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 nr_tests] [-h]\n", cmd);
 21	printf("       -i nr_tests      # rounds of test to run\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 nr_tests)
 49{
 50	int map0_fds[nr_tests], map1_fds[nr_tests], fd, i, j = 0;
 51	struct bpf_link **links = NULL;
 52	struct bpf_object *objs[nr_tests];
 53	struct bpf_program *prog;
 54
 55	for (i = 0; i < nr_tests; 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		/* One-time initialization */
 64		if (!links) {
 65			int nr_progs = 0;
 66
 67			bpf_object__for_each_program(prog, objs[i])
 68				nr_progs += 1;
 69
 70			links = calloc(nr_progs * nr_tests, sizeof(struct bpf_link *));
 71
 72			if (!links)
 73				goto cleanup;
 74		}
 75
 76		/* load BPF program */
 77		if (bpf_object__load(objs[i])) {
 78			fprintf(stderr, "loading BPF object file failed\n");
 79			goto cleanup;
 80		}
 81
 82		map0_fds[i] = bpf_object__find_map_fd_by_name(objs[i],
 83							      "enter_open_map");
 84		map1_fds[i] = bpf_object__find_map_fd_by_name(objs[i],
 85							      "exit_open_map");
 86		if (map0_fds[i] < 0 || map1_fds[i] < 0) {
 87			fprintf(stderr, "finding a map in obj file failed\n");
 88			goto cleanup;
 89		}
 90
 91		bpf_object__for_each_program(prog, objs[i]) {
 92			links[j] = bpf_program__attach(prog);
 93			if (libbpf_get_error(links[j])) {
 94				fprintf(stderr, "bpf_program__attach failed\n");
 95				links[j] = NULL;
 96				goto cleanup;
 97			}
 98			j++;
 99		}
100		printf("prog #%d: map ids %d %d\n", i, map0_fds[i], map1_fds[i]);
101	}
102
103	/* current load_bpf_file has perf_event_open default pid = -1
104	 * and cpu = 0, which permits attached bpf execution on
105	 * all cpus for all pid's. bpf program execution ignores
106	 * cpu affinity.
107	 */
108	/* trigger some "open" operations */
109	fd = open(filename, O_RDONLY);
110	if (fd < 0) {
111		fprintf(stderr, "open failed: %s\n", strerror(errno));
112		return 1;
113	}
114	close(fd);
115
116	/* verify the map */
117	for (i = 0; i < nr_tests; i++) {
118		verify_map(map0_fds[i]);
119		verify_map(map1_fds[i]);
120	}
121
122cleanup:
123	if (links) {
124		for (j--; j >= 0; j--)
125			bpf_link__destroy(links[j]);
126
127		free(links);
128	}
129
130	for (i--; i >= 0; i--)
131		bpf_object__close(objs[i]);
132	return 0;
133}
134
135int main(int argc, char **argv)
136{
137	int opt, nr_tests = 1;
138	char filename[256];
139
140	while ((opt = getopt(argc, argv, "i:h")) != -1) {
141		switch (opt) {
142		case 'i':
143			nr_tests = atoi(optarg);
144			break;
145		case 'h':
146		default:
147			usage(argv[0]);
148			return 0;
149		}
150	}
151
152	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
153
154	return test(filename, nr_tests);
155}