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