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