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