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 num_progs] [-h]\n", cmd); 21 printf(" -i num_progs # number of progs of the test\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 num_progs) 49 { 50 int map0_fds[num_progs], map1_fds[num_progs], fd, i, j = 0; 51 struct bpf_link *links[num_progs * 4]; 52 struct bpf_object *objs[num_progs]; 53 struct bpf_program *prog; 54 55 for (i = 0; i < num_progs; 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 /* load BPF program */ 64 if (bpf_object__load(objs[i])) { 65 fprintf(stderr, "loading BPF object file failed\n"); 66 goto cleanup; 67 } 68 69 map0_fds[i] = bpf_object__find_map_fd_by_name(objs[i], 70 "enter_open_map"); 71 map1_fds[i] = bpf_object__find_map_fd_by_name(objs[i], 72 "exit_open_map"); 73 if (map0_fds[i] < 0 || map1_fds[i] < 0) { 74 fprintf(stderr, "finding a map in obj file failed\n"); 75 goto cleanup; 76 } 77 78 bpf_object__for_each_program(prog, objs[i]) { 79 links[j] = bpf_program__attach(prog); 80 if (libbpf_get_error(links[j])) { 81 fprintf(stderr, "bpf_program__attach failed\n"); 82 links[j] = NULL; 83 goto cleanup; 84 } 85 j++; 86 } 87 printf("prog #%d: map ids %d %d\n", i, map0_fds[i], map1_fds[i]); 88 } 89 90 /* current load_bpf_file has perf_event_open default pid = -1 91 * and cpu = 0, which permits attached bpf execution on 92 * all cpus for all pid's. bpf program execution ignores 93 * cpu affinity. 94 */ 95 /* trigger some "open" operations */ 96 fd = open(filename, O_RDONLY); 97 if (fd < 0) { 98 fprintf(stderr, "open failed: %s\n", strerror(errno)); 99 return 1; 100 } 101 close(fd); 102 103 /* verify the map */ 104 for (i = 0; i < num_progs; i++) { 105 verify_map(map0_fds[i]); 106 verify_map(map1_fds[i]); 107 } 108 109 cleanup: 110 for (j--; j >= 0; j--) 111 bpf_link__destroy(links[j]); 112 113 for (i--; i >= 0; i--) 114 bpf_object__close(objs[i]); 115 return 0; 116 } 117 118 int main(int argc, char **argv) 119 { 120 int opt, num_progs = 1; 121 char filename[256]; 122 123 while ((opt = getopt(argc, argv, "i:h")) != -1) { 124 switch (opt) { 125 case 'i': 126 num_progs = atoi(optarg); 127 break; 128 case 'h': 129 default: 130 usage(argv[0]); 131 return 0; 132 } 133 } 134 135 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); 136 137 return test(filename, num_progs); 138 } 139