LXR linux/tools/testing/selftests/bpf/progs/test_core

   1// SPDX-License-Identifier: GPL-2.0
   2// Copyright (c) 2020 Facebook
   3#include <linux/bpf.h>
   4#include <bpf/bpf_helpers.h>
   5#include <bpf/bpf_core_read.h>
   6
   7struct task_struct {
   8        int tgid;
   9} __attribute__((preserve_access_index));
  10
  11struct {
  12        __uint(type, BPF_MAP_TYPE_ARRAY);
  13        __uint(max_entries, 1);
  14        __type(key, int);
  15        __type(value, int);
  16} exp_tgid_map SEC(".maps");
  17
  18struct {
  19        __uint(type, BPF_MAP_TYPE_ARRAY);
  20        __uint(max_entries, 1);
  21        __type(key, int);
  22        __type(value, int);
  23} results SEC(".maps");
  24
  25SEC("tp/raw_syscalls/sys_enter")
  26int handle_sys_enter(void *ctx)
  27{
  28        struct task_struct *task = (void *)bpf_get_current_task();
  29        int tgid = BPF_CORE_READ(task, tgid);
  30        int zero = 0;
  31        int real_tgid = bpf_get_current_pid_tgid() >> 32;
  32        int *exp_tgid = bpf_map_lookup_elem(&exp_tgid_map, &zero);
  33
  34        /* only pass through sys_enters from test process */
  35        if (!exp_tgid || *exp_tgid != real_tgid)
  36                return 0;
  37
  38        bpf_map_update_elem(&results, &zero, &tgid, 0);
  39
  40        return 0;
  41}
  42
  43char _license[] SEC("license") = "GPL";
  44