Initial import from FreeBSD RELENG_4:
[dragonfly.git] / sbin / mount_null / mount_null.c
CommitLineData
984263bc
MD
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 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#ifndef lint
38static const char copyright[] =
39"@(#) Copyright (c) 1992, 1993, 1994\n\
40 The Regents of the University of California. All rights reserved.\n";
41#endif /* not lint */
42
43#ifndef lint
44#if 0
45static char sccsid[] = "@(#)mount_null.c 8.6 (Berkeley) 4/26/95";
46#endif
47static const char rcsid[] =
48 "$FreeBSD: src/sbin/mount_null/mount_null.c,v 1.13 1999/10/09 11:54:11 phk Exp $";
49#endif /* not lint */
50
51#include <sys/param.h>
52#include <sys/mount.h>
53#include <miscfs/nullfs/null.h>
54
55#include <err.h>
56#include <stdio.h>
57#include <stdlib.h>
58#include <string.h>
59#include <sysexits.h>
60#include <unistd.h>
61
62#include "mntopts.h"
63
64struct mntopt mopts[] = {
65 MOPT_STDOPTS,
66 { NULL }
67};
68
69int subdir __P((const char *, const char *));
70static void usage __P((void)) __dead2;
71
72int
73main(argc, argv)
74 int argc;
75 char *argv[];
76{
77 struct null_args args;
78 int ch, mntflags;
79 char source[MAXPATHLEN];
80 char target[MAXPATHLEN];
81 struct vfsconf vfc;
82 int error;
83
84 mntflags = 0;
85 while ((ch = getopt(argc, argv, "o:")) != -1)
86 switch(ch) {
87 case 'o':
88 getmntopts(optarg, mopts, &mntflags, 0);
89 break;
90 case '?':
91 default:
92 usage();
93 }
94 argc -= optind;
95 argv += optind;
96
97 if (argc != 2)
98 usage();
99
100 /* resolve target and source with realpath(3) */
101 (void)checkpath(argv[0], target);
102 (void)checkpath(argv[1], source);
103
104 if (subdir(target, source) || subdir(source, target))
105 errx(EX_USAGE, "%s (%s) and %s are not distinct paths",
106 argv[0], target, argv[1]);
107
108 args.target = target;
109
110 error = getvfsbyname("null", &vfc);
111 if (error && vfsisloadable("null")) {
112 if(vfsload("null"))
113 err(EX_OSERR, "vfsload(null)");
114 endvfsent();
115 error = getvfsbyname("null", &vfc);
116 }
117 if (error)
118 errx(EX_OSERR, "null/loopback filesystem is not available");
119
120 if (mount(vfc.vfc_name, source, mntflags, &args))
121 err(1, NULL);
122 exit(0);
123}
124
125int
126subdir(p, dir)
127 const char *p;
128 const char *dir;
129{
130 int l;
131
132 l = strlen(dir);
133 if (l <= 1)
134 return (1);
135
136 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
137 return (1);
138
139 return (0);
140}
141
142static void
143usage()
144{
145 (void)fprintf(stderr,
146 "usage: mount_null [-o options] target_fs mount_point\n");
147 exit(1);
148}