1 /* $NetBSD: mount_null.c,v 1.13 2005/02/05 15:14:25 xtraeme Exp $ */ 2 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/cdefs.h> 36 #ifndef lint 37 __COPYRIGHT("@(#) Copyright (c) 1992, 1993, 1994\n\ 38 The Regents of the University of California. All rights reserved.\n"); 39 #endif /* not lint */ 40 41 #ifndef lint 42 #if 0 43 static char sccsid[] = "@(#)mount_null.c 8.6 (Berkeley) 4/26/95"; 44 #else 45 __RCSID("$NetBSD: mount_null.c,v 1.13 2005/02/05 15:14:25 xtraeme Exp $"); 46 #endif 47 #endif /* not lint */ 48 49 #include <sys/param.h> 50 #include <sys/mount.h> 51 #include <miscfs/nullfs/null.h> 52 53 #include <err.h> 54 #include <stdio.h> 55 #include <unistd.h> 56 #include <stdlib.h> 57 #include <string.h> 58 59 #include <mntopts.h> 60 61 static const struct mntopt mopts[] = { 62 MOPT_STDOPTS, 63 MOPT_GETARGS, 64 { NULL } 65 }; 66 67 int mount_null(int argc, char **argv); 68 static int subdir(const char *, const char *); 69 static void usage(void); 70 71 #ifndef MOUNT_NOMAIN 72 int 73 main(int argc, char **argv) 74 { 75 return mount_null(argc, argv); 76 } 77 #endif 78 79 int 80 mount_null(int argc, char *argv[]) 81 { 82 struct null_args args; 83 int ch, mntflags; 84 char target[MAXPATHLEN], canon_dir[MAXPATHLEN]; 85 86 mntflags = 0; 87 while ((ch = getopt(argc, argv, "o:")) != -1) 88 switch(ch) { 89 case 'o': 90 getmntopts(optarg, mopts, &mntflags, 0); 91 break; 92 case '?': 93 default: 94 usage(); 95 } 96 argc -= optind; 97 argv += optind; 98 99 if (argc != 2) 100 usage(); 101 102 if (realpath(argv[0], target) == NULL) /* Check device path */ 103 err(1, "realpath %s", argv[0]); 104 if (strncmp(argv[0], target, MAXPATHLEN)) { 105 warnx("\"%s\" is a relative path.", argv[0]); 106 warnx("using \"%s\" instead.", target); 107 } 108 109 if (realpath(argv[1], canon_dir) == NULL) /* Check mounton path */ 110 err(1, "realpath %s", argv[1]); 111 if (strncmp(argv[1], canon_dir, MAXPATHLEN)) { 112 warnx("\"%s\" is a relative path.", argv[1]); 113 warnx("using \"%s\" instead.", canon_dir); 114 } 115 116 if (subdir(target, canon_dir) || subdir(canon_dir, target)) 117 errx(1, "%s (%s) and %s (%s) are not distinct paths", 118 argv[0], target, argv[1], canon_dir); 119 120 args.la.target = target; 121 122 if (mount(MOUNT_NULL, canon_dir, mntflags, &args)) 123 err(1, "%s on %s", target, canon_dir); 124 exit(0); 125 } 126 127 static int 128 subdir(const char *p, 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 } 141 142 static void 143 usage(void) 144 { 145 (void)fprintf(stderr, 146 "usage: mount_null [-o options] target_fs mount_point\n"); 147 exit(1); 148 } 149