mount_nullfs.c revision 101270 
1/*
2 * Copyright (c) 1992, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software donated to Berkeley by
6 * Jan-Simon Pendry.
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 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#ifndef lint
38static const char copyright[] =
39"@(#) Copyright (c) 1992, 1993, 1994\n\
40	The Regents of the University of California.  All rights reserved.\n";
41#endif /* not lint */
42
43#ifndef lint
44#if 0
45static char sccsid[] = "@(#)mount_null.c	8.6 (Berkeley) 4/26/95";
46#endif
47static const char rcsid[] =
48  "$FreeBSD: head/sbin/mount_nullfs/mount_nullfs.c 101270 2002-08-03 16:03:21Z mux $";
49#endif /* not lint */
50
51#include <sys/param.h>
52#include <sys/mount.h>
53
54#include <err.h>
55#include <stdio.h>
56#include <stdlib.h>
57#include <string.h>
58#include <sysexits.h>
59#include <unistd.h>
60
61#include "mntopts.h"
62
63struct mntopt mopts[] = {
64	MOPT_STDOPTS,
65	{ NULL }
66};
67
68int	subdir(const char *, const char *);
69static void	usage(void) __dead2;
70
71int
72main(argc, argv)
73	int argc;
74	char *argv[];
75{
76	struct iovec iov[6];
77	int ch, mntflags;
78	char source[MAXPATHLEN];
79	char target[MAXPATHLEN];
80	int error;
81
82	mntflags = 0;
83	while ((ch = getopt(argc, argv, "o:")) != -1)
84		switch(ch) {
85		case 'o':
86			getmntopts(optarg, mopts, &mntflags, 0);
87			break;
88		case '?':
89		default:
90			usage();
91		}
92	argc -= optind;
93	argv += optind;
94
95	if (argc != 2)
96		usage();
97
98	/* resolve target and source with realpath(3) */
99	(void)checkpath(argv[0], target);
100	(void)checkpath(argv[1], source);
101
102	if (subdir(target, source) || subdir(source, target))
103		errx(EX_USAGE, "%s (%s) and %s are not distinct paths",
104		    argv[0], target, argv[1]);
105
106	iov[0].iov_base = "fstype";
107	iov[0].iov_len = sizeof("fstype");
108	iov[1].iov_base = "nullfs";
109	iov[1].iov_len = strlen("nullfs") + 1;
110	iov[2].iov_base = "fspath";
111	iov[2].iov_len = sizeof("fspath");
112	iov[3].iov_base = source;
113	iov[3].iov_len = strlen(source) + 1;
114	iov[4].iov_base = "target";
115	iov[4].iov_len = sizeof("target");
116	iov[5].iov_base = target;
117	iov[5].iov_len = strlen(target) + 1;
118
119	if (nmount(iov, 6, mntflags))
120		err(1, NULL);
121	exit(0);
122}
123
124int
125subdir(p, dir)
126	const char *p;
127	const char *dir;
128{
129	int l;
130
131	l = strlen(dir);
132	if (l <= 1)
133		return (1);
134
135	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
136		return (1);
137
138	return (0);
139}
140
141static void
142usage()
143{
144	(void)fprintf(stderr,
145		"usage: mount_nullfs [-o options] target_fs mount_point\n");
146	exit(1);
147}
148