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mount_null.c revision 1.1.1.2 
      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
     38 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 static char sccsid[] = "@(#)mount_null.c	8.6 (Berkeley) 4/26/95";
     45 #endif /* not lint */
     46 
     47 #include <sys/param.h>
     48 #include <sys/mount.h>
     49 #include <miscfs/nullfs/null.h>
     50 
     51 #include <err.h>
     52 #include <stdio.h>
     53 #include <unistd.h>
     54 #include <stdlib.h>
     55 #include <string.h>
     56 
     57 #include "mntopts.h"
     58 
     59 struct mntopt mopts[] = {
     60 	MOPT_STDOPTS,
     61 	{ NULL }
     62 };
     63 
     64 int	subdir __P((const char *, const char *));
     65 void	usage __P((void));
     66 
     67 int
     68 main(argc, argv)
     69 	int argc;
     70 	char *argv[];
     71 {
     72 	struct null_args args;
     73 	int ch, mntflags;
     74 	char target[MAXPATHLEN];
     75 
     76 	mntflags = 0;
     77 	while ((ch = getopt(argc, argv, "o:")) != EOF)
     78 		switch(ch) {
     79 		case 'o':
     80 			getmntopts(optarg, mopts, &mntflags, 0);
     81 			break;
     82 		case '?':
     83 		default:
     84 			usage();
     85 		}
     86 	argc -= optind;
     87 	argv += optind;
     88 
     89 	if (argc != 2)
     90 		usage();
     91 
     92 	if (realpath(argv[0], target) == 0)
     93 		err(1, "%s", target);
     94 
     95 	if (subdir(target, argv[1]) || subdir(argv[1], target))
     96 		errx(1, "%s (%s) and %s are not distinct paths",
     97 		    argv[0], target, argv[1]);
     98 
     99 	args.target = target;
    100 
    101 	if (mount("loopback", argv[1], mntflags, &args))
    102 		err(1, NULL);
    103 	exit(0);
    104 }
    105 
    106 int
    107 subdir(p, dir)
    108 	const char *p;
    109 	const char *dir;
    110 {
    111 	int l;
    112 
    113 	l = strlen(dir);
    114 	if (l <= 1)
    115 		return (1);
    116 
    117 	if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
    118 		return (1);
    119 
    120 	return (0);
    121 }
    122 
    123 void
    124 usage()
    125 {
    126 	(void)fprintf(stderr,
    127 		"usage: mount_null [-o options] target_fs mount_point\n");
    128 	exit(1);
    129 }
    130