mount_unionfs.c revision 4065 
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
38char 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
44static char sccsid[] = "@(#)mount_union.c	8.5 (Berkeley) 3/27/94";
45#endif /* not lint */
46
47#include <sys/param.h>
48#include <sys/mount.h>
49
50#include <miscfs/union/union.h>
51
52#include <err.h>
53#include <stdio.h>
54#include <stdlib.h>
55#include <string.h>
56#include <unistd.h>
57
58#include "mntopts.h"
59
60struct mntopt mopts[] = {
61	MOPT_STDOPTS,
62	{ NULL }
63};
64
65int	subdir __P((const char *, const char *));
66void	usage __P((void));
67
68int
69main(argc, argv)
70	int argc;
71	char *argv[];
72{
73	struct union_args args;
74	int ch, mntflags;
75	char target[MAXPATHLEN];
76	struct vfsconf *vfc;
77
78	mntflags = 0;
79	args.mntflags = UNMNT_ABOVE;
80	while ((ch = getopt(argc, argv, "bo:r")) != EOF)
81		switch (ch) {
82		case 'b':
83			args.mntflags &= ~UNMNT_OPMASK;
84			args.mntflags |= UNMNT_BELOW;
85			break;
86		case 'o':
87			getmntopts(optarg, mopts, &mntflags, 0);
88			break;
89		case 'r':
90			args.mntflags &= ~UNMNT_OPMASK;
91			args.mntflags |= UNMNT_REPLACE;
92			break;
93		case '?':
94		default:
95			usage();
96			/* NOTREACHED */
97		}
98	argc -= optind;
99	argv += optind;
100
101	if (argc != 2)
102		usage();
103
104	if (realpath(argv[0], target) == 0)
105		err(1, "%s", target);
106
107	if (subdir(target, argv[1]) || subdir(argv[1], target))
108		errx(1, "%s (%s) and %s are not distinct paths",
109		    argv[0], target, argv[1]);
110
111	args.target = target;
112
113	vfc = getvfsbyname("union");
114	if(!vfc && vfsisloadable("union")) {
115		if(vfsload("union"))
116			err(1, "vfsload(union)");
117		endvfsent();	/* flush cache */
118		vfc = getvfsbyname("union");
119	}
120
121	if (mount(vfc ? vfc->vfc_index : MOUNT_UNION, argv[1], mntflags, &args))
122		err(1, NULL);
123	exit(0);
124}
125
126int
127subdir(p, dir)
128	const char *p;
129	const char *dir;
130{
131	int l;
132
133	l = strlen(dir);
134	if (l <= 1)
135		return (1);
136
137	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
138		return (1);
139
140	return (0);
141}
142
143void
144usage()
145{
146	(void)fprintf(stderr,
147		"usage: mount_union [-br] [-o options] target_fs mount_point\n");
148	exit(1);
149}
150