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 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 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 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 } 115 116 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