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 <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <sysexits.h>
45 #include <unistd.h>
46
47 #include "mntopts.h"
48
49 static void usage(void) __dead2;
50
51 static int
stat_realpath(const char * path,char * resolved,struct stat * sbp)52 stat_realpath(const char *path, char *resolved, struct stat *sbp)
53 {
54 if (realpath(path, resolved) == NULL || stat(resolved, sbp) != 0)
55 return (1);
56 return (0);
57 }
58
59 int
main(int argc,char * argv[])60 main(int argc, char *argv[])
61 {
62 struct iovec *iov;
63 char *p, *val;
64 char mountpoint[MAXPATHLEN];
65 char target[MAXPATHLEN];
66 char errmsg[255];
67 int ch, iovlen;
68 char nullfs[] = "nullfs";
69 struct stat target_stat;
70 struct stat mountpoint_stat;
71
72 iov = NULL;
73 iovlen = 0;
74 errmsg[0] = '\0';
75 while ((ch = getopt(argc, argv, "o:")) != -1)
76 switch(ch) {
77 case 'o':
78 val = strdup("");
79 p = strchr(optarg, '=');
80 if (p != NULL) {
81 free(val);
82 *p = '\0';
83 val = p + 1;
84 }
85 build_iovec(&iov, &iovlen, optarg, val, (size_t)-1);
86 break;
87 case '?':
88 default:
89 usage();
90 }
91 argc -= optind;
92 argv += optind;
93
94 if (argc != 2)
95 usage();
96
97 /* resolve target and mountpoint with realpath(3) */
98 if (stat_realpath(argv[0], target, &target_stat) != 0)
99 err(EX_USAGE, "%s", target);
100 if (stat_realpath(argv[1], mountpoint, &mountpoint_stat) != 0)
101 err(EX_USAGE, "%s", mountpoint);
102 if (!S_ISDIR(target_stat.st_mode) && !S_ISREG(target_stat.st_mode))
103 errx(EX_USAGE, "%s: must be either a file or directory",
104 target);
105 if ((target_stat.st_mode & S_IFMT) !=
106 (mountpoint_stat.st_mode & S_IFMT))
107 errx(EX_USAGE,
108 "%s: must be same type as %s (file or directory)",
109 mountpoint, target);
110
111 build_iovec(&iov, &iovlen, "fstype", nullfs, (size_t)-1);
112 build_iovec(&iov, &iovlen, "fspath", mountpoint, (size_t)-1);
113 build_iovec(&iov, &iovlen, "target", target, (size_t)-1);
114 build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
115 if (nmount(iov, iovlen, 0) < 0) {
116 if (errmsg[0] != 0)
117 err(1, "%s: %s", mountpoint, errmsg);
118 else
119 err(1, "%s", mountpoint);
120 }
121 exit(0);
122 }
123
124 static void
usage(void)125 usage(void)
126 {
127 (void)fprintf(stderr,
128 "usage: mount_nullfs [-o options] target mount-point\n");
129 exit(1);
130 }
131