LXR linux/tools/testing/selftests/bpf/progs/get_cgroup_id

   1// SPDX-License-Identifier: GPL-2.0
   2// Copyright (c) 2018 Facebook
   3
   4#include <linux/bpf.h>
   5#include <bpf/bpf_helpers.h>
   6
   7struct {
   8        __uint(type, BPF_MAP_TYPE_ARRAY);
   9        __uint(max_entries, 1);
  10        __type(key, __u32);
  11        __type(value, __u64);
  12} cg_ids SEC(".maps");
  13
  14struct {
  15        __uint(type, BPF_MAP_TYPE_ARRAY);
  16        __uint(max_entries, 1);
  17        __type(key, __u32);
  18        __type(value, __u32);
  19} pidmap SEC(".maps");
  20
  21SEC("tracepoint/syscalls/sys_enter_nanosleep")
  22int trace(void *ctx)
  23{
  24        __u32 pid = bpf_get_current_pid_tgid();
  25        __u32 key = 0, *expected_pid;
  26        __u64 *val;
  27
  28        expected_pid = bpf_map_lookup_elem(&pidmap, &key);
  29        if (!expected_pid || *expected_pid != pid)
  30                return 0;
  31
  32        val = bpf_map_lookup_elem(&cg_ids, &key);
  33        if (val)
  34                *val = bpf_get_current_cgroup_id();
  35
  36        return 0;
  37}
  38
  39char _license[] SEC("license") = "GPL";
  40__u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */
  41