_var_btf_id; vt->info &= ~0xffff; vt->info |= BTF_FUNC_GLOBAL; } else { btf_var(vt)->linkage = BTF_VAR_GLOBAL_ALLOCATED; vt->type = int_btf_id; } vs->offset = off; vs->size = sizeof(int); } sec->size = off; } if (kcfg_sec) { sec = kcfg_sec; /* for kcfg externs calculate their offsets within a .kconfig map */ off = 0; for (i = 0; i < obj->nr_extern; i++) { ext = &obj->externs[i]; if (ext->type != EXT_KCFG) continue; ext->kcfg.data_off = roundup(off, ext->kcfg.align); off = ext->kcfg.data_off + ext->kcfg.sz; pr_debug("extern (kcfg) #%d: symbol %d, off %u, name %s\n", i, ext->sym_idx, ext->kcfg.data_off, ext->name); } sec->size = off; n = btf_vlen(sec); for (i = 0; i < n; i++) { struct btf_var_secinfo *vs = btf_var_secinfos(sec) + i; t = btf__type_by_id(obj->btf, vs->type); ext_name = btf__name_by_offset(obj->btf, t->name_off); ext = find_extern_by_name(obj, ext_name); if (!ext) { pr_warn("failed to find extern definition for BTF var '%s'\n", ext_name); return -ESRCH; } btf_var(t)->linkage = BTF_VAR_GLOBAL_ALLOCATED; vs->offset = ext->kcfg.data_off; } } return 0; } static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog) { return prog->sec_idx == obj->efile.text_shndx && obj->nr_programs > 1; } struct bpf_program * bpf_object__find_program_by_name(const struct bpf_object *obj, const char *name) { struct bpf_program *prog; bpf_object__for_each_program(prog, obj) { if (prog_is_subprog(obj, prog)) continue; if (!strcmp(prog->name, name)) return prog; } return errno = ENOENT, NULL; } static bool bpf_object__shndx_is_data(const struct bpf_object *obj, int shndx) { switch (obj->efile.secs[shndx].sec_type) { case SEC_BSS: case SEC_DATA: case SEC_RODATA: return true; default: return false; } } static bool bpf_object__shndx_is_maps(const struct bpf_object *obj, int shndx) { return shndx == obj->efile.btf_maps_shndx; } static enum libbpf_map_type bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx) { if (shndx == obj->efile.symbols_shndx) return LIBBPF_MAP_KCONFIG; switch (obj->efile.secs[shndx].sec_type) { case SEC_BSS: return LIBBPF_MAP_BSS; case SEC_DATA: return LIBBPF_MAP_DATA; case SEC_RODATA: return LIBBPF_MAP_RODATA; default: return LIBBPF_MAP_UNSPEC; } } static int bpf_program__record_reloc(struct bpf_program *prog, struct reloc_desc *reloc_desc, __u32 insn_idx, const char *sym_name, const Elf64_Sym *sym, const Elf64_Rel *rel) { struct bpf_insn *insn = &prog->insns[insn_idx]; size_t map_idx, nr_maps = prog->obj->nr_maps; struct bpf_object *obj = prog->obj; __u32 shdr_idx = sym->st_shndx; enum libbpf_map_type type; const char *sym_sec_name; struct bpf_map *map; if (!is_call_insn(insn) && !is_ldimm64_insn(insn)) { pr_warn("prog '%s': invalid relo against '%s' for insns[%d].code 0x%x\n", prog->name, sym_name, insn_idx, insn->code); return -LIBBPF_ERRNO__RELOC; } if (sym_is_extern(sym)) { int sym_idx = ELF64_R_SYM(rel->r_info); int i, n = obj->nr_extern; struct extern_desc *ext; for (i = 0; i < n; i++) { ext = &obj->externs[i]; if (ext->sym_idx == sym_idx) break; } if (i >= n) { pr_warn("prog '%s': extern relo failed to find extern for '%s' (%d)\n", prog->name, sym_name, sym_idx); return -LIBBPF_ERRNO__RELOC; } pr_debug("prog '%s': found extern #%d '%s' (sym %d) for insn #%u\n", prog->name, i, ext->name, ext->sym_idx, insn_idx); if (insn->code == (BPF_JMP | BPF_CALL)) reloc_desc->type = RELO_EXTERN_CALL; else reloc_desc->type = RELO_EXTERN_LD64; reloc_desc->insn_idx = insn_idx; reloc_desc->ext_idx = i; return 0; } /* sub-program call relocation */ if (is_call_insn(insn)) { if (insn->src_reg != BPF_PSEUDO_CALL) { pr_warn("prog '%s': incorrect bpf_call opcode\n", prog->name); return -LIBBPF_ERRNO__RELOC; } /* text_shndx can be 0, if no default "main" program exists */ if (!shdr_idx || shdr_idx != obj->efile.text_shndx) { sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx)); pr_warn("prog '%s': bad call relo against '%s' in section '%s'\n", prog->name, sym_name, sym_sec_name); return -LIBBPF_ERRNO__RELOC; } if (sym->st_value % BPF_INSN_SZ) { pr_warn("prog '%s': bad call relo against '%s' at offset %zu\n", prog->name, sym_name, (size_t)sym->st_value); return -LIBBPF_ERRNO__RELOC; } reloc_desc->type = RELO_CALL; reloc_desc->insn_idx = insn_idx; reloc_desc->sym_off = sym->st_value; return 0; } if (!shdr_idx || shdr_idx >= SHN_LORESERVE) { pr_warn("prog '%s': invalid relo against '%s' in special section 0x%x; forgot to initialize global var?..\n", prog->name, sym_name, shdr_idx); return -LIBBPF_ERRNO__RELOC; } /* loading subprog addresses */ if (sym_is_subprog(sym, obj->efile.text_shndx)) { /* global_func: sym->st_value = offset in the section, insn->imm = 0. * local_func: sym->st_value = 0, insn->imm = offset in the section. */ if ((sym->st_value % BPF_INSN_SZ) || (insn->imm % BPF_INSN_SZ)) { pr_warn("prog '%s': bad subprog addr relo against '%s' at offset %zu+%d\n", prog->name, sym_name, (size_t)sym->st_value, insn->imm); return -LIBBPF_ERRNO__RELOC; } reloc_desc->type = RELO_SUBPROG_ADDR; reloc_desc->insn_idx = insn_idx; reloc_desc->sym_off = sym->st_value; return 0; } type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx); sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx)); /* generic map reference relocation */ if (type == LIBBPF_MAP_UNSPEC) { if (!bpf_object__shndx_is_maps(obj, shdr_idx)) { pr_warn("prog '%s': bad map relo against '%s' in section '%s'\n", prog->name, sym_name, sym_sec_name); return -LIBBPF_ERRNO__RELOC; } for (map_idx = 0; map_idx < nr_maps; map_idx++) { map = &obj->maps[map_idx]; if (map->libbpf_type != type || map->sec_idx != sym->st_shndx || map->sec_offset != sym->st_value) continue; pr_debug("prog '%s': found map %zd (%s, sec %d, off %zu) for insn #%u\n", prog->name, map_idx, map->name, map->sec_idx, map->sec_offset, insn_idx); break; } if (map_idx >= nr_maps) { pr_warn("prog '%s': map relo failed to find map for section '%s', off %zu\n", prog->name, sym_sec_name, (size_t)sym->st_value); return -LIBBPF_ERRNO__RELOC; } reloc_desc->type = RELO_LD64; reloc_desc->insn_idx = insn_idx; reloc_desc->map_idx = map_idx; reloc_desc->sym_off = 0; /* sym->st_value determines map_idx */ return 0; } /* global data map relocation */ if (!bpf_object__shndx_is_data(obj, shdr_idx)) { pr_warn("prog '%s': bad data relo against section '%s'\n", prog->name, sym_sec_name); return -LIBBPF_ERRNO__RELOC; } for (map_idx = 0; map_idx < nr_maps; map_idx++) { map = &obj->maps[map_idx]; if (map->libbpf_type != type || map->sec_idx != sym->st_shndx) continue; pr_debug("prog '%s': found data map %zd (%s, sec %d, off %zu) for insn %u\n", prog->name, map_idx, map->name, map->sec_idx, map->sec_offset, insn_idx); break; } if (map_idx >= nr_maps) { pr_warn("prog '%s': data relo failed to find map for section '%s'\n", prog->name, sym_sec_name); return -LIBBPF_ERRNO__RELOC; } reloc_desc->type = RELO_DATA; reloc_desc->insn_idx = insn_idx; reloc_desc->map_idx = map_idx; reloc_desc->sym_off = sym->st_value; return 0; } static bool prog_contains_insn(const struct bpf_program *prog, size_t insn_idx) { return insn_idx >= prog->sec_insn_off && insn_idx < prog->sec_insn_off + prog->sec_insn_cnt; } static struct bpf_program *find_prog_by_sec_insn(const struct bpf_object *obj, size_t sec_idx, size_t insn_idx) { int l = 0, r = obj->nr_programs - 1, m; struct bpf_program *prog; if (!obj->nr_programs) return NULL; while (l < r) { m = l + (r - l + 1) / 2; prog = &obj->programs[m]; if (prog->sec_idx < sec_idx || (prog->sec_idx == sec_idx && prog->sec_insn_off <= insn_idx)) l = m; else r = m - 1; } /* matching program could be at index l, but it still might be the * wrong one, so we need to double check conditions for the last time */ prog = &obj->programs[l]; if (prog->sec_idx == sec_idx && prog_contains_insn(prog, insn_idx)) return prog; return NULL; } static int bpf_object__collect_prog_relos(struct bpf_object *obj, Elf64_Shdr *shdr, Elf_Data *data) { const char *relo_sec_name, *sec_name; size_t sec_idx = shdr->sh_info, sym_idx; struct bpf_program *prog; struct reloc_desc *relos; int err, i, nrels; const char *sym_name; __u32 insn_idx; Elf_Scn *scn; Elf_Data *scn_data; Elf64_Sym *sym; Elf64_Rel *rel; if (sec_idx >= obj->efile.sec_cnt) return -EINVAL; scn = elf_sec_by_idx(obj, sec_idx); scn_data = elf_sec_data(obj, scn); relo_sec_name = elf_sec_str(obj, shdr->sh_name); sec_name = elf_sec_name(obj, scn); if (!relo_sec_name || !sec_name) return -EINVAL; pr_debug("sec '%s': collecting relocation for section(%zu) '%s'\n", relo_sec_name, sec_idx, sec_name); nrels = shdr->sh_size / shdr->sh_entsize; for (i = 0; i < nrels; i++) { rel = elf_rel_by_idx(data, i); if (!rel) { pr_warn("sec '%s': failed to get relo #%d\n", relo_sec_name, i); return -LIBBPF_ERRNO__FORMAT; } sym_idx = ELF64_R_SYM(rel->r_info); sym = elf_sym_by_idx(obj, sym_idx); if (!sym) { pr_warn("sec '%s': symbol #%zu not found for relo #%d\n", relo_sec_name, sym_idx, i); return -LIBBPF_ERRNO__FORMAT; } if (sym->st_shndx >= obj->efile.sec_cnt) { pr_warn("sec '%s': corrupted symbol #%zu pointing to invalid section #%zu for relo #%d\n", relo_sec_name, sym_idx, (size_t)sym->st_shndx, i); return -LIBBPF_ERRNO__FORMAT; } if (rel->r_offset % BPF_INSN_SZ || rel->r_offset >= scn_data->d_size) { pr_warn("sec '%s': invalid offset 0x%zx for relo #%d\n", relo_sec_name, (size_t)rel->r_offset, i); return -LIBBPF_ERRNO__FORMAT; } insn_idx = rel->r_offset / BPF_INSN_SZ; /* relocations against static functions are recorded as * relocations against the section that contains a function; * in such case, symbol will be STT_SECTION and sym.st_name * will point to empty string (0), so fetch section name * instead */ if (ELF64_ST_TYPE(sym->st_info) == STT_SECTION && sym->st_name == 0) sym_name = elf_sec_name(obj, elf_sec_by_idx(obj, sym->st_shndx)); else sym_name = elf_sym_str(obj, sym->st_name); sym_name = sym_name ?: "<?"; pr_debug("sec '%s': relo #%d: insn #%u against '%s'\n", relo_sec_name, i, insn_idx, sym_name); prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx); if (!prog) { pr_debug("sec '%s': relo #%d: couldn't find program in section '%s' for insn #%u, probably overridden weak function, skipping...\n", relo_sec_name, i, sec_name, insn_idx); continue; } relos = libbpf_reallocarray(prog->reloc_desc, prog->nr_reloc + 1, sizeof(*relos)); if (!relos) return -ENOMEM; prog->reloc_desc = relos; /* adjust insn_idx to local BPF program frame of reference */ insn_idx -= prog->sec_insn_off; err = bpf_program__record_reloc(prog, &relos[prog->nr_reloc], insn_idx, sym_name, sym, rel); if (err) return err; prog->nr_reloc++; } return 0; } static int map_fill_btf_type_info(struct bpf_object *obj, struct bpf_map *map) { int id; if (!obj->btf) return -ENOENT; /* if it's BTF-defined map, we don't need to search for type IDs. * For struct_ops map, it does not need btf_key_type_id and * btf_value_type_id. */ if (map->sec_idx == obj->efile.btf_maps_shndx || bpf_map__is_struct_ops(map)) return 0; /* * LLVM annotates global data differently in BTF, that is, * only as '.data', '.bss' or '.rodata'. */ if (!bpf_map__is_internal(map)) return -ENOENT; id = btf__find_by_name(obj->btf, map->real_name); if (id < 0) return id; map->btf_key_type_id = 0; map->btf_value_type_id = id; return 0; } static int bpf_get_map_info_from_fdinfo(int fd, struct bpf_map_info *info) { char file[PATH_MAX], buff[4096]; FILE *fp; __u32 val; int err; snprintf(file, sizeof(file), "/proc/%d/fdinfo/%d", getpid(), fd); memset(info, 0, sizeof(*info)); fp = fopen(file, "re"); if (!fp) { err = -errno; pr_warn("failed to open %s: %d. No procfs support?\n", file, err); return err; } while (fgets(buff, sizeof(buff), fp)) { if (sscanf(buff, "map_type:\t%u", &val) == 1) info->type = val; else if (sscanf(buff, "key_size:\t%u", &val) == 1) info->key_size = val; else if (sscanf(buff, "value_size:\t%u", &val) == 1) info->value_size = val; else if (sscanf(buff, "max_entries:\t%u", &val) == 1) info->max_entries = val; else if (sscanf(buff, "map_flags:\t%i", &val) == 1) info->map_flags = val; } fclose(fp); return 0; } bool bpf_map__autocreate(const struct bpf_map *map) { return map->autocreate; } int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate) { if (map->obj->loaded) return libbpf_err(-EBUSY); map->autocreate = autocreate; return 0; } int bpf_map__reuse_fd(struct bpf_map *map, int fd) { struct bpf_map_info info; __u32 len = sizeof(info), name_len; int new_fd, err; char *new_name; memset(&info, 0, len); err = bpf_map_get_info_by_fd(fd, &info, &len); if (err && errno == EINVAL) err = bpf_get_map_info_from_fdinfo(fd, &info); if (err) return libbpf_err(err); name_len = strlen(info.name); if (name_len == BPF_OBJ_NAME_LEN - 1 && strncmp(map->name, info.name, name_len) == 0) new_name = strdup(map->name); else new_name = strdup(info.name); if (!new_name) return libbpf_err(-errno); /* * Like dup(), but make sure new FD is >= 3 and has O_CLOEXEC set. * This is similar to what we do in ensure_good_fd(), but without * closing original FD. */ new_fd = fcntl(fd, F_DUPFD_CLOEXEC, 3); if (new_fd < 0) { err = -errno; goto err_free_new_name; } err = zclose(map->fd); if (err) { err = -errno; goto err_close_new_fd; } free(map->name); map->fd = new_fd; map->name = new_name; map->def.type = info.type; map->def.key_size = info.key_size; map->def.value_size = info.value_size; map->def.max_entries = info.max_entries; map->def.map_flags = info.map_flags; map->btf_key_type_id = info.btf_key_type_id; map->btf_value_type_id = info.btf_value_type_id; map->reused = true; map->map_extra = info.map_extra; return 0; err_close_new_fd: close(new_fd); err_free_new_name: free(new_name); return libbpf_err(err); } __u32 bpf_map__max_entries(const struct bpf_map *map) { return map->def.max_entries; } struct bpf_map *bpf_map__inner_map(struct bpf_map *map) { if (!bpf_map_type__is_map_in_map(map->def.type)) return errno = EINVAL, NULL; return map->inner_map; } int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries) { if (map->obj->loaded) return libbpf_err(-EBUSY); map->def.max_entries = max_entries; /* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */ if (map_is_ringbuf(map)) map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries); return 0; } static int bpf_object__probe_loading(struct bpf_object *obj) { char *cp, errmsg[STRERR_BUFSIZE]; struct bpf_insn insns[] = { BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }; int ret, insn_cnt = ARRAY_SIZE(insns); if (obj->gen_loader) return 0; ret = bump_rlimit_memlock(); if (ret) pr_warn("Failed to bump RLIMIT_MEMLOCK (err = %d), you might need to do it explicitly!\n", ret); /* make sure basic loading works */ ret = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, NULL); if (ret < 0) ret = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, NULL); if (ret < 0) { ret = errno; cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg)); pr_warn("Error in %s():%s(%d). Couldn't load trivial BPF " "program. Make sure your kernel supports BPF " "(CONFIG_BPF_SYSCALL=y) and/or that RLIMIT_MEMLOCK is " "set to big enough value.\n", __func__, cp, ret); return -ret; } close(ret); return 0; } static int probe_fd(int fd) { if (fd >= 0) close(fd); return fd >= 0; } static int probe_kern_prog_name(void) { const size_t attr_sz = offsetofend(union bpf_attr, prog_name); struct bpf_insn insns[] = { BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }; union bpf_attr attr; int ret; memset(&attr, 0, attr_sz); attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER; attr.license = ptr_to_u64("GPL"); attr.insns = ptr_to_u64(insns); attr.insn_cnt = (__u32)ARRAY_SIZE(insns); libbpf_strlcpy(attr.prog_name, "libbpf_nametest", sizeof(attr.prog_name)); /* make sure loading with name works */ ret = sys_bpf_prog_load(&attr, attr_sz, PROG_LOAD_ATTEMPTS); return probe_fd(ret); } static int probe_kern_global_data(void) { char *cp, errmsg[STRERR_BUFSIZE]; struct bpf_insn insns[] = { BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16), BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42), BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }; int ret, map, insn_cnt = ARRAY_SIZE(insns); map = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_global", sizeof(int), 32, 1, NULL); if (map < 0) { ret = -errno; cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg)); pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n", __func__, cp, -ret); return ret; } insns[0].imm = map; ret = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, NULL); close(map); return probe_fd(ret); } static int probe_kern_btf(void) { static const char strs[] = "\0int"; __u32 types[] = { /* int */ BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), }; return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs))); } static int probe_kern_btf_func(void) { static const char strs[] = "\0int\0x\0a"; /* void x(int a) {} */ __u32 types[] = { /* int */ BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ /* FUNC_PROTO */ /* [2] */ BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0), BTF_PARAM_ENC(7, 1), /* FUNC x */ /* [3] */ BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2), }; return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs))); } static int probe_kern_btf_func_global(void) { static const char strs[] = "\0int\0x\0a"; /* static void x(int a) {} */ __u32 types[] = { /* int */ BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ /* FUNC_PROTO */ /* [2] */ BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0), BTF_PARAM_ENC(7, 1), /* FUNC x BTF_FUNC_GLOBAL */ /* [3] */ BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 2), }; return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs))); } static int probe_kern_btf_datasec(void) { static const char strs[] = "\0x\0.data"; /* static int a; */ __u32 types[] = { /* int */ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ /* VAR x */ /* [2] */ BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1), BTF_VAR_STATIC, /* DATASEC val */ /* [3] */ BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4), BTF_VAR_SECINFO_ENC(2, 0, 4), }; return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs))); } static int probe_kern_btf_float(void) { static const char strs[] = "\0float"; __u32 types[] = { /* float */ BTF_TYPE_FLOAT_ENC(1, 4), }; return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs))); } static int probe_kern_btf_decl_tag(void) { static const char strs[] = "\0tag"; __u32 types[] = { /* int */ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ /* VAR x */ /* [2] */ BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1), BTF_VAR_STATIC, /* attr */ BTF_TYPE_DECL_TAG_ENC(1, 2, -1), }; return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs))); } static int probe_kern_btf_type_tag(void) { static const char strs[] = "\0tag"; __u32 types[] = { /* int */ BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ /* attr */ BTF_TYPE_TYPE_TAG_ENC(1, 1), /* [2] */ /* ptr */ BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_PTR, 0, 0), 2), /* [3] */ }; return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs))); } static int probe_kern_array_mmap(void) { LIBBPF_OPTS(bpf_map_create_opts, opts, .map_flags = BPF_F_MMAPABLE); int fd; fd = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_mmap", sizeof(int), sizeof(int), 1, &opts); return probe_fd(fd); } static int probe_kern_exp_attach_type(void) { LIBBPF_OPTS(bpf_prog_load_opts, opts, .expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE); struct bpf_insn insns[] = { BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }; int fd, insn_cnt = ARRAY_SIZE(insns); /* use any valid combination of program type and (optional) * non-zero expected attach type (i.e., not a BPF_CGROUP_INET_INGRESS) * to see if kernel supports expected_attach_type field for * BPF_PROG_LOAD command */ fd = bpf_prog_load(BPF_PROG_TYPE_CGROUP_SOCK, NULL, "GPL", insns, insn_cnt, &opts); return probe_fd(fd); } static int probe_kern_probe_read_kernel(void) { struct bpf_insn insns[] = { BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), /* r1 = r10 (fp) */ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), /* r1 += -8 */ BPF_MOV64_IMM(BPF_REG_2, 8), /* r2 = 8 */ BPF_MOV64_IMM(BPF_REG_3, 0), /* r3 = 0 */ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_probe_read_kernel), BPF_EXIT_INSN(), }; int fd, insn_cnt = ARRAY_SIZE(insns); fd = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, NULL); return probe_fd(fd); } static int probe_prog_bind_map(void) { char *cp, errmsg[STRERR_BUFSIZE]; struct bpf_insn insns[] = { BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }; int ret, map, prog, insn_cnt = ARRAY_SIZE(insns); map = bpf_map_create(BPF_MAP_TYPE_ARRAY, "libbpf_det_bind", sizeof(int), 32, 1, NULL); if (map < 0) { ret = -errno; cp = libbpf_strerror_r(ret, errmsg, sizeof(errmsg)); pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n", __func__, cp, -ret); return ret; } prog = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", insns, insn_cnt, NULL); if (prog < 0) { close(map); return 0; } ret = bpf_prog_bind_map(prog, map, NULL); close(map); close(prog); return ret >= 0; } static int probe_module_btf(void) { static const char strs[] = "\0int"; __u32 types[] = { /* int */ BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), }; struct bpf_btf_info info; __u32 len = sizeof(info); char name[16]; int fd, err; fd = libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs)); if (fd < 0) return 0; /* BTF not supported at all */ memset(&info, 0, sizeof(info)); info.name = ptr_to_u64(name); info.name_len = sizeof(name); /* check that BPF_OBJ_GET_INFO_BY_FD supports specifying name pointer; * kernel's module BTF support coincides with support for * name/name_len fields in struct bpf_btf_info. */ err = bpf_btf_get_info_by_fd(fd, &info, &len); close(fd); return !err; } static int probe_perf_link(void) { struct bpf_insn insns[] = { BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }; int prog_fd, link_fd, err; prog_fd = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, ARRAY_SIZE(insns), NULL); if (prog_fd < 0) return -errno; /* use invalid perf_event FD to get EBADF, if link is supported; * otherwise EINVAL should be returned */ link_fd = bpf_link_create(prog_fd, -1, BPF_PERF_EVENT, NULL); err = -errno; /* close() can clobber errno */ if (link_fd >= 0) close(link_fd); close(prog_fd); return link_fd < 0 && err == -EBADF; } static int probe_uprobe_multi_link(void) { LIBBPF_OPTS(bpf_prog_load_opts, load_opts, .expected_attach_type = BPF_TRACE_UPROBE_MULTI, ); LIBBPF_OPTS(bpf_link_create_opts, link_opts); struct bpf_insn insns[] = { BPF_MOV64_IMM(BPF_REG_0, 0), BPF_EXIT_INSN(), }; int prog_fd, link_fd, err; unsigned long offset = 0; prog_fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, "GPL", insns, ARRAY_SIZE(insns), &load_opts); if (prog_fd < 0) return -errno; /* Creating uprobe in '/' binary should fail with -EBADF. */ link_opts.uprobe_multi.path = "/"; link_opts.uprobe_multi.offsets = &offset; link_opts.uprobe_multi.cnt = 1; link_fd = bpf_link_create(prog_fd, -1, BPF_TRACE_UPROBE_MULTI, &link_opts); err = -errno; /* close() can clobber errno */ if (link_fd >= 0) close(link_fd); close(prog_fd); return link_fd < 0 && err == -EBADF; } static int probe_kern_bpf_cookie(void) { struct bpf_insn insns[] = { BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_attach_cookie), BPF_EXIT_INSN(), }; int ret, insn_cnt = ARRAY_SIZE(insns); ret = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, "GPL", insns, insn_cnt, NULL); return probe_fd(ret); } static int probe_kern_btf_enum64(void) { static const char strs[] = "\0enum64"; __u32 types[] = { BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_ENUM64, 0, 0), 8), }; return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types), strs, sizeof(strs))); } static int probe_kern_syscall_wrapper(void); enum kern_feature_result { FEAT_UNKNOWN = 0, FEAT_SUPPORTED = 1, FEAT_MISSING = 2, }; typedef int (*feature_probe_fn)(void); static struct kern_feature_desc { const char *desc; feature_probe_fn probe; enum kern_feature_result res; } feature_probes[__FEAT_CNT] = { [FEAT_PROG_NAME] = { "BPF program name", probe_kern_prog_name, }, [FEAT_GLOBAL_DATA] = { "global variables", probe_kern_global_data, }, [FEAT_BTF] = { "minimal BTF", probe_kern_btf, }, [FEAT_BTF_FUNC] = { "BTF functions", probe_kern_btf_func, }, [FEAT_BTF_GLOBAL_FUNC] = { "BTF global function", probe_kern_btf_func_global, }, [FEAT_BTF_DATASEC] = { "BTF data section and variable", probe_kern_btf_datasec, }, [FEAT_ARRAY_MMAP] = { "ARRAY map mmap()", probe_kern_array_mmap, }, [FEAT_EXP_ATTACH_TYPE] = { "BPF_PROG_LOAD expected_attach_type attribute", probe_kern_exp_attach_type, }, [FEAT_PROBE_READ_KERN] = { "bpf_probe_read_kernel() helper", probe_kern_probe_read_kernel, }, [FEAT_PROG_BIND_MAP] = { "BPF_PROG_BIND_MAP support", probe_prog_bind_map, }, [FEAT_MODULE_BTF] = { "module BTF support", probe_module_btf, }, [FEAT_BTF_FLOAT] = { "BTF_KIND_FLOAT support", probe_kern_btf_float, }, [FEAT_PERF_LINK] = { "BPF perf link support", probe_perf_link, }, [FEAT_BTF_DECL_TAG] = { "BTF_KIND_DECL_TAG support", probe_kern_btf_decl_tag, }, [FEAT_BTF_TYPE_TAG] = { "BTF_KIND_TYPE_TAG support", probe_kern_btf_type_tag, }, [FEAT_MEMCG_ACCOUNT] = { "memcg-based memory accounting", probe_memcg_account, }, [FEAT_BPF_COOKIE] = { "BPF cookie support", probe_kern_bpf_cookie, }, [FEAT_BTF_ENUM64] = { "BTF_KIND_ENUM64 support", probe_kern_btf_enum64, }, [FEAT_SYSCALL_WRAPPER] = { "Kernel using syscall wrapper", probe_kern_syscall_wrapper, }, [FEAT_UPROBE_MULTI_LINK] = { "BPF multi-uprobe link support", probe_uprobe_multi_link, }, }; bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id) { struct kern_feature_desc *feat = &feature_probes[feat_id]; int ret; if (obj && obj->gen_loader) /* To generate loader program assume the latest kernel * to avoid doing extra prog_load, map_create syscalls. */ return true; if (READ_ONCE(feat->res) == FEAT_UNKNOWN) { ret = feat->probe(); if (ret > 0) { WRITE_ONCE(feat->res, FEAT_SUPPORTED); } else if (ret == 0) { WRITE_ONCE(feat->res, FEAT_MISSING); } else { pr_warn("Detection of kernel %s support failed: %d\n", feat->desc, ret); WRITE_ONCE(feat->res, FEAT_MISSING); } } return READ_ONCE(feat->res) == FEAT_SUPPORTED; } static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd) { struct bpf_map_info map_info; char msg[STRERR_BUFSIZE]; __u32 map_info_len = sizeof(map_info); int err; memset(&map_info, 0, map_info_len); err = bpf_map_get_info_by_fd(map_fd, &map_info, &map_info_len); if (err && errno == EINVAL) err = bpf_get_map_info_from_fdinfo(map_fd, &map_info); if (err) { pr_warn("failed to get map info for map FD %d: %s\n", map_fd, libbpf_strerror_r(errno, msg, sizeof(msg))); return false; } return (map_info.type == map->def.type && map_info.key_size == map->def.key_size && map_info.value_size == map->def.value_size && map_info.max_entries == map->def.max_entries && map_info.map_flags == map->def.map_flags && map_info.map_extra == map->map_extra); } static int bpf_object__reuse_map(struct bpf_map *map) { char *cp, errmsg[STRERR_BUFSIZE]; int err, pin_fd; pin_fd = bpf_obj_get(map->pin_path); if (pin_fd < 0) { err = -errno; if (err == -ENOENT) { pr_debug("found no pinned map to reuse at '%s'\n", map->pin_path); return 0; } cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); pr_warn("couldn't retrieve pinned map '%s': %s\n", map->pin_path, cp); return err; } if (!map_is_reuse_compat(map, pin_fd)) { pr_warn("couldn't reuse pinned map at '%s': parameter mismatch\n", map->pin_path); close(pin_fd); return -EINVAL; } err = bpf_map__reuse_fd(map, pin_fd); close(pin_fd); if (err) return err; map->pinned = true; pr_debug("reused pinned map at '%s'\n", map->pin_path); return 0; } static int bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map) { enum libbpf_map_type map_type = map->libbpf_type; char *cp, errmsg[STRERR_BUFSIZE]; int err, zero = 0; if (obj->gen_loader) { bpf_gen__map_update_elem(obj->gen_loader, map - obj->maps, map->mmaped, map->def.value_size); if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG) bpf_gen__map_freeze(obj->gen_loader, map - obj->maps); return 0; } err = bpf_map_update_elem(map->fd, &zero, map->mmaped, 0); if (err) { err = -errno; cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); pr_warn("Error setting initial map(%s) contents: %s\n", map->name, cp); return err; } /* Freeze .rodata and .kconfig map as read-only from syscall side. */ if (map_type == LIBBPF_MAP_RODATA || map_type == LIBBPF_MAP_KCONFIG) { err = bpf_map_freeze(map->fd); if (err) { err = -errno; cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); pr_warn("Error freezing map(%s) as read-only: %s\n", map->name, cp); return err; } } return 0; } static void bpf_map__destroy(struct bpf_map *map); static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, bool is_inner) { LIBBPF_OPTS(bpf_map_create_opts, create_attr); struct bpf_map_def *def = &map->def; const char *map_name = NULL; int err = 0; if (kernel_supports(obj, FEAT_PROG_NAME)) map_name = map->name; create_attr.map_ifindex = map->map_ifindex; create_attr.map_flags = def->map_flags; create_attr.numa_node = map->numa_node; create_attr.map_extra = map->map_extra; if (bpf_map__is_struct_ops(map)) create_attr.btf_vmlinux_value_type_id = map->btf_vmlinux_value_type_id; if (obj->btf && btf__fd(obj->btf) >= 0) { create_attr.btf_fd = btf__fd(obj->btf); create_attr.btf_key_type_id = map->btf_key_type_id; create_attr.btf_value_type_id = map->btf_value_type_id; } if (bpf_map_type__is_map_in_map(def->type)) { if (map->inner_map) { err = bpf_object__create_map(obj, map->inner_map, true); if (err) { pr_warn("map '%s': failed to create inner map: %d\n", map->name, err); return err; } map->inner_map_fd = bpf_map__fd(map->inner_map); } if (map->inner_map_fd >= 0) create_attr.inner_map_fd = map->inner_map_fd; } switch (def->type) { case BPF_MAP_TYPE_PERF_EVENT_ARRAY: case BPF_MAP_TYPE_CGROUP_ARRAY: case BPF_MAP_TYPE_STACK_TRACE: case BPF_MAP_TYPE_ARRAY_OF_MAPS: case BPF_MAP_TYPE_HASH_OF_MAPS: case BPF_MAP_TYPE_DEVMAP: case BPF_MAP_TYPE_DEVMAP_HASH: case BPF_MAP_TYPE_CPUMAP: case BPF_MAP_TYPE_XSKMAP: case BPF_MAP_TYPE_SOCKMAP: case BPF_MAP_TYPE_SOCKHASH: case BPF_MAP_TYPE_QUEUE: case BPF_MAP_TYPE_STACK: create_attr.btf_fd = 0; create_attr.btf_key_type_id = 0; create_attr.btf_value_type_id = 0; map->btf_key_type_id = 0; map->btf_value_type_id = 0; default: break; } if (obj->gen_loader) { bpf_gen__map_create(obj->gen_loader, def->type, map_name, def->key_size, def->value_size, def->max_entries, &create_attr, is_inner ? -1 : map - obj->maps); /* Pretend to have valid FD to pass various fd >= 0 checks. * This fd == 0 will not be used with any syscall and will be reset to -1 eventually. */ map->fd = 0; } else { map->fd = bpf_map_create(def->type, map_name, def->key_size, def->value_size, def->max_entries, &create_attr); } if (map->fd < 0 && (create_attr.btf_key_type_id || create_attr.btf_value_type_id)) { char *cp, errmsg[STRERR_BUFSIZE]; err = -errno; cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n", map->name, cp, err); create_attr.btf_fd = 0; create_attr.btf_key_type_id = 0; create_attr.btf_value_type_id = 0; map->btf_key_type_id = 0; map->btf_value_type_id = 0; map->fd = bpf_map_create(def->type, map_name, def->key_size, def->value_size, def->max_entries, &create_attr); } err = map->fd < 0 ? -errno : 0; if (bpf_map_type__is_map_in_map(def->type) && map->inner_map) { if (obj->gen_loader) map->inner_map->fd = -1; bpf_map__destroy(map->inner_map); zfree(&map->inner_map); } return err; } static int init_map_in_map_slots(struct bpf_object *obj, struct bpf_map *map) { const struct bpf_map *targ_map; unsigned int i; int fd, err = 0; for (i = 0; i < map->init_slots_sz; i++) { if (!map->init_slots[i]) continue; targ_map = map->init_slots[i]; fd = bpf_map__fd(targ_map); if (obj->gen_loader) { bpf_gen__populate_outer_map(obj->gen_loader, map - obj->maps, i, targ_map - obj->maps); } else { err = bpf_map_update_elem(map->fd, &i, &fd, 0); } if (err) { err = -errno; pr_warn("map '%s': failed to initialize slot [%d] to map '%s' fd=%d: %d\n", map->name, i, targ_map->name, fd, err); return err; } pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n", map->name, i, targ_map->name, fd); } zfree(&map->init_slots); map->init_slots_sz = 0; return 0; } static int init_prog_array_slots(struct bpf_object *obj, struct bpf_map *map) { const struct bpf_program *targ_prog; unsigned int i; int fd, err; if (obj->gen_loader) return -ENOTSUP; for (i = 0; i < map->init_slots_sz; i++) { if (!map->init_slots[i]) continue; targ_prog = map->init_slots[i]; fd = bpf_program__fd(targ_prog); err = bpf_map_update_elem(map->fd, &i, &fd, 0); if (err) { err = -errno; pr_warn("map '%s': failed to initialize slot [%d] to prog '%s' fd=%d: %d\n", map->name, i, targ_prog->name, fd, err); return err; } pr_debug("map '%s': slot [%d] set to prog '%s' fd=%d\n", map->name, i, targ_prog->name, fd); } zfree(&map->init_slots); map->init_slots_sz = 0; return 0; } static int bpf_object_init_prog_arrays(struct bpf_object *obj) { struct bpf_map *map; int i, err; for (i = 0; i < obj->nr_maps; i++) { map = &obj->maps[i]; if (!map->init_slots_sz || map->def.type != BPF_MAP_TYPE_PROG_ARRAY) continue; err = init_prog_array_slots(obj, map); if (err < 0) { zclose(map->fd); return err; } } return 0; } static int map_set_def_max_entries(struct bpf_map *map) { if (map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !map->def.max_entries) { int nr_cpus; nr_cpus = libbpf_num_possible_cpus(); if (nr_cpus < 0) { pr_warn("map '%s': failed to determine number of system CPUs: %d\n", map->name, nr_cpus); return nr_cpus; } pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus); map->def.max_entries = nr_cpus; } return 0; } static int bpf_object__create_maps(struct bpf_object *obj) { struct bpf_map *map; char *cp, errmsg[STRERR_BUFSIZE]; unsigned int i, j; int err; bool retried; for (i = 0; i < obj->nr_maps; i++) { map = &obj->maps[i]; /* To support old kernels, we skip creating global data maps * (.rodata, .data, .kconfig, etc); later on, during program * loading, if we detect that at least one of the to-be-loaded * programs is referencing any global data map, we'll error * out with program name and relocation index logged. * This approach allows to accommodate Clang emitting * unnecessary .rodata.str1.1 sections for string literals, * but also it allows to have CO-RE applications that use * global variables in some of BPF programs, but not others. * If those global variable-using programs are not loaded at * runtime due to bpf_program__set_autoload(prog, false), * bpf_object loading will succeed just fine even on old * kernels. */ if (bpf_map__is_internal(map) && !kernel_supports(obj, FEAT_GLOBAL_DATA)) map->autocreate = false; if (!map->autocreate) { pr_debug("map '%s': skipped auto-creating...\n", map->name); continue; } err = map_set_def_max_entries(map); if (err) goto err_out; retried = false; retry: if (map->pin_path) { err = bpf_object__reuse_map(map); if (err) { pr_warn("map '%s': error reusing pinned map\n", map->name); goto err_out; } if (retried && map->fd < 0) { pr_warn("map '%s': cannot find pinned map\n", map->name); err = -ENOENT; goto err_out; } } if (map->fd >= 0) { pr_debug("map '%s': skipping creation (preset fd=%d)\n", map->name, map->fd); } else { err = bpf_object__create_map(obj, map, false); if (err) goto err_out; pr_debug("map '%s': created successfully, fd=%d\n", map->name, map->fd); if (bpf_map__is_internal(map)) { err = bpf_object__populate_internal_map(obj, map); if (err < 0) { zclose(map->fd); goto err_out; } } if (map->init_slots_sz && map->def.type != BPF_MAP_TYPE_PROG_ARRAY) { err = init_map_in_map_slots(obj, map); if (err < 0) { zclose(map->fd); goto err_out; } } } if (map->pin_path && !map->pinned) { err = bpf_map__pin(map, NULL); if (err) { zclose(map->fd); if (!retried && err == -EEXIST) { retried = true; goto retry; } pr_warn("map '%s': failed to auto-pin at '%s': %d\n", map->name, map->pin_path, err); goto err_out; } } } return 0; err_out: cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); pr_warn("map '%s': failed to create: %s(%d)\n", map->name, cp, err); pr_perm_msg(err); for (j = 0; j < i; j++) zclose(obj->maps[j].fd); return err; } static bool bpf_core_is_flavor_sep(const char *s) { /* check X___Y name pattern, where X and Y are not underscores */ return s[0] != '_' && /* X */ s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */ s[4] != '_'; /* Y */ } /* Given 'some_struct_name___with_flavor' return the length of a name prefix * before last triple underscore. Struct name part after last triple * underscore is ignored by BPF CO-RE relocation during relocation matching. */ size_t bpf_core_essential_name_len(const char *name) { size_t n = strlen(name); int i; for (i = n - 5; i >= 0; i--) { if (bpf_core_is_flavor_sep(name + i)) return i + 1; } return n; } void bpf_core_free_cands(struct bpf_core_cand_list *cands) { if (!cands) return; free(cands->cands); free(cands); } int bpf_core_add_cands(struct bpf_core_cand *local_cand, size_t local_essent_len, const struct btf *targ_btf, const char *targ_btf_name, int targ_start_id, struct bpf_core_cand_list *cands) { struct bpf_core_cand *new_cands, *cand; const struct btf_type *t, *local_t; const char *targ_name, *local_name; size_t targ_essent_len; int n, i; local_t = btf__type_by_id(local_cand->btf, local_cand->id); local_name = btf__str_by_offset(local_cand->btf, local_t->name_off); n = btf__type_cnt(targ_btf); for (i = targ_start_id; i < n; i++) { t = btf__type_by_id(targ_btf, i); if (!btf_kind_core_compat(t, local_t)) continue; targ_name = btf__name_by_offset(targ_btf, t->name_off); if (str_is_empty(targ_name)) continue; targ_essent_len = bpf_core_essential_name_len(targ_name); if (targ_essent_len != local_essent_len) continue; if (strncmp(local_name, targ_name, local_essent_len) != 0) continue; pr_debug("CO-RE relocating [%d] %s %s: found target candidate [%d] %s %s in [%s]\n", local_cand->id, btf_kind_str(local_t), local_name, i, btf_kind_str(t), targ_name, targ_btf_name); new_cands = libbpf_reallocarray(cands->cands, cands->len + 1, sizeof(*cands->cands)); if (!new_cands) return -ENOMEM; cand = &new_cands[cands->len]; cand->btf = targ_btf; cand->id = i; cands->cands = new_cands; cands->len++; } return 0; } static int load_module_btfs(struct bpf_object *obj) { struct bpf_btf_info info; struct module_btf *mod_btf; struct btf *btf; char name[64]; __u32 id = 0, len; int err, fd; if (obj->btf_modules_loaded) return 0; if (obj->gen_loader) return 0; /* don't do this again, even if we find no module BTFs */ obj->btf_modules_loaded = true; /* kernel too old to support module BTFs */ if (!kernel_supports(obj, FEAT_MODULE_BTF)) return 0; while (true) { err = bpf_btf_get_next_id(id, &id); if (err && errno == ENOENT) return 0; if (err && errno == EPERM) { pr_debug("skipping module BTFs loading, missing privileges\n"); return 0; } if (err) { err = -errno; pr_warn("failed to iterate BTF objects: %d\n", err); return err; } fd = bpf_btf_get_fd_by_id(id); if (fd < 0) { if (errno == ENOENT) continue; /* expected race: BTF was unloaded */ err = -errno; pr_warn("failed to get BTF object #%d FD: %d\n", id, err); return err; } len = sizeof(info); memset(&info, 0, sizeof(info)); info.name = ptr_to_u64(name); info.name_len = sizeof(name); err = bpf_btf_get_info_by_fd(fd, &info, &len); if (err) { err = -errno; pr_warn("failed to get BTF object #%d info: %d\n", id, err); goto err_out; } /* ignore non-module BTFs */ if (!info.kernel_btf || strcmp(name, "vmlinux") == 0) { close(fd); continue; } btf = btf_get_from_fd(fd, obj->btf_vmlinux); err = libbpf_get_error(btf); if (err) { pr_warn("failed to load module [%s]'s BTF object #%d: %d\n", name, id, err); goto err_out; } err = libbpf_ensure_mem((void **)&obj->btf_modules, &obj->btf_module_cap, sizeof(*obj->btf_modules), obj->btf_module_cnt + 1); if (err) goto err_out; mod_btf = &obj->btf_modules[obj->btf_module_cnt++]; mod_btf->btf = btf; mod_btf->id = id; mod_btf->fd = fd; mod_btf->name = strdup(name); if (!mod_btf->name) { err = -ENOMEM; goto err_out; } continue; err_out: close(fd); return err; } return 0; } static struct bpf_core_cand_list * bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id) { struct bpf_core_cand local_cand = {}; struct bpf_core_cand_list *cands; const struct btf *main_btf; const struct btf_type *local_t; const char *local_name; size_t local_essent_len; int err, i; local_cand.btf = local_btf; local_cand.id = local_type_id; local_t = btf__type_by_id(local_btf, local_type_id); if (!local_t) return ERR_PTR(-EINVAL); local_name = btf__name_by_offset(local_btf, local_t->name_off); if (str_is_empty(local_name)) return ERR_PTR(-EINVAL); local_essent_len = bpf_core_essential_name_len(local_name); cands = calloc(1, sizeof(*cands)); if (!cands) return ERR_PTR(-ENOMEM); /* Attempt to find target candidates in vmlinux BTF first */ main_btf = obj->btf_vmlinux_override ?: obj->btf_vmlinux; err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf, "vmlinux", 1, cands); if (err) goto err_out; /* if vmlinux BTF has any candidate, don't got for module BTFs */ if (cands->len) return cands; /* if vmlinux BTF was overridden, don't attempt to load module BTFs */ if (obj->btf_vmlinux_override) return cands; /* now look through module BTFs, trying to still find candidates */ err = load_module_btfs(obj); if (err) goto err_out; for (i = 0; i < obj->btf_module_cnt; i++) { err = bpf_core_add_cands(&local_cand, local_essent_len, obj->btf_modules[i].btf, obj->btf_modules[i].name, btf__type_cnt(obj->btf_vmlinux), cands); if (err) goto err_out; } return cands; err_out: bpf_core_free_cands(cands); return ERR_PTR(err); } /* Check local and target types for compatibility. This check is used for * type-based CO-RE relocations and follow slightly different rules than * field-based relocations. This function assumes that root types were already * checked for name match. Beyond that initial root-level name check, names * are completely ignored. Compatibility rules are as follows: * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs are considered compatible, but * kind should match for local and target types (i.e., STRUCT is not * compatible with UNION); * - for ENUMs, the size is ignored; * - for INT, size and signedness are ignored; * - for ARRAY, dimensionality is ignored, element types are checked for * compatibility recursively; * - CONST/VOLATILE/RESTRICT modifiers are ignored; * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible; * - FUNC_PROTOs are compatible if they have compatible signature: same * number of input args and compatible return and argument types. * These rules are not set in stone and probably will be adjusted as we get * more experience with using BPF CO-RE relocations. */ int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id, const struct btf *targ_btf, __u32 targ_id) { return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id, 32); } int bpf_core_types_match(const struct btf *local_btf, __u32 local_id, const struct btf *targ_btf, __u32 targ_id) { return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false, 32); } static size_t bpf_core_hash_fn(const long key, void *ctx) { return key; } static bool bpf_core_equal_fn(const long k1, const long k2, void *ctx) { return k1 == k2; } static int record_relo_core(struct bpf_program *prog, const struct bpf_core_relo *core_relo, int insn_idx) { struct reloc_desc *relos, *relo; relos = libbpf_reallocarray(prog->reloc_desc, prog->nr_reloc + 1, sizeof(*relos)); if (!relos) return -ENOMEM; relo = &relos[prog->nr_reloc]; relo->type = RELO_CORE; relo->insn_idx = insn_idx; relo->core_relo = core_relo; prog->reloc_desc = relos; prog->nr_reloc++; return 0; } static const struct bpf_core_relo *find_relo_core(struct bpf_program *prog, int insn_idx) { struct reloc_desc *relo; int i; for (i = 0; i < prog->nr_reloc; i++) { relo = &prog->reloc_desc[i]; if (relo->type != RELO_CORE || relo->insn_idx != insn_idx) continue; return relo->core_relo; } return NULL; } static int bpf_core_resolve_relo(struct bpf_program *prog, const struct bpf_core_relo *relo, int relo_idx, const struct btf *local_btf, struct hashmap *cand_cache, struct bpf_core_relo_res *targ_res) { struct bpf_core_spec specs_scratch[3] = {}; struct bpf_core_cand_list *cands = NULL; const char *prog_name = prog->name; const struct btf_type *local_type; const char *local_name; __u32 local_id = relo->type_id; int err; local_type = btf__type_by_id(local_btf, local_id); if (!local_type) return -EINVAL; local_name = btf__name_by_offset(local_btf, local_type->name_off); if (!local_name) return -EINVAL; if (relo->kind != BPF_CORE_TYPE_ID_LOCAL && !hashmap__find(cand_cache, local_id, &cands)) { cands = bpf_core_find_cands(prog->obj, local_btf, local_id); if (IS_ERR(cands)) { pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n", prog_name, relo_idx, local_id, btf_kind_str(local_type), local_name, PTR_ERR(cands)); return PTR_ERR(cands); } err = hashmap__set(cand_cache, local_id, cands, NULL, NULL); if (err) { bpf_core_free_cands(cands); return err; } } return bpf_core_calc_relo_insn(prog_name, relo, relo_idx, local_btf, cands, specs_scratch, targ_res); } static int bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path) { const struct btf_ext_info_sec *sec; struct bpf_core_relo_res targ_res; const struct bpf_core_relo *rec; const struct btf_ext_info *seg; struct hashmap_entry *entry; struct hashmap *cand_cache = NULL; struct bpf_program *prog; struct bpf_insn *insn; const char *sec_name; int i, err = 0, insn_idx, sec_idx, sec_num; if (obj->btf_ext->core_relo_info.len == 0) return 0; if (targ_btf_path) { obj->btf_vmlinux_override = btf__parse(targ_btf_path, NULL); err = libbpf_get_error(obj->btf_vmlinux_override); if (err) { pr_warn("failed to parse target BTF: %d\n", err); return err; } } cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL); if (IS_ERR(cand_cache)) { err = PTR_ERR(cand_cache); goto out; } seg = &obj->btf_ext->core_relo_info; sec_num = 0; for_each_btf_ext_sec(seg, sec) { sec_idx = seg->sec_idxs[sec_num]; sec_num++; sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off); if (str_is_empty(sec_name)) { err = -EINVAL; goto out; } pr_debug("sec '%s': found %d CO-RE relocations\n", sec_name, sec->num_info); for_each_btf_ext_rec(seg, sec, i, rec) { if (rec->insn_off % BPF_INSN_SZ) return -EINVAL; insn_idx = rec->insn_off / BPF_INSN_SZ; prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx); if (!prog) { /* When __weak subprog is "overridden" by another instance * of the subprog from a different object file, linker still * appends all the .BTF.ext info that used to belong to that * eliminated subprogram. * This is similar to what x86-64 linker does for relocations. * So just ignore such relocations just like we ignore * subprog instructions when discovering subprograms. */ pr_debug("sec '%s': skipping CO-RE relocation #%d for insn #%d belonging to eliminated weak subprogram\n", sec_name, i, insn_idx); continue; } /* no need to apply CO-RE relocation if the program is * not going to be loaded */ if (!prog->autoload) continue; /* adjust insn_idx from section frame of reference to the local * program's frame of reference; (sub-)program code is not yet * relocated, so it's enough to just subtract in-section offset */ insn_idx = insn_idx - prog->sec_insn_off; if (insn_idx >= prog->insns_cnt) return -EINVAL; insn = &prog->insns[insn_idx]; err = record_relo_core(prog, rec, insn_idx); if (err) { pr_warn("prog '%s': relo #%d: failed to record relocation: %d\n", prog->name, i, err); goto out; } if (prog->obj->gen_loader) continue; err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res); if (err) { pr_warn("prog '%s': relo #%d: failed to relocate: %d\n", prog->name, i, err); goto out; } err = bpf_core_patch_insn(prog->name, insn, insn_idx, rec, i, &targ_res); if (err) { pr_warn("prog '%s': relo #%d: failed to patch insn #%u: %d\n", prog->name, i, insn_idx, err); goto out; } } } out: /* obj->btf_vmlinux and module BTFs are freed after object load */ btf__free(obj->btf_vmlinux_override); obj->btf_vmlinux_override = NULL; if (!IS_ERR_OR_NULL(cand_cache)) { hashmap__for_each_entry(cand_cache, entry, i) { bpf_core_free_cands(entry->pvalue); } hashmap__free(cand_cache); } return err; } /* base map load ldimm64 special constant, used also for log fixup logic */ #define POISON_LDIMM64_MAP_BASE 2001000000 #define POISON_LDIMM64_MAP_PFX "200100" static void poison_map_ldimm64(struct bpf_program *prog, int relo_idx, int insn_idx, struct bpf_insn *insn, int map_idx, const struct bpf_map *map) { int i; pr_debug("prog '%s': relo #%d: poisoning insn #%d that loads map #%d '%s'\n", prog->name, relo_idx, insn_idx, map_idx, map->name); /* we turn single ldimm64 into two identical invalid calls */ for (i = 0; i < 2; i++) { insn->code = BPF_JMP | BPF_CALL; insn->dst_reg = 0; insn->src_reg = 0; insn->off = 0; /* if this instruction is reachable (not a dead code), * verifier will complain with something like: * invalid func unknown#2001000123 * where lower 123 is map index into obj->maps[] array */ insn->imm = POISON_LDIMM64_MAP_BASE + map_idx; insn++; } } /* unresolved kfunc call special constant, used also for log fixup logic */ #define POISON_CALL_KFUNC_BASE 2002000000 #define POISON_CALL_KFUNC_PFX "2002" static void poison_kfunc_call(struct bpf_program *prog, int relo_idx, int insn_idx, struct bpf_insn *insn, int ext_idx, const struct extern_desc *ext) { pr_debug("prog '%s': relo #%d: poisoning insn #%d that calls kfunc '%s'\n", prog->name, relo_idx, insn_idx, ext->name); /* we turn kfunc call into invalid helper call with identifiable constant */ insn->code = BPF_JMP | BPF_CALL; insn->dst_reg = 0; insn->src_reg = 0; insn->off = 0; /* if this instruction is reachable (not a dead code), * verifier will complain with something like: * invalid func unknown#2001000123 * where lower 123 is extern index into obj->externs[] array */ insn->imm = POISON_CALL_KFUNC_BASE + ext_idx; } /* Relocate data references within program code: * - map references; * - global variable references; * - extern references. */ static int bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) { int i; for (i = 0; i < prog->nr_reloc; i++) { struct reloc_desc *relo = &prog->reloc_desc[i]; struct bpf_insn *insn = &prog->insns[relo->insn_idx]; const struct bpf_map *map; struct extern_desc *ext; switch (relo->type) { case RELO_LD64: map = &obj->maps[relo->map_idx]; if (obj->gen_loader) { insn[0].src_reg = BPF_PSEUDO_MAP_IDX; insn[0].imm = relo->map_idx; } else if (map->autocreate) { insn[0].src_reg = BPF_PSEUDO_MAP_FD; insn[0].imm = map->fd; } else { poison_map_ldimm64(prog, i, relo->insn_idx, insn, relo->map_idx, map); } break; case RELO_DATA: map = &obj->maps[relo->map_idx]; insn[1].imm = insn[0].imm + relo->sym_off; if (obj->gen_loader) { insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE; insn[0].imm = relo->map_idx; } else if (map->autocreate) { insn[0].src_reg = BPF_PSEUDO_MAP_VALUE; insn[0].imm = map->fd; } else { poison_map_ldimm64(prog, i, relo->insn_idx, insn, relo->map_idx, map); } break; case RELO_EXTERN_LD64: ext = &obj->externs[relo->ext_idx]; if (ext->type == EXT_KCFG) { if (obj->gen_loader) { insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE; insn[0].imm = obj->kconfig_map_idx; } else { insn[0].src_reg = BPF_PSEUDO_MAP_VALUE; insn[0].imm = obj->maps[obj->kconfig_map_idx].fd; } insn[1].imm = ext->kcfg.data_off; } else /* EXT_KSYM */ { if (ext->ksym.type_id && ext->is_set) { /* typed ksyms */ insn[0].src_reg = BPF_PSEUDO_BTF_ID; insn[0].imm = ext->ksym.kernel_btf_id; insn[1].imm = ext->ksym.kernel_btf_obj_fd; } else { /* typeless ksyms or unresolved typed ksyms */ insn[0].imm = (__u32)ext->ksym.addr; insn[1].imm = ext->ksym.addr >> 32; } } break; case RELO_EXTERN_CALL: ext = &obj->externs[relo->ext_idx]; insn[0].src_reg = BPF_PSEUDO_KFUNC_CALL; if (ext->is_set) { insn[0].imm = ext->ksym.kernel_btf_id; insn[0].off = ext->ksym.btf_fd_idx; } else { /* unresolved weak kfunc call */ poison_kfunc_call(prog, i, relo->insn_idx, insn, relo->ext_idx, ext); } break; case RELO_SUBPROG_ADDR: if (insn[0].src_reg != BPF_PSEUDO_FUNC) { pr_warn("prog '%s': relo #%d: bad insn\n", prog->name, i); return -EINVAL; } /* handled already */ break; case RELO_CALL: /* handled already */ break; case RELO_CORE: /* will be handled by bpf_program_record_relos() */ break; default: pr_warn("prog '%s': relo #%d: bad relo type %d\n", prog->name, i, relo->type); return -EINVAL; } } return 0; } static int adjust_prog_btf_ext_info(const struct bpf_object *obj, const struct bpf_program *prog, const struct btf_ext_info *ext_info, void **prog_info, __u32 *prog_rec_cnt, __u32 *prog_rec_sz) { void *copy_start = NULL, *copy_end = NULL; void *rec, *rec_end, *new_prog_info; const struct btf_ext_info_sec *sec; size_t old_sz, new_sz; int i, sec_num, sec_idx, off_adj; sec_num = 0; for_each_btf_ext_sec(ext_info, sec) { sec_idx = ext_info->sec_idxs[sec_num]; sec_num++; if (prog->sec_idx != sec_idx) continue; for_each_btf_ext_rec(ext_info, sec, i, rec) { __u32 insn_off = *(__u32 *)rec / BPF_INSN_SZ; if (insn_off < prog->sec_insn_off) continue; if (insn_off >= prog->sec_insn_off + prog->sec_insn_cnt) break; if (!copy_start) copy_start = rec; copy_end = rec + ext_info->rec_size; } if (!copy_start) return -ENOENT; /* append func/line info of a given (sub-)program to the main * program func/line info */ old_sz = (size_t)(*prog_rec_cnt) * ext_info->rec_size; new_sz = old_sz + (copy_end - copy_start); new_prog_info = realloc(*prog_info, new_sz); if (!new_prog_info) return -ENOMEM; *prog_info = new_prog_info; *prog_rec_cnt = new_sz / ext_info->rec_size; memcpy(new_prog_info + old_sz, copy_start, copy_end - copy_start); /* Kernel instruction offsets are in units of 8-byte * instructions, while .BTF.ext instruction offsets generated * by Clang are in units of bytes. So convert Clang offsets * into kernel offsets and adjust offset according to program * relocated position. */ off_adj = prog->sub_insn_off - prog->sec_insn_off; rec = new_prog_info + old_sz; rec_end = new_prog_info + new_sz; for (; rec < rec_end; rec += ext_info->rec_size) { __u32 *insn_off = rec; *insn_off = *insn_off / BPF_INSN_SZ + off_adj; } *prog_rec_sz = ext_info->rec_size; return 0; } return -ENOENT; } static int reloc_prog_func_and_line_info(const struct bpf_object *obj, struct bpf_program *main_prog, const struct bpf_program *prog) { int err; /* no .BTF.ext relocation if .BTF.ext is missing or kernel doesn't * supprot func/line info */ if (!obj->btf_ext || !kernel_supports(obj, FEAT_BTF_FUNC)) return 0; /* only attempt func info relocation if main program's func_info * relocation was successful */ if (main_prog != prog && !main_prog->func_info) goto line_info; err = adjust_prog_btf_ext_info(obj, prog, &obj->btf_ext->func_info, &main_prog->func_info, &main_prog->func_info_cnt, &main_prog->func_info_rec_size); if (err) { if (err != -ENOENT) { pr_warn("prog '%s': error relocating .BTF.ext function info: %d\n", prog->name, err); return err; } if (main_prog->func_info) { /* * Some info has already been found but has problem * in the last btf_ext reloc. Must have to error out. */ pr_warn("prog '%s': missing .BTF.ext function info.\n", prog->name); return err; } /* Have problem loading the very first info. Ignore the rest. */ pr_warn("prog '%s': missing .BTF.ext function info for the main program, skipping all of .BTF.ext func info.\n", prog->name); } line_info: /* don't relocate line info if main program's relocation failed */ if (main_prog != prog && !main_prog->line_info) return 0; err = adjust_prog_btf_ext_info(obj, prog, &obj->btf_ext->line_info, &main_prog->line_info, &main_prog->line_info_cnt, &main_prog->line_info_rec_size); if (err) { if (err != -ENOENT) { pr_warn("prog '%s': error relocating .BTF.ext line info: %d\n", prog->name, err); return err; } if (main_prog->line_info) { /* * Some info has already been found but has problem * in the last btf_ext reloc. Must have to error out. */ pr_warn("prog '%s': missing .BTF.ext line info.\n", prog->name); return err; } /* Have problem loading the very first info. Ignore the rest. */ pr_warn("prog '%s': missing .BTF.ext line info for the main program, skipping all of .BTF.ext line info.