1 // SPDX-License-Identifier: GPL-2.0 2 #include <stdio.h> 3 #include <unistd.h> 4 #include <string.h> 5 #include <assert.h> 6 #include <sys/resource.h> 7 #include <bpf/libbpf.h> 8 #include <bpf/bpf.h> 9 #include "trace_helpers.h" 10 11 int main(int ac, char **argv) 12 { 13 struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; 14 char filename[256], symbol[256]; 15 struct bpf_object *obj = NULL; 16 struct bpf_link *links[20]; 17 long key, next_key, value; 18 struct bpf_program *prog; 19 int map_fd, i, j = 0; 20 const char *section; 21 struct ksym *sym; 22 23 if (setrlimit(RLIMIT_MEMLOCK, &r)) { 24 perror("setrlimit(RLIMIT_MEMLOCK)"); 25 return 1; 26 } 27 28 if (load_kallsyms()) { 29 printf("failed to process /proc/kallsyms\n"); 30 return 2; 31 } 32 33 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); 34 obj = bpf_object__open_file(filename, NULL); 35 if (libbpf_get_error(obj)) { 36 fprintf(stderr, "ERROR: opening BPF object file failed\n"); 37 obj = NULL; 38 goto cleanup; 39 } 40 41 /* load BPF program */ 42 if (bpf_object__load(obj)) { 43 fprintf(stderr, "ERROR: loading BPF object file failed\n"); 44 goto cleanup; 45 } 46 47 map_fd = bpf_object__find_map_fd_by_name(obj, "my_map"); 48 if (map_fd < 0) { 49 fprintf(stderr, "ERROR: finding a map in obj file failed\n"); 50 goto cleanup; 51 } 52 53 bpf_object__for_each_program(prog, obj) { 54 section = bpf_program__section_name(prog); 55 if (sscanf(section, "kprobe/%s", symbol) != 1) 56 continue; 57 58 /* Attach prog only when symbol exists */ 59 if (ksym_get_addr(symbol)) { 60 links[j] = bpf_program__attach(prog); 61 if (libbpf_get_error(links[j])) { 62 fprintf(stderr, "bpf_program__attach failed\n"); 63 links[j] = NULL; 64 goto cleanup; 65 } 66 j++; 67 } 68 } 69 70 for (i = 0; i < 5; i++) { 71 key = 0; 72 printf("kprobing funcs:"); 73 while (bpf_map_get_next_key(map_fd, &key, &next_key) == 0) { 74 bpf_map_lookup_elem(map_fd, &next_key, &value); 75 assert(next_key == value); 76 sym = ksym_search(value); 77 key = next_key; 78 if (!sym) { 79 printf("ksym not found. Is kallsyms loaded?\n"); 80 continue; 81 } 82 83 printf(" %s", sym->name); 84 } 85 if (key) 86 printf("\n"); 87 key = 0; 88 while (bpf_map_get_next_key(map_fd, &key, &next_key) == 0) 89 bpf_map_delete_elem(map_fd, &next_key); 90 sleep(1); 91 } 92 93 cleanup: 94 for (j--; j >= 0; j--) 95 bpf_link__destroy(links[j]); 96 97 bpf_object__close(obj); 98 return 0; 99 } 100