mount_nullfs.c revision 77042 
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 77042 2001-05-23 14:58:19Z ru $";
49#endif /* not lint */
50
51#include <sys/param.h>
52#include <sys/mount.h>
53#include <fs/nullfs/null.h>
54
55#include <err.h>
56#include <stdio.h>
57#include <stdlib.h>
58#include <string.h>
59#include <sysexits.h>
60#include <unistd.h>
61
62#include "mntopts.h"
63
64struct mntopt mopts[] = {
65	MOPT_STDOPTS,
66	{ NULL }
67};
68
69int	subdir __P((const char *, const char *));
70static void	usage __P((void)) __dead2;
71
72int
73main(argc, argv)
74	int argc;
75	char *argv[];
76{
77	struct null_args args;
78	int ch, mntflags;
79	char source[MAXPATHLEN];
80	char target[MAXPATHLEN];
81	struct vfsconf vfc;
82	int error;
83
84	mntflags = 0;
85	while ((ch = getopt(argc, argv, "o:")) != -1)
86		switch(ch) {
87		case 'o':
88			getmntopts(optarg, mopts, &mntflags, 0);
89			break;
90		case '?':
91		default:
92			usage();
93		}
94	argc -= optind;
95	argv += optind;
96
97	if (argc != 2)
98		usage();
99
100	/* resolve target and source with realpath(3) */
101	(void)checkpath(argv[0], target);
102	(void)checkpath(argv[1], source);
103
104	if (subdir(target, source) || subdir(source, target))
105		errx(EX_USAGE, "%s (%s) and %s are not distinct paths",
106		    argv[0], target, argv[1]);
107
108	args.target = target;
109
110	error = getvfsbyname("nullfs", &vfc);
111	if (error && vfsisloadable("nullfs")) {
112		if(vfsload("nullfs"))
113			err(EX_OSERR, "vfsload(nullfs)");
114		endvfsent();
115		error = getvfsbyname("nullfs", &vfc);
116	}
117	if (error)
118		errx(EX_OSERR, "null/loopback filesystem is not available");
119
120	if (mount(vfc.vfc_name, source, mntflags, &args))
121		err(1, NULL);
122	exit(0);
123}
124
125int
126subdir(p, dir)
127	const char *p;
128	const char *dir;
129{
130	int l;
131
132	l = strlen(dir);
133	if (l <= 1)
134		return (1);
135
136	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
137		return (1);
138
139	return (0);
140}
141
142static void
143usage()
144{
145	(void)fprintf(stderr,
146		"usage: mount_nullfs [-o options] target_fs mount_point\n");
147	exit(1);
148}
149