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 <bpf/libbpf.h>
 12#include <bpf/bpf.h>
 13
 14/* This program verifies bpf attachment to tracepoint sys_enter_* and sys_exit_*.
 15 * This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
 16 */
 17
 18static void usage(const char *cmd)
 19{
 20	printf("USAGE: %s [-i num_progs] [-h]\n", cmd);
 21	printf("       -i num_progs      # number of progs of the test\n");
 22	printf("       -h                # help\n");
 23}
 24
 25static void verify_map(int map_id)
 26{
 27	__u32 key = 0;
 28	__u32 val;
 29
 30	if (bpf_map_lookup_elem(map_id, &key, &val) != 0) {
 31		fprintf(stderr, "map_lookup failed: %s\n", strerror(errno));
 32		return;
 33	}
 34	if (val == 0) {
 35		fprintf(stderr, "failed: map #%d returns value 0\n", map_id);
 36		return;
 37	}
 38
 39	printf("verify map:%d val: %d\n", map_id, val);
 40
 41	val = 0;
 42	if (bpf_map_update_elem(map_id, &key, &val, BPF_ANY) != 0) {
 43		fprintf(stderr, "map_update failed: %s\n", strerror(errno));
 44		return;
 45	}
 46}
 47
 48static int test(char *filename, int num_progs)
 49{
 50	int map0_fds[num_progs], map1_fds[num_progs], fd, i, j = 0;
 51	struct bpf_link *links[num_progs * 4];
 52	struct bpf_object *objs[num_progs];
 53	struct bpf_program *prog;
 54
 55	for (i = 0; i < num_progs; i++) {
 56		objs[i] = bpf_object__open_file(filename, NULL);
 57		if (libbpf_get_error(objs[i])) {
 58			fprintf(stderr, "opening BPF object file failed\n");
 59			objs[i] = NULL;
 60			goto cleanup;
 61		}
 62
 63		/* load BPF program */
 64		if (bpf_object__load(objs[i])) {
 65			fprintf(stderr, "loading BPF object file failed\n");
 66			goto cleanup;
 67		}
 68
 69		map0_fds[i] = bpf_object__find_map_fd_by_name(objs[i],
 70							      "enter_open_map");
 71		map1_fds[i] = bpf_object__find_map_fd_by_name(objs[i],
 72							      "exit_open_map");
 73		if (map0_fds[i] < 0 || map1_fds[i] < 0) {
 74			fprintf(stderr, "finding a map in obj file failed\n");
 75			goto cleanup;
 76		}
 77
 78		bpf_object__for_each_program(prog, objs[i]) {
 79			links[j] = bpf_program__attach(prog);
 80			if (libbpf_get_error(links[j])) {
 81				fprintf(stderr, "bpf_program__attach failed\n");
 82				links[j] = NULL;
 83				goto cleanup;
 84			}
 85			j++;
 86		}
 87		printf("prog #%d: map ids %d %d\n", i, map0_fds[i], map1_fds[i]);
 88	}
 89
 90	/* current load_bpf_file has perf_event_open default pid = -1
 91	 * and cpu = 0, which permits attached bpf execution on
 92	 * all cpus for all pid's. bpf program execution ignores
 93	 * cpu affinity.
 94	 */
 95	/* trigger some "open" operations */
 96	fd = open(filename, O_RDONLY);
 97	if (fd < 0) {
 98		fprintf(stderr, "open failed: %s\n", strerror(errno));
 99		return 1;
100	}
101	close(fd);
102
103	/* verify the map */
104	for (i = 0; i < num_progs; i++) {
105		verify_map(map0_fds[i]);
106		verify_map(map1_fds[i]);
107	}
108
109cleanup:
110	for (j--; j >= 0; j--)
111		bpf_link__destroy(links[j]);
112
113	for (i--; i >= 0; i--)
114		bpf_object__close(objs[i]);
115	return 0;
116}
117
118int main(int argc, char **argv)
119{
120	int opt, num_progs = 1;
121	char filename[256];
122
123	while ((opt = getopt(argc, argv, "i:h")) != -1) {
124		switch (opt) {
125		case 'i':
126			num_progs = atoi(optarg);
127			break;
128		case 'h':
129		default:
130			usage(argv[0]);
131			return 0;
132		}
133	}
134
135	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
136
137	return test(filename, num_progs);
138}