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 #include <sys/param.h>
36 #include <sys/mount.h>
37 #include <sys/stat.h>
38 #include <sys/uio.h>
39
40 #include <err.h>
41 #include <mntopts.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <sysexits.h>
46 #include <unistd.h>
47
48 static void usage(void) __dead2;
49
50 static int
stat_realpath(const char * path,char * resolved,struct stat * sbp)51 stat_realpath(const char *path, char *resolved, struct stat *sbp)
52 {
53 if (realpath(path, resolved) == NULL || stat(resolved, sbp) != 0)
54 return (1);
55 return (0);
56 }
57
58 int
main(int argc,char * argv[])59 main(int argc, char *argv[])
60 {
61 struct iovec *iov;
62 char *p, *val;
63 char mountpoint[MAXPATHLEN];
64 char target[MAXPATHLEN];
65 char errmsg[255];
66 int ch, iovlen;
67 char nullfs[] = "nullfs";
68 struct stat target_stat;
69 struct stat mountpoint_stat;
70
71 iov = NULL;
72 iovlen = 0;
73 errmsg[0] = '\0';
74 while ((ch = getopt(argc, argv, "o:")) != -1)
75 switch(ch) {
76 case 'o':
77 val = strdup("");
78 p = strchr(optarg, '=');
79 if (p != NULL) {
80 free(val);
81 *p = '\0';
82 val = p + 1;
83 }
84 build_iovec(&iov, &iovlen, optarg, val, (size_t)-1);
85 break;
86 case '?':
87 default:
88 usage();
89 }
90 argc -= optind;
91 argv += optind;
92
93 if (argc != 2)
94 usage();
95
96 /* resolve target and mountpoint with realpath(3) */
97 if (stat_realpath(argv[0], target, &target_stat) != 0)
98 err(EX_USAGE, "%s", target);
99 if (stat_realpath(argv[1], mountpoint, &mountpoint_stat) != 0)
100 err(EX_USAGE, "%s", mountpoint);
101 if (!S_ISDIR(target_stat.st_mode) && !S_ISREG(target_stat.st_mode))
102 errx(EX_USAGE, "%s: must be either a file or directory",
103 target);
104 if ((target_stat.st_mode & S_IFMT) !=
105 (mountpoint_stat.st_mode & S_IFMT))
106 errx(EX_USAGE,
107 "%s: must be same type as %s (file or directory)",
108 mountpoint, target);
109
110 build_iovec(&iov, &iovlen, "fstype", nullfs, (size_t)-1);
111 build_iovec(&iov, &iovlen, "fspath", mountpoint, (size_t)-1);
112 build_iovec(&iov, &iovlen, "target", target, (size_t)-1);
113 build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
114 if (nmount(iov, iovlen, 0) < 0) {
115 if (errmsg[0] != 0)
116 err(1, "%s: %s", mountpoint, errmsg);
117 else
118 err(1, "%s", mountpoint);
119 }
120 exit(0);
121 }
122
123 static void
usage(void)124 usage(void)
125 {
126 (void)fprintf(stderr,
127 "usage: mount_nullfs [-o options] target mount-point\n");
128 exit(1);
129 }
130