cregit-Linux how code gets into the kernel

Release 4.14 samples/bpf/tracex2_kern.c

Directory: samples/bpf
/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 */
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/version.h>
#include <uapi/linux/bpf.h>
#include "bpf_helpers.h"

struct bpf_map_def SEC("maps") my_map = {
	.type = BPF_MAP_TYPE_HASH,
	.key_size = sizeof(long),
	.value_size = sizeof(long),
	.max_entries = 1024,
};

/* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe
 * example will no longer be meaningful
 */
SEC("kprobe/kfree_skb")

int bpf_prog2(struct pt_regs *ctx) { long loc = 0; long init_val = 1; long *value; /* read ip of kfree_skb caller. * non-portable version of __builtin_return_address(0) */ BPF_KPROBE_READ_RET_IP(loc, ctx); value = bpf_map_lookup_elem(&my_map, &loc); if (value) *value += 1; else bpf_map_update_elem(&my_map, &loc, &init_val, BPF_ANY); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Alexei Starovoitov6795.71%133.33%
Naveen N. Rao22.86%133.33%
Michael Holzheu11.43%133.33%
Total70100.00%3100.00%


static unsigned int log2(unsigned int v) { unsigned int r; unsigned int shift; r = (v > 0xFFFF) << 4; v >>= r; shift = (v > 0xFF) << 3; v >>= shift; r |= shift; shift = (v > 0xF) << 2; v >>= shift; r |= shift; shift = (v > 0x3) << 1; v >>= shift; r |= shift; r |= (v >> 1); return r; }

Contributors

PersonTokensPropCommitsCommitProp
Alexei Starovoitov98100.00%1100.00%
Total98100.00%1100.00%


static unsigned int log2l(unsigned long v) { unsigned int hi = v >> 32; if (hi) return log2(hi) + 32; else return log2(v); }

Contributors

PersonTokensPropCommitsCommitProp
Alexei Starovoitov38100.00%1100.00%
Total38100.00%1100.00%

struct hist_key { char comm[16]; u64 pid_tgid; u64 uid_gid; u64 index; }; struct bpf_map_def SEC("maps") my_hist_map = { .type = BPF_MAP_TYPE_PERCPU_HASH, .key_size = sizeof(struct hist_key), .value_size = sizeof(long), .max_entries = 1024, }; SEC("kprobe/sys_write")
int bpf_prog3(struct pt_regs *ctx) { long write_size = PT_REGS_PARM3(ctx); long init_val = 1; long *value; struct hist_key key; key.index = log2l(write_size); key.pid_tgid = bpf_get_current_pid_tgid(); key.uid_gid = bpf_get_current_uid_gid(); bpf_get_current_comm(&key.comm, sizeof(key.comm)); value = bpf_map_lookup_elem(&my_hist_map, &key); if (value) __sync_fetch_and_add(value, 1); else bpf_map_update_elem(&my_hist_map, &key, &init_val, BPF_ANY); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Alexei Starovoitov10697.25%266.67%
Michael Holzheu32.75%133.33%
Total109100.00%3100.00%

char _license[] SEC("license") = "GPL"; u32 _version SEC("version") = LINUX_VERSION_CODE;

Overall Contributors

PersonTokensPropCommitsCommitProp
Alexei Starovoitov44598.45%350.00%
Michael Holzheu40.88%116.67%
Naveen N. Rao20.44%116.67%
Daniel Borkmann10.22%116.67%
Total452100.00%6100.00%
Directory: samples/bpf
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