root/tools/testing/selftests/bpf/progs/get_cgroup_id_kern.c

DEFINITIONS

1. SEC

   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 {
   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 
  14 struct {
  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 
  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 */