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#include <sys/param.h>
39#include <sys/mount.h>
40#include <sys/uio.h>
41#include <sys/errno.h>
42
43#include <err.h>
44#include <stdio.h>
45#include <stdlib.h>
46#include <string.h>
47#include <sysexits.h>
48#include <unistd.h>
49#include <grp.h>
50#include <pwd.h>
51
52#include "mntopts.h"
53
54static int
55subdir(const char *p, const char *dir)
56{
57	int		l;
58
59	l = strlen(dir);
60	if (l <= 1)
61		return (1);
62
63	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
64		return (1);
65
66	return (0);
67}
68
69static void
70usage(void)
71{
72	(void)fprintf(stderr,
73	    "usage: mount_unionfs [-o options] directory uniondir\n");
74	exit(EX_USAGE);
75}
76
77static void
78parse_gid(const char *s, char *buf, size_t bufsize)
79{
80	struct group *gr;
81	char *inval;
82
83	if ((gr = getgrnam(s)) != NULL)
84		snprintf(buf, bufsize, "%d", gr->gr_gid);
85	else {
86		strtol(s, &inval, 10);
87		if (*inval != 0) {
88                       errx(EX_NOUSER, "unknown group id: %s", s);
89                       usage();
90		} else {
91			strncpy(buf, s, bufsize);
92		}
93	}
94}
95
96static void
97parse_uid(const char *s, char *buf, size_t bufsize)
98{
99	struct passwd  *pw;
100	char *inval;
101
102	if ((pw = getpwnam(s)) != NULL)
103		snprintf(buf, bufsize, "%d", pw->pw_uid);
104	else {
105		strtol(s, &inval, 10);
106		if (*inval != 0) {
107                       errx(EX_NOUSER, "unknown user id: %s", s);
108                       usage();
109		} else {
110			strncpy(buf, s, bufsize);
111		}
112	}
113}
114
115int
116main(int argc, char *argv[])
117{
118	struct iovec	*iov;
119	int ch, iovlen;
120	char source [MAXPATHLEN], target[MAXPATHLEN], errmsg[255];
121	char uid_str[20], gid_str[20];
122	char fstype[] = "unionfs";
123	char *p, *val;
124
125	iov = NULL;
126	iovlen = 0;
127	memset(errmsg, 0, sizeof(errmsg));
128
129	while ((ch = getopt(argc, argv, "bo:")) != -1) {
130		switch (ch) {
131		case 'b':
132			printf("\n  -b is deprecated.  Use \"-o below\" instead\n");
133			build_iovec(&iov, &iovlen, "below", NULL, 0);
134			break;
135		case 'o':
136                        p = strchr(optarg, '=');
137                        val = NULL;
138                        if (p != NULL) {
139                                *p = '\0';
140                                val = p + 1;
141				if (strcmp(optarg, "gid") == 0) {
142					parse_gid(val, gid_str, sizeof(gid_str));
143					val = gid_str;
144				}
145				else if (strcmp(optarg, "uid") == 0) {
146					parse_uid(val, uid_str, sizeof(uid_str));
147					val = uid_str;
148				}
149                        }
150                        build_iovec(&iov, &iovlen, optarg, val, (size_t)-1);
151			break;
152		case '?':
153		default:
154			usage();
155			/* NOTREACHED */
156		}
157	}
158	argc -= optind;
159	argv += optind;
160
161	if (argc != 2)
162		usage();
163
164	/* resolve both target and source with realpath(3) */
165	if (checkpath(argv[0], target) != 0)
166		err(EX_USAGE, "%s", target);
167	if (checkpath(argv[1], source) != 0)
168		err(EX_USAGE, "%s", source);
169
170	if (subdir(target, source) || subdir(source, target))
171		errx(EX_USAGE, "%s (%s) and %s (%s) are not distinct paths",
172		     argv[0], target, argv[1], source);
173
174	build_iovec(&iov, &iovlen, "fstype", fstype, (size_t)-1);
175	build_iovec(&iov, &iovlen, "fspath", source, (size_t)-1);
176	build_iovec(&iov, &iovlen, "from", target, (size_t)-1);
177	build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
178
179	if (nmount(iov, iovlen, 0))
180		err(EX_OSERR, "%s: %s", source, errmsg);
181	exit(0);
182}
183