mount_nullfs.c revision 97187 
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 97187 2002-05-23 23:08:27Z 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	struct vfsconf vfc;
81	int error;
82
83	mntflags = 0;
84	while ((ch = getopt(argc, argv, "o:")) != -1)
85		switch(ch) {
86		case 'o':
87			getmntopts(optarg, mopts, &mntflags, 0);
88			break;
89		case '?':
90		default:
91			usage();
92		}
93	argc -= optind;
94	argv += optind;
95
96	if (argc != 2)
97		usage();
98
99	/* resolve target and source with realpath(3) */
100	(void)checkpath(argv[0], target);
101	(void)checkpath(argv[1], source);
102
103	if (subdir(target, source) || subdir(source, target))
104		errx(EX_USAGE, "%s (%s) and %s are not distinct paths",
105		    argv[0], target, argv[1]);
106
107	error = getvfsbyname("nullfs", &vfc);
108	if (error && vfsisloadable("nullfs")) {
109		if(vfsload("nullfs"))
110			err(EX_OSERR, "vfsload(nullfs)");
111		endvfsent();
112		error = getvfsbyname("nullfs", &vfc);
113	}
114	if (error)
115		errx(EX_OSERR, "null/loopback filesystem is not available");
116
117	iov[0].iov_base = "fstype";
118	iov[0].iov_len = sizeof("fstype");
119	iov[1].iov_base = vfc.vfc_name;
120	iov[1].iov_len = strlen(vfc.vfc_name) + 1;
121	iov[2].iov_base = "fspath";
122	iov[2].iov_len = sizeof("fspath");
123	iov[3].iov_base = source;
124	iov[3].iov_len = strlen(source) + 1;
125	iov[4].iov_base = "target";
126	iov[4].iov_len = sizeof("target");
127	iov[5].iov_base = target;
128	iov[5].iov_len = strlen(target) + 1;
129
130	if (nmount(iov, 6, mntflags))
131		err(1, NULL);
132	exit(0);
133}
134
135int
136subdir(p, dir)
137	const char *p;
138	const char *dir;
139{
140	int l;
141
142	l = strlen(dir);
143	if (l <= 1)
144		return (1);
145
146	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
147		return (1);
148
149	return (0);
150}
151
152static void
153usage()
154{
155	(void)fprintf(stderr,
156		"usage: mount_nullfs [-o options] target_fs mount_point\n");
157	exit(1);
158}
159