mount_unionfs.c revision 166684 
1/*-
2 * Copyright (c) 1992, 1993, 1994
3 *	The Regents of the University of California.
4 * Copyright (c) 2005, 2006 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc.
5 * Copyright (c) 2006 Daichi Goto <daichi@freebsd.org>
6 * All rights reserved.
7 *
8 * This code is derived from software donated to Berkeley by
9 * Jan-Simon Pendry.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#ifndef lint
37static const char copyright[] =
38"@(#) Copyright (c) 1992, 1993, 1994\n\
39	The Regents of the University of California.  All rights reserved.\n";
40#endif /* not lint */
41
42#ifndef lint
43#if 0
44static char sccsid[] = "@(#)mount_union.c	8.5 (Berkeley) 3/27/94";
45#else
46static const char rcsid[] =
47  "$FreeBSD: head/sbin/mount_unionfs/mount_unionfs.c 166684 2007-02-13 05:39:38Z rodrigc $";
48#endif
49#endif /* not lint */
50
51#include <sys/param.h>
52#include <sys/mount.h>
53#include <sys/uio.h>
54#include <sys/errno.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#include <grp.h>
63#include <pwd.h>
64
65#include "mntopts.h"
66
67static int
68subdir(const char *p, const char *dir)
69{
70	int		l;
71
72	l = strlen(dir);
73	if (l <= 1)
74		return (1);
75
76	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
77		return (1);
78
79	return (0);
80}
81
82static void
83usage(void)
84{
85	(void)fprintf(stderr,
86	    "usage: mount_unionfs [-o options] directory uniondir\n");
87	exit(EX_USAGE);
88}
89
90static void
91parse_gid(const char *s, char *buf, size_t bufsize)
92{
93	struct group *gr;
94	char *inval;
95
96	if ((gr = getgrnam(s)) != NULL)
97		snprintf(buf, bufsize, "%d", gr->gr_gid);
98	else {
99		strtol(s, &inval, 10);
100		if (*inval != 0) {
101                       errx(EX_NOUSER, "unknown group id: %s", s);
102                       usage();
103		} else {
104			strncpy(buf, s, bufsize);
105		}
106	}
107}
108
109static void
110parse_uid(const char *s, char *buf, size_t bufsize)
111{
112	struct passwd  *pw;
113	char *inval;
114
115	if ((pw = getpwnam(s)) != NULL)
116		snprintf(buf, bufsize, "%d", pw->pw_uid);
117	else {
118		strtol(s, &inval, 10);
119		if (*inval != 0) {
120                       errx(EX_NOUSER, "unknown user id: %s", s);
121                       usage();
122		} else {
123			strncpy(buf, s, bufsize);
124		}
125	}
126}
127
128int
129main(int argc, char *argv[])
130{
131	struct iovec	*iov;
132	int ch, mntflags, iovlen;
133	char source [MAXPATHLEN], target[MAXPATHLEN], errmsg[255];
134	char uid_str[20], gid_str[20];
135	char fstype[] = "unionfs";
136	char *p, *val;
137
138	iov = NULL;
139	iovlen = 0;
140	mntflags = 0;
141	memset(errmsg, 0, sizeof(errmsg));
142
143	while ((ch = getopt(argc, argv, "bo:")) != -1) {
144		switch (ch) {
145		case 'b':
146			printf("\n  -b is deprecated.  Use \"-o below\" instead\n");
147			build_iovec(&iov, &iovlen, "below", NULL, 0);
148			break;
149		case 'o':
150                        p = strchr(optarg, '=');
151                        val = NULL;
152                        if (p != NULL) {
153                                *p = '\0';
154                                val = p + 1;
155				if (strcmp(optarg, "gid") == 0) {
156					parse_gid(val, gid_str, sizeof(gid_str));
157					val = gid_str;
158				}
159				else if (strcmp(optarg, "uid") == 0) {
160					parse_uid(val, uid_str, sizeof(uid_str));
161					val = uid_str;
162				}
163                        }
164                        build_iovec(&iov, &iovlen, optarg, val, (size_t)-1);
165			break;
166		case '?':
167		default:
168			usage();
169			/* NOTREACHED */
170		}
171	}
172	argc -= optind;
173	argv += optind;
174
175	if (argc != 2)
176		usage();
177
178	/* resolve both target and source with realpath(3) */
179	(void)checkpath(argv[0], target);
180	(void)checkpath(argv[1], source);
181
182	if (subdir(target, source) || subdir(source, target))
183		errx(EX_USAGE, "%s (%s) and %s (%s) are not distinct paths",
184		     argv[0], target, argv[1], source);
185
186	build_iovec(&iov, &iovlen, "fstype", fstype, (size_t)-1);
187	build_iovec(&iov, &iovlen, "fspath", source, (size_t)-1);
188	build_iovec(&iov, &iovlen, "from", target, (size_t)-1);
189	build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
190
191	if (nmount(iov, iovlen, mntflags))
192		err(EX_OSERR, "%s: %s", source, errmsg);
193	exit(0);
194}
195