LXR linux/samples/bpf/test_current_task_under_cgroup

   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/bpf_helpers.h>
  12#include <uapi/linux/utsname.h>
  13#include "trace_common.h"
  14
  15struct {
  16        __uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
  17        __uint(key_size, sizeof(u32));
  18        __uint(value_size, sizeof(u32));
  19        __uint(max_entries, 1);
  20} cgroup_map SEC(".maps");
  21
  22struct {
  23        __uint(type, BPF_MAP_TYPE_ARRAY);
  24        __type(key, u32);
  25        __type(value, u64);
  26        __uint(max_entries, 1);
  27} perf_map SEC(".maps");
  28
  29/* Writes the last PID that called sync to a map at index 0 */
  30SEC("kprobe/" SYSCALL(sys_sync))
  31int bpf_prog1(struct pt_regs *ctx)
  32{
  33        u64 pid = bpf_get_current_pid_tgid();
  34        int idx = 0;
  35
  36        if (!bpf_current_task_under_cgroup(&cgroup_map, 0))
  37                return 0;
  38
  39        bpf_map_update_elem(&perf_map, &idx, &pid, BPF_ANY);
  40        return 0;
  41}
  42
  43char _license[] SEC("license") = "GPL";
  44u32 _version SEC("version") = LINUX_VERSION_CODE;
  45