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