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