1 /*
2 * Copyright (c) 1992, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software donated to Berkeley by
6 * Jan-Simon Pendry.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #ifndef lint
34 static const char copyright[] =
35 "@(#) Copyright (c) 1992, 1993, 1994\n\
36 The Regents of the University of California. All rights reserved.\n";
37 #endif /* not lint */
38
39 #ifndef lint
40 #if 0
41 static char sccsid[] = "@(#)mount_null.c 8.6 (Berkeley) 4/26/95";
42 #endif
43 static const char rcsid[] =
44 "$FreeBSD$";
45 #endif /* not lint */
46
47 #include <sys/param.h>
48 #include <sys/mount.h>
49 #include <sys/uio.h>
50
51 #include <err.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <sysexits.h>
56 #include <unistd.h>
57
58 #include "mntopts.h"
59
60 int subdir(const char *, const char *);
61 static void usage(void) __dead2;
62
63 int
main(int argc,char * argv[])64 main(int argc, char *argv[])
65 {
66 struct iovec *iov;
67 char *p, *val;
68 char source[MAXPATHLEN];
69 char target[MAXPATHLEN];
70 char errmsg[255];
71 int ch, iovlen;
72 char nullfs[] = "nullfs";
73
74 iov = NULL;
75 iovlen = 0;
76 errmsg[0] = '\0';
77 while ((ch = getopt(argc, argv, "o:")) != -1)
78 switch(ch) {
79 case 'o':
80 val = strdup("");
81 p = strchr(optarg, '=');
82 if (p != NULL) {
83 free(val);
84 *p = '\0';
85 val = p + 1;
86 }
87 build_iovec(&iov, &iovlen, optarg, val, (size_t)-1);
88 break;
89 case '?':
90 default:
91 usage();
92 }
93 argc -= optind;
94 argv += optind;
95
96 if (argc != 2)
97 usage();
98
99 /* resolve target and source with realpath(3) */
100 if (checkpath(argv[0], target) != 0)
101 err(EX_USAGE, "%s", target);
102 if (checkpath(argv[1], source) != 0)
103 err(EX_USAGE, "%s", source);
104
105 if (subdir(target, source) || subdir(source, target))
106 errx(EX_USAGE, "%s (%s) and %s are not distinct paths",
107 argv[0], target, argv[1]);
108
109 build_iovec(&iov, &iovlen, "fstype", nullfs, (size_t)-1);
110 build_iovec(&iov, &iovlen, "fspath", source, (size_t)-1);
111 build_iovec(&iov, &iovlen, "target", target, (size_t)-1);
112 build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
113 if (nmount(iov, iovlen, 0) < 0) {
114 if (errmsg[0] != 0)
115 err(1, "%s: %s", source, errmsg);
116 else
117 err(1, "%s", source);
118 }
119 exit(0);
120 }
121
122 int
subdir(const char * p,const char * dir)123 subdir(const char *p, const char *dir)
124 {
125 int l;
126
127 l = strlen(dir);
128 if (l <= 1)
129 return (1);
130
131 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
132 return (1);
133
134 return (0);
135 }
136
137 static void
usage(void)138 usage(void)
139 {
140 (void)fprintf(stderr,
141 "usage: mount_nullfs [-o options] target mount-point\n");
142 exit(1);
143 }
144