// SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2020 Facebook #include <linux/bpf.h> #include <bpf/bpf_helpers.h> char _license[] SEC("license") = "GPL"; struct sample { int pid; int seq; long value; char comm[16]; }; struct ringbuf_map { __uint(type, BPF_MAP_TYPE_RINGBUF); /* libbpf will adjust to valid page size */ __uint(max_entries, 1000); } ringbuf1 SEC(".maps"), ringbuf2 SEC(".maps"); struct { __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS); __uint(max_entries, 4); __type(key, int); __array(values, struct ringbuf_map); } ringbuf_arr SEC(".maps") = { .values = { [0] = &ringbuf1, [2] = &ringbuf2, }, }; struct { __uint(type, BPF_MAP_TYPE_HASH_OF_MAPS); __uint(max_entries, 1); __type(key, int); __array(values, struct ringbuf_map); } ringbuf_hash SEC(".maps") = { .values = { [0] = &ringbuf1, }, }; /* inputs */ int pid = 0; int target_ring = 0; long value = 0; /* outputs */ long total = 0; long dropped = 0; long skipped = 0; SEC("tp/syscalls/sys_enter_getpgid") int test_ringbuf(void *ctx) { int cur_pid = bpf_get_current_pid_tgid() >> 32; struct sample *sample; void *rb; int zero = 0; if (cur_pid != pid) return 0; rb = bpf_map_lookup_elem(&ringbuf_arr, &target_ring); if (!rb) { skipped += 1; return 1; } sample = bpf_ringbuf_reserve(rb, sizeof(*sample), 0); if (!sample) { dropped += 1; return 1; } sample->pid = pid; bpf_get_current_comm(sample->comm, sizeof(sample->comm)); sample->value = value; sample->seq = total; total += 1; bpf_ringbuf_submit(sample, 0); return 0; }