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 
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 */
41