mount_nullfs.c revision 23680 
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
38char 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/*
45static char sccsid[] = "@(#)mount_null.c	8.6 (Berkeley) 4/26/95";
46*/
47static const char rcsid[] =
48	"$Id: mount_null.c,v 1.7 1997/02/22 14:32:51 peter 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 target[MAXPATHLEN];
80	struct vfsconf vfc;
81	int error;
82
83	mntflags = 0;
84	while ((ch = getopt(argc, argv, "o:")) != EOF)
85		switch(ch) {
86		case 'o':
87			getmntopts(optarg, mopts, &mntflags, 0);
88			break;
89		case '?':
90		default:
91			usage();
92		}
93	argc -= optind;
94	argv += optind;
95
96	if (argc != 2)
97		usage();
98
99	if (realpath(argv[0], target) == 0)
100		err(EX_OSERR, "%s", target);
101
102	if (subdir(target, argv[1]) || subdir(argv[1], target))
103		errx(EX_USAGE, "%s (%s) and %s are not distinct paths",
104		    argv[0], target, argv[1]);
105
106	args.target = target;
107
108	error = getvfsbyname("null", &vfc);
109	if (error && vfsisloadable("null")) {
110		if(vfsload("null"))
111			err(EX_OSERR, "vfsload(null)");
112		endvfsent();
113		error = getvfsbyname("null", &vfc);
114	}
115	if (error)
116		errx(EX_OSERR, "null/loopback filesystem is not available");
117
118	if (mount(vfc.vfc_name, argv[1], mntflags, &args))
119		err(1, NULL);
120	exit(0);
121}
122
123int
124subdir(p, dir)
125	const char *p;
126	const char *dir;
127{
128	int l;
129
130	l = strlen(dir);
131	if (l <= 1)
132		return (1);
133
134	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
135		return (1);
136
137	return (0);
138}
139
140static void
141usage()
142{
143	(void)fprintf(stderr,
144		"usage: mount_null [-o options] target_fs mount_point\n");
145	exit(1);
146}
147