mount_unionfs.c revision 128073 
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 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#ifndef lint
34static const char copyright[] =
35"@(#) Copyright (c) 1992, 1993, 1994\n\
36	The Regents of the University of California.  All rights reserved.\n";
37#endif /* not lint */
38
39#ifndef lint
40#if 0
41static char sccsid[] = "@(#)mount_union.c	8.5 (Berkeley) 3/27/94";
42#else
43static const char rcsid[] =
44  "$FreeBSD: head/sbin/mount_unionfs/mount_unionfs.c 128073 2004-04-09 19:58:40Z markm $";
45#endif
46#endif /* not lint */
47
48#include <sys/param.h>
49#include <sys/mount.h>
50#include <sys/uio.h>
51
52#include <err.h>
53#include <stdio.h>
54#include <stdlib.h>
55#include <string.h>
56#include <sysexits.h>
57#include <unistd.h>
58
59#include "mntopts.h"
60
61static struct mntopt mopts[] = {
62	MOPT_STDOPTS,
63	{ NULL }
64};
65
66static int	subdir(const char *, const char *);
67static void	usage (void) __dead2;
68
69int
70main(argc, argv)
71	int argc;
72	char *argv[];
73{
74	struct iovec iov[8];
75	int ch, mntflags;
76	char source[MAXPATHLEN];
77	char target[MAXPATHLEN];
78	int iovcnt;
79
80	iovcnt = 6;
81	mntflags = 0;
82	while ((ch = getopt(argc, argv, "bo:r")) != -1)
83		switch (ch) {
84		case 'b':
85			iov[6].iov_base = "below";
86			iov[6].iov_len = strlen(iov[6].iov_base) + 1;
87			iov[7].iov_base = NULL;
88			iov[7].iov_len = 0;
89			iovcnt = 8;
90			break;
91		case 'o':
92			getmntopts(optarg, mopts, &mntflags, 0);
93			break;
94		case 'r':
95			iov[6].iov_base = "replace";
96			iov[6].iov_len = strlen(iov[6].iov_base) + 1;
97			iov[7].iov_base = NULL;
98			iov[7].iov_len = 0;
99			iovcnt = 8;
100			break;
101		case '?':
102		default:
103			usage();
104			/* NOTREACHED */
105		}
106	argc -= optind;
107	argv += optind;
108
109	if (argc != 2)
110		usage();
111
112	/* resolve both target and source with realpath(3) */
113	(void)checkpath(argv[0], target);
114	(void)checkpath(argv[1], source);
115
116	if (subdir(target, source) || subdir(source, target))
117		errx(EX_USAGE, "%s (%s) and %s (%s) are not distinct paths",
118		    argv[0], target, argv[1], source);
119
120	iov[0].iov_base = "fstype";
121	iov[0].iov_len = strlen(iov[0].iov_base) + 1;
122	iov[1].iov_base = "unionfs";
123	iov[1].iov_len = strlen(iov[1].iov_base) + 1;
124	iov[2].iov_base = "fspath";
125	iov[2].iov_len = strlen(iov[2].iov_base) + 1;
126	iov[3].iov_base = source;
127	iov[3].iov_len = strlen(source) + 1;
128	iov[4].iov_base = "target";
129	iov[4].iov_len = strlen(iov[4].iov_base) + 1;
130	iov[5].iov_base = target;
131	iov[5].iov_len = strlen(target) + 1;
132	if (nmount(iov, iovcnt, mntflags))
133		err(EX_OSERR, "%s", target);
134	exit(0);
135}
136
137int
138subdir(p, dir)
139	const char *p;
140	const char *dir;
141{
142	int l;
143
144	l = strlen(dir);
145	if (l <= 1)
146		return (1);
147
148	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
149		return (1);
150
151	return (0);
152}
153
154void
155usage()
156{
157	(void)fprintf(stderr,
158		"usage: mount_unionfs [-br] [-o options] target_fs mount_point\n");
159	exit(EX_USAGE);
160}
161