projects/linux·blob master · refs

155 lines · 3.4 KiB

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
18static 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
25static 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
48static 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
122cleanup:
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
135int 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}