\n", prog->name); } return 0; } static int cmp_relo_by_insn_idx(const void *key, const void *elem) { size_t insn_idx = *(const size_t *)key; const struct reloc_desc *relo = elem; if (insn_idx == relo->insn_idx) return 0; return insn_idx < relo->insn_idx ? -1 : 1; } static struct reloc_desc *find_prog_insn_relo(const struct bpf_program *prog, size_t insn_idx) { if (!prog->nr_reloc) return NULL; return bsearch(&insn_idx, prog->reloc_desc, prog->nr_reloc, sizeof(*prog->reloc_desc), cmp_relo_by_insn_idx); } static int append_subprog_relos(struct bpf_program *main_prog, struct bpf_program *subprog) { int new_cnt = main_prog->nr_reloc + subprog->nr_reloc; struct reloc_desc *relos; int i; if (main_prog == subprog) return 0; relos = libbpf_reallocarray(main_prog->reloc_desc, new_cnt, sizeof(*relos)); /* if new count is zero, reallocarray can return a valid NULL result; * in this case the previous pointer will be freed, so we *have to* * reassign old pointer to the new value (even if it's NULL) */ if (!relos && new_cnt) return -ENOMEM; if (subprog->nr_reloc) memcpy(relos + main_prog->nr_reloc, subprog->reloc_desc, sizeof(*relos) * subprog->nr_reloc); for (i = main_prog->nr_reloc; i < new_cnt; i++) relos[i].insn_idx += subprog->sub_insn_off; /* After insn_idx adjustment the 'relos' array is still sorted * by insn_idx and doesn't break bsearch. */ main_prog->reloc_desc = relos; main_prog->nr_reloc = new_cnt; return 0; } static int bpf_object__append_subprog_code(struct bpf_object *obj, struct bpf_program *main_prog, struct bpf_program *subprog) { struct bpf_insn *insns; size_t new_cnt; int err; subprog->sub_insn_off = main_prog->insns_cnt; new_cnt = main_prog->insns_cnt + subprog->insns_cnt; insns = libbpf_reallocarray(main_prog->insns, new_cnt, sizeof(*insns)); if (!insns) { pr_warn("prog '%s': failed to realloc prog code\n", main_prog->name); return -ENOMEM; } main_prog->insns = insns; main_prog->insns_cnt = new_cnt; memcpy(main_prog->insns + subprog->sub_insn_off, subprog->insns, subprog->insns_cnt * sizeof(*insns)); pr_debug("prog '%s': added %zu insns from sub-prog '%s'\n", main_prog->name, subprog->insns_cnt, subprog->name); /* The subprog insns are now appended. Append its relos too. */ err = append_subprog_relos(main_prog, subprog); if (err) return err; return 0; } static int bpf_object__reloc_code(struct bpf_object *obj, struct bpf_program *main_prog, struct bpf_program *prog) { size_t sub_insn_idx, insn_idx; struct bpf_program *subprog; struct reloc_desc *relo; struct bpf_insn *insn; int err; err = reloc_prog_func_and_line_info(obj, main_prog, prog); if (err) return err; for (insn_idx = 0; insn_idx < prog->sec_insn_cnt; insn_idx++) { insn = &main_prog->insns[prog->sub_insn_off + insn_idx]; if (!insn_is_subprog_call(insn) && !insn_is_pseudo_func(insn)) continue; relo = find_prog_insn_relo(prog, insn_idx); if (relo && relo->type == RELO_EXTERN_CALL) /* kfunc relocations will be handled later * in bpf_object__relocate_data() */ continue; if (relo && relo->type != RELO_CALL && relo->type != RELO_SUBPROG_ADDR) { pr_warn("prog '%s': unexpected relo for insn #%zu, type %d\n", prog->name, insn_idx, relo->type); return -LIBBPF_ERRNO__RELOC; } if (relo) { /* sub-program instruction index is a combination of * an offset of a symbol pointed to by relocation and * call instruction's imm field; for global functions, * call always has imm = -1, but for static functions * relocation is against STT_SECTION and insn->imm * points to a start of a static function * * for subprog addr relocation, the relo->sym_off + insn->imm is * the byte offset in the corresponding section. */ if (relo->type == RELO_CALL) sub_insn_idx = relo->sym_off / BPF_INSN_SZ + insn->imm + 1; else sub_insn_idx = (relo->sym_off + insn->imm) / BPF_INSN_SZ; } else if (insn_is_pseudo_func(insn)) { /* * RELO_SUBPROG_ADDR relo is always emitted even if both * functions are in the same section, so it shouldn't reach here. */ pr_warn("prog '%s': missing subprog addr relo for insn #%zu\n", prog->name, insn_idx); return -LIBBPF_ERRNO__RELOC; } else { /* if subprogram call is to a static function within * the same ELF section, there won't be any relocation * emitted, but it also means there is no additional * offset necessary, insns->imm is relative to * instruction's original position within the section */ sub_insn_idx = prog->sec_insn_off + insn_idx + insn->imm + 1; } /* we enforce that sub-programs should be in .text section */ subprog = find_prog_by_sec_insn(obj, obj->efile.text_shndx, sub_insn_idx); if (!subprog) { pr_warn("prog '%s': no .text section found yet sub-program call exists\n", prog->name); return -LIBBPF_ERRNO__RELOC; } /* if it's the first call instruction calling into this * subprogram (meaning this subprog hasn't been processed * yet) within the context of current main program: * - append it at the end of main program's instructions blog; * - process is recursively, while current program is put on hold; * - if that subprogram calls some other not yet processes * subprogram, same thing will happen recursively until * there are no more unprocesses subprograms left to append * and relocate. */ if (subprog->sub_insn_off == 0) { err = bpf_object__append_subprog_code(obj, main_prog, subprog); if (err) return err; err = bpf_object__reloc_code(obj, main_prog, subprog); if (err) return err; } /* main_prog->insns memory could have been re-allocated, so * calculate pointer again */ insn = &main_prog->insns[prog->sub_insn_off + insn_idx]; /* calculate correct instruction position within current main * prog; each main prog can have a different set of * subprograms appended (potentially in different order as * well), so position of any subprog can be different for * different main programs */ insn->imm = subprog->sub_insn_off - (prog->sub_insn_off + insn_idx) - 1; pr_debug("prog '%s': insn #%zu relocated, imm %d points to subprog '%s' (now at %zu offset)\n", prog->name, insn_idx, insn->imm, subprog->name, subprog->sub_insn_off); } return 0; } /* * Relocate sub-program calls. * * Algorithm operates as follows. Each entry-point BPF program (referred to as * main prog) is processed separately. For each subprog (non-entry functions, * that can be called from either entry progs or other subprogs) gets their * sub_insn_off reset to zero. This serves as indicator that this subprogram * hasn't been yet appended and relocated within current main prog. Once its * relocated, sub_insn_off will point at the position within current main prog * where given subprog was appended. This will further be used to relocate all * the call instructions jumping into this subprog. * * We start with main program and process all call instructions. If the call * is into a subprog that hasn't been processed (i.e., subprog->sub_insn_off * is zero), subprog instructions are appended at the end of main program's * instruction array. Then main program is "put on hold" while we recursively * process newly appended subprogram. If that subprogram calls into another * subprogram that hasn't been appended, new subprogram is appended again to * the *main* prog's instructions (subprog's instructions are always left * untouched, as they need to be in unmodified state for subsequent main progs * and subprog instructions are always sent only as part of a main prog) and * the process continues recursively. Once all the subprogs called from a main * prog or any of its subprogs are appended (and relocated), all their * positions within finalized instructions array are known, so it's easy to * rewrite call instructions with correct relative offsets, corresponding to * desired target subprog. * * Its important to realize that some subprogs might not be called from some * main prog and any of its called/used subprogs. Those will keep their * subprog->sub_insn_off as zero at all times and won't be appended to current * main prog and won't be relocated within the context of current main prog. * They might still be used from other main progs later. * * Visually this process can be shown as below. Suppose we have two main * programs mainA and mainB and BPF object contains three subprogs: subA, * subB, and subC. mainA calls only subA, mainB calls only subC, but subA and * subC both call subB: * * +--------+ +-------+ * | v v | * +--+---+ +--+-+-+ +---+--+ * | subA | | subB | | subC | * +--+---+ +------+ +---+--+ * ^ ^ * | | * +---+-------+ +------+----+ * | mainA | | mainB | * +-----------+ +-----------+ * * We'll start relocating mainA, will find subA, append it and start * processing sub A recursively: * * +-----------+------+ * | mainA | subA | * +-----------+------+ * * At this point we notice that subB is used from subA, so we append it and * relocate (there are no further subcalls from subB): * * +-----------+------+------+ * | mainA | subA | subB | * +-----------+------+------+ * * At this point, we relocate subA calls, then go one level up and finish with * relocatin mainA calls. mainA is done. * * For mainB process is similar but results in different order. We start with * mainB and skip subA and subB, as mainB never calls them (at least * directly), but we see subC is needed, so we append and start processing it: * * +-----------+------+ * | mainB | subC | * +-----------+------+ * Now we see subC needs subB, so we go back to it, append and relocate it: * * +-----------+------+------+ * | mainB | subC | subB | * +-----------+------+------+ * * At this point we unwind recursion, relocate calls in subC, then in mainB. */ static int bpf_object__relocate_calls(struct bpf_object *obj, struct bpf_program *prog) { struct bpf_program *subprog; int i, err; /* mark all subprogs as not relocated (yet) within the context of * current main program */ for (i = 0; i < obj->nr_programs; i++) { subprog = &obj->programs[i]; if (!prog_is_subprog(obj, subprog)) continue; subprog->sub_insn_off = 0; } err = bpf_object__reloc_code(obj, prog, prog); if (err) return err; return 0; } static void bpf_object__free_relocs(struct bpf_object *obj) { struct bpf_program *prog; int i; /* free up relocation descriptors */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; zfree(&prog->reloc_desc); prog->nr_reloc = 0; } } static int cmp_relocs(const void *_a, const void *_b) { const struct reloc_desc *a = _a; const struct reloc_desc *b = _b; if (a->insn_idx != b->insn_idx) return a->insn_idx < b->insn_idx ? -1 : 1; /* no two relocations should have the same insn_idx, but ... */ if (a->type != b->type) return a->type < b->type ? -1 : 1; return 0; } static void bpf_object__sort_relos(struct bpf_object *obj) { int i; for (i = 0; i < obj->nr_programs; i++) { struct bpf_program *p = &obj->programs[i]; if (!p->nr_reloc) continue; qsort(p->reloc_desc, p->nr_reloc, sizeof(*p->reloc_desc), cmp_relocs); } } static int bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path) { struct bpf_program *prog; size_t i, j; int err; if (obj->btf_ext) { err = bpf_object__relocate_core(obj, targ_btf_path); if (err) { pr_warn("failed to perform CO-RE relocations: %d\n", err); return err; } bpf_object__sort_relos(obj); } /* Before relocating calls pre-process relocations and mark * few ld_imm64 instructions that points to subprogs. * Otherwise bpf_object__reloc_code() later would have to consider * all ld_imm64 insns as relocation candidates. That would * reduce relocation speed, since amount of find_prog_insn_relo() * would increase and most of them will fail to find a relo. */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; for (j = 0; j < prog->nr_reloc; j++) { struct reloc_desc *relo = &prog->reloc_desc[j]; struct bpf_insn *insn = &prog->insns[relo->insn_idx]; /* mark the insn, so it's recognized by insn_is_pseudo_func() */ if (relo->type == RELO_SUBPROG_ADDR) insn[0].src_reg = BPF_PSEUDO_FUNC; } } /* relocate subprogram calls and append used subprograms to main * programs; each copy of subprogram code needs to be relocated * differently for each main program, because its code location might * have changed. * Append subprog relos to main programs to allow data relos to be * processed after text is completely relocated. */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; /* sub-program's sub-calls are relocated within the context of * its main program only */ if (prog_is_subprog(obj, prog)) continue; if (!prog->autoload) continue; err = bpf_object__relocate_calls(obj, prog); if (err) { pr_warn("prog '%s': failed to relocate calls: %d\n", prog->name, err); return err; } /* Now, also append exception callback if it has not been done already. */ if (prog->exception_cb_idx >= 0) { struct bpf_program *subprog = &obj->programs[prog->exception_cb_idx]; /* Calling exception callback directly is disallowed, which the * verifier will reject later. In case it was processed already, * we can skip this step, otherwise for all other valid cases we * have to append exception callback now. */ if (subprog->sub_insn_off == 0) { err = bpf_object__append_subprog_code(obj, prog, subprog); if (err) return err; err = bpf_object__reloc_code(obj, prog, subprog); if (err) return err; } } } /* Process data relos for main programs */ for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; if (prog_is_subprog(obj, prog)) continue; if (!prog->autoload) continue; err = bpf_object__relocate_data(obj, prog); if (err) { pr_warn("prog '%s': failed to relocate data references: %d\n", prog->name, err); return err; } } return 0; } static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, Elf64_Shdr *shdr, Elf_Data *data); static int bpf_object__collect_map_relos(struct bpf_object *obj, Elf64_Shdr *shdr, Elf_Data *data) { const int bpf_ptr_sz = 8, host_ptr_sz = sizeof(void *); int i, j, nrels, new_sz; const struct btf_var_secinfo *vi = NULL; const struct btf_type *sec, *var, *def; struct bpf_map *map = NULL, *targ_map = NULL; struct bpf_program *targ_prog = NULL; bool is_prog_array, is_map_in_map; const struct btf_member *member; const char *name, *mname, *type; unsigned int moff; Elf64_Sym *sym; Elf64_Rel *rel; void *tmp; if (!obj->efile.btf_maps_sec_btf_id || !obj->btf) return -EINVAL; sec = btf__type_by_id(obj->btf, obj->efile.btf_maps_sec_btf_id); if (!sec) return -EINVAL; nrels = shdr->sh_size / shdr->sh_entsize; for (i = 0; i < nrels; i++) { rel = elf_rel_by_idx(data, i); if (!rel) { pr_warn(".maps relo #%d: failed to get ELF relo\n", i); return -LIBBPF_ERRNO__FORMAT; } sym = elf_sym_by_idx(obj, ELF64_R_SYM(rel->r_info)); if (!sym) { pr_warn(".maps relo #%d: symbol %zx not found\n", i, (size_t)ELF64_R_SYM(rel->r_info)); return -LIBBPF_ERRNO__FORMAT; } name = elf_sym_str(obj, sym->st_name) ?: "<?>"; pr_debug(".maps relo #%d: for %zd value %zd rel->r_offset %zu name %d ('%s')\n", i, (ssize_t)(rel->r_info >> 32), (size_t)sym->st_value, (size_t)rel->r_offset, sym->st_name, name); for (j = 0; j < obj->nr_maps; j++) { map = &obj->maps[j]; if (map->sec_idx != obj->efile.btf_maps_shndx) continue; vi = btf_var_secinfos(sec) + map->btf_var_idx; if (vi->offset <= rel->r_offset && rel->r_offset + bpf_ptr_sz <= vi->offset + vi->size) break; } if (j == obj->nr_maps) { pr_warn(".maps relo #%d: cannot find map '%s' at rel->r_offset %zu\n", i, name, (size_t)rel->r_offset); return -EINVAL; } is_map_in_map = bpf_map_type__is_map_in_map(map->def.type); is_prog_array = map->def.type == BPF_MAP_TYPE_PROG_ARRAY; type = is_map_in_map ? "map" : "prog"; if (is_map_in_map) { if (sym->st_shndx != obj->efile.btf_maps_shndx) { pr_warn(".maps relo #%d: '%s' isn't a BTF-defined map\n", i, name); return -LIBBPF_ERRNO__RELOC; } if (map->def.type == BPF_MAP_TYPE_HASH_OF_MAPS && map->def.key_size != sizeof(int)) { pr_warn(".maps relo #%d: hash-of-maps '%s' should have key size %zu.\n", i, map->name, sizeof(int)); return -EINVAL; } targ_map = bpf_object__find_map_by_name(obj, name); if (!targ_map) { pr_warn(".maps relo #%d: '%s' isn't a valid map reference\n", i, name); return -ESRCH; } } else if (is_prog_array) { targ_prog = bpf_object__find_program_by_name(obj, name); if (!targ_prog) { pr_warn(".maps relo #%d: '%s' isn't a valid program reference\n", i, name); return -ESRCH; } if (targ_prog->sec_idx != sym->st_shndx || targ_prog->sec_insn_off * 8 != sym->st_value || prog_is_subprog(obj, targ_prog)) { pr_warn(".maps relo #%d: '%s' isn't an entry-point program\n", i, name); return -LIBBPF_ERRNO__RELOC; } } else { return -EINVAL; } var = btf__type_by_id(obj->btf, vi->type); def = skip_mods_and_typedefs(obj->btf, var->type, NULL); if (btf_vlen(def) == 0) return -EINVAL; member = btf_members(def) + btf_vlen(def) - 1; mname = btf__name_by_offset(obj->btf, member->name_off); if (strcmp(mname, "values")) return -EINVAL; moff = btf_member_bit_offset(def, btf_vlen(def) - 1) / 8; if (rel->r_offset - vi->offset < moff) return -EINVAL; moff = rel->r_offset - vi->offset - moff; /* here we use BPF pointer size, which is always 64 bit, as we * are parsing ELF that was built for BPF target */ if (moff % bpf_ptr_sz) return -EINVAL; moff /= bpf_ptr_sz; if (moff >= map->init_slots_sz) { new_sz = moff + 1; tmp = libbpf_reallocarray(map->init_slots, new_sz, host_ptr_sz); if (!tmp) return -ENOMEM; map->init_slots = tmp; memset(map->init_slots + map->init_slots_sz, 0, (new_sz - map->init_slots_sz) * host_ptr_sz); map->init_slots_sz = new_sz; } map->init_slots[moff] = is_map_in_map ? (void *)targ_map : (void *)targ_prog; pr_debug(".maps relo #%d: map '%s' slot [%d] points to %s '%s'\n", i, map->name, moff, type, name); } return 0; } static int bpf_object__collect_relos(struct bpf_object *obj) { int i, err; for (i = 0; i < obj->efile.sec_cnt; i++) { struct elf_sec_desc *sec_desc = &obj->efile.secs[i]; Elf64_Shdr *shdr; Elf_Data *data; int idx; if (sec_desc->sec_type != SEC_RELO) continue; shdr = sec_desc->shdr; data = sec_desc->data; idx = shdr->sh_info; if (shdr->sh_type != SHT_REL) { pr_warn("internal error at %d\n", __LINE__); return -LIBBPF_ERRNO__INTERNAL; } if (idx == obj->efile.st_ops_shndx || idx == obj->efile.st_ops_link_shndx) err = bpf_object__collect_st_ops_relos(obj, shdr, data); else if (idx == obj->efile.btf_maps_shndx) err = bpf_object__collect_map_relos(obj, shdr, data); else err = bpf_object__collect_prog_relos(obj, shdr, data); if (err) return err; } bpf_object__sort_relos(obj); return 0; } static bool insn_is_helper_call(struct bpf_insn *insn, enum bpf_func_id *func_id) { if (BPF_CLASS(insn->code) == BPF_JMP && BPF_OP(insn->code) == BPF_CALL && BPF_SRC(insn->code) == BPF_K && insn->src_reg == 0 && insn->dst_reg == 0) { *func_id = insn->imm; return true; } return false; } static int bpf_object__sanitize_prog(struct bpf_object *obj, struct bpf_program *prog) { struct bpf_insn *insn = prog->insns; enum bpf_func_id func_id; int i; if (obj->gen_loader) return 0; for (i = 0; i < prog->insns_cnt; i++, insn++) { if (!insn_is_helper_call(insn, &func_id)) continue; /* on kernels that don't yet support * bpf_probe_read_{kernel,user}[_str] helpers, fall back * to bpf_probe_read() which works well for old kernels */ switch (func_id) { case BPF_FUNC_probe_read_kernel: case BPF_FUNC_probe_read_user: if (!kernel_supports(obj, FEAT_PROBE_READ_KERN)) insn->imm = BPF_FUNC_probe_read; break; case BPF_FUNC_probe_read_kernel_str: case BPF_FUNC_probe_read_user_str: if (!kernel_supports(obj, FEAT_PROBE_READ_KERN)) insn->imm = BPF_FUNC_probe_read_str; break; default: break; } } return 0; } static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attach_name, int *btf_obj_fd, int *btf_type_id); /* this is called as prog->sec_def->prog_prepare_load_fn for libbpf-supported sec_defs */ static int libbpf_prepare_prog_load(struct bpf_program *prog, struct bpf_prog_load_opts *opts, long cookie) { enum sec_def_flags def = cookie; /* old kernels might not support specifying expected_attach_type */ if ((def & SEC_EXP_ATTACH_OPT) && !kernel_supports(prog->obj, FEAT_EXP_ATTACH_TYPE)) opts->expected_attach_type = 0; if (def & SEC_SLEEPABLE) opts->prog_flags |= BPF_F_SLEEPABLE; if (prog->type == BPF_PROG_TYPE_XDP && (def & SEC_XDP_FRAGS)) opts->prog_flags |= BPF_F_XDP_HAS_FRAGS; /* special check for usdt to use uprobe_multi link */ if ((def & SEC_USDT) && kernel_supports(prog->obj, FEAT_UPROBE_MULTI_LINK)) prog->expected_attach_type = BPF_TRACE_UPROBE_MULTI; if ((def & SEC_ATTACH_BTF) && !prog->attach_btf_id) { int btf_obj_fd = 0, btf_type_id = 0, err; const char *attach_name; attach_name = strchr(prog->sec_name, '/'); if (!attach_name) { /* if BPF program is annotated with just SEC("fentry") * (or similar) without declaratively specifying * target, then it is expected that target will be * specified with bpf_program__set_attach_target() at * runtime before BPF object load step. If not, then * there is nothing to load into the kernel as BPF * verifier won't be able to validate BPF program * correctness anyways. */ pr_warn("prog '%s': no BTF-based attach target is specified, use bpf_program__set_attach_target()\n", prog->name); return -EINVAL; } attach_name++; /* skip over / */ err = libbpf_find_attach_btf_id(prog, attach_name, &btf_obj_fd, &btf_type_id); if (err) return err; /* cache resolved BTF FD and BTF type ID in the prog */ prog->attach_btf_obj_fd = btf_obj_fd; prog->attach_btf_id = btf_type_id; /* but by now libbpf common logic is not utilizing * prog->atach_btf_obj_fd/prog->attach_btf_id anymore because * this callback is called after opts were populated by * libbpf, so this callback has to update opts explicitly here */ opts->attach_btf_obj_fd = btf_obj_fd; opts->attach_btf_id = btf_type_id; } return 0; } static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_sz); static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt, const char *license, __u32 kern_version, int *prog_fd) { LIBBPF_OPTS(bpf_prog_load_opts, load_attr); const char *prog_name = NULL; char *cp, errmsg[STRERR_BUFSIZE]; size_t log_buf_size = 0; char *log_buf = NULL, *tmp; int btf_fd, ret, err; bool own_log_buf = true; __u32 log_level = prog->log_level; if (prog->type == BPF_PROG_TYPE_UNSPEC) { /* * The program type must be set. Most likely we couldn't find a proper * section definition at load time, and thus we didn't infer the type. */ pr_warn("prog '%s': missing BPF prog type, check ELF section name '%s'\n", prog->name, prog->sec_name); return -EINVAL; } if (!insns || !insns_cnt) return -EINVAL; if (kernel_supports(obj, FEAT_PROG_NAME)) prog_name = prog->name; load_attr.attach_prog_fd = prog->attach_prog_fd; load_attr.attach_btf_obj_fd = prog->attach_btf_obj_fd; load_attr.attach_btf_id = prog->attach_btf_id; load_attr.kern_version = kern_version; load_attr.prog_ifindex = prog->prog_ifindex; /* specify func_info/line_info only if kernel supports them */ btf_fd = bpf_object__btf_fd(obj); if (btf_fd >= 0 && kernel_supports(obj, FEAT_BTF_FUNC)) { load_attr.prog_btf_fd = btf_fd; load_attr.func_info = prog->func_info; load_attr.func_info_rec_size = prog->func_info_rec_size; load_attr.func_info_cnt = prog->func_info_cnt; load_attr.line_info = prog->line_info; load_attr.line_info_rec_size = prog->line_info_rec_size; load_attr.line_info_cnt = prog->line_info_cnt; } load_attr.log_level = log_level; load_attr.prog_flags = prog->prog_flags; load_attr.fd_array = obj->fd_array; /* adjust load_attr if sec_def provides custom preload callback */ if (prog->sec_def && prog->sec_def->prog_prepare_load_fn) { err = prog->sec_def->prog_prepare_load_fn(prog, &load_attr, prog->sec_def->cookie); if (err < 0) { pr_warn("prog '%s': failed to prepare load attributes: %d\n", prog->name, err); return err; } insns = prog->insns; insns_cnt = prog->insns_cnt; } /* allow prog_prepare_load_fn to change expected_attach_type */ load_attr.expected_attach_type = prog->expected_attach_type; if (obj->gen_loader) { bpf_gen__prog_load(obj->gen_loader, prog->type, prog->name, license, insns, insns_cnt, &load_attr, prog - obj->programs); *prog_fd = -1; return 0; } retry_load: /* if log_level is zero, we don't request logs initially even if * custom log_buf is specified; if the program load fails, then we'll * bump log_level to 1 and use either custom log_buf or we'll allocate * our own and retry the load to get details on what failed */ if (log_level) { if (prog->log_buf) { log_buf = prog->log_buf; log_buf_size = prog->log_size; own_log_buf = false; } else if (obj->log_buf) { log_buf = obj->log_buf; log_buf_size = obj->log_size; own_log_buf = false; } else { log_buf_size = max((size_t)BPF_LOG_BUF_SIZE, log_buf_size * 2); tmp = realloc(log_buf, log_buf_size); if (!tmp) { ret = -ENOMEM; goto out; } log_buf = tmp; log_buf[0] = '\0'; own_log_buf = true; } } load_attr.log_buf = log_buf; load_attr.log_size = log_buf_size; load_attr.log_level = log_level; ret = bpf_prog_load(prog->type, prog_name, license, insns, insns_cnt, &load_attr); if (ret >= 0) { if (log_level && own_log_buf) { pr_debug("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n", prog->name, log_buf); } if (obj->has_rodata && kernel_supports(obj, FEAT_PROG_BIND_MAP)) { struct bpf_map *map; int i; for (i = 0; i < obj->nr_maps; i++) { map = &prog->obj->maps[i]; if (map->libbpf_type != LIBBPF_MAP_RODATA) continue; if (bpf_prog_bind_map(ret, bpf_map__fd(map), NULL)) { cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warn("prog '%s': failed to bind map '%s': %s\n", prog->name, map->real_name, cp); /* Don't fail hard if can't bind rodata. */ } } } *prog_fd = ret; ret = 0; goto out; } if (log_level == 0) { log_level = 1; goto retry_load; } /* On ENOSPC, increase log buffer size and retry, unless custom * log_buf is specified. * Be careful to not overflow u32, though. Kernel's log buf size limit * isn't part of UAPI so it can always be bumped to full 4GB. So don't * multiply by 2 unless we are sure we'll fit within 32 bits. * Currently, we'll get -EINVAL when we reach (UINT_MAX >> 2). */ if (own_log_buf && errno == ENOSPC && log_buf_size <= UINT_MAX / 2) goto retry_load; ret = -errno; /* post-process verifier log to improve error descriptions */ fixup_verifier_log(prog, log_buf, log_buf_size); cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warn("prog '%s': BPF program load failed: %s\n", prog->name, cp); pr_perm_msg(ret); if (own_log_buf && log_buf && log_buf[0] != '\0') { pr_warn("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n", prog->name, log_buf); } out: if (own_log_buf) free(log_buf); return ret; } static char *find_prev_line(char *buf, char *cur) { char *p; if (cur == buf) /* end of a log buf */ return NULL; p = cur - 1; while (p - 1 >= buf && *(p - 1) != '\n') p--; return p; } static void patch_log(char *buf, size_t buf_sz, size_t log_sz, char *orig, size_t orig_sz, const char *patch) { /* size of the remaining log content to the right from the to-be-replaced part */ size_t rem_sz = (buf + log_sz) - (orig + orig_sz); size_t patch_sz = strlen(patch); if (patch_sz != orig_sz) { /* If patch line(s) are longer than original piece of verifier log, * shift log contents by (patch_sz - orig_sz) bytes to the right * starting from after to-be-replaced part of the log. * * If patch line(s) are shorter than original piece of verifier log, * shift log contents by (orig_sz - patch_sz) bytes to the left * starting from after to-be-replaced part of the log * * We need to be careful about not overflowing available * buf_sz capacity. If that's the case, we'll truncate the end * of the original log, as necessary. */ if (patch_sz > orig_sz) { if (orig + patch_sz >= buf + buf_sz) { /* patch is big enough to cover remaining space completely */ patch_sz -= (orig + patch_sz) - (buf + buf_sz) + 1; rem_sz = 0; } else if (patch_sz - orig_sz > buf_sz - log_sz) { /* patch causes part of remaining log to be truncated */ rem_sz -= (patch_sz - orig_sz) - (buf_sz - log_sz); } } /* shift remaining log to the right by calculated amount */ memmove(orig + patch_sz, orig + orig_sz, rem_sz); } memcpy(orig, patch, patch_sz); } static void fixup_log_failed_core_relo(struct bpf_program *prog, char *buf, size_t buf_sz, size_t log_sz, char *line1, char *line2, char *line3) { /* Expected log for failed and not properly guarded CO-RE relocation: * line1 -> 123: (85) call unknown#195896080 * line2 -> invalid func unknown#195896080 * line3 -> <anything else or end of buffer> * * "123" is the index of the instruction that was poisoned. We extract * instruction index to find corresponding CO-RE relocation and * replace this part of the log with more relevant information about * failed CO-RE relocation. */ const struct bpf_core_relo *relo; struct bpf_core_spec spec; char patch[512], spec_buf[256]; int insn_idx, err, spec_len; if (sscanf(line1, "%d: (%*d) call unknown#195896080\n", &insn_idx) != 1) return; relo = find_relo_core(prog, insn_idx); if (!relo) return; err = bpf_core_parse_spec(prog->name, prog->obj->btf, relo, &spec); if (err) return; spec_len = bpf_core_format_spec(spec_buf, sizeof(spec_buf), &spec); snprintf(patch, sizeof(patch), "%d: <invalid CO-RE relocation>\n" "failed to resolve CO-RE relocation %s%s\n", insn_idx, spec_buf, spec_len >= sizeof(spec_buf) ? "..." : ""); patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch); } static void fixup_log_missing_map_load(struct bpf_program *prog, char *buf, size_t buf_sz, size_t log_sz, char *line1, char *line2, char *line3) { /* Expected log for failed and not properly guarded map reference: * line1 -> 123: (85) call unknown#2001000345 * line2 -> invalid func unknown#2001000345 * line3 -> <anything else or end of buffer> * * "123" is the index of the instruction that was poisoned. * "345" in "2001000345" is a map index in obj->maps to fetch map name. */ struct bpf_object *obj = prog->obj; const struct bpf_map *map; int insn_idx, map_idx; char patch[128]; if (sscanf(line1, "%d: (%*d) call unknown#%d\n", &insn_idx, &map_idx) != 2) return; map_idx -= POISON_LDIMM64_MAP_BASE; if (map_idx < 0 || map_idx >= obj->nr_maps) return; map = &obj->maps[map_idx]; snprintf(patch, sizeof(patch), "%d: <invalid BPF map reference>\n" "BPF map '%s' is referenced but wasn't created\n", insn_idx, map->name); patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch); } static void fixup_log_missing_kfunc_call(struct bpf_program *prog, char *buf, size_t buf_sz, size_t log_sz, char *line1, char *line2, char *line3) { /* Expected log for failed and not properly guarded kfunc call: * line1 -> 123: (85) call unknown#2002000345 * line2 -> invalid func unknown#2002000345 * line3 -> <anything else or end of buffer> * * "123" is the index of the instruction that was poisoned. * "345" in "2002000345" is an extern index in obj->externs to fetch kfunc name. */ struct bpf_object *obj = prog->obj; const struct extern_desc *ext; int insn_idx, ext_idx; char patch[128]; if (sscanf(line1, "%d: (%*d) call unknown#%d\n", &insn_idx, &ext_idx) != 2) return; ext_idx -= POISON_CALL_KFUNC_BASE; if (ext_idx < 0 || ext_idx >= obj->nr_extern) return; ext = &obj->externs[ext_idx]; snprintf(patch, sizeof(patch), "%d: <invalid kfunc call>\n" "kfunc '%s' is referenced but wasn't resolved\n", insn_idx, ext->name); patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch); } static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_sz) { /* look for familiar error patterns in last N lines of the log */ const size_t max_last_line_cnt = 10; char *prev_line, *cur_line, *next_line; size_t log_sz; int i; if (!buf) return; log_sz = strlen(buf) + 1; next_line = buf + log_sz - 1; for (i = 0; i < max_last_line_cnt; i++, next_line = cur_line) { cur_line = find_prev_line(buf, next_line); if (!cur_line) return; if (str_has_pfx(cur_line, "invalid func unknown#195896080\n")) { prev_line = find_prev_line(buf, cur_line); if (!prev_line) continue; /* failed CO-RE relocation case */ fixup_log_failed_core_relo(prog, buf, buf_sz, log_sz, prev_line, cur_line, next_line); return; } else if (str_has_pfx(cur_line, "invalid func unknown#"POISON_LDIMM64_MAP_PFX)) { prev_line = find_prev_line(buf, cur_line); if (!prev_line) continue; /* reference to uncreated BPF map */ fixup_log_missing_map_load(prog, buf, buf_sz, log_sz, prev_line, cur_line, next_line); return; } else if (str_has_pfx(cur_line, "invalid func unknown#"POISON_CALL_KFUNC_PFX)) { prev_line = find_prev_line(buf, cur_line); if (!prev_line) continue; /* reference to unresolved kfunc */ fixup_log_missing_kfunc_call(prog, buf, buf_sz, log_sz, prev_line, cur_line, next_line); return; } } } static int bpf_program_record_relos(struct bpf_program *prog) { struct bpf_object *obj = prog->obj; int i; for (i = 0; i < prog->nr_reloc; i++) { struct reloc_desc *relo = &prog->reloc_desc[i]; struct extern_desc *ext = &obj->externs[relo->ext_idx]; int kind; switch (relo->type) { case RELO_EXTERN_LD64: if (ext->type != EXT_KSYM) continue; kind = btf_is_var(btf__type_by_id(obj->btf, ext->btf_id)) ? BTF_KIND_VAR : BTF_KIND_FUNC; bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak, !ext->ksym.type_id, true, kind, relo->insn_idx); break; case RELO_EXTERN_CALL: bpf_gen__record_extern(obj->gen_loader, ext->name, ext->is_weak, false, false, BTF_KIND_FUNC, relo->insn_idx); break; case RELO_CORE: { struct bpf_core_relo cr = { .insn_off = relo->insn_idx * 8, .type_id = relo->core_relo->type_id, .access_str_off = relo->core_relo->access_str_off, .kind = relo->core_relo->kind, }; bpf_gen__record_relo_core(obj->gen_loader, &cr); break; } default: continue; } } return 0; } static int bpf_object__load_progs(struct bpf_object *obj, int log_level) { struct bpf_program *prog; size_t i; int err; for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; err = bpf_object__sanitize_prog(obj, prog); if (err) return err; } for (i = 0; i < obj->nr_programs; i++) { prog = &obj->programs[i]; if (prog_is_subprog(obj, prog)) continue; if (!prog->autoload) { pr_debug("prog '%s': skipped loading\n", prog->name); continue; } prog->log_level |= log_level; if (obj->gen_loader) bpf_program_record_relos(prog); err = bpf_object_load_prog(obj, prog, prog->insns, prog->insns_cnt, obj->license, obj->kern_version, &prog->fd); if (err) { pr_warn("prog '%s': failed to load: %d\n", prog->name, err); return err; } } bpf_object__free_relocs(obj); return 0; } static const struct bpf_sec_def *find_sec_def(const char *sec_name); static int bpf_object_init_progs(struct bpf_object *obj, const struct bpf_object_open_opts *opts) { struct bpf_program *prog; int err; bpf_object__for_each_program(prog, obj) { prog->sec_def = find_sec_def(prog->sec_name); if (!prog->sec_def) { /* couldn't guess, but user might manually specify */ pr_debug("prog '%s': unrecognized ELF section name '%s'\n", prog->name, prog->sec_name); continue; } prog->type = prog->sec_def->prog_type; prog->expected_attach_type = prog->sec_def->expected_attach_type; /* sec_def can have custom callback which should be called * after bpf_program is initialized to adjust its properties */ if (prog->sec_def->prog_setup_fn) { err = prog->sec_def->prog_setup_fn(prog, prog->sec_def->cookie); if (err < 0) { pr_warn("prog '%s': failed to initialize: %d\n", prog->name, err); return err; } } } return 0; } static struct bpf_object *bpf_object_open(const char *path, const void *obj_buf, size_t obj_buf_sz, const struct bpf_object_open_opts *opts) { const char *obj_name, *kconfig, *btf_tmp_path; struct bpf_object *obj; char tmp_name[64]; int err; char *log_buf; size_t log_size; __u32 log_level; if (elf_version(EV_CURRENT) == EV_NONE) { pr_warn("failed to init libelf for %s\n", path ? : "(mem buf)"); return ERR_PTR(-LIBBPF_ERRNO__LIBELF); } if (!OPTS_VALID(opts, bpf_object_open_opts)) return ERR_PTR(-EINVAL); obj_name = OPTS_GET(opts, object_name, NULL); if (obj_buf) { if (!obj_name) { snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx", (unsigned long)obj_buf, (unsigned long)obj_buf_sz); obj_name = tmp_name; } path = obj_name; pr_debug("loading object '%s' from buffer\n", obj_name); } log_buf = OPTS_GET(opts, kernel_log_buf, NULL); log_size = OPTS_GET(opts, kernel_log_size, 0); log_level = OPTS_GET(opts, kernel_log_level, 0); if (log_size > UINT_MAX) return ERR_PTR(-EINVAL); if (log_size && !log_buf) return ERR_PTR(-EINVAL); obj = bpf_object__new(path, obj_buf, obj_buf_sz, obj_name); if (IS_ERR(obj)) return obj; obj->log_buf = log_buf; obj->log_size = log_size; obj->log_level = log_level; btf_tmp_path = OPTS_GET(opts, btf_custom_path, NULL); if (btf_tmp_path) { if (strlen(btf_tmp_path) >= PATH_MAX) { err = -ENAMETOOLONG; goto out; } obj->btf_custom_path = strdup(btf_tmp_path); if (!obj->btf_custom_path) { err = -ENOMEM; goto out; } } kconfig = OPTS_GET(opts, kconfig, NULL); if (kconfig) { obj->kconfig = strdup(kconfig); if (!obj->kconfig) { err = -ENOMEM; goto out; } } err = bpf_object__elf_init(obj); err = err ? : bpf_object__check_endianness(obj); err = err ? : bpf_object__elf_collect(obj); err = err ? : bpf_object__collect_externs(obj); err = err ? : bpf_object_fixup_btf(obj); err = err ? : bpf_object__init_maps(obj, opts); err = err ? : bpf_object_init_progs(obj, opts); err = err ? : bpf_object__collect_relos(obj); if (err) goto out; bpf_object__elf_finish(obj); return obj; out: bpf_object__close(obj); return ERR_PTR(err); } struct bpf_object * bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts) { if (!path) return libbpf_err_ptr(-EINVAL); pr_debug("loading %s\n", path); return libbpf_ptr(bpf_object_open(path, NULL, 0, opts)); } struct bpf_object *bpf_object__open(const char *path) { return bpf_object__open_file(path, NULL); } struct bpf_object * bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz, const struct bpf_object_open_opts *opts) { if (!obj_buf || obj_buf_sz == 0) return libbpf_err_ptr(-EINVAL); return libbpf_ptr(bpf_object_open(NULL, obj_buf, obj_buf_sz, opts)); } static int bpf_object_unload(struct bpf_object *obj) { size_t i; if (!obj) return libbpf_err(-EINVAL); for (i = 0; i < obj->nr_maps; i++) { zclose(obj->maps[i].fd); if (obj->maps[i].st_ops) zfree(&obj->maps[i].st_ops->kern_vdata); } for (i = 0; i < obj->nr_programs; i++) bpf_program__unload(&obj->programs[i]); return 0; } static int bpf_object__sanitize_maps(struct bpf_object *obj) { struct bpf_map *m; bpf_object__for_each_map(m, obj) { if (!bpf_map__is_internal(m)) continue; if (!kernel_supports(obj, FEAT_ARRAY_MMAP)) m->def.map_flags &= ~BPF_F_MMAPABLE; } return 0; } int libbpf_kallsyms_parse(kallsyms_cb_t cb, void *ctx) { char sym_type, sym_name[500]; unsigned long long sym_addr; int ret, err = 0; FILE *f; f = fopen("/proc/kallsyms", "re"); if (!f) { err = -errno; pr_warn("failed to open /proc/kallsyms: %d\n", err); return err; } while (true) { ret = fscanf(f, "%llx %c %499s%*[^\n]\n", &sym_addr, &sym_type, sym_name); if (ret == EOF && feof(f)) break; if (ret != 3) { pr_warn("failed to read kallsyms entry: %d\n", ret); err = -EINVAL; break; } err = cb(sym_addr, sym_type, sym_name, ctx); if (err) break; } fclose(f); return err; } static int kallsyms_cb(unsigned long long sym_addr, char sym_type, const char *sym_name, void *ctx) { struct bpf_object *obj = ctx; const struct btf_type *t; struct extern_desc *ext; ext = find_extern_by_name(obj, sym_name); if (!ext || ext->type != EXT_KSYM) return 0; t = btf__type_by_id(obj->btf, ext->btf_id); if (!btf_is_var(t)) return 0; if (ext->is_set && ext->ksym.addr != sym_addr) { pr_warn("extern (ksym) '%s': resolution is ambiguous: 0x%llx or 0x%llx\n", sym_name, ext->ksym.addr, sym_addr); return -EINVAL; } if (!ext->is_set) { ext->is_set = true; ext->ksym.addr = sym_addr; pr_debug("extern (ksym) '%s': set to 0x%llx\n", sym_name, sym_addr); } return 0; } static int bpf_object__read_kallsyms_file(struct bpf_object *obj) { return libbpf_kallsyms_parse(kallsyms_cb, obj); } static int find_ksym_btf_id(struct bpf_object *obj, const char *ksym_name, __u16 kind, struct btf **res_btf, struct module_btf **res_mod_btf) { struct module_btf *mod_btf; struct btf *btf; int i, id, err; btf = obj->btf_vmlinux; mod_btf = NULL; id = btf__find_by_name_kind(btf, ksym_name, kind); if (id == -ENOENT) { err = load_module_btfs(obj); if (err) return err; for (i = 0; i < obj->btf_module_cnt; i++) { /* we assume module_btf's BTF FD is always >0 */ mod_btf = &obj->btf_modules[i]; btf = mod_btf->btf; id = btf__find_by_name_kind_own(btf, ksym_name, kind); if (id != -ENOENT) break; } } if (id <= 0) return -ESRCH; *res_btf = btf; *res_mod_btf = mod_btf; return id; } static int bpf_object__resolve_ksym_var_btf_id(struct bpf_object *obj, struct extern_desc *ext) { const struct btf_type *targ_var, *targ_type; __u32 targ_type_id, local_type_id; struct module_btf *mod_btf = NULL; const char *targ_var_name; struct btf *btf = NULL; int id, err; id = find_ksym_btf_id(obj, ext->name, BTF_KIND_VAR, &btf, &mod_btf); if (id < 0) { if (id == -ESRCH && ext->is_weak) return 0; pr_warn("extern (var ksym) '%s': not found in kernel BTF\n", ext->name); return id; } /* find local type_id */ local_type_id = ext->ksym.type_id; /* find target type_id */ targ_var = btf__type_by_id(btf, id); targ_var_name = btf__name_by_offset(btf, targ_var->name_off); targ_type = skip_mods_and_typedefs(btf, targ_var->type, &targ_type_id); err = bpf_core_types_are_compat(obj->btf, local_type_id, btf, targ_type_id); if (err <= 0) { const struct btf_type *local_type; const char *targ_name, *local_name; local_type = btf__type_by_id(obj->btf, local_type_id); local_name = btf__name_by_offset(obj->btf, local_type->name_off); targ_name = btf__name_by_offset(btf, targ_type->name_off); pr_warn("extern (var ksym) '%s': incompatible types, expected [%d] %s %s, but kernel has [%d] %s %s\n", ext->name, local_type_id, btf_kind_str(local_type), local_name, targ_type_id, btf_kind_str(targ_type), targ_name); return -EINVAL; } ext->is_set = true; ext->ksym.kernel_btf_obj_fd = mod_btf ? mod_btf->fd : 0; ext->ksym.kernel_btf_id = id; pr_debug("extern (var ksym) '%s': resolved to [%d] %s %s\n", ext->name, id, btf_kind_str(targ_var), targ_var_name); return 0; } static int bpf_object__resolve_ksym_func_btf_id(struct bpf_object *obj, struct extern_desc *ext) { int local_func_proto_id, kfunc_proto_id, kfunc_id; struct module_btf *mod_btf = NULL; const struct btf_type *kern_func; struct btf *kern_btf = NULL; int ret; local_func_proto_id = ext->ksym.type_id; kfunc_id = find_ksym_btf_id(obj, ext->essent_name ?: ext->name, BTF_KIND_FUNC, &kern_btf, &mod_btf); if (kfunc_id < 0) { if (kfunc_id == -ESRCH && ext->is_weak) return 0; pr_warn("extern (func ksym) '%s': not found in kernel or module BTFs\n", ext->name); return kfunc_id; } kern_func = btf__type_by_id(kern_btf, kfunc_id); kfunc_proto_id = kern_func->type; ret = bpf_core_types_are_compat(obj->btf, local_func_proto_id, kern_btf, kfunc_proto_id); if (ret <= 0) { if (ext->is_weak) return 0; pr_warn("extern (func ksym) '%s': func_proto [%d] incompatible with %s [%d]\n", ext->name, local_func_proto_id, mod_btf ? mod_btf->name : "vmlinux", kfunc_proto_id); return -EINVAL; } /* set index for module BTF fd in fd_array, if unset */ if (mod_btf && !mod_btf->fd_array_idx) { /* insn->off is s16 */ if (obj->fd_array_cnt == INT16_MAX) { pr_warn("extern (func ksym) '%s': module BTF fd index %d too big to fit in bpf_insn offset\n", ext->name, mod_btf->fd_array_idx); return -E2BIG; } /* Cannot use index 0 for module BTF fd */ if (!obj->fd_array_cnt) obj->fd_array_cnt = 1; ret = libbpf_ensure_mem((void **)&obj->fd_array, &obj->fd_array_cap, sizeof(int), obj->fd_array_cnt + 1); if (ret) return ret; mod_btf->fd_array_idx = obj->fd_array_cnt; /* we assume module BTF FD is always >0 */ obj->fd_array[obj->fd_array_cnt++] = mod_btf->fd; } ext->is_set = true; ext->ksym.kernel_btf_id = kfunc_id; ext->ksym.btf_fd_idx = mod_btf ? mod_btf->fd_array_idx : 0; /* Also set kernel_btf_obj_fd to make sure that bpf_object__relocate_data() * populates FD into ld_imm64 insn when it's used to point to kfunc. * {kernel_btf_id, btf_fd_idx} -> fixup bpf_call. * {kernel_btf_id, kernel_btf_obj_fd} -> fixup ld_imm64. */ ext->ksym.kernel_btf_obj_fd = mod_btf ? mod_btf->fd : 0; pr_debug("extern (func ksym) '%s': resolved to %s [%d]\n", ext->name, mod_btf ? mod_btf->name : "vmlinux", kfunc_id); return 0; } static int bpf_object__resolve_ksyms_btf_id(struct bpf_object *obj) { const struct btf_type *t; struct extern_desc *ext; int i, err; for (i = 0; i < obj->nr_extern; i++) { ext = &obj->externs[i]; if (ext->type != EXT_KSYM || !ext->ksym.type_id) continue; if (obj->gen_loader) { ext->is_set = true; ext->ksym.kernel_btf_obj_fd = 0; ext->ksym.kernel_btf_id = 0; continue; } t = btf__type_by_id(obj->btf, ext->btf_id); if (btf_is_var(t)) err = bpf_object__resolve_ksym_var_btf_id(obj, ext); else err = bpf_object__resolve_ksym_func_btf_id(obj, ext); if (err) return err; } return 0; } static int bpf_object__resolve_externs(struct bpf_object *obj, const char *extra_kconfig) { bool need_config = false, need_kallsyms = false; bool need_vmlinux_btf = false; struct extern_desc *ext; void *kcfg_data = NULL; int err, i; if (obj->nr_extern == 0) return 0; if (obj->kconfig_map_idx >= 0) kcfg_data = obj->maps[obj->kconfig_map_idx].mmaped; for (i = 0; i < obj->nr_extern; i++) { ext = &obj->externs[i]; if (ext->type == EXT_KSYM) { if (ext->ksym.type_id) need_vmlinux_btf = true; else need_kallsyms = true; continue; } else if (ext->type == EXT_KCFG) { void *ext_ptr = kcfg_data + ext->kcfg.data_off; __u64 value = 0; /* Kconfig externs need actual /proc/config.gz */ if (str_has_pfx(ext->name, "CONFIG_")) { need_config = true; continue; } /* Virtual kcfg externs are customly handled by libbpf */ if (strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) { value = get_kernel_version(); if (!value) { pr_warn("extern (kcfg) '%s': failed to get kernel version\n", ext->name); return -EINVAL; } } else if (strcmp(ext->name, "LINUX_HAS_BPF_COOKIE") == 0) { value = kernel_supports(obj, FEAT_BPF_COOKIE); } else if (strcmp(ext->name, "LINUX_HAS_SYSCALL_WRAPPER") == 0) { value = kernel_supports(obj, FEAT_SYSCALL_WRAPPER); } else if (!str_has_pfx(ext->name, "LINUX_") || !ext->is_weak) { /* Currently libbpf supports only CONFIG_ and LINUX_ prefixed * __kconfig externs, where LINUX_ ones are virtual and filled out * customly by libbpf (their values don't come from Kconfig). * If LINUX_xxx variable is not recognized by libbpf, but is marked * __weak, it defaults to zero value, just like for CONFIG_xxx * externs. */ pr_warn("extern (kcfg) '%s': unrecognized virtual extern\n", ext->name); return -EINVAL; } err = set_kcfg_value_num(ext, ext_ptr, value); if (err) return err; pr_debug("extern (kcfg) '%s': set to 0x%llx\n", ext->name, (long long)value); } else { pr_warn("extern '%s': unrecognized extern kind\n", ext->name); return -EINVAL; } } if (need_config && extra_kconfig) { err = bpf_object__read_kconfig_mem(obj, extra_kconfig, kcfg_data); if (err) return -EINVAL; need_config = false; for (i = 0; i < obj->nr_extern; i++) { ext = &obj->externs[i]; if (ext->type == EXT_KCFG && !ext->is_set) { need_config = true; break; } } } if (need_config) { err = bpf_object__read_kconfig_file(obj, kcfg_data); if (err) return -EINVAL; } if (need_kallsyms) { err = bpf_object__read_kallsyms_file(obj); if (err) return -EINVAL; } if (need_vmlinux_btf) { err = bpf_object__resolve_ksyms_btf_id(obj); if (err) return -EINVAL; } for (i = 0; i < obj->nr_extern; i++) { ext = &obj->externs[i]; if (!ext->is_set && !ext->is_weak) { pr_warn("extern '%s' (strong): not resolved\n", ext->name); return -ESRCH; } else if (!ext->is_set) { pr_debug("extern '%s' (weak): not resolved, defaulting to zero\n", ext->name); } } return 0; } static void bpf_map_prepare_vdata(const struct bpf_map *map) { struct bpf_struct_ops *st_ops; __u32 i; st_ops = map->st_ops; for (i = 0; i < btf_vlen(st_ops->type); i++) { struct bpf_program *prog = st_ops->progs[i]; void *kern_data; int prog_fd; if (!prog) continue; prog_fd = bpf_program__fd(prog); kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i]; *(unsigned long *)kern_data = prog_fd; } } static int bpf_object_prepare_struct_ops(struct bpf_object *obj) { int i; for (i = 0; i < obj->nr_maps; i++) if (bpf_map__is_struct_ops(&obj->maps[i])) bpf_map_prepare_vdata(&obj->maps[i]); return 0; } static int bpf_object_load(struct bpf_object *obj, int extra_log_level, const char *target_btf_path) { int err, i; if (!obj) return libbpf_err(-EINVAL); if (obj->loaded) { pr_warn("object '%s': load can't be attempted twice\n", obj->name); return libbpf_err(-EINVAL); } if (obj->gen_loader) bpf_gen__init(obj->gen_loader, extra_log_level, obj->nr_programs, obj->nr_maps); err = bpf_object__probe_loading(obj); err = err ? : bpf_object__load_vmlinux_btf(obj, false); err = err ? : bpf_object__resolve_externs(obj, obj->kconfig); err = err ? : bpf_object__sanitize_and_load_btf(obj); err = err ? : bpf_object__sanitize_maps(obj); err = err ? : bpf_object__init_kern_struct_ops_maps(obj); err = err ? : bpf_object__create_maps(obj); err = err ? : bpf_object__relocate(obj, obj->btf_custom_path ? : target_btf_path); err = err ? : bpf_object__load_progs(obj, extra_log_level); err = err ? : bpf_object_init_prog_arrays(obj); err = err ? : bpf_object_prepare_struct_ops(obj); if (obj->gen_loader) { /* reset FDs */ if (obj->btf) btf__set_fd(obj->btf, -1); for (i = 0; i < obj->nr_maps; i++) obj->maps[i].fd = -1; if (!err) err = bpf_gen__finish(obj->gen_loader, obj->nr_programs, obj->nr_maps); } /* clean up fd_array */ zfree(&obj->fd_array); /* clean up module BTFs */ for (i = 0; i < obj->btf_module_cnt; i++) { close(obj->btf_modules[i].fd); btf__free(obj->btf_modules[i].btf); free(obj->btf_modules[i].name); } free(obj->btf_modules); /* clean up vmlinux BTF */ btf__free(obj->btf_vmlinux); obj->btf_vmlinux = NULL; obj->loaded = true; /* doesn't matter if successfully or not */ if (err) goto out; return 0; out: /* unpin any maps that were auto-pinned during load */ for (i = 0; i < obj->nr_maps; i++) if (obj->maps[i].pinned && !obj->maps[i].reused) bpf_map__unpin(&obj->maps[i], NULL); bpf_object_unload(obj); pr_warn("failed to load object '%s'\n", obj->path); return libbpf_err(err); } int bpf_object__load(struct bpf_object *obj) { return bpf_object_load(obj, 0, NULL); } static int make_parent_dir(const char *path) { char *cp, errmsg[STRERR_BUFSIZE]; char *dname, *dir; int err = 0; dname = strdup(path); if (dname == NULL) return -ENOMEM; dir = dirname(dname); if (mkdir(dir, 0700) && errno != EEXIST) err = -errno; free(dname); if (err) { cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); pr_warn("failed to mkdir %s: %s\n", path, cp); } return err; } static int check_path(const char *path) { char *cp, errmsg[STRERR_BUFSIZE]; struct statfs st_fs; char *dname, *dir; int err = 0; if (path == NULL) return -EINVAL; dname = strdup(path); if (dname == NULL) return -ENOMEM; dir = dirname(dname); if (statfs(dir, &st_fs)) { cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warn("failed to statfs %s: %s\n", dir, cp); err = -errno; } free(dname); if (!err && st_fs.f_type != BPF_FS_MAGIC) { pr_warn("specified path %s is not on BPF FS\n", path); err = -EINVAL; } return err; } int bpf_program__pin(struct bpf_program *prog, const char *path) { char *cp, errmsg[STRERR_BUFSIZE]; int err; if (prog->fd < 0) { pr_warn("prog '%s': can't pin program that wasn't loaded\n", prog->name); return libbpf_err(-EINVAL); } err = make_parent_dir(path); if (err) return libbpf_err(err); err = check_path(path); if (err) return libbpf_err(err); if (bpf_obj_pin(prog->fd, path)) { err = -errno; cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); pr_warn("prog '%s': failed to pin at '%s': %s\n", prog->name, path, cp); return libbpf_err(err); } pr_debug("prog '%s': pinned at '%s'\n", prog->name, path); return 0; } int bpf_program__unpin(struct bpf_program *prog, const char *path) { int err; if (prog->fd < 0) { pr_warn("prog '%s': can't unpin program that wasn't loaded\n", prog->name); return libbpf_err(-EINVAL); } err = check_path(path); if (err) return libbpf_err(err); err = unlink(path); if (err) return libbpf_err(-errno); pr_debug("prog '%s': unpinned from '%s'\n", prog->name, path); return 0; } int bpf_map__pin(struct bpf_map *map, const char *path) { char *cp, errmsg[STRERR_BUFSIZE]; int err; if (map == NULL) { pr_warn("invalid map pointer\n"); return libbpf_err(-EINVAL); } if (map->pin_path) { if (path && strcmp(path, map->pin_path)) { pr_warn("map '%s' already has pin path '%s' different from '%s'\n", bpf_map__name(map), map->pin_path, path); return libbpf_err(-EINVAL); } else if (map->pinned) { pr_debug("map '%s' already pinned at '%s'; not re-pinning\n", bpf_map__name(map), map->pin_path); return 0; } } else { if (!path) { pr_warn("missing a path to pin map '%s' at\n", bpf_map__name(map)); return libbpf_err(-EINVAL); } else if (map->pinned) { pr_warn("map '%s' already pinned\n", bpf_map__name(map)); return libbpf_err(-EEXIST); } map->pin_path = strdup(path); if (!map->pin_path) { err = -errno; goto out_err; } } err = make_parent_dir(map->pin_path); if (err) return libbpf_err(err); err = check_path(map->pin_path); if (err) return libbpf_err(err); if (bpf_obj_pin(map->fd, map->pin_path)) { err = -errno; goto out_err; } map->pinned = true; pr_debug("pinned map '%s'\n", map->pin_path); return 0; out_err: cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); pr_warn("failed to pin map: %s\n", cp); return libbpf_err(err); } int bpf_map__unpin(struct bpf_map *map, const char *path) { int err; if (map == NULL) { pr_warn("invalid map pointer\n"); return libbpf_err(-EINVAL); } if (map->pin_path) { if (path && strcmp(path, map->pin_path)) { pr_warn("map '%s' already has pin path '%s' different from '%s'\n", bpf_map__name(map), map->pin_path, path); return libbpf_err(-EINVAL); } path = map->pin_path; } else if (!path) { pr_warn("no path to unpin map '%s' from\n", bpf_map__name(map)); return libbpf_err(-EINVAL); } err = check_path(path); if (err) return libbpf_err(err); err = unlink(path); if (err != 0) return libbpf_err(-errno); map->pinned = false; pr_debug("unpinned map '%s' from '%s'\n", bpf_map__name(map), path); return 0; } int bpf_map__set_pin_path(struct bpf_map *map, const char *path) { char *new = NULL; if (path) { new = strdup(path); if (!new) return libbpf_err(-errno); } free(map->pin_path); map->pin_path = new; return 0; } __alias(bpf_map__pin_path) const char *bpf_map__get_pin_path(const struct bpf_map *map); const char *bpf_map__pin_path(const struct bpf_map *map) { return map->pin_path; } bool bpf_map__is_pinned(const struct bpf_map *map) { return map->pinned; } static void sanitize_pin_path(char *s) { /* bpffs disallows periods in path names */ while (*s) { if (*s == '.') *s = '_'; s++; } } int bpf_object__pin_maps(struct bpf_object *obj, const char *path) { struct bpf_map *map; int err; if (!obj) return libbpf_err(-ENOENT); if (!obj->loaded) { pr_warn("object not yet loaded; load it first\n"); return libbpf_err(-ENOENT); } bpf_object__for_each_map(map, obj) { char *pin_path = NULL; char buf[PATH_MAX]; if (!map->autocreate) continue; if (path) { err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map)); if (err) goto err_unpin_maps; sanitize_pin_path(buf); pin_path = buf; } else if (!map->pin_path) { continue; } err = bpf_map__pin(map, pin_path); if (err) goto err_unpin_maps; } return 0; err_unpin_maps: while ((map = bpf_object__prev_map(obj, map))) { if (!map->pin_path) continue; bpf_map__unpin(map, NULL); } return libbpf_err(err); } int bpf_object__unpin_maps(struct bpf_object *obj, const char *path) { struct bpf_map *map; int err; if (!obj) return libbpf_err(-ENOENT); bpf_object__for_each_map(map, obj) { char *pin_path = NULL; char buf[PATH_MAX]; if (path) { err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map)); if (err) return libbpf_err(err); sanitize_pin_path(buf); pin_path = buf; } else if (!map->pin_path) { continue; } err = bpf_map__unpin(map, pin_path); if (err) return libbpf_err(err); } return 0; } int bpf_object__pin_programs(struct bpf_object *obj, const char *path) { struct bpf_program *prog; char buf[PATH_MAX]; int err; if (!obj) return libbpf_err(-ENOENT); if (!obj->loaded) { pr_warn("object not yet loaded; load it first\n"); return libbpf_err(-ENOENT); } bpf_object__for_each_program(prog, obj) { err = pathname_concat(buf, sizeof(buf), path, prog->name); if (err) goto err_unpin_programs; err = bpf_program__pin(prog, buf); if (err) goto err_unpin_programs; } return 0; err_unpin_programs: while ((prog = bpf_object__prev_program(obj, prog))) { if (pathname_concat(buf, sizeof(buf), path, prog->name)) continue; bpf_program__unpin(prog, buf); } return libbpf_err(err); } int bpf_object__unpin_programs(struct bpf_object *obj, const char *path) { struct bpf_program *prog; int err; if (!obj) return libbpf_err(-ENOENT); bpf_object__for_each_program(prog, obj) { char buf[PATH_MAX]; err = pathname_concat(buf, sizeof(buf), path, prog->name); if (err) return libbpf_err(err); err = bpf_program__unpin(prog, buf); if (err) return libbpf_err(err); } return 0; } int bpf_object__pin(struct bpf_object *obj, const char *path) { int err; err = bpf_object__pin_maps(obj, path); if (err) return libbpf_err(err); err = bpf_object__pin_programs(obj, path); if (err) { bpf_object__unpin_maps(obj, path); return libbpf_err(err); } return 0; } int bpf_object__unpin(struct bpf_object *obj, const char *path) { int err; err = bpf_object__unpin_programs(obj, path); if (err) return libbpf_err(err); err = bpf_object__unpin_maps(obj, path); if (err) return libbpf_err(err); return 0; } static void bpf_map__destroy(struct bpf_map *map) { if (map->inner_map) { bpf_map__destroy(map->inner_map); zfree(&map->inner_map); } zfree(&map->init_slots); map->init_slots_sz = 0; if (map->mmaped) { size_t mmap_sz; mmap_sz = bpf_map_mmap_sz(map->def.value_size, map->def.max_entries); munmap(map->mmaped, mmap_sz); map->mmaped = NULL; } if (map->st_ops) { zfree(&map->st_ops->data); zfree(&map->st_ops->progs); zfree(&map->st_ops->kern_func_off); zfree(&map->st_ops); } zfree(&map->name); zfree(&map->real_name); zfree(&map->pin_path); if (map->fd >= 0) zclose(map->fd); } void bpf_object__close(struct bpf_object *obj) { size_t i; if (IS_ERR_OR_NULL(obj)) return; usdt_manager_free(obj->usdt_man); obj->usdt_man = NULL; bpf_gen__free(obj->gen_loader); bpf_object__elf_finish(obj); bpf_object_unload(obj); btf__free(obj->btf); btf__free(obj->btf_vmlinux); btf_ext__free(obj->btf_ext); for (i = 0; i < obj->nr_maps; i++) bpf_map__destroy(&obj->maps[i]); zfree(&obj->btf_custom_path); zfree(&obj->kconfig); for (i = 0; i < obj->nr_extern; i++) zfree(&obj->externs[i].essent_name); zfree(&obj->externs); obj->nr_extern = 0; zfree(&obj->maps); obj->nr_maps = 0; if (obj->programs && obj->nr_programs) { for (i = 0; i < obj->nr_programs; i++) bpf_program__exit(&obj->programs[i]); } zfree(&obj->programs); free(obj); } const char *bpf_object__name(const struct bpf_object *obj) { return obj ? obj->name : libbpf_err_ptr(-EINVAL); } unsigned int bpf_object__kversion(const struct bpf_object *obj) { return obj ? obj->kern_version : 0; } struct btf *bpf_object__btf(const struct bpf_object *obj) { return obj ? obj->btf : NULL; } int bpf_object__btf_fd(const struct bpf_object *obj) { return obj->btf ? btf__fd(obj->btf) : -1; } int bpf_object__set_kversion(struct bpf_object *obj, __u32 kern_version) { if (obj->loaded) return libbpf_err(-EINVAL); obj->kern_version = kern_version; return 0; } int bpf_object__gen_loader(struct bpf_object *obj, struct gen_loader_opts *opts) { struct bpf_gen *gen; if (!opts) return -EFAULT; if (!OPTS_VALID(opts, gen_loader_opts)) return -EINVAL; gen = calloc(sizeof(*gen), 1); if (!gen) return -ENOMEM; gen->opts = opts; obj->gen_loader = gen; return 0; } static struct bpf_program * __bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj, bool forward) { size_t nr_programs = obj->nr_programs; ssize_t idx; if (!nr_programs) return NULL; if (!p) /* Iter from the beginning */ return forward ? &obj->programs[0] : &obj->programs[nr_programs - 1]; if (p->obj != obj) { pr_warn("error: program handler doesn't match object\n"); return errno = EINVAL, NULL; } idx = (p - obj->programs) + (forward ? 