tools/testing/selftests/bpf/get_cgroup_id_kern.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2018 Facebook
   3
   4 #include <linux/bpf.h>
   5 #include "bpf_helpers.h"
   6
   7 struct bpf_map_def SEC("maps") cg_ids = {
   8         .type = BPF_MAP_TYPE_ARRAY,
   9         .key_size = sizeof(__u32),
  10         .value_size = sizeof(__u64),
  11         .max_entries = 1,
  12 };
  13
  14 struct bpf_map_def SEC("maps") pidmap = {
  15         .type = BPF_MAP_TYPE_ARRAY,
  16         .key_size = sizeof(__u32),
  17         .value_size = sizeof(__u32),
  18         .max_entries = 1,
  19 };
  20
  21 SEC("tracepoint/syscalls/sys_enter_nanosleep")
  22 int 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
  39 char _license[] SEC("license") = "GPL";
  40 __u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */