xref: /openbmc/linux/samples/bpf/syscall_tp_kern.c (revision 3e30a927)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2017 Facebook
3  */
4 #include <uapi/linux/bpf.h>
5 #include <bpf/bpf_helpers.h>
6 
7 struct syscalls_enter_open_args {
8 	unsigned long long unused;
9 	long syscall_nr;
10 	long filename_ptr;
11 	long flags;
12 	long mode;
13 };
14 
15 struct syscalls_exit_open_args {
16 	unsigned long long unused;
17 	long syscall_nr;
18 	long ret;
19 };
20 
21 struct bpf_map_def SEC("maps") enter_open_map = {
22 	.type = BPF_MAP_TYPE_ARRAY,
23 	.key_size = sizeof(u32),
24 	.value_size = sizeof(u32),
25 	.max_entries = 1,
26 };
27 
28 struct bpf_map_def SEC("maps") exit_open_map = {
29 	.type = BPF_MAP_TYPE_ARRAY,
30 	.key_size = sizeof(u32),
31 	.value_size = sizeof(u32),
32 	.max_entries = 1,
33 };
34 
35 static __always_inline void count(void *map)
36 {
37 	u32 key = 0;
38 	u32 *value, init_val = 1;
39 
40 	value = bpf_map_lookup_elem(map, &key);
41 	if (value)
42 		*value += 1;
43 	else
44 		bpf_map_update_elem(map, &key, &init_val, BPF_NOEXIST);
45 }
46 
47 SEC("tracepoint/syscalls/sys_enter_open")
48 int trace_enter_open(struct syscalls_enter_open_args *ctx)
49 {
50 	count(&enter_open_map);
51 	return 0;
52 }
53 
54 SEC("tracepoint/syscalls/sys_enter_openat")
55 int trace_enter_open_at(struct syscalls_enter_open_args *ctx)
56 {
57 	count(&enter_open_map);
58 	return 0;
59 }
60 
61 SEC("tracepoint/syscalls/sys_exit_open")
62 int trace_enter_exit(struct syscalls_exit_open_args *ctx)
63 {
64 	count(&exit_open_map);
65 	return 0;
66 }
67 
68 SEC("tracepoint/syscalls/sys_exit_openat")
69 int trace_enter_exit_at(struct syscalls_exit_open_args *ctx)
70 {
71 	count(&exit_open_map);
72 	return 0;
73 }
74