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