xref: /freebsd/sbin/mount_unionfs/mount_unionfs.c (revision eddb9a0d785dc4430d17603f5b5ed6529d4035ac)
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
38 static 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
45 static char sccsid[] = "@(#)mount_union.c	8.5 (Berkeley) 3/27/94";
46 #else
47 static const char rcsid[] =
48   "$FreeBSD$";
49 #endif
50 #endif /* not lint */
51 
52 #include <sys/param.h>
53 #include <sys/mount.h>
54 #include <sys/uio.h>
55 
56 #include <err.h>
57 #include <stdio.h>
58 #include <stdlib.h>
59 #include <string.h>
60 #include <sysexits.h>
61 #include <unistd.h>
62 
63 #include "mntopts.h"
64 
65 static struct mntopt mopts[] = {
66 	MOPT_STDOPTS,
67 	{ NULL }
68 };
69 
70 static int	subdir(const char *, const char *);
71 static void	usage (void) __dead2;
72 
73 int
74 main(argc, argv)
75 	int argc;
76 	char *argv[];
77 {
78 	struct iovec iov[8];
79 	int ch, mntflags;
80 	char source[MAXPATHLEN];
81 	char target[MAXPATHLEN];
82 	int iovcnt;
83 
84 	iovcnt = 6;
85 	mntflags = 0;
86 	while ((ch = getopt(argc, argv, "bo:r")) != -1)
87 		switch (ch) {
88 		case 'b':
89 			iov[6].iov_base = "below";
90 			iov[6].iov_len = strlen(iov[6].iov_base) + 1;
91 			iov[7].iov_base = NULL;
92 			iov[7].iov_len = 0;
93 			iovcnt = 8;
94 			break;
95 		case 'o':
96 			getmntopts(optarg, mopts, &mntflags, 0);
97 			break;
98 		case 'r':
99 			iov[6].iov_base = "replace";
100 			iov[6].iov_len = strlen(iov[6].iov_base) + 1;
101 			iov[7].iov_base = NULL;
102 			iov[7].iov_len = 0;
103 			iovcnt = 8;
104 			break;
105 		case '?':
106 		default:
107 			usage();
108 			/* NOTREACHED */
109 		}
110 	argc -= optind;
111 	argv += optind;
112 
113 	if (argc != 2)
114 		usage();
115 
116 	/* resolve both target and source with realpath(3) */
117 	(void)checkpath(argv[0], target);
118 	(void)checkpath(argv[1], source);
119 
120 	if (subdir(target, source) || subdir(source, target))
121 		errx(EX_USAGE, "%s (%s) and %s (%s) are not distinct paths",
122 		    argv[0], target, argv[1], source);
123 
124 	iov[0].iov_base = "fstype";
125 	iov[0].iov_len = strlen(iov[0].iov_base) + 1;
126 	iov[1].iov_base = "unionfs";
127 	iov[1].iov_len = strlen(iov[1].iov_base) + 1;
128 	iov[2].iov_base = "fspath";
129 	iov[2].iov_len = strlen(iov[2].iov_base) + 1;
130 	iov[3].iov_base = source;
131 	iov[3].iov_len = strlen(source) + 1;
132 	iov[4].iov_base = "target";
133 	iov[4].iov_len = strlen(iov[4].iov_base) + 1;
134 	iov[5].iov_base = target;
135 	iov[5].iov_len = strlen(target) + 1;
136 	if (nmount(iov, iovcnt, mntflags))
137 		err(EX_OSERR, "%s", target);
138 	exit(0);
139 }
140 
141 int
142 subdir(p, dir)
143 	const char *p;
144 	const char *dir;
145 {
146 	int l;
147 
148 	l = strlen(dir);
149 	if (l <= 1)
150 		return (1);
151 
152 	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
153 		return (1);
154 
155 	return (0);
156 }
157 
158 void
159 usage()
160 {
161 	(void)fprintf(stderr,
162 		"usage: mount_unionfs [-br] [-o options] target_fs mount_point\n");
163 	exit(EX_USAGE);
164 }
165