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 } 156