1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1992, 1993, 1994
5 *	The Regents of the University of California.
6 * Copyright (c) 2005, 2006 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc.
7 * Copyright (c) 2006 Daichi Goto <daichi@freebsd.org>
8 * All rights reserved.
9 *
10 * This code is derived from software donated to Berkeley by
11 * Jan-Simon Pendry.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 * 3. Neither the name of the University nor the names of its contributors
22 *    may be used to endorse or promote products derived from this software
23 *    without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 */
37
38#ifndef lint
39static const char copyright[] =
40"@(#) Copyright (c) 1992, 1993, 1994\n\
41	The Regents of the University of California.  All rights reserved.\n";
42#endif /* not lint */
43
44#ifndef lint
45#if 0
46static char sccsid[] = "@(#)mount_union.c	8.5 (Berkeley) 3/27/94";
47#else
48static const char rcsid[] =
49  "$FreeBSD$";
50#endif
51#endif /* not lint */
52
53#include <sys/param.h>
54#include <sys/mount.h>
55#include <sys/uio.h>
56#include <sys/errno.h>
57
58#include <err.h>
59#include <stdio.h>
60#include <stdlib.h>
61#include <string.h>
62#include <sysexits.h>
63#include <unistd.h>
64#include <grp.h>
65#include <pwd.h>
66
67#include "mntopts.h"
68
69static int
70subdir(const char *p, const char *dir)
71{
72	int		l;
73
74	l = strlen(dir);
75	if (l <= 1)
76		return (1);
77
78	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
79		return (1);
80
81	return (0);
82}
83
84static void
85usage(void)
86{
87	(void)fprintf(stderr,
88	    "usage: mount_unionfs [-o options] directory uniondir\n");
89	exit(EX_USAGE);
90}
91
92static void
93parse_gid(const char *s, char *buf, size_t bufsize)
94{
95	struct group *gr;
96	char *inval;
97
98	if ((gr = getgrnam(s)) != NULL)
99		snprintf(buf, bufsize, "%d", gr->gr_gid);
100	else {
101		strtol(s, &inval, 10);
102		if (*inval != 0) {
103                       errx(EX_NOUSER, "unknown group id: %s", s);
104                       usage();
105		} else {
106			strncpy(buf, s, bufsize);
107		}
108	}
109}
110
111static void
112parse_uid(const char *s, char *buf, size_t bufsize)
113{
114	struct passwd  *pw;
115	char *inval;
116
117	if ((pw = getpwnam(s)) != NULL)
118		snprintf(buf, bufsize, "%d", pw->pw_uid);
119	else {
120		strtol(s, &inval, 10);
121		if (*inval != 0) {
122                       errx(EX_NOUSER, "unknown user id: %s", s);
123                       usage();
124		} else {
125			strncpy(buf, s, bufsize);
126		}
127	}
128}
129
130int
131main(int argc, char *argv[])
132{
133	struct iovec	*iov;
134	int ch, iovlen;
135	char source [MAXPATHLEN], target[MAXPATHLEN], errmsg[255];
136	char uid_str[20], gid_str[20];
137	char fstype[] = "unionfs";
138	char *p, *val;
139
140	iov = NULL;
141	iovlen = 0;
142	memset(errmsg, 0, sizeof(errmsg));
143
144	while ((ch = getopt(argc, argv, "bo:")) != -1) {
145		switch (ch) {
146		case 'b':
147			printf("\n  -b is deprecated.  Use \"-o below\" instead\n");
148			build_iovec(&iov, &iovlen, "below", NULL, 0);
149			break;
150		case 'o':
151                        p = strchr(optarg, '=');
152                        val = NULL;
153                        if (p != NULL) {
154                                *p = '\0';
155                                val = p + 1;
156				if (strcmp(optarg, "gid") == 0) {
157					parse_gid(val, gid_str, sizeof(gid_str));
158					val = gid_str;
159				}
160				else if (strcmp(optarg, "uid") == 0) {
161					parse_uid(val, uid_str, sizeof(uid_str));
162					val = uid_str;
163				}
164                        }
165                        build_iovec(&iov, &iovlen, optarg, val, (size_t)-1);
166			break;
167		case '?':
168		default:
169			usage();
170			/* NOTREACHED */
171		}
172	}
173	argc -= optind;
174	argv += optind;
175
176	if (argc != 2)
177		usage();
178
179	/* resolve both target and source with realpath(3) */
180	if (checkpath(argv[0], target) != 0)
181		err(EX_USAGE, "%s", target);
182	if (checkpath(argv[1], source) != 0)
183		err(EX_USAGE, "%s", source);
184
185	if (subdir(target, source) || subdir(source, target))
186		errx(EX_USAGE, "%s (%s) and %s (%s) are not distinct paths",
187		     argv[0], target, argv[1], source);
188
189	build_iovec(&iov, &iovlen, "fstype", fstype, (size_t)-1);
190	build_iovec(&iov, &iovlen, "fspath", source, (size_t)-1);
191	build_iovec(&iov, &iovlen, "from", target, (size_t)-1);
192	build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
193
194	if (nmount(iov, iovlen, 0))
195		err(EX_OSERR, "%s: %s", source, errmsg);
196	exit(0);
197}
198