1 /* $NetBSD: mount_null.c,v 1.19 2011/08/29 14:35:02 joerg 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\ 38 The Regents of the University of California. All rights reserved."); 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 1.19 2011/08/29 14:35:02 joerg 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 MOPT_NULL, 65 }; 66 67 int mount_null(int argc, char **argv); 68 static int subdir(const char *, const char *); 69 __dead 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 mntoptparse_t mp; 86 87 mntflags = 0; 88 while ((ch = getopt(argc, argv, "o:")) != -1) 89 switch(ch) { 90 case 'o': 91 mp = getmntopts(optarg, mopts, &mntflags, 0); 92 if (mp == NULL) 93 err(1, "getmntopts"); 94 freemntopts(mp); 95 break; 96 case '?': 97 default: 98 usage(); 99 } 100 argc -= optind; 101 argv += optind; 102 103 if (argc != 2) 104 usage(); 105 106 if (realpath(argv[0], target) == NULL) /* Check device path */ 107 err(1, "realpath %s", argv[0]); 108 if (strncmp(argv[0], target, MAXPATHLEN)) { 109 warnx("\"%s\" is a relative path.", argv[0]); 110 warnx("using \"%s\" instead.", target); 111 } 112 113 if (realpath(argv[1], canon_dir) == NULL) /* Check mounton path */ 114 err(1, "realpath %s", argv[1]); 115 if (strncmp(argv[1], canon_dir, MAXPATHLEN)) { 116 warnx("\"%s\" is a relative path.", argv[1]); 117 warnx("using \"%s\" instead.", canon_dir); 118 } 119 120 if (subdir(target, canon_dir) || subdir(canon_dir, target)) 121 errx(1, "%s (%s) and %s (%s) are not distinct paths", 122 argv[0], target, argv[1], canon_dir); 123 124 args.la.target = target; 125 126 if (mount(MOUNT_NULL, canon_dir, mntflags, &args, sizeof args) == -1) 127 err(1, "%s on %s", target, canon_dir); 128 exit(0); 129 } 130 131 static int 132 subdir(const char *p, const char *dir) 133 { 134 int l; 135 136 l = strlen(dir); 137 if (l <= 1) 138 return (1); 139 140 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0')) 141 return (1); 142 143 return (0); 144 } 145 146 static void 147 usage(void) 148 { 149 (void)fprintf(stderr, 150 "usage: mount_null [-o options] target_fs mount_point\n"); 151 exit(1); 152 } 153