1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2021 Facebook */
3
4#include "vmlinux.h"
5#include <bpf/bpf_helpers.h>
6#include <bpf/bpf_tracing.h>
7
8char _license[] SEC("license") = "GPL";
9
10struct {
11 __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
12 __uint(map_flags, BPF_F_NO_PREALLOC);
13 __type(key, int);
14 __type(value, long);
15} enter_id SEC(".maps");
16
17#define MAGIC_VALUE 0xabcd1234
18
19pid_t target_pid = 0;
20int mismatch_cnt = 0;
21int enter_cnt = 0;
22int exit_cnt = 0;
23
24SEC("tp_btf/sys_enter")
25int BPF_PROG(on_enter, struct pt_regs *regs, long id)
26{
27 struct task_struct *task;
28 long *ptr;
29
30 task = bpf_get_current_task_btf();
31 if (task->pid != target_pid)
32 return 0;
33
34 ptr = bpf_task_storage_get(&enter_id, task, 0,
35 BPF_LOCAL_STORAGE_GET_F_CREATE);
36 if (!ptr)
37 return 0;
38
39 __sync_fetch_and_add(&enter_cnt, 1);
40 *ptr = MAGIC_VALUE + enter_cnt;
41
42 return 0;
43}
44
45SEC("tp_btf/sys_exit")
46int BPF_PROG(on_exit, struct pt_regs *regs, long id)
47{
48 struct task_struct *task;
49 long *ptr;
50
51 task = bpf_get_current_task_btf();
52 if (task->pid != target_pid)
53 return 0;
54
55 ptr = bpf_task_storage_get(&enter_id, task, 0,
56 BPF_LOCAL_STORAGE_GET_F_CREATE);
57 if (!ptr)
58 return 0;
59
60 __sync_fetch_and_add(&exit_cnt, 1);
61 if (*ptr != MAGIC_VALUE + exit_cnt)
62 __sync_fetch_and_add(&mismatch_cnt, 1);
63 return 0;
64}
65

source code of linux/tools/testing/selftests/bpf/progs/task_local_storage.c