1/*-
2 * Copyright (c) 2017 The NetBSD Foundation, Inc.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to The NetBSD Foundation
6 * by Christos Zoulas.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 * POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#include <stdio.h>
31#include <stdlib.h>
32#include <err.h>
33#include <sys/sysctl.h>
34
35static int
36getprocpath(char *path, size_t len, pid_t pid)
37{
38	const int name[] = {
39	    CTL_KERN, KERN_PROC_ARGS, pid, KERN_PROC_PATHNAME,
40	};
41     	return sysctl(name, __arraycount(name), path, &len, NULL, 0);
42}
43
44int
45main(int argc, char *argv[])
46{
47	if (argc != 2) {
48		fprintf(stderr, "Usage: %s <pid>\n", getprogname());
49		return EXIT_FAILURE;
50	}
51
52	char buf[MAXPATHLEN];
53	pid_t pid = atoi(argv[1]);
54
55	if (getprocpath(buf, sizeof(buf), pid) == -1)
56		err(EXIT_FAILURE, "sysctl: %d", pid);
57	printf("%s\n", buf);
58	return EXIT_SUCCESS;
59}
60