1 : -1); if (idx >= obj->nr_programs || idx < 0) return NULL; return &obj->programs[idx]; } struct bpf_program * bpf_object__next_program(const struct bpf_object *obj, struct bpf_program *prev) { struct bpf_program *prog = prev; do { prog = __bpf_program__iter(prog, obj, true); } while (prog && prog_is_subprog(obj, prog)); return prog; } struct bpf_program * bpf_object__prev_program(const struct bpf_object *obj, struct bpf_program *next) { struct bpf_program *prog = next; do { prog = __bpf_program__iter(prog, obj, false); } while (prog && prog_is_subprog(obj, prog)); return prog; } void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex) { prog->prog_ifindex = ifindex; } const char *bpf_program__name(const struct bpf_program *prog) { return prog->name; } const char *bpf_program__section_name(const struct bpf_program *prog) { return prog->sec_name; } bool bpf_program__autoload(const struct bpf_program *prog) { return prog->autoload; } int bpf_program__set_autoload(struct bpf_program *prog, bool autoload) { if (prog->obj->loaded) return libbpf_err(-EINVAL); prog->autoload = autoload; return 0; } bool bpf_program__autoattach(const struct bpf_program *prog) { return prog->autoattach; } void bpf_program__set_autoattach(struct bpf_program *prog, bool autoattach) { prog->autoattach = autoattach; } const struct bpf_insn *bpf_program__insns(const struct bpf_program *prog) { return prog->insns; } size_t bpf_program__insn_cnt(const struct bpf_program *prog) { return prog->insns_cnt; } int bpf_program__set_insns(struct bpf_program *prog, struct bpf_insn *new_insns, size_t new_insn_cnt) { struct bpf_insn *insns; if (prog->obj->loaded) return -EBUSY; insns = libbpf_reallocarray(prog->insns, new_insn_cnt, sizeof(*insns)); /* NULL is a valid return from reallocarray if the new count is zero */ if (!insns && new_insn_cnt) { pr_warn("prog '%s': failed to realloc prog code\n", prog->name); return -ENOMEM; } memcpy(insns, new_insns, new_insn_cnt * sizeof(*insns)); prog->insns = insns; prog->insns_cnt = new_insn_cnt; return 0; } int bpf_program__fd(const struct bpf_program *prog) { if (!prog) return libbpf_err(-EINVAL); if (prog->fd < 0) return libbpf_err(-ENOENT); return prog->fd; } __alias(bpf_program__type) enum bpf_prog_type bpf_program__get_type(const struct bpf_program *prog); enum bpf_prog_type bpf_program__type(const struct bpf_program *prog) { return prog->type; } static size_t custom_sec_def_cnt; static struct bpf_sec_def *custom_sec_defs; static struct bpf_sec_def custom_fallback_def; static bool has_custom_fallback_def; static int last_custom_sec_def_handler_id; int bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type) { if (prog->obj->loaded) return libbpf_err(-EBUSY); /* if type is not changed, do nothing */ if (prog->type == type) return 0; prog->type = type; /* If a program type was changed, we need to reset associated SEC() * handler, as it will be invalid now. The only exception is a generic * fallback handler, which by definition is program type-agnostic and * is a catch-all custom handler, optionally set by the application, * so should be able to handle any type of BPF program. */ if (prog->sec_def != &custom_fallback_def) prog->sec_def = NULL; return 0; } __alias(bpf_program__expected_attach_type) enum bpf_attach_type bpf_program__get_expected_attach_type(const struct bpf_program *prog); enum bpf_attach_type bpf_program__expected_attach_type(const struct bpf_program *prog) { return prog->expected_attach_type; } int bpf_program__set_expected_attach_type(struct bpf_program *prog, enum bpf_attach_type type) { if (prog->obj->loaded) return libbpf_err(-EBUSY); prog->expected_attach_type = type; return 0; } __u32 bpf_program__flags(const struct bpf_program *prog) { return prog->prog_flags; } int bpf_program__set_flags(struct bpf_program *prog, __u32 flags) { if (prog->obj->loaded) return libbpf_err(-EBUSY); prog->prog_flags = flags; return 0; } __u32 bpf_program__log_level(const struct bpf_program *prog) { return prog->log_level; } int bpf_program__set_log_level(struct bpf_program *prog, __u32 log_level) { if (prog->obj->loaded) return libbpf_err(-EBUSY); prog->log_level = log_level; return 0; } const char *bpf_program__log_buf(const struct bpf_program *prog, size_t *log_size) { *log_size = prog->log_size; return prog->log_buf; } int bpf_program__set_log_buf(struct bpf_program *prog, char *log_buf, size_t log_size) { if (log_size && !log_buf) return -EINVAL; if (prog->log_size > UINT_MAX) return -EINVAL; if (prog->obj->loaded) return -EBUSY; prog->log_buf = log_buf; prog->log_size = log_size; return 0; } #define SEC_DEF(sec_pfx, ptype, atype, flags, ...) { \ .sec = (char *)sec_pfx, \ .prog_type = BPF_PROG_TYPE_##ptype, \ .expected_attach_type = atype, \ .cookie = (long)(flags), \ .prog_prepare_load_fn = libbpf_prepare_prog_load, \ __VA_ARGS__ \ } static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link); static int attach_uprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link); static int attach_ksyscall(const struct bpf_program *prog, long cookie, struct bpf_link **link); static int attach_usdt(const struct bpf_program *prog, long cookie, struct bpf_link **link); static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link); static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link); static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_link **link); static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link); static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link); static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link); static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link); static const struct bpf_sec_def section_defs[] = { SEC_DEF("socket", SOCKET_FILTER, 0, SEC_NONE), SEC_DEF("sk_reuseport/migrate", SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT_OR_MIGRATE, SEC_ATTACHABLE), SEC_DEF("sk_reuseport", SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT, SEC_ATTACHABLE), SEC_DEF("kprobe+", KPROBE, 0, SEC_NONE, attach_kprobe), SEC_DEF("uprobe+", KPROBE, 0, SEC_NONE, attach_uprobe), SEC_DEF("uprobe.s+", KPROBE, 0, SEC_SLEEPABLE, attach_uprobe), SEC_DEF("kretprobe+", KPROBE, 0, SEC_NONE, attach_kprobe), SEC_DEF("uretprobe+", KPROBE, 0, SEC_NONE, attach_uprobe), SEC_DEF("uretprobe.s+", KPROBE, 0, SEC_SLEEPABLE, attach_uprobe), SEC_DEF("kprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi), SEC_DEF("kretprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi), SEC_DEF("uprobe.multi+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi), SEC_DEF("uretprobe.multi+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi), SEC_DEF("uprobe.multi.s+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi), SEC_DEF("uretprobe.multi.s+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi), SEC_DEF("ksyscall+", KPROBE, 0, SEC_NONE, attach_ksyscall), SEC_DEF("kretsyscall+", KPROBE, 0, SEC_NONE, attach_ksyscall), SEC_DEF("usdt+", KPROBE, 0, SEC_USDT, attach_usdt), SEC_DEF("usdt.s+", KPROBE, 0, SEC_USDT | SEC_SLEEPABLE, attach_usdt), SEC_DEF("tc/ingress", SCHED_CLS, BPF_TCX_INGRESS, SEC_NONE), /* alias for tcx */ SEC_DEF("tc/egress", SCHED_CLS, BPF_TCX_EGRESS, SEC_NONE), /* alias for tcx */ SEC_DEF("tcx/ingress", SCHED_CLS, BPF_TCX_INGRESS, SEC_NONE), SEC_DEF("tcx/egress", SCHED_CLS, BPF_TCX_EGRESS, SEC_NONE), SEC_DEF("tc", SCHED_CLS, 0, SEC_NONE), /* deprecated / legacy, use tcx */ SEC_DEF("classifier", SCHED_CLS, 0, SEC_NONE), /* deprecated / legacy, use tcx */ SEC_DEF("action", SCHED_ACT, 0, SEC_NONE), /* deprecated / legacy, use tcx */ SEC_DEF("netkit/primary", SCHED_CLS, BPF_NETKIT_PRIMARY, SEC_NONE), SEC_DEF("netkit/peer", SCHED_CLS, BPF_NETKIT_PEER, SEC_NONE), SEC_DEF("tracepoint+", TRACEPOINT, 0, SEC_NONE, attach_tp), SEC_DEF("tp+", TRACEPOINT, 0, SEC_NONE, attach_tp), SEC_DEF("raw_tracepoint+", RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp), SEC_DEF("raw_tp+", RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp), SEC_DEF("raw_tracepoint.w+", RAW_TRACEPOINT_WRITABLE, 0, SEC_NONE, attach_raw_tp), SEC_DEF("raw_tp.w+", RAW_TRACEPOINT_WRITABLE, 0, SEC_NONE, attach_raw_tp), SEC_DEF("tp_btf+", TRACING, BPF_TRACE_RAW_TP, SEC_ATTACH_BTF, attach_trace), SEC_DEF("fentry+", TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF, attach_trace), SEC_DEF("fmod_ret+", TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF, attach_trace), SEC_DEF("fexit+", TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF, attach_trace), SEC_DEF("fentry.s+", TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), SEC_DEF("fmod_ret.s+", TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), SEC_DEF("fexit.s+", TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), SEC_DEF("freplace+", EXT, 0, SEC_ATTACH_BTF, attach_trace), SEC_DEF("lsm+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF, attach_lsm), SEC_DEF("lsm.s+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_lsm), SEC_DEF("lsm_cgroup+", LSM, BPF_LSM_CGROUP, SEC_ATTACH_BTF), SEC_DEF("iter+", TRACING, BPF_TRACE_ITER, SEC_ATTACH_BTF, attach_iter), SEC_DEF("iter.s+", TRACING, BPF_TRACE_ITER, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_iter), SEC_DEF("syscall", SYSCALL, 0, SEC_SLEEPABLE), SEC_DEF("xdp.frags/devmap", XDP, BPF_XDP_DEVMAP, SEC_XDP_FRAGS), SEC_DEF("xdp/devmap", XDP, BPF_XDP_DEVMAP, SEC_ATTACHABLE), SEC_DEF("xdp.frags/cpumap", XDP, BPF_XDP_CPUMAP, SEC_XDP_FRAGS), SEC_DEF("xdp/cpumap", XDP, BPF_XDP_CPUMAP, SEC_ATTACHABLE), SEC_DEF("xdp.frags", XDP, BPF_XDP, SEC_XDP_FRAGS), SEC_DEF("xdp", XDP, BPF_XDP, SEC_ATTACHABLE_OPT), SEC_DEF("perf_event", PERF_EVENT, 0, SEC_NONE), SEC_DEF("lwt_in", LWT_IN, 0, SEC_NONE), SEC_DEF("lwt_out", LWT_OUT, 0, SEC_NONE), SEC_DEF("lwt_xmit", LWT_XMIT, 0, SEC_NONE), SEC_DEF("lwt_seg6local", LWT_SEG6LOCAL, 0, SEC_NONE), SEC_DEF("sockops", SOCK_OPS, BPF_CGROUP_SOCK_OPS, SEC_ATTACHABLE_OPT), SEC_DEF("sk_skb/stream_parser", SK_SKB, BPF_SK_SKB_STREAM_PARSER, SEC_ATTACHABLE_OPT), SEC_DEF("sk_skb/stream_verdict",SK_SKB, BPF_SK_SKB_STREAM_VERDICT, SEC_ATTACHABLE_OPT), SEC_DEF("sk_skb", SK_SKB, 0, SEC_NONE), SEC_DEF("sk_msg", SK_MSG, BPF_SK_MSG_VERDICT, SEC_ATTACHABLE_OPT), SEC_DEF("lirc_mode2", LIRC_MODE2, BPF_LIRC_MODE2, SEC_ATTACHABLE_OPT), SEC_DEF("flow_dissector", FLOW_DISSECTOR, BPF_FLOW_DISSECTOR, SEC_ATTACHABLE_OPT), SEC_DEF("cgroup_skb/ingress", CGROUP_SKB, BPF_CGROUP_INET_INGRESS, SEC_ATTACHABLE_OPT), SEC_DEF("cgroup_skb/egress", CGROUP_SKB, BPF_CGROUP_INET_EGRESS, SEC_ATTACHABLE_OPT), SEC_DEF("cgroup/skb", CGROUP_SKB, 0, SEC_NONE), SEC_DEF("cgroup/sock_create", CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE), SEC_DEF("cgroup/sock_release", CGROUP_SOCK, BPF_CGROUP_INET_SOCK_RELEASE, SEC_ATTACHABLE), SEC_DEF("cgroup/sock", CGROUP_SOCK, BPF_CGROUP_INET_SOCK_CREATE, SEC_ATTACHABLE_OPT), SEC_DEF("cgroup/post_bind4", CGROUP_SOCK, BPF_CGROUP_INET4_POST_BIND, SEC_ATTACHABLE), SEC_DEF("cgroup/post_bind6", CGROUP_SOCK, BPF_CGROUP_INET6_POST_BIND, SEC_ATTACHABLE), SEC_DEF("cgroup/bind4", CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_BIND, SEC_ATTACHABLE), SEC_DEF("cgroup/bind6", CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_BIND, SEC_ATTACHABLE), SEC_DEF("cgroup/connect4", CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_CONNECT, SEC_ATTACHABLE), SEC_DEF("cgroup/connect6", CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_CONNECT, SEC_ATTACHABLE), SEC_DEF("cgroup/connect_unix", CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_CONNECT, SEC_ATTACHABLE), SEC_DEF("cgroup/sendmsg4", CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_SENDMSG, SEC_ATTACHABLE), SEC_DEF("cgroup/sendmsg6", CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_SENDMSG, SEC_ATTACHABLE), SEC_DEF("cgroup/sendmsg_unix", CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_SENDMSG, SEC_ATTACHABLE), SEC_DEF("cgroup/recvmsg4", CGROUP_SOCK_ADDR, BPF_CGROUP_UDP4_RECVMSG, SEC_ATTACHABLE), SEC_DEF("cgroup/recvmsg6", CGROUP_SOCK_ADDR, BPF_CGROUP_UDP6_RECVMSG, SEC_ATTACHABLE), SEC_DEF("cgroup/recvmsg_unix", CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_RECVMSG, SEC_ATTACHABLE), SEC_DEF("cgroup/getpeername4", CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETPEERNAME, SEC_ATTACHABLE), SEC_DEF("cgroup/getpeername6", CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETPEERNAME, SEC_ATTACHABLE), SEC_DEF("cgroup/getpeername_unix", CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_GETPEERNAME, SEC_ATTACHABLE), SEC_DEF("cgroup/getsockname4", CGROUP_SOCK_ADDR, BPF_CGROUP_INET4_GETSOCKNAME, SEC_ATTACHABLE), SEC_DEF("cgroup/getsockname6", CGROUP_SOCK_ADDR, BPF_CGROUP_INET6_GETSOCKNAME, SEC_ATTACHABLE), SEC_DEF("cgroup/getsockname_unix", CGROUP_SOCK_ADDR, BPF_CGROUP_UNIX_GETSOCKNAME, SEC_ATTACHABLE), SEC_DEF("cgroup/sysctl", CGROUP_SYSCTL, BPF_CGROUP_SYSCTL, SEC_ATTACHABLE), SEC_DEF("cgroup/getsockopt", CGROUP_SOCKOPT, BPF_CGROUP_GETSOCKOPT, SEC_ATTACHABLE), SEC_DEF("cgroup/setsockopt", CGROUP_SOCKOPT, BPF_CGROUP_SETSOCKOPT, SEC_ATTACHABLE), SEC_DEF("cgroup/dev", CGROUP_DEVICE, BPF_CGROUP_DEVICE, SEC_ATTACHABLE_OPT), SEC_DEF("struct_ops+", STRUCT_OPS, 0, SEC_NONE), SEC_DEF("struct_ops.s+", STRUCT_OPS, 0, SEC_SLEEPABLE), SEC_DEF("sk_lookup", SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE), SEC_DEF("netfilter", NETFILTER, BPF_NETFILTER, SEC_NONE), }; int libbpf_register_prog_handler(const char *sec, enum bpf_prog_type prog_type, enum bpf_attach_type exp_attach_type, const struct libbpf_prog_handler_opts *opts) { struct bpf_sec_def *sec_def; if (!OPTS_VALID(opts, libbpf_prog_handler_opts)) return libbpf_err(-EINVAL); if (last_custom_sec_def_handler_id == INT_MAX) /* prevent overflow */ return libbpf_err(-E2BIG); if (sec) { sec_def = libbpf_reallocarray(custom_sec_defs, custom_sec_def_cnt + 1, sizeof(*sec_def)); if (!sec_def) return libbpf_err(-ENOMEM); custom_sec_defs = sec_def; sec_def = &custom_sec_defs[custom_sec_def_cnt]; } else { if (has_custom_fallback_def) return libbpf_err(-EBUSY); sec_def = &custom_fallback_def; } sec_def->sec = sec ? strdup(sec) : NULL; if (sec && !sec_def->sec) return libbpf_err(-ENOMEM); sec_def->prog_type = prog_type; sec_def->expected_attach_type = exp_attach_type; sec_def->cookie = OPTS_GET(opts, cookie, 0); sec_def->prog_setup_fn = OPTS_GET(opts, prog_setup_fn, NULL); sec_def->prog_prepare_load_fn = OPTS_GET(opts, prog_prepare_load_fn, NULL); sec_def->prog_attach_fn = OPTS_GET(opts, prog_attach_fn, NULL); sec_def->handler_id = ++last_custom_sec_def_handler_id; if (sec) custom_sec_def_cnt++; else has_custom_fallback_def = true; return sec_def->handler_id; } int libbpf_unregister_prog_handler(int handler_id) { struct bpf_sec_def *sec_defs; int i; if (handler_id <= 0) return libbpf_err(-EINVAL); if (has_custom_fallback_def && custom_fallback_def.handler_id == handler_id) { memset(&custom_fallback_def, 0, sizeof(custom_fallback_def)); has_custom_fallback_def = false; return 0; } for (i = 0; i < custom_sec_def_cnt; i++) { if (custom_sec_defs[i].handler_id == handler_id) break; } if (i == custom_sec_def_cnt) return libbpf_err(-ENOENT); free(custom_sec_defs[i].sec); for (i = i + 1; i < custom_sec_def_cnt; i++) custom_sec_defs[i - 1] = custom_sec_defs[i]; custom_sec_def_cnt--; /* try to shrink the array, but it's ok if we couldn't */ sec_defs = libbpf_reallocarray(custom_sec_defs, custom_sec_def_cnt, sizeof(*sec_defs)); /* if new count is zero, reallocarray can return a valid NULL result; * in this case the previous pointer will be freed, so we *have to* * reassign old pointer to the new value (even if it's NULL) */ if (sec_defs || custom_sec_def_cnt == 0) custom_sec_defs = sec_defs; return 0; } static bool sec_def_matches(const struct bpf_sec_def *sec_def, const char *sec_name) { size_t len = strlen(sec_def->sec); /* "type/" always has to have proper SEC("type/extras") form */ if (sec_def->sec[len - 1] == '/') { if (str_has_pfx(sec_name, sec_def->sec)) return true; return false; } /* "type+" means it can be either exact SEC("type") or * well-formed SEC("type/extras") with proper '/' separator */ if (sec_def->sec[len - 1] == '+') { len--; /* not even a prefix */ if (strncmp(sec_name, sec_def->sec, len) != 0) return false; /* exact match or has '/' separator */ if (sec_name[len] == '\0' || sec_name[len] == '/') return true; return false; } return strcmp(sec_name, sec_def->sec) == 0; } static const struct bpf_sec_def *find_sec_def(const char *sec_name) { const struct bpf_sec_def *sec_def; int i, n; n = custom_sec_def_cnt; for (i = 0; i < n; i++) { sec_def = &custom_sec_defs[i]; if (sec_def_matches(sec_def, sec_name)) return sec_def; } n = ARRAY_SIZE(section_defs); for (i = 0; i < n; i++) { sec_def = §ion_defs[i]; if (sec_def_matches(sec_def, sec_name)) return sec_def; } if (has_custom_fallback_def) return &custom_fallback_def; return NULL; } #define MAX_TYPE_NAME_SIZE 32 static char *libbpf_get_type_names(bool attach_type) { int i, len = ARRAY_SIZE(section_defs) * MAX_TYPE_NAME_SIZE; char *buf; buf = malloc(len); if (!buf) return NULL; buf[0] = '\0'; /* Forge string buf with all available names */ for (i = 0; i < ARRAY_SIZE(section_defs); i++) { const struct bpf_sec_def *sec_def = §ion_defs[i]; if (attach_type) { if (sec_def->prog_prepare_load_fn != libbpf_prepare_prog_load) continue; if (!(sec_def->cookie & SEC_ATTACHABLE)) continue; } if (strlen(buf) + strlen(section_defs[i].sec) + 2 > len) { free(buf); return NULL; } strcat(buf, " "); strcat(buf, section_defs[i].sec); } return buf; } int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type, enum bpf_attach_type *expected_attach_type) { const struct bpf_sec_def *sec_def; char *type_names; if (!name) return libbpf_err(-EINVAL); sec_def = find_sec_def(name); if (sec_def) { *prog_type = sec_def->prog_type; *expected_attach_type = sec_def->expected_attach_type; return 0; } pr_debug("failed to guess program type from ELF section '%s'\n", name); type_names = libbpf_get_type_names(false); if (type_names != NULL) { pr_debug("supported section(type) names are:%s\n", type_names); free(type_names); } return libbpf_err(-ESRCH); } const char *libbpf_bpf_attach_type_str(enum bpf_attach_type t) { if (t < 0 || t >= ARRAY_SIZE(attach_type_name)) return NULL; return attach_type_name[t]; } const char *libbpf_bpf_link_type_str(enum bpf_link_type t) { if (t < 0 || t >= ARRAY_SIZE(link_type_name)) return NULL; return link_type_name[t]; } const char *libbpf_bpf_map_type_str(enum bpf_map_type t) { if (t < 0 || t >= ARRAY_SIZE(map_type_name)) return NULL; return map_type_name[t]; } const char *libbpf_bpf_prog_type_str(enum bpf_prog_type t) { if (t < 0 || t >= ARRAY_SIZE(prog_type_name)) return NULL; return prog_type_name[t]; } static struct bpf_map *find_struct_ops_map_by_offset(struct bpf_object *obj, int sec_idx, size_t offset) { struct bpf_map *map; size_t i; for (i = 0; i < obj->nr_maps; i++) { map = &obj->maps[i]; if (!bpf_map__is_struct_ops(map)) continue; if (map->sec_idx == sec_idx && map->sec_offset <= offset && offset - map->sec_offset < map->def.value_size) return map; } return NULL; } /* Collect the reloc from ELF and populate the st_ops->progs[] */ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj, Elf64_Shdr *shdr, Elf_Data *data) { const struct btf_member *member; struct bpf_struct_ops *st_ops; struct bpf_program *prog; unsigned int shdr_idx; const struct btf *btf; struct bpf_map *map; unsigned int moff, insn_idx; const char *name; __u32 member_idx; Elf64_Sym *sym; Elf64_Rel *rel; int i, nrels; btf = obj->btf; nrels = shdr->sh_size / shdr->sh_entsize; for (i = 0; i < nrels; i++) { rel = elf_rel_by_idx(data, i); if (!rel) { pr_warn("struct_ops reloc: failed to get %d reloc\n", i); return -LIBBPF_ERRNO__FORMAT; } sym = elf_sym_by_idx(obj, ELF64_R_SYM(rel->r_info)); if (!sym) { pr_warn("struct_ops reloc: symbol %zx not found\n", (size_t)ELF64_R_SYM(rel->r_info)); return -LIBBPF_ERRNO__FORMAT; } name = elf_sym_str(obj, sym->st_name) ?: "<?>"; map = find_struct_ops_map_by_offset(obj, shdr->sh_info, rel->r_offset); if (!map) { pr_warn("struct_ops reloc: cannot find map at rel->r_offset %zu\n", (size_t)rel->r_offset); return -EINVAL; } moff = rel->r_offset - map->sec_offset; shdr_idx = sym->st_shndx; st_ops = map->st_ops; pr_debug("struct_ops reloc %s: for %lld value %lld shdr_idx %u rel->r_offset %zu map->sec_offset %zu name %d (\'%s\')\n", map->name, (long long)(rel->r_info >> 32), (long long)sym->st_value, shdr_idx, (size_t)rel->r_offset, map->sec_offset, sym->st_name, name); if (shdr_idx >= SHN_LORESERVE) { pr_warn("struct_ops reloc %s: rel->r_offset %zu shdr_idx %u unsupported non-static function\n", map->name, (size_t)rel->r_offset, shdr_idx); return -LIBBPF_ERRNO__RELOC; } if (sym->st_value % BPF_INSN_SZ) { pr_warn("struct_ops reloc %s: invalid target program offset %llu\n", map->name, (unsigned long long)sym->st_value); return -LIBBPF_ERRNO__FORMAT; } insn_idx = sym->st_value / BPF_INSN_SZ; member = find_member_by_offset(st_ops->type, moff * 8); if (!member) { pr_warn("struct_ops reloc %s: cannot find member at moff %u\n", map->name, moff); return -EINVAL; } member_idx = member - btf_members(st_ops->type); name = btf__name_by_offset(btf, member->name_off); if (!resolve_func_ptr(btf, member->type, NULL)) { pr_warn("struct_ops reloc %s: cannot relocate non func ptr %s\n", map->name, name); return -EINVAL; } prog = find_prog_by_sec_insn(obj, shdr_idx, insn_idx); if (!prog) { pr_warn("struct_ops reloc %s: cannot find prog at shdr_idx %u to relocate func ptr %s\n", map->name, shdr_idx, name); return -EINVAL; } /* prevent the use of BPF prog with invalid type */ if (prog->type != BPF_PROG_TYPE_STRUCT_OPS) { pr_warn("struct_ops reloc %s: prog %s is not struct_ops BPF program\n", map->name, prog->name); return -EINVAL; } /* if we haven't yet processed this BPF program, record proper * attach_btf_id and member_idx */ if (!prog->attach_btf_id) { prog->attach_btf_id = st_ops->type_id; prog->expected_attach_type = member_idx; } /* struct_ops BPF prog can be re-used between multiple * .struct_ops & .struct_ops.link as long as it's the * same struct_ops struct definition and the same * function pointer field */ if (prog->attach_btf_id != st_ops->type_id || prog->expected_attach_type != member_idx) { pr_warn("struct_ops reloc %s: cannot use prog %s in sec %s with type %u attach_btf_id %u expected_attach_type %u for func ptr %s\n", map->name, prog->name, prog->sec_name, prog->type, prog->attach_btf_id, prog->expected_attach_type, name); return -EINVAL; } st_ops->progs[member_idx] = prog; } return 0; } #define BTF_TRACE_PREFIX "btf_trace_" #define BTF_LSM_PREFIX "bpf_lsm_" #define BTF_ITER_PREFIX "bpf_iter_" #define BTF_MAX_NAME_SIZE 128 void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type, const char **prefix, int *kind) { switch (attach_type) { case BPF_TRACE_RAW_TP: *prefix = BTF_TRACE_PREFIX; *kind = BTF_KIND_TYPEDEF; break; case BPF_LSM_MAC: case BPF_LSM_CGROUP: *prefix = BTF_LSM_PREFIX; *kind = BTF_KIND_FUNC; break; case BPF_TRACE_ITER: *prefix = BTF_ITER_PREFIX; *kind = BTF_KIND_FUNC; break; default: *prefix = ""; *kind = BTF_KIND_FUNC; } } static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix, const char *name, __u32 kind) { char btf_type_name[BTF_MAX_NAME_SIZE]; int ret; ret = snprintf(btf_type_name, sizeof(btf_type_name), "%s%s", prefix, name); /* snprintf returns the number of characters written excluding the * terminating null. So, if >= BTF_MAX_NAME_SIZE are written, it * indicates truncation. */ if (ret < 0 || ret >= sizeof(btf_type_name)) return -ENAMETOOLONG; return btf__find_by_name_kind(btf, btf_type_name, kind); } static inline int find_attach_btf_id(struct btf *btf, const char *name, enum bpf_attach_type attach_type) { const char *prefix; int kind; btf_get_kernel_prefix_kind(attach_type, &prefix, &kind); return find_btf_by_prefix_kind(btf, prefix, name, kind); } int libbpf_find_vmlinux_btf_id(const char *name, enum bpf_attach_type attach_type) { struct btf *btf; int err; btf = btf__load_vmlinux_btf(); err = libbpf_get_error(btf); if (err) { pr_warn("vmlinux BTF is not found\n"); return libbpf_err(err); } err = find_attach_btf_id(btf, name, attach_type); if (err <= 0) pr_warn("%s is not found in vmlinux BTF\n", name); btf__free(btf); return libbpf_err(err); } static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd) { struct bpf_prog_info info; __u32 info_len = sizeof(info); struct btf *btf; int err; memset(&info, 0, info_len); err = bpf_prog_get_info_by_fd(attach_prog_fd, &info, &info_len); if (err) { pr_warn("failed bpf_prog_get_info_by_fd for FD %d: %d\n", attach_prog_fd, err); return err; } err = -EINVAL; if (!info.btf_id) { pr_warn("The target program doesn't have BTF\n"); goto out; } btf = btf__load_from_kernel_by_id(info.btf_id); err = libbpf_get_error(btf); if (err) { pr_warn("Failed to get BTF %d of the program: %d\n", info.btf_id, err); goto out; } err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC); btf__free(btf); if (err <= 0) { pr_warn("%s is not found in prog's BTF\n", name); goto out; } out: return err; } static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name, enum bpf_attach_type attach_type, int *btf_obj_fd, int *btf_type_id) { int ret, i; ret = find_attach_btf_id(obj->btf_vmlinux, attach_name, attach_type); if (ret > 0) { *btf_obj_fd = 0; /* vmlinux BTF */ *btf_type_id = ret; return 0; } if (ret != -ENOENT) return ret; ret = load_module_btfs(obj); if (ret) return ret; for (i = 0; i < obj->btf_module_cnt; i++) { const struct module_btf *mod = &obj->btf_modules[i]; ret = find_attach_btf_id(mod->btf, attach_name, attach_type); if (ret > 0) { *btf_obj_fd = mod->fd; *btf_type_id = ret; return 0; } if (ret == -ENOENT) continue; return ret; } return -ESRCH; } static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attach_name, int *btf_obj_fd, int *btf_type_id) { enum bpf_attach_type attach_type = prog->expected_attach_type; __u32 attach_prog_fd = prog->attach_prog_fd; int err = 0; /* BPF program's BTF ID */ if (prog->type == BPF_PROG_TYPE_EXT || attach_prog_fd) { if (!attach_prog_fd) { pr_warn("prog '%s': attach program FD is not set\n", prog->name); return -EINVAL; } err = libbpf_find_prog_btf_id(attach_name, attach_prog_fd); if (err < 0) { pr_warn("prog '%s': failed to find BPF program (FD %d) BTF ID for '%s': %d\n", prog->name, attach_prog_fd, attach_name, err); return err; } *btf_obj_fd = 0; *btf_type_id = err; return 0; } /* kernel/module BTF ID */ if (prog->obj->gen_loader) { bpf_gen__record_attach_target(prog->obj->gen_loader, attach_name, attach_type); *btf_obj_fd = 0; *btf_type_id = 1; } else { err = find_kernel_btf_id(prog->obj, attach_name, attach_type, btf_obj_fd, btf_type_id); } if (err) { pr_warn("prog '%s': failed to find kernel BTF type ID of '%s': %d\n", prog->name, attach_name, err); return err; } return 0; } int libbpf_attach_type_by_name(const char *name, enum bpf_attach_type *attach_type) { char *type_names; const struct bpf_sec_def *sec_def; if (!name) return libbpf_err(-EINVAL); sec_def = find_sec_def(name); if (!sec_def) { pr_debug("failed to guess attach type based on ELF section name '%s'\n", name); type_names = libbpf_get_type_names(true); if (type_names != NULL) { pr_debug("attachable section(type) names are:%s\n", type_names); free(type_names); } return libbpf_err(-EINVAL); } if (sec_def->prog_prepare_load_fn != libbpf_prepare_prog_load) return libbpf_err(-EINVAL); if (!(sec_def->cookie & SEC_ATTACHABLE)) return libbpf_err(-EINVAL); *attach_type = sec_def->expected_attach_type; return 0; } int bpf_map__fd(const struct bpf_map *map) { return map ? map->fd : libbpf_err(-EINVAL); } static bool map_uses_real_name(const struct bpf_map *map) { /* Since libbpf started to support custom .data.* and .rodata.* maps, * their user-visible name differs from kernel-visible name. Users see * such map's corresponding ELF section name as a map name. * This check distinguishes .data/.rodata from .data.* and .rodata.