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
11int 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
93cleanup:
94	for (j--; j >= 0; j--)
95		bpf_link__destroy(links[j]);
96
97	bpf_object__close(obj);
98	return 0;
99}
100