1 /* Copyright (c) 2016 Sargun Dhillon <sargun@sargun.me>
2 *
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
6 */
7
8 #include <linux/ptrace.h>
9 #include <uapi/linux/bpf.h>
10 #include <linux/version.h>
11 #include "bpf_helpers.h"
12 #include <uapi/linux/utsname.h>
13
14 struct bpf_map_def SEC("maps") cgroup_map = {
15 .type = BPF_MAP_TYPE_CGROUP_ARRAY,
16 .key_size = sizeof(u32),
17 .value_size = sizeof(u32),
18 .max_entries = 1,
19 };
20
21 struct bpf_map_def SEC("maps") perf_map = {
22 .type = BPF_MAP_TYPE_ARRAY,
23 .key_size = sizeof(u32),
24 .value_size = sizeof(u64),
25 .max_entries = 1,
26 };
27
28 /* Writes the last PID that called sync to a map at index 0 */
29 SEC("kprobe/sys_sync")
bpf_prog1(struct pt_regs * ctx)30 int bpf_prog1(struct pt_regs *ctx)
31 {
32 u64 pid = bpf_get_current_pid_tgid();
33 int idx = 0;
34
35 if (!bpf_current_task_under_cgroup(&cgroup_map, 0))
36 return 0;
37
38 bpf_map_update_elem(&perf_map, &idx, &pid, BPF_ANY);
39 return 0;
40 }
41
42 char _license[] SEC("license") = "GPL";
43 u32 _version SEC("version") = LINUX_VERSION_CODE;
44