* * maps to know which name has to be returned to the user. */ if (map->libbpf_type == LIBBPF_MAP_DATA && strcmp(map->real_name, DATA_SEC) != 0) return true; if (map->libbpf_type == LIBBPF_MAP_RODATA && strcmp(map->real_name, RODATA_SEC) != 0) return true; return false; } const char *bpf_map__name(const struct bpf_map *map) { if (!map) return NULL; if (map_uses_real_name(map)) return map->real_name; return map->name; } enum bpf_map_type bpf_map__type(const struct bpf_map *map) { return map->def.type; } int bpf_map__set_type(struct bpf_map *map, enum bpf_map_type type) { if (map->fd >= 0) return libbpf_err(-EBUSY); map->def.type = type; return 0; } __u32 bpf_map__map_flags(const struct bpf_map *map) { return map->def.map_flags; } int bpf_map__set_map_flags(struct bpf_map *map, __u32 flags) { if (map->fd >= 0) return libbpf_err(-EBUSY); map->def.map_flags = flags; return 0; } __u64 bpf_map__map_extra(const struct bpf_map *map) { return map->map_extra; } int bpf_map__set_map_extra(struct bpf_map *map, __u64 map_extra) { if (map->fd >= 0) return libbpf_err(-EBUSY); map->map_extra = map_extra; return 0; } __u32 bpf_map__numa_node(const struct bpf_map *map) { return map->numa_node; } int bpf_map__set_numa_node(struct bpf_map *map, __u32 numa_node) { if (map->fd >= 0) return libbpf_err(-EBUSY); map->numa_node = numa_node; return 0; } __u32 bpf_map__key_size(const struct bpf_map *map) { return map->def.key_size; } int bpf_map__set_key_size(struct bpf_map *map, __u32 size) { if (map->fd >= 0) return libbpf_err(-EBUSY); map->def.key_size = size; return 0; } __u32 bpf_map__value_size(const struct bpf_map *map) { return map->def.value_size; } static int map_btf_datasec_resize(struct bpf_map *map, __u32 size) { struct btf *btf; struct btf_type *datasec_type, *var_type; struct btf_var_secinfo *var; const struct btf_type *array_type; const struct btf_array *array; int vlen, element_sz, new_array_id; __u32 nr_elements; /* check btf existence */ btf = bpf_object__btf(map->obj); if (!btf) return -ENOENT; /* verify map is datasec */ datasec_type = btf_type_by_id(btf, bpf_map__btf_value_type_id(map)); if (!btf_is_datasec(datasec_type)) { pr_warn("map '%s': cannot be resized, map value type is not a datasec\n", bpf_map__name(map)); return -EINVAL; } /* verify datasec has at least one var */ vlen = btf_vlen(datasec_type); if (vlen == 0) { pr_warn("map '%s': cannot be resized, map value datasec is empty\n", bpf_map__name(map)); return -EINVAL; } /* verify last var in the datasec is an array */ var = &btf_var_secinfos(datasec_type)[vlen - 1]; var_type = btf_type_by_id(btf, var->type); array_type = skip_mods_and_typedefs(btf, var_type->type, NULL); if (!btf_is_array(array_type)) { pr_warn("map '%s': cannot be resized, last var must be an array\n", bpf_map__name(map)); return -EINVAL; } /* verify request size aligns with array */ array = btf_array(array_type); element_sz = btf__resolve_size(btf, array->type); if (element_sz <= 0 || (size - var->offset) % element_sz != 0) { pr_warn("map '%s': cannot be resized, element size (%d) doesn't align with new total size (%u)\n", bpf_map__name(map), element_sz, size); return -EINVAL; } /* create a new array based on the existing array, but with new length */ nr_elements = (size - var->offset) / element_sz; new_array_id = btf__add_array(btf, array->index_type, array->type, nr_elements); if (new_array_id < 0) return new_array_id; /* adding a new btf type invalidates existing pointers to btf objects, * so refresh pointers before proceeding */ datasec_type = btf_type_by_id(btf, map->btf_value_type_id); var = &btf_var_secinfos(datasec_type)[vlen - 1]; var_type = btf_type_by_id(btf, var->type); /* finally update btf info */ datasec_type->size = size; var->size = size - var->offset; var_type->type = new_array_id; return 0; } int bpf_map__set_value_size(struct bpf_map *map, __u32 size) { if (map->fd >= 0) return libbpf_err(-EBUSY); if (map->mmaped) { int err; size_t mmap_old_sz, mmap_new_sz; mmap_old_sz = bpf_map_mmap_sz(map->def.value_size, map->def.max_entries); mmap_new_sz = bpf_map_mmap_sz(size, map->def.max_entries); err = bpf_map_mmap_resize(map, mmap_old_sz, mmap_new_sz); if (err) { pr_warn("map '%s': failed to resize memory-mapped region: %d\n", bpf_map__name(map), err); return err; } err = map_btf_datasec_resize(map, size); if (err && err != -ENOENT) { pr_warn("map '%s': failed to adjust resized BTF, clearing BTF key/value info: %d\n", bpf_map__name(map), err); map->btf_value_type_id = 0; map->btf_key_type_id = 0; } } map->def.value_size = size; return 0; } __u32 bpf_map__btf_key_type_id(const struct bpf_map *map) { return map ? map->btf_key_type_id : 0; } __u32 bpf_map__btf_value_type_id(const struct bpf_map *map) { return map ? map->btf_value_type_id : 0; } int bpf_map__set_initial_value(struct bpf_map *map, const void *data, size_t size) { if (!map->mmaped || map->libbpf_type == LIBBPF_MAP_KCONFIG || size != map->def.value_size || map->fd >= 0) return libbpf_err(-EINVAL); memcpy(map->mmaped, data, size); return 0; } void *bpf_map__initial_value(struct bpf_map *map, size_t *psize) { if (!map->mmaped) return NULL; *psize = map->def.value_size; return map->mmaped; } bool bpf_map__is_internal(const struct bpf_map *map) { return map->libbpf_type != LIBBPF_MAP_UNSPEC; } __u32 bpf_map__ifindex(const struct bpf_map *map) { return map->map_ifindex; } int bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex) { if (map->fd >= 0) return libbpf_err(-EBUSY); map->map_ifindex = ifindex; return 0; } int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd) { if (!bpf_map_type__is_map_in_map(map->def.type)) { pr_warn("error: unsupported map type\n"); return libbpf_err(-EINVAL); } if (map->inner_map_fd != -1) { pr_warn("error: inner_map_fd already specified\n"); return libbpf_err(-EINVAL); } if (map->inner_map) { bpf_map__destroy(map->inner_map); zfree(&map->inner_map); } map->inner_map_fd = fd; return 0; } static struct bpf_map * __bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i) { ssize_t idx; struct bpf_map *s, *e; if (!obj || !obj->maps) return errno = EINVAL, NULL; s = obj->maps; e = obj->maps + obj->nr_maps; if ((m < s) || (m >= e)) { pr_warn("error in %s: map handler doesn't belong to object\n", __func__); return errno = EINVAL, NULL; } idx = (m - obj->maps) + i; if (idx >= obj->nr_maps || idx < 0) return NULL; return &obj->maps[idx]; } struct bpf_map * bpf_object__next_map(const struct bpf_object *obj, const struct bpf_map *prev) { if (prev == NULL) return obj->maps; return __bpf_map__iter(prev, obj, 1); } struct bpf_map * bpf_object__prev_map(const struct bpf_object *obj, const struct bpf_map *next) { if (next == NULL) { if (!obj->nr_maps) return NULL; return obj->maps + obj->nr_maps - 1; } return __bpf_map__iter(next, obj, -1); } struct bpf_map * bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name) { struct bpf_map *pos; bpf_object__for_each_map(pos, obj) { /* if it's a special internal map name (which always starts * with dot) then check if that special name matches the * real map name (ELF section name) */ if (name[0] == '.') { if (pos->real_name && strcmp(pos->real_name, name) == 0) return pos; continue; } /* otherwise map name has to be an exact match */ if (map_uses_real_name(pos)) { if (strcmp(pos->real_name, name) == 0) return pos; continue; } if (strcmp(pos->name, name) == 0) return pos; } return errno = ENOENT, NULL; } int bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name) { return bpf_map__fd(bpf_object__find_map_by_name(obj, name)); } static int validate_map_op(const struct bpf_map *map, size_t key_sz, size_t value_sz, bool check_value_sz) { if (map->fd <= 0) return -ENOENT; if (map->def.key_size != key_sz) { pr_warn("map '%s': unexpected key size %zu provided, expected %u\n", map->name, key_sz, map->def.key_size); return -EINVAL; } if (!check_value_sz) return 0; switch (map->def.type) { case BPF_MAP_TYPE_PERCPU_ARRAY: case BPF_MAP_TYPE_PERCPU_HASH: case BPF_MAP_TYPE_LRU_PERCPU_HASH: case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE: { int num_cpu = libbpf_num_possible_cpus(); size_t elem_sz = roundup(map->def.value_size, 8); if (value_sz != num_cpu * elem_sz) { pr_warn("map '%s': unexpected value size %zu provided for per-CPU map, expected %d * %zu = %zd\n", map->name, value_sz, num_cpu, elem_sz, num_cpu * elem_sz); return -EINVAL; } break; } default: if (map->def.value_size != value_sz) { pr_warn("map '%s': unexpected value size %zu provided, expected %u\n", map->name, value_sz, map->def.value_size); return -EINVAL; } break; } return 0; } int bpf_map__lookup_elem(const struct bpf_map *map, const void *key, size_t key_sz, void *value, size_t value_sz, __u64 flags) { int err; err = validate_map_op(map, key_sz, value_sz, true); if (err) return libbpf_err(err); return bpf_map_lookup_elem_flags(map->fd, key, value, flags); } int bpf_map__update_elem(const struct bpf_map *map, const void *key, size_t key_sz, const void *value, size_t value_sz, __u64 flags) { int err; err = validate_map_op(map, key_sz, value_sz, true); if (err) return libbpf_err(err); return bpf_map_update_elem(map->fd, key, value, flags); } int bpf_map__delete_elem(const struct bpf_map *map, const void *key, size_t key_sz, __u64 flags) { int err; err = validate_map_op(map, key_sz, 0, false /* check_value_sz */); if (err) return libbpf_err(err); return bpf_map_delete_elem_flags(map->fd, key, flags); } int bpf_map__lookup_and_delete_elem(const struct bpf_map *map, const void *key, size_t key_sz, void *value, size_t value_sz, __u64 flags) { int err; err = validate_map_op(map, key_sz, value_sz, true); if (err) return libbpf_err(err); return bpf_map_lookup_and_delete_elem_flags(map->fd, key, value, flags); } int bpf_map__get_next_key(const struct bpf_map *map, const void *cur_key, void *next_key, size_t key_sz) { int err; err = validate_map_op(map, key_sz, 0, false /* check_value_sz */); if (err) return libbpf_err(err); return bpf_map_get_next_key(map->fd, cur_key, next_key); } long libbpf_get_error(const void *ptr) { if (!IS_ERR_OR_NULL(ptr)) return 0; if (IS_ERR(ptr)) errno = -PTR_ERR(ptr); /* If ptr == NULL, then errno should be already set by the failing * API, because libbpf never returns NULL on success and it now always * sets errno on error. So no extra errno handling for ptr == NULL * case. */ return -errno; } /* Replace link's underlying BPF program with the new one */ int bpf_link__update_program(struct bpf_link *link, struct bpf_program *prog) { int ret; ret = bpf_link_update(bpf_link__fd(link), bpf_program__fd(prog), NULL); return libbpf_err_errno(ret); } /* Release "ownership" of underlying BPF resource (typically, BPF program * attached to some BPF hook, e.g., tracepoint, kprobe, etc). Disconnected * link, when destructed through bpf_link__destroy() call won't attempt to * detach/unregisted that BPF resource. This is useful in situations where, * say, attached BPF program has to outlive userspace program that attached it * in the system. Depending on type of BPF program, though, there might be * additional steps (like pinning BPF program in BPF FS) necessary to ensure * exit of userspace program doesn't trigger automatic detachment and clean up * inside the kernel. */ void bpf_link__disconnect(struct bpf_link *link) { link->disconnected = true; } int bpf_link__destroy(struct bpf_link *link) { int err = 0; if (IS_ERR_OR_NULL(link)) return 0; if (!link->disconnected && link->detach) err = link->detach(link); if (link->pin_path) free(link->pin_path); if (link->dealloc) link->dealloc(link); else free(link); return libbpf_err(err); } int bpf_link__fd(const struct bpf_link *link) { return link->fd; } const char *bpf_link__pin_path(const struct bpf_link *link) { return link->pin_path; } static int bpf_link__detach_fd(struct bpf_link *link) { return libbpf_err_errno(close(link->fd)); } struct bpf_link *bpf_link__open(const char *path) { struct bpf_link *link; int fd; fd = bpf_obj_get(path); if (fd < 0) { fd = -errno; pr_warn("failed to open link at %s: %d\n", path, fd); return libbpf_err_ptr(fd); } link = calloc(1, sizeof(*link)); if (!link) { close(fd); return libbpf_err_ptr(-ENOMEM); } link->detach = &bpf_link__detach_fd; link->fd = fd; link->pin_path = strdup(path); if (!link->pin_path) { bpf_link__destroy(link); return libbpf_err_ptr(-ENOMEM); } return link; } int bpf_link__detach(struct bpf_link *link) { return bpf_link_detach(link->fd) ? -errno : 0; } int bpf_link__pin(struct bpf_link *link, const char *path) { int err; if (link->pin_path) return libbpf_err(-EBUSY); err = make_parent_dir(path); if (err) return libbpf_err(err); err = check_path(path); if (err) return libbpf_err(err); link->pin_path = strdup(path); if (!link->pin_path) return libbpf_err(-ENOMEM); if (bpf_obj_pin(link->fd, link->pin_path)) { err = -errno; zfree(&link->pin_path); return libbpf_err(err); } pr_debug("link fd=%d: pinned at %s\n", link->fd, link->pin_path); return 0; } int bpf_link__unpin(struct bpf_link *link) { int err; if (!link->pin_path) return libbpf_err(-EINVAL); err = unlink(link->pin_path); if (err != 0) return -errno; pr_debug("link fd=%d: unpinned from %s\n", link->fd, link->pin_path); zfree(&link->pin_path); return 0; } struct bpf_link_perf { struct bpf_link link; int perf_event_fd; /* legacy kprobe support: keep track of probe identifier and type */ char *legacy_probe_name; bool legacy_is_kprobe; bool legacy_is_retprobe; }; static int remove_kprobe_event_legacy(const char *probe_name, bool retprobe); static int remove_uprobe_event_legacy(const char *probe_name, bool retprobe); static int bpf_link_perf_detach(struct bpf_link *link) { struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); int err = 0; if (ioctl(perf_link->perf_event_fd, PERF_EVENT_IOC_DISABLE, 0) < 0) err = -errno; if (perf_link->perf_event_fd != link->fd) close(perf_link->perf_event_fd); close(link->fd); /* legacy uprobe/kprobe needs to be removed after perf event fd closure */ if (perf_link->legacy_probe_name) { if (perf_link->legacy_is_kprobe) { err = remove_kprobe_event_legacy(perf_link->legacy_probe_name, perf_link->legacy_is_retprobe); } else { err = remove_uprobe_event_legacy(perf_link->legacy_probe_name, perf_link->legacy_is_retprobe); } } return err; } static void bpf_link_perf_dealloc(struct bpf_link *link) { struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); free(perf_link->legacy_probe_name); free(perf_link); } struct bpf_link *bpf_program__attach_perf_event_opts(const struct bpf_program *prog, int pfd, const struct bpf_perf_event_opts *opts) { char errmsg[STRERR_BUFSIZE]; struct bpf_link_perf *link; int prog_fd, link_fd = -1, err; bool force_ioctl_attach; if (!OPTS_VALID(opts, bpf_perf_event_opts)) return libbpf_err_ptr(-EINVAL); if (pfd < 0) { pr_warn("prog '%s': invalid perf event FD %d\n", prog->name, pfd); return libbpf_err_ptr(-EINVAL); } prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { pr_warn("prog '%s': can't attach BPF program w/o FD (did you load it?)\n", prog->name); return libbpf_err_ptr(-EINVAL); } link = calloc(1, sizeof(*link)); if (!link) return libbpf_err_ptr(-ENOMEM); link->link.detach = &bpf_link_perf_detach; link->link.dealloc = &bpf_link_perf_dealloc; link->perf_event_fd = pfd; force_ioctl_attach = OPTS_GET(opts, force_ioctl_attach, false); if (kernel_supports(prog->obj, FEAT_PERF_LINK) && !force_ioctl_attach) { DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_opts, .perf_event.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0)); link_fd = bpf_link_create(prog_fd, pfd, BPF_PERF_EVENT, &link_opts); if (link_fd < 0) { err = -errno; pr_warn("prog '%s': failed to create BPF link for perf_event FD %d: %d (%s)\n", prog->name, pfd, err, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); goto err_out; } link->link.fd = link_fd; } else { if (OPTS_GET(opts, bpf_cookie, 0)) { pr_warn("prog '%s': user context value is not supported\n", prog->name); err = -EOPNOTSUPP; goto err_out; } if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) { err = -errno; pr_warn("prog '%s': failed to attach to perf_event FD %d: %s\n", prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); if (err == -EPROTO) pr_warn("prog '%s': try add PERF_SAMPLE_CALLCHAIN to or remove exclude_callchain_[kernel|user] from pfd %d\n", prog->name, pfd); goto err_out; } link->link.fd = pfd; } if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) { err = -errno; pr_warn("prog '%s': failed to enable perf_event FD %d: %s\n", prog->name, pfd, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); goto err_out; } return &link->link; err_out: if (link_fd >= 0) close(link_fd); free(link); return libbpf_err_ptr(err); } struct bpf_link *bpf_program__attach_perf_event(const struct bpf_program *prog, int pfd) { return bpf_program__attach_perf_event_opts(prog, pfd, NULL); } /* * this function is expected to parse integer in the range of [0, 2^31-1] from * given file using scanf format string fmt. If actual parsed value is * negative, the result might be indistinguishable from error */ static int parse_uint_from_file(const char *file, const char *fmt) { char buf[STRERR_BUFSIZE]; int err, ret; FILE *f; f = fopen(file, "re"); if (!f) { err = -errno; pr_debug("failed to open '%s': %s\n", file, libbpf_strerror_r(err, buf, sizeof(buf))); return err; } err = fscanf(f, fmt, &ret); if (err != 1) { err = err == EOF ? -EIO : -errno; pr_debug("failed to parse '%s': %s\n", file, libbpf_strerror_r(err, buf, sizeof(buf))); fclose(f); return err; } fclose(f); return ret; } static int determine_kprobe_perf_type(void) { const char *file = "/sys/bus/event_source/devices/kprobe/type"; return parse_uint_from_file(file, "%d\n"); } static int determine_uprobe_perf_type(void) { const char *file = "/sys/bus/event_source/devices/uprobe/type"; return parse_uint_from_file(file, "%d\n"); } static int determine_kprobe_retprobe_bit(void) { const char *file = "/sys/bus/event_source/devices/kprobe/format/retprobe"; return parse_uint_from_file(file, "config:%d\n"); } static int determine_uprobe_retprobe_bit(void) { const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe"; return parse_uint_from_file(file, "config:%d\n"); } #define PERF_UPROBE_REF_CTR_OFFSET_BITS 32 #define PERF_UPROBE_REF_CTR_OFFSET_SHIFT 32 static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name, uint64_t offset, int pid, size_t ref_ctr_off) { const size_t attr_sz = sizeof(struct perf_event_attr); struct perf_event_attr attr; char errmsg[STRERR_BUFSIZE]; int type, pfd; if ((__u64)ref_ctr_off >= (1ULL << PERF_UPROBE_REF_CTR_OFFSET_BITS)) return -EINVAL; memset(&attr, 0, attr_sz); type = uprobe ? determine_uprobe_perf_type() : determine_kprobe_perf_type(); if (type < 0) { pr_warn("failed to determine %s perf type: %s\n", uprobe ? "uprobe" : "kprobe", libbpf_strerror_r(type, errmsg, sizeof(errmsg))); return type; } if (retprobe) { int bit = uprobe ? determine_uprobe_retprobe_bit() : determine_kprobe_retprobe_bit(); if (bit < 0) { pr_warn("failed to determine %s retprobe bit: %s\n", uprobe ? "uprobe" : "kprobe", libbpf_strerror_r(bit, errmsg, sizeof(errmsg))); return bit; } attr.config |= 1 << bit; } attr.size = attr_sz; attr.type = type; attr.config |= (__u64)ref_ctr_off << PERF_UPROBE_REF_CTR_OFFSET_SHIFT; attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */ attr.config2 = offset; /* kprobe_addr or probe_offset */ /* pid filter is meaningful only for uprobes */ pfd = syscall(__NR_perf_event_open, &attr, pid < 0 ? -1 : pid /* pid */, pid == -1 ? 0 : -1 /* cpu */, -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC); return pfd >= 0 ? pfd : -errno; } static int append_to_file(const char *file, const char *fmt, ...) { int fd, n, err = 0; va_list ap; char buf[1024]; va_start(ap, fmt); n = vsnprintf(buf, sizeof(buf), fmt, ap); va_end(ap); if (n < 0 || n >= sizeof(buf)) return -EINVAL; fd = open(file, O_WRONLY | O_APPEND | O_CLOEXEC, 0); if (fd < 0) return -errno; if (write(fd, buf, n) < 0) err = -errno; close(fd); return err; } #define DEBUGFS "/sys/kernel/debug/tracing" #define TRACEFS "/sys/kernel/tracing" static bool use_debugfs(void) { static int has_debugfs = -1; if (has_debugfs < 0) has_debugfs = faccessat(AT_FDCWD, DEBUGFS, F_OK, AT_EACCESS) == 0; return has_debugfs == 1; } static const char *tracefs_path(void) { return use_debugfs() ? DEBUGFS : TRACEFS; } static const char *tracefs_kprobe_events(void) { return use_debugfs() ? DEBUGFS"/kprobe_events" : TRACEFS"/kprobe_events"; } static const char *tracefs_uprobe_events(void) { return use_debugfs() ? DEBUGFS"/uprobe_events" : TRACEFS"/uprobe_events"; } static const char *tracefs_available_filter_functions(void) { return use_debugfs() ? DEBUGFS"/available_filter_functions" : TRACEFS"/available_filter_functions"; } static const char *tracefs_available_filter_functions_addrs(void) { return use_debugfs() ? DEBUGFS"/available_filter_functions_addrs" : TRACEFS"/available_filter_functions_addrs"; } static void gen_kprobe_legacy_event_name(char *buf, size_t buf_sz, const char *kfunc_name, size_t offset) { static int index = 0; int i; snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx_%d", getpid(), kfunc_name, offset, __sync_fetch_and_add(&index, 1)); /* sanitize binary_path in the probe name */ for (i = 0; buf[i]; i++) { if (!isalnum(buf[i])) buf[i] = '_'; } } static int add_kprobe_event_legacy(const char *probe_name, bool retprobe, const char *kfunc_name, size_t offset) { return append_to_file(tracefs_kprobe_events(), "%c:%s/%s %s+0x%zx", retprobe ? 'r' : 'p', retprobe ? "kretprobes" : "kprobes", probe_name, kfunc_name, offset); } static int remove_kprobe_event_legacy(const char *probe_name, bool retprobe) { return append_to_file(tracefs_kprobe_events(), "-:%s/%s", retprobe ? "kretprobes" : "kprobes", probe_name); } static int determine_kprobe_perf_type_legacy(const char *probe_name, bool retprobe) { char file[256]; snprintf(file, sizeof(file), "%s/events/%s/%s/id", tracefs_path(), retprobe ? "kretprobes" : "kprobes", probe_name); return parse_uint_from_file(file, "%d\n"); } static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe, const char *kfunc_name, size_t offset, int pid) { const size_t attr_sz = sizeof(struct perf_event_attr); struct perf_event_attr attr; char errmsg[STRERR_BUFSIZE]; int type, pfd, err; err = add_kprobe_event_legacy(probe_name, retprobe, kfunc_name, offset); if (err < 0) { pr_warn("failed to add legacy kprobe event for '%s+0x%zx': %s\n", kfunc_name, offset, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); return err; } type = determine_kprobe_perf_type_legacy(probe_name, retprobe); if (type < 0) { err = type; pr_warn("failed to determine legacy kprobe event id for '%s+0x%zx': %s\n", kfunc_name, offset, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); goto err_clean_legacy; } memset(&attr, 0, attr_sz); attr.size = attr_sz; attr.config = type; attr.type = PERF_TYPE_TRACEPOINT; pfd = syscall(__NR_perf_event_open, &attr, pid < 0 ? -1 : pid, /* pid */ pid == -1 ? 0 : -1, /* cpu */ -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC); if (pfd < 0) { err = -errno; pr_warn("legacy kprobe perf_event_open() failed: %s\n", libbpf_strerror_r(err, errmsg, sizeof(errmsg))); goto err_clean_legacy; } return pfd; err_clean_legacy: /* Clear the newly added legacy kprobe_event */ remove_kprobe_event_legacy(probe_name, retprobe); return err; } static const char *arch_specific_syscall_pfx(void) { #if defined(__x86_64__) return "x64"; #elif defined(__i386__) return "ia32"; #elif defined(__s390x__) return "s390x"; #elif defined(__s390__) return "s390"; #elif defined(__arm__) return "arm"; #elif defined(__aarch64__) return "arm64"; #elif defined(__mips__) return "mips"; #elif defined(__riscv) return "riscv"; #elif defined(__powerpc__) return "powerpc"; #elif defined(__powerpc64__) return "powerpc64"; #else return NULL; #endif } static int probe_kern_syscall_wrapper(void) { char syscall_name[64]; const char *ksys_pfx; ksys_pfx = arch_specific_syscall_pfx(); if (!ksys_pfx) return 0; snprintf(syscall_name, sizeof(syscall_name), "__%s_sys_bpf", ksys_pfx); if (determine_kprobe_perf_type() >= 0) { int pfd; pfd = perf_event_open_probe(false, false, syscall_name, 0, getpid(), 0); if (pfd >= 0) close(pfd); return pfd >= 0 ? 1 : 0; } else { /* legacy mode */ char probe_name[128]; gen_kprobe_legacy_event_name(probe_name, sizeof(probe_name), syscall_name, 0); if (add_kprobe_event_legacy(probe_name, false, syscall_name, 0) < 0) return 0; (void)remove_kprobe_event_legacy(probe_name, false); return 1; } } struct bpf_link * bpf_program__attach_kprobe_opts(const struct bpf_program *prog, const char *func_name, const struct bpf_kprobe_opts *opts) { DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts); enum probe_attach_mode attach_mode; char errmsg[STRERR_BUFSIZE]; char *legacy_probe = NULL; struct bpf_link *link; size_t offset; bool retprobe, legacy; int pfd, err; if (!OPTS_VALID(opts, bpf_kprobe_opts)) return libbpf_err_ptr(-EINVAL); attach_mode = OPTS_GET(opts, attach_mode, PROBE_ATTACH_MODE_DEFAULT); retprobe = OPTS_GET(opts, retprobe, false); offset = OPTS_GET(opts, offset, 0); pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); legacy = determine_kprobe_perf_type() < 0; switch (attach_mode) { case PROBE_ATTACH_MODE_LEGACY: legacy = true; pe_opts.force_ioctl_attach = true; break; case PROBE_ATTACH_MODE_PERF: if (legacy) return libbpf_err_ptr(-ENOTSUP); pe_opts.force_ioctl_attach = true; break; case PROBE_ATTACH_MODE_LINK: if (legacy || !kernel_supports(prog->obj, FEAT_PERF_LINK)) return libbpf_err_ptr(-ENOTSUP); break; case PROBE_ATTACH_MODE_DEFAULT: break; default: return libbpf_err_ptr(-EINVAL); } if (!legacy) { pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name, offset, -1 /* pid */, 0 /* ref_ctr_off */); } else { char probe_name[256]; gen_kprobe_legacy_event_name(probe_name, sizeof(probe_name), func_name, offset); legacy_probe = strdup(probe_name); if (!legacy_probe) return libbpf_err_ptr(-ENOMEM); pfd = perf_event_kprobe_open_legacy(legacy_probe, retprobe, func_name, offset, -1 /* pid */); } if (pfd < 0) { err = -errno; pr_warn("prog '%s': failed to create %s '%s+0x%zx' perf event: %s\n", prog->name, retprobe ? "kretprobe" : "kprobe", func_name, offset, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); goto err_out; } link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts); err = libbpf_get_error(link); if (err) { close(pfd); pr_warn("prog '%s': failed to attach to %s '%s+0x%zx': %s\n", prog->name, retprobe ? "kretprobe" : "kprobe", func_name, offset, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); goto err_clean_legacy; } if (legacy) { struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); perf_link->legacy_probe_name = legacy_probe; perf_link->legacy_is_kprobe = true; perf_link->legacy_is_retprobe = retprobe; } return link; err_clean_legacy: if (legacy) remove_kprobe_event_legacy(legacy_probe, retprobe); err_out: free(legacy_probe); return libbpf_err_ptr(err); } struct bpf_link *bpf_program__attach_kprobe(const struct bpf_program *prog, bool retprobe, const char *func_name) { DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts, .retprobe = retprobe, ); return bpf_program__attach_kprobe_opts(prog, func_name, &opts); } struct bpf_link *bpf_program__attach_ksyscall(const struct bpf_program *prog, const char *syscall_name, const struct bpf_ksyscall_opts *opts) { LIBBPF_OPTS(bpf_kprobe_opts, kprobe_opts); char func_name[128]; if (!OPTS_VALID(opts, bpf_ksyscall_opts)) return libbpf_err_ptr(-EINVAL); if (kernel_supports(prog->obj, FEAT_SYSCALL_WRAPPER)) { /* arch_specific_syscall_pfx() should never return NULL here * because it is guarded by kernel_supports(). However, since * compiler does not know that we have an explicit conditional * as well. */ snprintf(func_name, sizeof(func_name), "__%s_sys_%s", arch_specific_syscall_pfx() ? : "", syscall_name); } else { snprintf(func_name, sizeof(func_name), "__se_sys_%s", syscall_name); } kprobe_opts.retprobe = OPTS_GET(opts, retprobe, false); kprobe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); return bpf_program__attach_kprobe_opts(prog, func_name, &kprobe_opts); } /* Adapted from perf/util/string.c */ bool glob_match(const char *str, const char *pat) { while (*str && *pat && *pat != '*') { if (*pat == '?') { /* Matches any single character */ str++; pat++; continue; } if (*str != *pat) return false; str++; pat++; } /* Check wild card */ if (*pat == '*') { while (*pat == '*') pat++; if (!*pat) /* Tail wild card matches all */ return true; while (*str) if (glob_match(str++, pat)) return true; } return !*str && !*pat; } struct kprobe_multi_resolve { const char *pattern; unsigned long *addrs; size_t cap; size_t cnt; }; struct avail_kallsyms_data { char **syms; size_t cnt; struct kprobe_multi_resolve *res; }; static int avail_func_cmp(const void *a, const void *b) { return strcmp(*(const char **)a, *(const char **)b); } static int avail_kallsyms_cb(unsigned long long sym_addr, char sym_type, const char *sym_name, void *ctx) { struct avail_kallsyms_data *data = ctx; struct kprobe_multi_resolve *res = data->res; int err; if (!bsearch(&sym_name, data->syms, data->cnt, sizeof(*data->syms), avail_func_cmp)) return 0; err = libbpf_ensure_mem((void **)&res->addrs, &res->cap, sizeof(*res->addrs), res->cnt + 1); if (err) return err; res->addrs[res->cnt++] = (unsigned long)sym_addr; return 0; } static int libbpf_available_kallsyms_parse(struct kprobe_multi_resolve *res) { const char *available_functions_file = tracefs_available_filter_functions(); struct avail_kallsyms_data data; char sym_name[500]; FILE *f; int err = 0, ret, i; char **syms = NULL; size_t cap = 0, cnt = 0; f = fopen(available_functions_file, "re"); if (!f) { err = -errno; pr_warn("failed to open %s: %d\n", available_functions_file, err); return err; } while (true) { char *name; ret = fscanf(f, "%499s%*[^\n]\n", sym_name); if (ret == EOF && feof(f)) break; if (ret != 1) { pr_warn("failed to parse available_filter_functions entry: %d\n", ret); err = -EINVAL; goto cleanup; } if (!glob_match(sym_name, res->pattern)) continue; err = libbpf_ensure_mem((void **)&syms, &cap, sizeof(*syms), cnt + 1); if (err) goto cleanup; name = strdup(sym_name); if (!name) { err = -errno; goto cleanup; } syms[cnt++] = name; } /* no entries found, bail out */ if (cnt == 0) { err = -ENOENT; goto cleanup; } /* sort available functions */ qsort(syms, cnt, sizeof(*syms), avail_func_cmp); data.syms = syms; data.res = res; data.cnt = cnt; libbpf_kallsyms_parse(avail_kallsyms_cb, &data); if (res->cnt == 0) err = -ENOENT; cleanup: for (i = 0; i < cnt; i++) free((char *)syms[i]); free(syms); fclose(f); return err; } static bool has_available_filter_functions_addrs(void) { return access(tracefs_available_filter_functions_addrs(), R_OK) != -1; } static int libbpf_available_kprobes_parse(struct kprobe_multi_resolve *res) { const char *available_path = tracefs_available_filter_functions_addrs(); char sym_name[500]; FILE *f; int ret, err = 0; unsigned long long sym_addr; f = fopen(available_path, "re"); if (!f) { err = -errno; pr_warn("failed to open %s: %d\n", available_path, err); return err; } while (true) { ret = fscanf(f, "%llx %499s%*[^\n]\n", &sym_addr, sym_name); if (ret == EOF && feof(f)) break; if (ret != 2) { pr_warn("failed to parse available_filter_functions_addrs entry: %d\n", ret); err = -EINVAL; goto cleanup; } if (!glob_match(sym_name, res->pattern)) continue; err = libbpf_ensure_mem((void **)&res->addrs, &res->cap, sizeof(*res->addrs), res->cnt + 1); if (err) goto cleanup; res->addrs[res->cnt++] = (unsigned long)sym_addr; } if (res->cnt == 0) err = -ENOENT; cleanup: fclose(f); return err; } struct bpf_link * bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog, const char *pattern, const struct bpf_kprobe_multi_opts *opts) { LIBBPF_OPTS(bpf_link_create_opts, lopts); struct kprobe_multi_resolve res = { .pattern = pattern, }; struct bpf_link *link = NULL; char errmsg[STRERR_BUFSIZE]; const unsigned long *addrs; int err, link_fd, prog_fd; const __u64 *cookies; const char **syms; bool retprobe; size_t cnt; if (!OPTS_VALID(opts, bpf_kprobe_multi_opts)) return libbpf_err_ptr(-EINVAL); syms = OPTS_GET(opts, syms, false); addrs = OPTS_GET(opts, addrs, false); cnt = OPTS_GET(opts, cnt, false); cookies = OPTS_GET(opts, cookies, false); if (!pattern && !addrs && !syms) return libbpf_err_ptr(-EINVAL); if (pattern && (addrs || syms || cookies || cnt)) return libbpf_err_ptr(-EINVAL); if (!pattern && !cnt) return libbpf_err_ptr(-EINVAL); if (addrs && syms) return libbpf_err_ptr(-EINVAL); if (pattern) { if (has_available_filter_functions_addrs()) err = libbpf_available_kprobes_parse(&res); else err = libbpf_available_kallsyms_parse(&res); if (err) goto error; addrs = res.addrs; cnt = res.cnt; } retprobe = OPTS_GET(opts, retprobe, false); lopts.kprobe_multi.syms = syms; lopts.kprobe_multi.addrs = addrs; lopts.kprobe_multi.cookies = cookies; lopts.kprobe_multi.cnt = cnt; lopts.kprobe_multi.flags = retprobe ? BPF_F_KPROBE_MULTI_RETURN : 0; link = calloc(1, sizeof(*link)); if (!link) { err = -ENOMEM; goto error; } link->detach = &bpf_link__detach_fd; prog_fd = bpf_program__fd(prog); link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_KPROBE_MULTI, &lopts); if (link_fd < 0) { err = -errno; pr_warn("prog '%s': failed to attach: %s\n", prog->name, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); goto error; } link->fd = link_fd; free(res.addrs); return link; error: free(link); free(res.addrs); return libbpf_err_ptr(err); } static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link) { DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts); unsigned long offset = 0; const char *func_name; char *func; int n; *link = NULL; /* no auto-attach for SEC("kprobe") and SEC("kretprobe") */ if (strcmp(prog->sec_name, "kprobe") == 0 || strcmp(prog->sec_name, "kretprobe") == 0) return 0; opts.retprobe = str_has_pfx(prog->sec_name, "kretprobe/"); if (opts.retprobe) func_name = prog->sec_name + sizeof("kretprobe/") - 1; else func_name = prog->sec_name + sizeof("kprobe/") - 1; n = sscanf(func_name, "%m[a-zA-Z0-9_.]