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
8 char _license[] SEC("license") = "GPL";
9
10 struct {
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
19 pid_t target_pid = 0;
20 int mismatch_cnt = 0;
21 int enter_cnt = 0;
22 int exit_cnt = 0;
23
24 SEC("tp_btf/sys_enter")
25 int 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
45 SEC("tp_btf/sys_exit")
46 int 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
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