1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1992, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software donated to Berkeley by
8 * Jan-Simon Pendry.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #ifndef lint
36 static const char copyright[] =
37 "@(#) Copyright (c) 1992, 1993, 1994\n\
38 The Regents of the University of California. All rights reserved.\n";
39 #endif /* not lint */
40
41 #ifndef lint
42 #if 0
43 static char sccsid[] = "@(#)mount_null.c 8.6 (Berkeley) 4/26/95";
44 #endif
45 #endif /* not lint */
46
47 #include <sys/param.h>
48 #include <sys/mount.h>
49 #include <sys/stat.h>
50 #include <sys/uio.h>
51
52 #include <err.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56 #include <sysexits.h>
57 #include <unistd.h>
58
59 #include "mntopts.h"
60
61 static void usage(void) __dead2;
62
63 static int
stat_realpath(const char * path,char * resolved,struct stat * sbp)64 stat_realpath(const char *path, char *resolved, struct stat *sbp)
65 {
66 if (realpath(path, resolved) == NULL || stat(resolved, sbp) != 0)
67 return (1);
68 return (0);
69 }
70
71 int
main(int argc,char * argv[])72 main(int argc, char *argv[])
73 {
74 struct iovec *iov;
75 char *p, *val;
76 char mountpoint[MAXPATHLEN];
77 char target[MAXPATHLEN];
78 char errmsg[255];
79 int ch, iovlen;
80 char nullfs[] = "nullfs";
81 struct stat target_stat;
82 struct stat mountpoint_stat;
83
84 iov = NULL;
85 iovlen = 0;
86 errmsg[0] = '\0';
87 while ((ch = getopt(argc, argv, "o:")) != -1)
88 switch(ch) {
89 case 'o':
90 val = strdup("");
91 p = strchr(optarg, '=');
92 if (p != NULL) {
93 free(val);
94 *p = '\0';
95 val = p + 1;
96 }
97 build_iovec(&iov, &iovlen, optarg, val, (size_t)-1);
98 break;
99 case '?':
100 default:
101 usage();
102 }
103 argc -= optind;
104 argv += optind;
105
106 if (argc != 2)
107 usage();
108
109 /* resolve target and mountpoint with realpath(3) */
110 if (stat_realpath(argv[0], target, &target_stat) != 0)
111 err(EX_USAGE, "%s", target);
112 if (stat_realpath(argv[1], mountpoint, &mountpoint_stat) != 0)
113 err(EX_USAGE, "%s", mountpoint);
114 if (!S_ISDIR(target_stat.st_mode) && !S_ISREG(target_stat.st_mode))
115 errx(EX_USAGE, "%s: must be either a file or directory",
116 target);
117 if ((target_stat.st_mode & S_IFMT) !=
118 (mountpoint_stat.st_mode & S_IFMT))
119 errx(EX_USAGE,
120 "%s: must be same type as %s (file or directory)",
121 mountpoint, target);
122
123 build_iovec(&iov, &iovlen, "fstype", nullfs, (size_t)-1);
124 build_iovec(&iov, &iovlen, "fspath", mountpoint, (size_t)-1);
125 build_iovec(&iov, &iovlen, "target", target, (size_t)-1);
126 build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
127 if (nmount(iov, iovlen, 0) < 0) {
128 if (errmsg[0] != 0)
129 err(1, "%s: %s", mountpoint, errmsg);
130 else
131 err(1, "%s", mountpoint);
132 }
133 exit(0);
134 }
135
136 static void
usage(void)137 usage(void)
138 {
139 (void)fprintf(stderr,
140 "usage: mount_nullfs [-o options] target mount-point\n");
141 exit(1);
142 }
143