+%li", &func, &offset); if (n < 1) { pr_warn("kprobe name is invalid: %s\n", func_name); return -EINVAL; } if (opts.retprobe && offset != 0) { free(func); pr_warn("kretprobes do not support offset specification\n"); return -EINVAL; } opts.offset = offset; *link = bpf_program__attach_kprobe_opts(prog, func, &opts); free(func); return libbpf_get_error(*link); } static int attach_ksyscall(const struct bpf_program *prog, long cookie, struct bpf_link **link) { LIBBPF_OPTS(bpf_ksyscall_opts, opts); const char *syscall_name; *link = NULL; /* no auto-attach for SEC("ksyscall") and SEC("kretsyscall") */ if (strcmp(prog->sec_name, "ksyscall") == 0 || strcmp(prog->sec_name, "kretsyscall") == 0) return 0; opts.retprobe = str_has_pfx(prog->sec_name, "kretsyscall/"); if (opts.retprobe) syscall_name = prog->sec_name + sizeof("kretsyscall/") - 1; else syscall_name = prog->sec_name + sizeof("ksyscall/") - 1; *link = bpf_program__attach_ksyscall(prog, syscall_name, &opts); return *link ? 0 : -errno; } static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link) { LIBBPF_OPTS(bpf_kprobe_multi_opts, opts); const char *spec; char *pattern; int n; *link = NULL; /* no auto-attach for SEC("kprobe.multi") and SEC("kretprobe.multi") */ if (strcmp(prog->sec_name, "kprobe.multi") == 0 || strcmp(prog->sec_name, "kretprobe.multi") == 0) return 0; opts.retprobe = str_has_pfx(prog->sec_name, "kretprobe.multi/"); if (opts.retprobe) spec = prog->sec_name + sizeof("kretprobe.multi/") - 1; else spec = prog->sec_name + sizeof("kprobe.multi/") - 1; n = sscanf(spec, "%m[a-zA-Z0-9_.*?]", &pattern); if (n < 1) { pr_warn("kprobe multi pattern is invalid: %s\n", pattern); return -EINVAL; } *link = bpf_program__attach_kprobe_multi_opts(prog, pattern, &opts); free(pattern); return libbpf_get_error(*link); } static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link) { char *probe_type = NULL, *binary_path = NULL, *func_name = NULL; LIBBPF_OPTS(bpf_uprobe_multi_opts, opts); int n, ret = -EINVAL; *link = NULL; n = sscanf(prog->sec_name, "%m[^/]/%m[^:]:%m[^\n]", &probe_type, &binary_path, &func_name); switch (n) { case 1: /* handle SEC("u[ret]probe") - format is valid, but auto-attach is impossible. */ ret = 0; break; case 3: opts.retprobe = strcmp(probe_type, "uretprobe.multi") == 0; *link = bpf_program__attach_uprobe_multi(prog, -1, binary_path, func_name, &opts); ret = libbpf_get_error(*link); break; default: pr_warn("prog '%s': invalid format of section definition '%s'\n", prog->name, prog->sec_name); break; } free(probe_type); free(binary_path); free(func_name); return ret; } static void gen_uprobe_legacy_event_name(char *buf, size_t buf_sz, const char *binary_path, uint64_t offset) { int i; snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx", getpid(), binary_path, (size_t)offset); /* sanitize binary_path in the probe name */ for (i = 0; buf[i]; i++) { if (!isalnum(buf[i])) buf[i] = '_'; } } static inline int add_uprobe_event_legacy(const char *probe_name, bool retprobe, const char *binary_path, size_t offset) { return append_to_file(tracefs_uprobe_events(), "%c:%s/%s %s:0x%zx", retprobe ? 'r' : 'p', retprobe ? "uretprobes" : "uprobes", probe_name, binary_path, offset); } static inline int remove_uprobe_event_legacy(const char *probe_name, bool retprobe) { return append_to_file(tracefs_uprobe_events(), "-:%s/%s", retprobe ? "uretprobes" : "uprobes", probe_name); } static int determine_uprobe_perf_type_legacy(const char *probe_name, bool retprobe) { char file[512]; snprintf(file, sizeof(file), "%s/events/%s/%s/id", tracefs_path(), retprobe ? "uretprobes" : "uprobes", probe_name); return parse_uint_from_file(file, "%d\n"); } static int perf_event_uprobe_open_legacy(const char *probe_name, bool retprobe, const char *binary_path, size_t offset, int pid) { const size_t attr_sz = sizeof(struct perf_event_attr); struct perf_event_attr attr; int type, pfd, err; err = add_uprobe_event_legacy(probe_name, retprobe, binary_path, offset); if (err < 0) { pr_warn("failed to add legacy uprobe event for %s:0x%zx: %d\n", binary_path, (size_t)offset, err); return err; } type = determine_uprobe_perf_type_legacy(probe_name, retprobe); if (type < 0) { err = type; pr_warn("failed to determine legacy uprobe event id for %s:0x%zx: %d\n", binary_path, offset, err); goto err_clean_legacy; } memset(&attr, 0, attr_sz); attr.size = attr_sz; attr.config = type; attr.type = PERF_TYPE_TRACEPOINT; pfd = syscall(__NR_perf_event_open, &attr, pid < 0 ? -1 : pid, /* pid */ pid == -1 ? 0 : -1, /* cpu */ -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC); if (pfd < 0) { err = -errno; pr_warn("legacy uprobe perf_event_open() failed: %d\n", err); goto err_clean_legacy; } return pfd; err_clean_legacy: /* Clear the newly added legacy uprobe_event */ remove_uprobe_event_legacy(probe_name, retprobe); return err; } /* Find offset of function name in archive specified by path. Currently * supported are .zip files that do not compress their contents, as used on * Android in the form of APKs, for example. "file_name" is the name of the ELF * file inside the archive. "func_name" matches symbol name or name@@LIB for * library functions. * * An overview of the APK format specifically provided here: * https://en.wikipedia.org/w/index.php?title=Apk_(file_format)&oldid=1139099120#Package_contents */ static long elf_find_func_offset_from_archive(const char *archive_path, const char *file_name, const char *func_name) { struct zip_archive *archive; struct zip_entry entry; long ret; Elf *elf; archive = zip_archive_open(archive_path); if (IS_ERR(archive)) { ret = PTR_ERR(archive); pr_warn("zip: failed to open %s: %ld\n", archive_path, ret); return ret; } ret = zip_archive_find_entry(archive, file_name, &entry); if (ret) { pr_warn("zip: could not find archive member %s in %s: %ld\n", file_name, archive_path, ret); goto out; } pr_debug("zip: found entry for %s in %s at 0x%lx\n", file_name, archive_path, (unsigned long)entry.data_offset); if (entry.compression) { pr_warn("zip: entry %s of %s is compressed and cannot be handled\n", file_name, archive_path); ret = -LIBBPF_ERRNO__FORMAT; goto out; } elf = elf_memory((void *)entry.data, entry.data_length); if (!elf) { pr_warn("elf: could not read elf file %s from %s: %s\n", file_name, archive_path, elf_errmsg(-1)); ret = -LIBBPF_ERRNO__LIBELF; goto out; } ret = elf_find_func_offset(elf, file_name, func_name); if (ret > 0) { pr_debug("elf: symbol address match for %s of %s in %s: 0x%x + 0x%lx = 0x%lx\n", func_name, file_name, archive_path, entry.data_offset, ret, ret + entry.data_offset); ret += entry.data_offset; } elf_end(elf); out: zip_archive_close(archive); return ret; } static const char *arch_specific_lib_paths(void) { /* * Based on https://packages.debian.org/sid/libc6. * * Assume that the traced program is built for the same architecture * as libbpf, which should cover the vast majority of cases. */ #if defined(__x86_64__) return "/lib/x86_64-linux-gnu"; #elif defined(__i386__) return "/lib/i386-linux-gnu"; #elif defined(__s390x__) return "/lib/s390x-linux-gnu"; #elif defined(__s390__) return "/lib/s390-linux-gnu"; #elif defined(__arm__) && defined(__SOFTFP__) return "/lib/arm-linux-gnueabi"; #elif defined(__arm__) && !defined(__SOFTFP__) return "/lib/arm-linux-gnueabihf"; #elif defined(__aarch64__) return "/lib/aarch64-linux-gnu"; #elif defined(__mips__) && defined(__MIPSEL__) && _MIPS_SZLONG == 64 return "/lib/mips64el-linux-gnuabi64"; #elif defined(__mips__) && defined(__MIPSEL__) && _MIPS_SZLONG == 32 return "/lib/mipsel-linux-gnu"; #elif defined(__powerpc64__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ return "/lib/powerpc64le-linux-gnu"; #elif defined(__sparc__) && defined(__arch64__) return "/lib/sparc64-linux-gnu"; #elif defined(__riscv) && __riscv_xlen == 64 return "/lib/riscv64-linux-gnu"; #else return NULL; #endif } /* Get full path to program/shared library. */ static int resolve_full_path(const char *file, char *result, size_t result_sz) { const char *search_paths[3] = {}; int i, perm; if (str_has_sfx(file, ".so") || strstr(file, ".so.")) { search_paths[0] = getenv("LD_LIBRARY_PATH"); search_paths[1] = "/usr/lib64:/usr/lib"; search_paths[2] = arch_specific_lib_paths(); perm = R_OK; } else { search_paths[0] = getenv("PATH"); search_paths[1] = "/usr/bin:/usr/sbin"; perm = R_OK | X_OK; } for (i = 0; i < ARRAY_SIZE(search_paths); i++) { const char *s; if (!search_paths[i]) continue; for (s = search_paths[i]; s != NULL; s = strchr(s, ':')) { char *next_path; int seg_len; if (s[0] == ':') s++; next_path = strchr(s, ':'); seg_len = next_path ? next_path - s : strlen(s); if (!seg_len) continue; snprintf(result, result_sz, "%.*s/%s", seg_len, s, file); /* ensure it has required permissions */ if (faccessat(AT_FDCWD, result, perm, AT_EACCESS) < 0) continue; pr_debug("resolved '%s' to '%s'\n", file, result); return 0; } } return -ENOENT; } struct bpf_link * bpf_program__attach_uprobe_multi(const struct bpf_program *prog, pid_t pid, const char *path, const char *func_pattern, const struct bpf_uprobe_multi_opts *opts) { const unsigned long *ref_ctr_offsets = NULL, *offsets = NULL; LIBBPF_OPTS(bpf_link_create_opts, lopts); unsigned long *resolved_offsets = NULL; int err = 0, link_fd, prog_fd; struct bpf_link *link = NULL; char errmsg[STRERR_BUFSIZE]; char full_path[PATH_MAX]; const __u64 *cookies; const char **syms; size_t cnt; if (!OPTS_VALID(opts, bpf_uprobe_multi_opts)) return libbpf_err_ptr(-EINVAL); syms = OPTS_GET(opts, syms, NULL); offsets = OPTS_GET(opts, offsets, NULL); ref_ctr_offsets = OPTS_GET(opts, ref_ctr_offsets, NULL); cookies = OPTS_GET(opts, cookies, NULL); cnt = OPTS_GET(opts, cnt, 0); /* * User can specify 2 mutually exclusive set of inputs: * * 1) use only path/func_pattern/pid arguments * * 2) use path/pid with allowed combinations of: * syms/offsets/ref_ctr_offsets/cookies/cnt * * - syms and offsets are mutually exclusive * - ref_ctr_offsets and cookies are optional * * Any other usage results in error. */ if (!path) return libbpf_err_ptr(-EINVAL); if (!func_pattern && cnt == 0) return libbpf_err_ptr(-EINVAL); if (func_pattern) { if (syms || offsets || ref_ctr_offsets || cookies || cnt) return libbpf_err_ptr(-EINVAL); } else { if (!!syms == !!offsets) return libbpf_err_ptr(-EINVAL); } if (func_pattern) { if (!strchr(path, '/')) { err = resolve_full_path(path, full_path, sizeof(full_path)); if (err) { pr_warn("prog '%s': failed to resolve full path for '%s': %d\n", prog->name, path, err); return libbpf_err_ptr(err); } path = full_path; } err = elf_resolve_pattern_offsets(path, func_pattern, &resolved_offsets, &cnt); if (err < 0) return libbpf_err_ptr(err); offsets = resolved_offsets; } else if (syms) { err = elf_resolve_syms_offsets(path, cnt, syms, &resolved_offsets); if (err < 0) return libbpf_err_ptr(err); offsets = resolved_offsets; } lopts.uprobe_multi.path = path; lopts.uprobe_multi.offsets = offsets; lopts.uprobe_multi.ref_ctr_offsets = ref_ctr_offsets; lopts.uprobe_multi.cookies = cookies; lopts.uprobe_multi.cnt = cnt; lopts.uprobe_multi.flags = OPTS_GET(opts, retprobe, false) ? BPF_F_UPROBE_MULTI_RETURN : 0; if (pid == 0) pid = getpid(); if (pid > 0) lopts.uprobe_multi.pid = pid; link = calloc(1, sizeof(*link)); if (!link) { err = -ENOMEM; goto error; } link->detach = &bpf_link__detach_fd; prog_fd = bpf_program__fd(prog); link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &lopts); if (link_fd < 0) { err = -errno; pr_warn("prog '%s': failed to attach multi-uprobe: %s\n", prog->name, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); goto error; } link->fd = link_fd; free(resolved_offsets); return link; error: free(resolved_offsets); free(link); return libbpf_err_ptr(err); } LIBBPF_API struct bpf_link * bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid, const char *binary_path, size_t func_offset, const struct bpf_uprobe_opts *opts) { const char *archive_path = NULL, *archive_sep = NULL; char errmsg[STRERR_BUFSIZE], *legacy_probe = NULL; DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts); enum probe_attach_mode attach_mode; char full_path[PATH_MAX]; struct bpf_link *link; size_t ref_ctr_off; int pfd, err; bool retprobe, legacy; const char *func_name; if (!OPTS_VALID(opts, bpf_uprobe_opts)) return libbpf_err_ptr(-EINVAL); attach_mode = OPTS_GET(opts, attach_mode, PROBE_ATTACH_MODE_DEFAULT); retprobe = OPTS_GET(opts, retprobe, false); ref_ctr_off = OPTS_GET(opts, ref_ctr_offset, 0); pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); if (!binary_path) return libbpf_err_ptr(-EINVAL); /* Check if "binary_path" refers to an archive. */ archive_sep = strstr(binary_path, "!/"); if (archive_sep) { full_path[0] = '\0'; libbpf_strlcpy(full_path, binary_path, min(sizeof(full_path), (size_t)(archive_sep - binary_path + 1))); archive_path = full_path; binary_path = archive_sep + 2; } else if (!strchr(binary_path, '/')) { err = resolve_full_path(binary_path, full_path, sizeof(full_path)); if (err) { pr_warn("prog '%s': failed to resolve full path for '%s': %d\n", prog->name, binary_path, err); return libbpf_err_ptr(err); } binary_path = full_path; } func_name = OPTS_GET(opts, func_name, NULL); if (func_name) { long sym_off; if (archive_path) { sym_off = elf_find_func_offset_from_archive(archive_path, binary_path, func_name); binary_path = archive_path; } else { sym_off = elf_find_func_offset_from_file(binary_path, func_name); } if (sym_off < 0) return libbpf_err_ptr(sym_off); func_offset += sym_off; } legacy = determine_uprobe_perf_type() < 0; switch (attach_mode) { case PROBE_ATTACH_MODE_LEGACY: legacy = true; pe_opts.force_ioctl_attach = true; break; case PROBE_ATTACH_MODE_PERF: if (legacy) return libbpf_err_ptr(-ENOTSUP); pe_opts.force_ioctl_attach = true; break; case PROBE_ATTACH_MODE_LINK: if (legacy || !kernel_supports(prog->obj, FEAT_PERF_LINK)) return libbpf_err_ptr(-ENOTSUP); break; case PROBE_ATTACH_MODE_DEFAULT: break; default: return libbpf_err_ptr(-EINVAL); } if (!legacy) { pfd = perf_event_open_probe(true /* uprobe */, retprobe, binary_path, func_offset, pid, ref_ctr_off); } else { char probe_name[PATH_MAX + 64]; if (ref_ctr_off) return libbpf_err_ptr(-EINVAL); gen_uprobe_legacy_event_name(probe_name, sizeof(probe_name), binary_path, func_offset); legacy_probe = strdup(probe_name); if (!legacy_probe) return libbpf_err_ptr(-ENOMEM); pfd = perf_event_uprobe_open_legacy(legacy_probe, retprobe, binary_path, func_offset, pid); } if (pfd < 0) { err = -errno; pr_warn("prog '%s': failed to create %s '%s:0x%zx' perf event: %s\n", prog->name, retprobe ? "uretprobe" : "uprobe", binary_path, func_offset, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); goto err_out; } link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts); err = libbpf_get_error(link); if (err) { close(pfd); pr_warn("prog '%s': failed to attach to %s '%s:0x%zx': %s\n", prog->name, retprobe ? "uretprobe" : "uprobe", binary_path, func_offset, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); goto err_clean_legacy; } if (legacy) { struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); perf_link->legacy_probe_name = legacy_probe; perf_link->legacy_is_kprobe = false; perf_link->legacy_is_retprobe = retprobe; } return link; err_clean_legacy: if (legacy) remove_uprobe_event_legacy(legacy_probe, retprobe); err_out: free(legacy_probe); return libbpf_err_ptr(err); } /* Format of u[ret]probe section definition supporting auto-attach: * u[ret]probe/binary:function[+offset] * * binary can be an absolute/relative path or a filename; the latter is resolved to a * full binary path via bpf_program__attach_uprobe_opts. * * Specifying uprobe+ ensures we carry out strict matching; either "uprobe" must be * specified (and auto-attach is not possible) or the above format is specified for * auto-attach. */ static int attach_uprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link) { DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, opts); char *probe_type = NULL, *binary_path = NULL, *func_name = NULL, *func_off; int n, c, ret = -EINVAL; long offset = 0; *link = NULL; n = sscanf(prog->sec_name, "%m[^/]/%m[^:]:%m[^\n]", &probe_type, &binary_path, &func_name); switch (n) { case 1: /* handle SEC("u[ret]probe") - format is valid, but auto-attach is impossible. */ ret = 0; break; case 2: pr_warn("prog '%s': section '%s' missing ':function[+offset]' specification\n", prog->name, prog->sec_name); break; case 3: /* check if user specifies `+offset`, if yes, this should be * the last part of the string, make sure sscanf read to EOL */ func_off = strrchr(func_name, '+'); if (func_off) { n = sscanf(func_off, "+%li%n", &offset, &c); if (n == 1 && *(func_off + c) == '\0') func_off[0] = '\0'; else offset = 0; } opts.retprobe = strcmp(probe_type, "uretprobe") == 0 || strcmp(probe_type, "uretprobe.s") == 0; if (opts.retprobe && offset != 0) { pr_warn("prog '%s': uretprobes do not support offset specification\n", prog->name); break; } opts.func_name = func_name; *link = bpf_program__attach_uprobe_opts(prog, -1, binary_path, offset, &opts); ret = libbpf_get_error(*link); break; default: pr_warn("prog '%s': invalid format of section definition '%s'\n", prog->name, prog->sec_name); break; } free(probe_type); free(binary_path); free(func_name); return ret; } struct bpf_link *bpf_program__attach_uprobe(const struct bpf_program *prog, bool retprobe, pid_t pid, const char *binary_path, size_t func_offset) { DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, opts, .retprobe = retprobe); return bpf_program__attach_uprobe_opts(prog, pid, binary_path, func_offset, &opts); } struct bpf_link *bpf_program__attach_usdt(const struct bpf_program *prog, pid_t pid, const char *binary_path, const char *usdt_provider, const char *usdt_name, const struct bpf_usdt_opts *opts) { char resolved_path[512]; struct bpf_object *obj = prog->obj; struct bpf_link *link; __u64 usdt_cookie; int err; if (!OPTS_VALID(opts, bpf_uprobe_opts)) return libbpf_err_ptr(-EINVAL); if (bpf_program__fd(prog) < 0) { pr_warn("prog '%s': can't attach BPF program w/o FD (did you load it?)\n", prog->name); return libbpf_err_ptr(-EINVAL); } if (!binary_path) return libbpf_err_ptr(-EINVAL); if (!strchr(binary_path, '/')) { err = resolve_full_path(binary_path, resolved_path, sizeof(resolved_path)); if (err) { pr_warn("prog '%s': failed to resolve full path for '%s': %d\n", prog->name, binary_path, err); return libbpf_err_ptr(err); } binary_path = resolved_path; } /* USDT manager is instantiated lazily on first USDT attach. It will * be destroyed together with BPF object in bpf_object__close(). */ if (IS_ERR(obj->usdt_man)) return libbpf_ptr(obj->usdt_man); if (!obj->usdt_man) { obj->usdt_man = usdt_manager_new(obj); if (IS_ERR(obj->usdt_man)) return libbpf_ptr(obj->usdt_man); } usdt_cookie = OPTS_GET(opts, usdt_cookie, 0); link = usdt_manager_attach_usdt(obj->usdt_man, prog, pid, binary_path, usdt_provider, usdt_name, usdt_cookie); err = libbpf_get_error(link); if (err) return libbpf_err_ptr(err); return link; } static int attach_usdt(const struct bpf_program *prog, long cookie, struct bpf_link **link) { char *path = NULL, *provider = NULL, *name = NULL; const char *sec_name; int n, err; sec_name = bpf_program__section_name(prog); if (strcmp(sec_name, "usdt") == 0) { /* no auto-attach for just SEC("usdt") */ *link = NULL; return 0; } n = sscanf(sec_name, "usdt/%m[^:]:%m[^:]:%m[^:]", &path, &provider, &name); if (n != 3) { pr_warn("invalid section '%s', expected SEC(\"usdt/<path>:<provider>:<name>\")\n", sec_name); err = -EINVAL; } else { *link = bpf_program__attach_usdt(prog, -1 /* any process */, path, provider, name, NULL); err = libbpf_get_error(*link); } free(path); free(provider); free(name); return err; } static int determine_tracepoint_id(const char *tp_category, const char *tp_name) { char file[PATH_MAX]; int ret; ret = snprintf(file, sizeof(file), "%s/events/%s/%s/id", tracefs_path(), tp_category, tp_name); if (ret < 0) return -errno; if (ret >= sizeof(file)) { pr_debug("tracepoint %s/%s path is too long\n", tp_category, tp_name); return -E2BIG; } return parse_uint_from_file(file, "%d\n"); } static int perf_event_open_tracepoint(const char *tp_category, const char *tp_name) { const size_t attr_sz = sizeof(struct perf_event_attr); struct perf_event_attr attr; char errmsg[STRERR_BUFSIZE]; int tp_id, pfd, err; tp_id = determine_tracepoint_id(tp_category, tp_name); if (tp_id < 0) { pr_warn("failed to determine tracepoint '%s/%s' perf event ID: %s\n", tp_category, tp_name, libbpf_strerror_r(tp_id, errmsg, sizeof(errmsg))); return tp_id; } memset(&attr, 0, attr_sz); attr.type = PERF_TYPE_TRACEPOINT; attr.size = attr_sz; attr.config = tp_id; pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */, -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC); if (pfd < 0) { err = -errno; pr_warn("tracepoint '%s/%s' perf_event_open() failed: %s\n", tp_category, tp_name, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); return err; } return pfd; } struct bpf_link *bpf_program__attach_tracepoint_opts(const struct bpf_program *prog, const char *tp_category, const char *tp_name, const struct bpf_tracepoint_opts *opts) { DECLARE_LIBBPF_OPTS(bpf_perf_event_opts, pe_opts); char errmsg[STRERR_BUFSIZE]; struct bpf_link *link; int pfd, err; if (!OPTS_VALID(opts, bpf_tracepoint_opts)) return libbpf_err_ptr(-EINVAL); pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); pfd = perf_event_open_tracepoint(tp_category, tp_name); if (pfd < 0) { pr_warn("prog '%s': failed to create tracepoint '%s/%s' perf event: %s\n", prog->name, tp_category, tp_name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); return libbpf_err_ptr(pfd); } link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts); err = libbpf_get_error(link); if (err) { close(pfd); pr_warn("prog '%s': failed to attach to tracepoint '%s/%s': %s\n", prog->name, tp_category, tp_name, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); return libbpf_err_ptr(err); } return link; } struct bpf_link *bpf_program__attach_tracepoint(const struct bpf_program *prog, const char *tp_category, const char *tp_name) { return bpf_program__attach_tracepoint_opts(prog, tp_category, tp_name, NULL); } static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link) { char *sec_name, *tp_cat, *tp_name; *link = NULL; /* no auto-attach for SEC("tp") or SEC("tracepoint") */ if (strcmp(prog->sec_name, "tp") == 0 || strcmp(prog->sec_name, "tracepoint") == 0) return 0; sec_name = strdup(prog->sec_name); if (!sec_name) return -ENOMEM; /* extract "tp/<category>/<name>" or "tracepoint/<category>/<name>" */ if (str_has_pfx(prog->sec_name, "tp/")) tp_cat = sec_name + sizeof("tp/") - 1; else tp_cat = sec_name + sizeof("tracepoint/") - 1; tp_name = strchr(tp_cat, '/'); if (!tp_name) { free(sec_name); return -EINVAL; } *tp_name = '\0'; tp_name++; *link = bpf_program__attach_tracepoint(prog, tp_cat, tp_name); free(sec_name); return libbpf_get_error(*link); } struct bpf_link *bpf_program__attach_raw_tracepoint(const struct bpf_program *prog, const char *tp_name) { char errmsg[STRERR_BUFSIZE]; struct bpf_link *link; int prog_fd, pfd; prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { pr_warn("prog '%s': can't attach before loaded\n", prog->name); return libbpf_err_ptr(-EINVAL); } link = calloc(1, sizeof(*link)); if (!link) return libbpf_err_ptr(-ENOMEM); link->detach = &bpf_link__detach_fd; pfd = bpf_raw_tracepoint_open(tp_name, prog_fd); if (pfd < 0) { pfd = -errno; free(link); pr_warn("prog '%s': failed to attach to raw tracepoint '%s': %s\n", prog->name, tp_name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); return libbpf_err_ptr(pfd); } link->fd = pfd; return link; } static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link) { static const char *const prefixes[] = { "raw_tp", "raw_tracepoint", "raw_tp.w", "raw_tracepoint.w", }; size_t i; const char *tp_name = NULL; *link = NULL; for (i = 0; i < ARRAY_SIZE(prefixes); i++) { size_t pfx_len; if (!str_has_pfx(prog->sec_name, prefixes[i])) continue; pfx_len = strlen(prefixes[i]); /* no auto-attach case of, e.g., SEC("raw_tp") */ if (prog->sec_name[pfx_len] == '\0') return 0; if (prog->sec_name[pfx_len] != '/') continue; tp_name = prog->sec_name + pfx_len + 1; break; } if (!tp_name) { pr_warn("prog '%s': invalid section name '%s'\n", prog->name, prog->sec_name); return -EINVAL; } *link = bpf_program__attach_raw_tracepoint(prog, tp_name); return libbpf_get_error(*link); } /* Common logic for all BPF program types that attach to a btf_id */ static struct bpf_link *bpf_program__attach_btf_id(const struct bpf_program *prog, const struct bpf_trace_opts *opts) { LIBBPF_OPTS(bpf_link_create_opts, link_opts); char errmsg[STRERR_BUFSIZE]; struct bpf_link *link; int prog_fd, pfd; if (!OPTS_VALID(opts, bpf_trace_opts)) return libbpf_err_ptr(-EINVAL); prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { pr_warn("prog '%s': can't attach before loaded\n", prog->name); return libbpf_err_ptr(-EINVAL); } link = calloc(1, sizeof(*link)); if (!link) return libbpf_err_ptr(-ENOMEM); link->detach = &bpf_link__detach_fd; /* libbpf is smart enough to redirect to BPF_RAW_TRACEPOINT_OPEN on old kernels */ link_opts.tracing.cookie = OPTS_GET(opts, cookie, 0); pfd = bpf_link_create(prog_fd, 0, bpf_program__expected_attach_type(prog), &link_opts); if (pfd < 0) { pfd = -errno; free(link); pr_warn("prog '%s': failed to attach: %s\n", prog->name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); return libbpf_err_ptr(pfd); } link->fd = pfd; return link; } struct bpf_link *bpf_program__attach_trace(const struct bpf_program *prog) { return bpf_program__attach_btf_id(prog, NULL); } struct bpf_link *bpf_program__attach_trace_opts(const struct bpf_program *prog, const struct bpf_trace_opts *opts) { return bpf_program__attach_btf_id(prog, opts); } struct bpf_link *bpf_program__attach_lsm(const struct bpf_program *prog) { return bpf_program__attach_btf_id(prog, NULL); } static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_link **link) { *link = bpf_program__attach_trace(prog); return libbpf_get_error(*link); } static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link) { *link = bpf_program__attach_lsm(prog); return libbpf_get_error(*link); } static struct bpf_link * bpf_program_attach_fd(const struct bpf_program *prog, int target_fd, const char *target_name, const struct bpf_link_create_opts *opts) { enum bpf_attach_type attach_type; char errmsg[STRERR_BUFSIZE]; struct bpf_link *link; int prog_fd, link_fd; prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { pr_warn("prog '%s': can't attach before loaded\n", prog->name); return libbpf_err_ptr(-EINVAL); } link = calloc(1, sizeof(*link)); if (!link) return libbpf_err_ptr(-ENOMEM); link->detach = &bpf_link__detach_fd; attach_type = bpf_program__expected_attach_type(prog); link_fd = bpf_link_create(prog_fd, target_fd, attach_type, opts); if (link_fd < 0) { link_fd = -errno; free(link); pr_warn("prog '%s': failed to attach to %s: %s\n", prog->name, target_name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); return libbpf_err_ptr(link_fd); } link->fd = link_fd; return link; } struct bpf_link * bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd) { return bpf_program_attach_fd(prog, cgroup_fd, "cgroup", NULL); } struct bpf_link * bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd) { return bpf_program_attach_fd(prog, netns_fd, "netns", NULL); } struct bpf_link *bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex) { /* target_fd/target_ifindex use the same field in LINK_CREATE */ return bpf_program_attach_fd(prog, ifindex, "xdp", NULL); } struct bpf_link * bpf_program__attach_tcx(const struct bpf_program *prog, int ifindex, const struct bpf_tcx_opts *opts) { LIBBPF_OPTS(bpf_link_create_opts, link_create_opts); __u32 relative_id; int relative_fd; if (!OPTS_VALID(opts, bpf_tcx_opts)) return libbpf_err_ptr(-EINVAL); relative_id = OPTS_GET(opts, relative_id, 0); relative_fd = OPTS_GET(opts, relative_fd, 0); /* validate we don't have unexpected combinations of non-zero fields */ if (!ifindex) { pr_warn("prog '%s': target netdevice ifindex cannot be zero\n", prog->name); return libbpf_err_ptr(-EINVAL); } if (relative_fd && relative_id) { pr_warn("prog '%s': relative_fd and relative_id cannot be set at the same time\n", prog->name); return libbpf_err_ptr(-EINVAL); } link_create_opts.tcx.expected_revision = OPTS_GET(opts, expected_revision, 0); link_create_opts.tcx.relative_fd = relative_fd; link_create_opts.tcx.relative_id = relative_id; link_create_opts.flags = OPTS_GET(opts, flags, 0); /* target_fd/target_ifindex use the same field in LINK_CREATE */ return bpf_program_attach_fd(prog, ifindex, "tcx", &link_create_opts); } struct bpf_link * bpf_program__attach_netkit(const