GNU Linux-libre 6.6.15-gnu
[releases.git] / samples / bpf / syscall_tp_user.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2017 Facebook
3  */
4 #include <stdio.h>
5 #include <unistd.h>
6 #include <fcntl.h>
7 #include <stdlib.h>
8 #include <string.h>
9 #include <linux/perf_event.h>
10 #include <errno.h>
11 #include <bpf/libbpf.h>
12 #include <bpf/bpf.h>
13
14 /* This program verifies bpf attachment to tracepoint sys_enter_* and sys_exit_*.
15  * This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
16  */
17
18 static void usage(const char *cmd)
19 {
20         printf("USAGE: %s [-i nr_tests] [-h]\n", cmd);
21         printf("       -i nr_tests      # rounds of test to run\n");
22         printf("       -h               # help\n");
23 }
24
25 static void verify_map(int map_id)
26 {
27         __u32 key = 0;
28         __u32 val;
29
30         if (bpf_map_lookup_elem(map_id, &key, &val) != 0) {
31                 fprintf(stderr, "map_lookup failed: %s\n", strerror(errno));
32                 return;
33         }
34         if (val == 0) {
35                 fprintf(stderr, "failed: map #%d returns value 0\n", map_id);
36                 return;
37         }
38
39         printf("verify map:%d val: %d\n", map_id, val);
40
41         val = 0;
42         if (bpf_map_update_elem(map_id, &key, &val, BPF_ANY) != 0) {
43                 fprintf(stderr, "map_update failed: %s\n", strerror(errno));
44                 return;
45         }
46 }
47
48 static int test(char *filename, int nr_tests)
49 {
50         int map0_fds[nr_tests], map1_fds[nr_tests], fd, i, j = 0;
51         struct bpf_link **links = NULL;
52         struct bpf_object *objs[nr_tests];
53         struct bpf_program *prog;
54
55         for (i = 0; i < nr_tests; i++) {
56                 objs[i] = bpf_object__open_file(filename, NULL);
57                 if (libbpf_get_error(objs[i])) {
58                         fprintf(stderr, "opening BPF object file failed\n");
59                         objs[i] = NULL;
60                         goto cleanup;
61                 }
62
63                 /* One-time initialization */
64                 if (!links) {
65                         int nr_progs = 0;
66
67                         bpf_object__for_each_program(prog, objs[i])
68                                 nr_progs += 1;
69
70                         links = calloc(nr_progs * nr_tests, sizeof(struct bpf_link *));
71
72                         if (!links)
73                                 goto cleanup;
74                 }
75
76                 /* load BPF program */
77                 if (bpf_object__load(objs[i])) {
78                         fprintf(stderr, "loading BPF object file failed\n");
79                         goto cleanup;
80                 }
81
82                 map0_fds[i] = bpf_object__find_map_fd_by_name(objs[i],
83                                                               "enter_open_map");
84                 map1_fds[i] = bpf_object__find_map_fd_by_name(objs[i],
85                                                               "exit_open_map");
86                 if (map0_fds[i] < 0 || map1_fds[i] < 0) {
87                         fprintf(stderr, "finding a map in obj file failed\n");
88                         goto cleanup;
89                 }
90
91                 bpf_object__for_each_program(prog, objs[i]) {
92                         links[j] = bpf_program__attach(prog);
93                         if (libbpf_get_error(links[j])) {
94                                 fprintf(stderr, "bpf_program__attach failed\n");
95                                 links[j] = NULL;
96                                 goto cleanup;
97                         }
98                         j++;
99                 }
100                 printf("prog #%d: map ids %d %d\n", i, map0_fds[i], map1_fds[i]);
101         }
102
103         /* current load_bpf_file has perf_event_open default pid = -1
104          * and cpu = 0, which permits attached bpf execution on
105          * all cpus for all pid's. bpf program execution ignores
106          * cpu affinity.
107          */
108         /* trigger some "open" operations */
109         fd = open(filename, O_RDONLY);
110         if (fd < 0) {
111                 fprintf(stderr, "open failed: %s\n", strerror(errno));
112                 return 1;
113         }
114         close(fd);
115
116         /* verify the map */
117         for (i = 0; i < nr_tests; i++) {
118                 verify_map(map0_fds[i]);
119                 verify_map(map1_fds[i]);
120         }
121
122 cleanup:
123         if (links) {
124                 for (j--; j >= 0; j--)
125                         bpf_link__destroy(links[j]);
126
127                 free(links);
128         }
129
130         for (i--; i >= 0; i--)
131                 bpf_object__close(objs[i]);
132         return 0;
133 }
134
135 int main(int argc, char **argv)
136 {
137         int opt, nr_tests = 1;
138         char filename[256];
139
140         while ((opt = getopt(argc, argv, "i:h")) != -1) {
141                 switch (opt) {
142                 case 'i':
143                         nr_tests = atoi(optarg);
144                         break;
145                 case 'h':
146                 default:
147                         usage(argv[0]);
148                         return 0;
149                 }
150         }
151
152         snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
153
154         return test(filename, nr_tests);
155 }