struct bpf_program *prog, int ifindex, const struct bpf_netkit_opts *opts) { LIBBPF_OPTS(bpf_link_create_opts, link_create_opts); __u32 relative_id; int relative_fd; if (!OPTS_VALID(opts, bpf_netkit_opts)) return libbpf_err_ptr(-EINVAL); relative_id = OPTS_GET(opts, relative_id, 0); relative_fd = OPTS_GET(opts, relative_fd, 0); /* validate we don't have unexpected combinations of non-zero fields */ if (!ifindex) { pr_warn("prog '%s': target netdevice ifindex cannot be zero\n", prog->name); return libbpf_err_ptr(-EINVAL); } if (relative_fd && relative_id) { pr_warn("prog '%s': relative_fd and relative_id cannot be set at the same time\n", prog->name); return libbpf_err_ptr(-EINVAL); } link_create_opts.netkit.expected_revision = OPTS_GET(opts, expected_revision, 0); link_create_opts.netkit.relative_fd = relative_fd; link_create_opts.netkit.relative_id = relative_id; link_create_opts.flags = OPTS_GET(opts, flags, 0); return bpf_program_attach_fd(prog, ifindex, "netkit", &link_create_opts); } struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog, int target_fd, const char *attach_func_name) { int btf_id; if (!!target_fd != !!attach_func_name) { pr_warn("prog '%s': supply none or both of target_fd and attach_func_name\n", prog->name); return libbpf_err_ptr(-EINVAL); } if (prog->type != BPF_PROG_TYPE_EXT) { pr_warn("prog '%s': only BPF_PROG_TYPE_EXT can attach as freplace", prog->name); return libbpf_err_ptr(-EINVAL); } if (target_fd) { LIBBPF_OPTS(bpf_link_create_opts, target_opts); btf_id = libbpf_find_prog_btf_id(attach_func_name, target_fd); if (btf_id < 0) return libbpf_err_ptr(btf_id); target_opts.target_btf_id = btf_id; return bpf_program_attach_fd(prog, target_fd, "freplace", &target_opts); } else { /* no target, so use raw_tracepoint_open for compatibility * with old kernels */ return bpf_program__attach_trace(prog); } } struct bpf_link * bpf_program__attach_iter(const struct bpf_program *prog, const struct bpf_iter_attach_opts *opts) { DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_create_opts); char errmsg[STRERR_BUFSIZE]; struct bpf_link *link; int prog_fd, link_fd; __u32 target_fd = 0; if (!OPTS_VALID(opts, bpf_iter_attach_opts)) return libbpf_err_ptr(-EINVAL); link_create_opts.iter_info = OPTS_GET(opts, link_info, (void *)0); link_create_opts.iter_info_len = OPTS_GET(opts, link_info_len, 0); prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { pr_warn("prog '%s': can't attach before loaded\n", prog->name); return libbpf_err_ptr(-EINVAL); } link = calloc(1, sizeof(*link)); if (!link) return libbpf_err_ptr(-ENOMEM); link->detach = &bpf_link__detach_fd; link_fd = bpf_link_create(prog_fd, target_fd, BPF_TRACE_ITER, &link_create_opts); if (link_fd < 0) { link_fd = -errno; free(link); pr_warn("prog '%s': failed to attach to iterator: %s\n", prog->name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); return libbpf_err_ptr(link_fd); } link->fd = link_fd; return link; } static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link) { *link = bpf_program__attach_iter(prog, NULL); return libbpf_get_error(*link); } struct bpf_link *bpf_program__attach_netfilter(const struct bpf_program *prog, const struct bpf_netfilter_opts *opts) { LIBBPF_OPTS(bpf_link_create_opts, lopts); struct bpf_link *link; int prog_fd, link_fd; if (!OPTS_VALID(opts, bpf_netfilter_opts)) return libbpf_err_ptr(-EINVAL); prog_fd = bpf_program__fd(prog); if (prog_fd < 0) { pr_warn("prog '%s': can't attach before loaded\n", prog->name); return libbpf_err_ptr(-EINVAL); } link = calloc(1, sizeof(*link)); if (!link) return libbpf_err_ptr(-ENOMEM); link->detach = &bpf_link__detach_fd; lopts.netfilter.pf = OPTS_GET(opts, pf, 0); lopts.netfilter.hooknum = OPTS_GET(opts, hooknum, 0); lopts.netfilter.priority = OPTS_GET(opts, priority, 0); lopts.netfilter.flags = OPTS_GET(opts, flags, 0); link_fd = bpf_link_create(prog_fd, 0, BPF_NETFILTER, &lopts); if (link_fd < 0) { char errmsg[STRERR_BUFSIZE]; link_fd = -errno; free(link); pr_warn("prog '%s': failed to attach to netfilter: %s\n", prog->name, libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); return libbpf_err_ptr(link_fd); } link->fd = link_fd; return link; } struct bpf_link *bpf_program__attach(const struct bpf_program *prog) { struct bpf_link *link = NULL; int err; if (!prog->sec_def || !prog->sec_def->prog_attach_fn) return libbpf_err_ptr(-EOPNOTSUPP); err = prog->sec_def->prog_attach_fn(prog, prog->sec_def->cookie, &link); if (err) return libbpf_err_ptr(err); /* When calling bpf_program__attach() explicitly, auto-attach support * is expected to work, so NULL returned link is considered an error. * This is different for skeleton's attach, see comment in * bpf_object__attach_skeleton(). */ if (!link) return libbpf_err_ptr(-EOPNOTSUPP); return link; } struct bpf_link_struct_ops { struct bpf_link link; int map_fd; }; static int bpf_link__detach_struct_ops(struct bpf_link *link) { struct bpf_link_struct_ops *st_link; __u32 zero = 0; st_link = container_of(link, struct bpf_link_struct_ops, link); if (st_link->map_fd < 0) /* w/o a real link */ return bpf_map_delete_elem(link->fd, &zero); return close(link->fd); } struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map) { struct bpf_link_struct_ops *link; __u32 zero = 0; int err, fd; if (!bpf_map__is_struct_ops(map) || map->fd == -1) return libbpf_err_ptr(-EINVAL); link = calloc(1, sizeof(*link)); if (!link) return libbpf_err_ptr(-EINVAL); /* kern_vdata should be prepared during the loading phase. */ err = bpf_map_update_elem(map->fd, &zero, map->st_ops->kern_vdata, 0); /* It can be EBUSY if the map has been used to create or * update a link before. We don't allow updating the value of * a struct_ops once it is set. That ensures that the value * never changed. So, it is safe to skip EBUSY. */ if (err && (!(map->def.map_flags & BPF_F_LINK) || err != -EBUSY)) { free(link); return libbpf_err_ptr(err); } link->link.detach = bpf_link__detach_struct_ops; if (!(map->def.map_flags & BPF_F_LINK)) { /* w/o a real link */ link->link.fd = map->fd; link->map_fd = -1; return &link->link; } fd = bpf_link_create(map->fd, 0, BPF_STRUCT_OPS, NULL); if (fd < 0) { free(link); return libbpf_err_ptr(fd); } link->link.fd = fd; link->map_fd = map->fd; return &link->link; } /* * Swap the back struct_ops of a link with a new struct_ops map. */ int bpf_link__update_map(struct bpf_link *link, const struct bpf_map *map) { struct bpf_link_struct_ops *st_ops_link; __u32 zero = 0; int err; if (!bpf_map__is_struct_ops(map) || map->fd < 0) return -EINVAL; st_ops_link = container_of(link, struct bpf_link_struct_ops, link); /* Ensure the type of a link is correct */ if (st_ops_link->map_fd < 0) return -EINVAL; err = bpf_map_update_elem(map->fd, &zero, map->st_ops->kern_vdata, 0); /* It can be EBUSY if the map has been used to create or * update a link before. We don't allow updating the value of * a struct_ops once it is set. That ensures that the value * never changed. So, it is safe to skip EBUSY. */ if (err && err != -EBUSY) return err; err = bpf_link_update(link->fd, map->fd, NULL); if (err < 0) return err; st_ops_link->map_fd = map->fd; return 0; } typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(struct perf_event_header *hdr, void *private_data); static enum bpf_perf_event_ret perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size, void **copy_mem, size_t *copy_size, bpf_perf_event_print_t fn, void *private_data) { struct perf_event_mmap_page *header = mmap_mem; __u64 data_head = ring_buffer_read_head(header); __u64 data_tail = header->data_tail; void *base = ((__u8 *)header) + page_size; int ret = LIBBPF_PERF_EVENT_CONT; struct perf_event_header *ehdr; size_t ehdr_size; while (data_head != data_tail) { ehdr = base + (data_tail & (mmap_size - 1)); ehdr_size = ehdr->size; if (((void *)ehdr) + ehdr_size > base + mmap_size) { void *copy_start = ehdr; size_t len_first = base + mmap_size - copy_start; size_t len_secnd = ehdr_size - len_first; if (*copy_size < ehdr_size) { free(*copy_mem); *copy_mem = malloc(ehdr_size); if (!*copy_mem) { *copy_size = 0; ret = LIBBPF_PERF_EVENT_ERROR; break; } *copy_size = ehdr_size; } memcpy(*copy_mem, copy_start, len_first); memcpy(*copy_mem + len_first, base, len_secnd); ehdr = *copy_mem; } ret = fn(ehdr, private_data); data_tail += ehdr_size; if (ret != LIBBPF_PERF_EVENT_CONT) break; } ring_buffer_write_tail(header, data_tail); return libbpf_err(ret); } struct perf_buffer; struct perf_buffer_params { struct perf_event_attr *attr; /* if event_cb is specified, it takes precendence */ perf_buffer_event_fn event_cb; /* sample_cb and lost_cb are higher-level common-case callbacks */ perf_buffer_sample_fn sample_cb; perf_buffer_lost_fn lost_cb; void *ctx; int cpu_cnt; int *cpus; int *map_keys; }; struct perf_cpu_buf { struct perf_buffer *pb; void *base; /* mmap()'ed memory */ void *buf; /* for reconstructing segmented data */ size_t buf_size; int fd; int cpu; int map_key; }; struct perf_buffer { perf_buffer_event_fn event_cb; perf_buffer_sample_fn sample_cb; perf_buffer_lost_fn lost_cb; void *ctx; /* passed into callbacks */ size_t page_size; size_t mmap_size; struct perf_cpu_buf **cpu_bufs; struct epoll_event *events; int cpu_cnt; /* number of allocated CPU buffers */ int epoll_fd; /* perf event FD */ int map_fd; /* BPF_MAP_TYPE_PERF_EVENT_ARRAY BPF map FD */ }; static void perf_buffer__free_cpu_buf(struct perf_buffer *pb, struct perf_cpu_buf *cpu_buf) { if (!cpu_buf) return; if (cpu_buf->base && munmap(cpu_buf->base, pb->mmap_size + pb->page_size)) pr_warn("failed to munmap cpu_buf #%d\n", cpu_buf->cpu); if (cpu_buf->fd >= 0) { ioctl(cpu_buf->fd, PERF_EVENT_IOC_DISABLE, 0); close(cpu_buf->fd); } free(cpu_buf->buf); free(cpu_buf); } void perf_buffer__free(struct perf_buffer *pb) { int i; if (IS_ERR_OR_NULL(pb)) return; if (pb->cpu_bufs) { for (i = 0; i < pb->cpu_cnt; i++) { struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i]; if (!cpu_buf) continue; bpf_map_delete_elem(pb->map_fd, &cpu_buf->map_key); perf_buffer__free_cpu_buf(pb, cpu_buf); } free(pb->cpu_bufs); } if (pb->epoll_fd >= 0) close(pb->epoll_fd); free(pb->events); free(pb); } static struct perf_cpu_buf * perf_buffer__open_cpu_buf(struct perf_buffer *pb, struct perf_event_attr *attr, int cpu, int map_key) { struct perf_cpu_buf *cpu_buf; char msg[STRERR_BUFSIZE]; int err; cpu_buf = calloc(1, sizeof(*cpu_buf)); if (!cpu_buf) return ERR_PTR(-ENOMEM); cpu_buf->pb = pb; cpu_buf->cpu = cpu; cpu_buf->map_key = map_key; cpu_buf->fd = syscall(__NR_perf_event_open, attr, -1 /* pid */, cpu, -1, PERF_FLAG_FD_CLOEXEC); if (cpu_buf->fd < 0) { err = -errno; pr_warn("failed to open perf buffer event on cpu #%d: %s\n", cpu, libbpf_strerror_r(err, msg, sizeof(msg))); goto error; } cpu_buf->base = mmap(NULL, pb->mmap_size + pb->page_size, PROT_READ | PROT_WRITE, MAP_SHARED, cpu_buf->fd, 0); if (cpu_buf->base == MAP_FAILED) { cpu_buf->base = NULL; err = -errno; pr_warn("failed to mmap perf buffer on cpu #%d: %s\n", cpu, libbpf_strerror_r(err, msg, sizeof(msg))); goto error; } if (ioctl(cpu_buf->fd, PERF_EVENT_IOC_ENABLE, 0) < 0) { err = -errno; pr_warn("failed to enable perf buffer event on cpu #%d: %s\n", cpu, libbpf_strerror_r(err, msg, sizeof(msg))); goto error; } return cpu_buf; error: perf_buffer__free_cpu_buf(pb, cpu_buf); return (struct perf_cpu_buf *)ERR_PTR(err); } static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, struct perf_buffer_params *p); struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt, perf_buffer_sample_fn sample_cb, perf_buffer_lost_fn lost_cb, void *ctx, const struct perf_buffer_opts *opts) { const size_t attr_sz = sizeof(struct perf_event_attr); struct perf_buffer_params p = {}; struct perf_event_attr attr; __u32 sample_period; if (!OPTS_VALID(opts, perf_buffer_opts)) return libbpf_err_ptr(-EINVAL); sample_period = OPTS_GET(opts, sample_period, 1); if (!sample_period) sample_period = 1; memset(&attr, 0, attr_sz); attr.size = attr_sz; attr.config = PERF_COUNT_SW_BPF_OUTPUT; attr.type = PERF_TYPE_SOFTWARE; attr.sample_type = PERF_SAMPLE_RAW; attr.sample_period = sample_period; attr.wakeup_events = sample_period; p.attr = &attr; p.sample_cb = sample_cb; p.lost_cb = lost_cb; p.ctx = ctx; return libbpf_ptr(__perf_buffer__new(map_fd, page_cnt, &p)); } struct perf_buffer *perf_buffer__new_raw(int map_fd, size_t page_cnt, struct perf_event_attr *attr, perf_buffer_event_fn event_cb, void *ctx, const struct perf_buffer_raw_opts *opts) { struct perf_buffer_params p = {}; if (!attr) return libbpf_err_ptr(-EINVAL); if (!OPTS_VALID(opts, perf_buffer_raw_opts)) return libbpf_err_ptr(-EINVAL); p.attr = attr; p.event_cb = event_cb; p.ctx = ctx; p.cpu_cnt = OPTS_GET(opts, cpu_cnt, 0); p.cpus = OPTS_GET(opts, cpus, NULL); p.map_keys = OPTS_GET(opts, map_keys, NULL); return libbpf_ptr(__perf_buffer__new(map_fd, page_cnt, &p)); } static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt, struct perf_buffer_params *p) { const char *online_cpus_file = "/sys/devices/system/cpu/online"; struct bpf_map_info map; char msg[STRERR_BUFSIZE]; struct perf_buffer *pb; bool *online = NULL; __u32 map_info_len; int err, i, j, n; if (page_cnt == 0 || (page_cnt & (page_cnt - 1))) { pr_warn("page count should be power of two, but is %zu\n", page_cnt); return ERR_PTR(-EINVAL); } /* best-effort sanity checks */ memset(&map, 0, sizeof(map)); map_info_len = sizeof(map); err = bpf_map_get_info_by_fd(map_fd, &map, &map_info_len); if (err) { err = -errno; /* if BPF_OBJ_GET_INFO_BY_FD is supported, will return * -EBADFD, -EFAULT, or -E2BIG on real error */ if (err != -EINVAL) { pr_warn("failed to get map info for map FD %d: %s\n", map_fd, libbpf_strerror_r(err, msg, sizeof(msg))); return ERR_PTR(err); } pr_debug("failed to get map info for FD %d; API not supported? Ignoring...\n", map_fd); } else { if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) { pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n", map.name); return ERR_PTR(-EINVAL); } } pb = calloc(1, sizeof(*pb)); if (!pb) return ERR_PTR(-ENOMEM); pb->event_cb = p->event_cb; pb->sample_cb = p->sample_cb; pb->lost_cb = p->lost_cb; pb->ctx = p->ctx; pb->page_size = getpagesize(); pb->mmap_size = pb->page_size * page_cnt; pb->map_fd = map_fd; pb->epoll_fd = epoll_create1(EPOLL_CLOEXEC); if (pb->epoll_fd < 0) { err = -errno; pr_warn("failed to create epoll instance: %s\n", libbpf_strerror_r(err, msg, sizeof(msg))); goto error; } if (p->cpu_cnt > 0) { pb->cpu_cnt = p->cpu_cnt; } else { pb->cpu_cnt = libbpf_num_possible_cpus(); if (pb->cpu_cnt < 0) { err = pb->cpu_cnt; goto error; } if (map.max_entries && map.max_entries < pb->cpu_cnt) pb->cpu_cnt = map.max_entries; } pb->events = calloc(pb->cpu_cnt, sizeof(*pb->events)); if (!pb->events) { err = -ENOMEM; pr_warn("failed to allocate events: out of memory\n"); goto error; } pb->cpu_bufs = calloc(pb->cpu_cnt, sizeof(*pb->cpu_bufs)); if (!pb->cpu_bufs) { err = -ENOMEM; pr_warn("failed to allocate buffers: out of memory\n"); goto error; } err = parse_cpu_mask_file(online_cpus_file, &online, &n); if (err) { pr_warn("failed to get online CPU mask: %d\n", err); goto error; } for (i = 0, j = 0; i < pb->cpu_cnt; i++) { struct perf_cpu_buf *cpu_buf; int cpu, map_key; cpu = p->cpu_cnt > 0 ? p->cpus[i] : i; map_key = p->cpu_cnt > 0 ? p->map_keys[i] : i; /* in case user didn't explicitly requested particular CPUs to * be attached to, skip offline/not present CPUs */ if (p->cpu_cnt <= 0 && (cpu >= n || !online[cpu])) continue; cpu_buf = perf_buffer__open_cpu_buf(pb, p->attr, cpu, map_key); if (IS_ERR(cpu_buf)) { err = PTR_ERR(cpu_buf); goto error; } pb->cpu_bufs[j] = cpu_buf; err = bpf_map_update_elem(pb->map_fd, &map_key, &cpu_buf->fd, 0); if (err) { err = -errno; pr_warn("failed to set cpu #%d, key %d -> perf FD %d: %s\n", cpu, map_key, cpu_buf->fd, libbpf_strerror_r(err, msg, sizeof(msg))); goto error; } pb->events[j].events = EPOLLIN; pb->events[j].data.ptr = cpu_buf; if (epoll_ctl(pb->epoll_fd, EPOLL_CTL_ADD, cpu_buf->fd, &pb->events[j]) < 0) { err = -errno; pr_warn("failed to epoll_ctl cpu #%d perf FD %d: %s\n", cpu, cpu_buf->fd, libbpf_strerror_r(err, msg, sizeof(msg))); goto error; } j++; } pb->cpu_cnt = j; free(online); return pb; error: free(online); if (pb) perf_buffer__free(pb); return ERR_PTR(err); } struct perf_sample_raw { struct perf_event_header header; uint32_t size; char data[]; }; struct perf_sample_lost { struct perf_event_header header; uint64_t id; uint64_t lost; uint64_t sample_id; }; static enum bpf_perf_event_ret perf_buffer__process_record(struct perf_event_header *e, void *ctx) { struct perf_cpu_buf *cpu_buf = ctx; struct perf_buffer *pb = cpu_buf->pb; void *data = e; /* user wants full control over parsing perf event */ if (pb->event_cb) return pb->event_cb(pb->ctx, cpu_buf->cpu, e); switch (e->type) { case PERF_RECORD_SAMPLE: { struct perf_sample_raw *s = data; if (pb->sample_cb) pb->sample_cb(pb->ctx, cpu_buf->cpu, s->data, s->size); break; } case PERF_RECORD_LOST: { struct perf_sample_lost *s = data; if (pb->lost_cb) pb->lost_cb(pb->ctx, cpu_buf->cpu, s->lost); break; } default: pr_warn("unknown perf sample type %d\n", e->type); return LIBBPF_PERF_EVENT_ERROR; } return LIBBPF_PERF_EVENT_CONT; } static int perf_buffer__process_records(struct perf_buffer *pb, struct perf_cpu_buf *cpu_buf) { enum bpf_perf_event_ret ret; ret = perf_event_read_simple(cpu_buf->base, pb->mmap_size, pb->page_size, &cpu_buf->buf, &cpu_buf->buf_size, perf_buffer__process_record, cpu_buf); if (ret != LIBBPF_PERF_EVENT_CONT) return ret; return 0; } int perf_buffer__epoll_fd(const struct perf_buffer *pb) { return pb->epoll_fd; } int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms) { int i, cnt, err; cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, timeout_ms); if (cnt < 0) return -errno; for (i = 0; i < cnt; i++) { struct perf_cpu_buf *cpu_buf = pb->events[i].data.ptr; err = perf_buffer__process_records(pb, cpu_buf); if (err) { pr_warn("error while processing records: %d\n", err); return libbpf_err(err); } } return cnt; } /* Return number of PERF_EVENT_ARRAY map slots set up by this perf_buffer * manager. */ size_t perf_buffer__buffer_cnt(const struct perf_buffer *pb) { return pb->cpu_cnt; } /* * Return perf_event FD of a ring buffer in *buf_idx* slot of * PERF_EVENT_ARRAY BPF map. This FD can be polled for new data using * select()/poll()/epoll() Linux syscalls. */ int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx) { struct perf_cpu_buf *cpu_buf; if (buf_idx >= pb->cpu_cnt) return libbpf_err(-EINVAL); cpu_buf = pb->cpu_bufs[buf_idx]; if (!cpu_buf) return libbpf_err(-ENOENT); return cpu_buf->fd; } int perf_buffer__buffer(struct perf_buffer *pb, int buf_idx, void **buf, size_t *buf_size) { struct perf_cpu_buf *cpu_buf; if (buf_idx >= pb->cpu_cnt) return libbpf_err(-EINVAL); cpu_buf = pb->cpu_bufs[buf_idx]; if (!cpu_buf) return libbpf_err(-ENOENT); *buf = cpu_buf->base; *buf_size = pb->mmap_size; return 0; } /* * Consume data from perf ring buffer corresponding to slot *buf_idx* in * PERF_EVENT_ARRAY BPF map without waiting/polling. If there is no data to * consume, do nothing and return success. * Returns: * - 0 on success; * - <0 on failure. */ int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx) { struct perf_cpu_buf *cpu_buf; if (buf_idx >= pb->cpu_cnt) return libbpf_err(-EINVAL); cpu_buf = pb->cpu_bufs[buf_idx]; if (!cpu_buf) return libbpf_err(-ENOENT); return perf_buffer__process_records(pb, cpu_buf); } int perf_buffer__consume(struct perf_buffer *pb) { int i, err; for (i = 0; i < pb->cpu_cnt; i++) { struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i]; if (!cpu_buf) continue; err = perf_buffer__process_records(pb, cpu_buf); if (err) { pr_warn("perf_buffer: failed to process records in buffer #%d: %d\n", i, err); return libbpf_err(err); } } return 0; } int bpf_program__set_attach_target(struct bpf_program *prog, int attach_prog_fd, const char *attach_func_name) { int btf_obj_fd = 0, btf_id = 0, err; if (!prog || attach_prog_fd < 0) return libbpf_err(-EINVAL); if (prog->obj->loaded) return libbpf_err(-EINVAL); if (attach_prog_fd && !attach_func_name) { /* remember attach_prog_fd and let bpf_program__load() find * BTF ID during the program load */ prog->attach_prog_fd = attach_prog_fd; return 0; } if (attach_prog_fd) { btf_id = libbpf_find_prog_btf_id(attach_func_name, attach_prog_fd); if (btf_id < 0) return libbpf_err(btf_id); } else { if (!attach_func_name) return libbpf_err(-EINVAL); /* load btf_vmlinux, if not yet */ err = bpf_object__load_vmlinux_btf(prog->obj, true); if (err) return libbpf_err(err); err = find_kernel_btf_id(prog->obj, attach_func_name, prog->expected_attach_type, &btf_obj_fd, &btf_id); if (err) return libbpf_err(err); } prog->attach_btf_id = btf_id; prog->attach_btf_obj_fd = btf_obj_fd; prog->attach_prog_fd = attach_prog_fd; return 0; } int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz) { int err = 0, n, len, start, end = -1; bool *tmp; *mask = NULL; *mask_sz = 0; /* Each sub string separated by ',' has format \d+-\d+ or \d+ */ while (*s) { if (*s == ',' || *s == '\n') { s++; continue; } n = sscanf(s, "%d%n-%d%n", &start, &len, &end, &len); if (n <= 0 || n > 2) { pr_warn("Failed to get CPU range %s: %d\n", s, n); err = -EINVAL; goto cleanup; } else if (n == 1) { end = start; } if (start < 0 || start > end) { pr_warn("Invalid CPU range [%d,%d] in %s\n", start, end, s); err = -EINVAL; goto cleanup; } tmp = realloc(*mask, end + 1); if (!tmp) { err = -ENOMEM; goto cleanup; } *mask = tmp; memset(tmp + *mask_sz, 0, start - *mask_sz); memset(tmp + start, 1, end - start + 1); *mask_sz = end + 1; s += len; } if (!*mask_sz) { pr_warn("Empty CPU range\n"); return -EINVAL; } return 0; cleanup: free(*mask); *mask = NULL; return err; } int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz) { int fd, err = 0, len; char buf[128]; fd = open(fcpu, O_RDONLY | O_CLOEXEC); if (fd < 0) { err = -errno; pr_warn("Failed to open cpu mask file %s: %d\n", fcpu, err); return err; } len = read(fd, buf, sizeof(buf)); close(fd); if (len <= 0) { err = len ? -errno : -EINVAL; pr_warn("Failed to read cpu mask from %s: %d\n", fcpu, err); return err; } if (len >= sizeof(buf)) { pr_warn("CPU mask is too big in file %s\n", fcpu); return -E2BIG; } buf[len] = '\0'; return parse_cpu_mask_str(buf, mask, mask_sz); } int libbpf_num_possible_cpus(void) { static const char *fcpu = "/sys/devices/system/cpu/possible"; static int cpus; int err, n, i, tmp_cpus; bool *mask; tmp_cpus = READ_ONCE(cpus); if (tmp_cpus > 0) return tmp_cpus; err = parse_cpu_mask_file(fcpu, &mask, &n); if (err) return libbpf_err(err); tmp_cpus = 0; for (i = 0; i < n; i++) { if (mask[i]) tmp_cpus++; } free(mask); WRITE_ONCE(cpus, tmp_cpus); return tmp_cpus; } static int populate_skeleton_maps(const struct bpf_object *obj, struct bpf_map_skeleton *maps, size_t map_cnt) { int i; for (i = 0; i < map_cnt; i++) { struct bpf_map **map = maps[i].map; const char *name = maps[i].name; void **mmaped = maps[i].mmaped; *map = bpf_object__find_map_by_name(obj, name); if (!*map) { pr_warn("failed to find skeleton map '%s'\n", name); return -ESRCH; } /* externs shouldn't be pre-setup from user code */ if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_KCONFIG) *mmaped = (*map)->mmaped; } return 0; } static int populate_skeleton_progs(const struct bpf_object *obj, struct bpf_prog_skeleton *progs, size_t prog_cnt) { int i; for (i = 0; i < prog_cnt; i++) { struct bpf_program **prog = progs[i].prog; const char *name = progs[i].name; *prog = bpf_object__find_program_by_name(obj, name); if (!*prog) { pr_warn("failed to find skeleton program '%s'\n", name); return -ESRCH; } } return 0; } int bpf_object__open_skeleton(struct bpf_object_skeleton *s, const struct bpf_object_open_opts *opts) { DECLARE_LIBBPF_OPTS(bpf_object_open_opts, skel_opts, .object_name = s->name, ); struct bpf_object *obj; int err; /* Attempt to preserve opts->object_name, unless overriden by user * explicitly. Overwriting object name for skeletons is discouraged, * as it breaks global data maps, because they contain object name * prefix as their own map name prefix. When skeleton is generated, * bpftool is making an assumption that this name will stay the same. */ if (opts) { memcpy(&skel_opts, opts, sizeof(*opts)); if (!opts->object_name) skel_opts.object_name = s->name; } obj = bpf_object__open_mem(s->data, s->data_sz, &skel_opts); err = libbpf_get_error(obj); if (err) { pr_warn("failed to initialize skeleton BPF object '%s': %d\n", s->name, err); return libbpf_err(err); } *s->obj = obj; err = populate_skeleton_maps(obj, s->maps, s->map_cnt); if (err) { pr_warn("failed to populate skeleton maps for '%s': %d\n", s->name, err); return libbpf_err(err); } err = populate_skeleton_progs(obj, s->progs, s->prog_cnt); if (err) { pr_warn("failed to populate skeleton progs for '%s': %d\n", s->name, err); return libbpf_err(err); } return 0; } int bpf_object__open_subskeleton(struct bpf_object_subskeleton *s) { int err, len, var_idx, i; const char *var_name; const struct bpf_map *map; struct btf *btf; __u32 map_type_id; const struct btf_type *map_type, *var_type; const struct bpf_var_skeleton *var_skel; struct btf_var_secinfo *var; if (!s->obj) return libbpf_err(-EINVAL); btf = bpf_object__btf(s->obj); if (!btf) { pr_warn("subskeletons require BTF at runtime (object %s)\n", bpf_object__name(s->obj)); return libbpf_err(-errno); } err = populate_skeleton_maps(s->obj, s->maps, s->map_cnt); if (err) { pr_warn("failed to populate subskeleton maps: %d\n", err); return libbpf_err(err); } err = populate_skeleton_progs(s->obj, s->progs, s->prog_cnt); if (err) { pr_warn("failed to populate subskeleton maps: %d\n", err); return libbpf_err(err); } for (var_idx = 0; var_idx < s->var_cnt; var_idx++) { var_skel = &s->vars[var_idx]; map = *var_skel->map; map_type_id = bpf_map__btf_value_type_id(map); map_type = btf__type_by_id(btf, map_type_id); if (!btf_is_datasec(map_type)) { pr_warn("type for map '%1$s' is not a datasec: %2$s", bpf_map__name(map), __btf_kind_str(btf_kind(map_type))); return libbpf_err(-EINVAL); } len = btf_vlen(map_type); var = btf_var_secinfos(map_type); for (i = 0; i < len; i++, var++) { var_type = btf__type_by_id(btf, var->type); var_name = btf__name_by_offset(btf, var_type->name_off); if (strcmp(var_name, var_skel->name) == 0) { *var_skel->addr = map->mmaped + var->offset; break; } } } return 0; } void bpf_object__destroy_subskeleton(struct bpf_object_subskeleton *s) { if (!s) return; free(s->maps); free(s->progs); free(s->vars); free(s); } int bpf_object__load_skeleton(struct bpf_object_skeleton *s) { int i, err; err = bpf_object__load(*s->obj); if (err) { pr_warn("failed to load BPF skeleton '%s': %d\n", s->name, err); return libbpf_err(err); } for (i = 0; i < s->map_cnt; i++) { struct bpf_map *map = *s->maps[i].map; size_t mmap_sz = bpf_map_mmap_sz(map->def.value_size, map->def.max_entries); int prot, map_fd = bpf_map__fd(map); void **mmaped = s->maps[i].mmaped; if (!mmaped) continue; if (!(map->def.map_flags & BPF_F_MMAPABLE)) { *mmaped = NULL; continue; } if (map->def.map_flags & BPF_F_RDONLY_PROG) prot = PROT_READ; else prot = PROT_READ | PROT_WRITE; /* Remap anonymous mmap()-ed "map initialization image" as * a BPF map-backed mmap()-ed memory, but preserving the same * memory address. This will cause kernel to change process' * page table to point to a different piece of kernel memory, * but from userspace point of view memory address (and its * contents, being identical at this point) will stay the * same. This mapping will be released by bpf_object__close() * as per normal clean up procedure, so we don't need to worry * about it from skeleton's clean up perspective. */ *mmaped = mmap(map->mmaped, mmap_sz, prot, MAP_SHARED | MAP_FIXED, map_fd, 0); if (*mmaped == MAP_FAILED) { err = -errno; *mmaped = NULL; pr_warn("failed to re-mmap() map '%s': %d\n", bpf_map__name(map), err); return libbpf_err(err); } } return 0; } int bpf_object__attach_skeleton(struct bpf_object_skeleton *s) { int i, err; for (i = 0; i < s->prog_cnt; i++) { struct bpf_program *prog = *s->progs[i].prog; struct bpf_link **link = s->progs[i].link; if (!prog->autoload || !prog->autoattach) continue; /* auto-attaching not supported for this program */ if (!prog->sec_def || !prog->sec_def->prog_attach_fn) continue; /* if user already set the link manually, don't attempt auto-attach */ if (*link) continue; err = prog->sec_def->prog_attach_fn(prog, prog->sec_def->cookie, link); if (err) { pr_warn("prog '%s': failed to auto-attach: %d\n", bpf_program__name(prog), err); return libbpf_err(err); } /* It's possible that for some SEC() definitions auto-attach * is supported in some cases (e.g., if definition completely * specifies target information), but is not in other cases. * SEC("uprobe") is one such case. If user specified target * binary and function name, such BPF program can be * auto-attached. But if not, it shouldn't trigger skeleton's * attach to fail. It should just be skipped. * attach_fn signals such case with returning 0 (no error) and * setting link to NULL. */ } return 0; } void bpf_object__detach_skeleton(struct bpf_object_skeleton *s) { int i; for (i = 0; i < s->prog_cnt; i++) { struct bpf_link **link = s->progs[i].link; bpf_link__destroy(*link); *link = NULL; } } void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s) { if (!s) return; if (s->progs) bpf_object__detach_skeleton(s); if (s->obj) bpf_object__close(*s->obj); free(s->maps); free(s->progs); free(s); }
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