1 /* $NetBSD: mount_union.c,v 1.21 2008/07/20 01:20:23 lukem 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_union.c 8.6 (Berkeley) 4/26/95"; 44 #else 45 __RCSID("$NetBSD: mount_union.c,v 1.21 2008/07/20 01:20:23 lukem Exp $"); 46 #endif 47 #endif /* not lint */ 48 49 #include <sys/param.h> 50 #include <sys/mount.h> 51 52 #include <miscfs/union/union.h> 53 54 #include <err.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <unistd.h> 59 #include <util.h> 60 61 #include <mntopts.h> 62 63 static const struct mntopt mopts[] = { 64 MOPT_STDOPTS, 65 MOPT_GETARGS, 66 MOPT_NULL, 67 }; 68 69 int mount_union(int argc, char **argv); 70 static int subdir(const char *, const char *); 71 static void usage(void); 72 73 #ifndef MOUNT_NOMAIN 74 int 75 main(int argc, char **argv) 76 { 77 return mount_union(argc, argv); 78 } 79 #endif 80 81 int 82 mount_union(int argc, char *argv[]) 83 { 84 struct union_args args; 85 int ch, mntflags; 86 char target[MAXPATHLEN], canon_dir[MAXPATHLEN]; 87 mntoptparse_t mp; 88 89 90 mntflags = 0; 91 args.mntflags = UNMNT_ABOVE; 92 while ((ch = getopt(argc, argv, "bo:")) != -1) 93 switch (ch) { 94 case 'b': 95 args.mntflags &= ~UNMNT_OPMASK; 96 args.mntflags |= UNMNT_BELOW; 97 break; 98 case 'o': 99 mp = getmntopts(optarg, mopts, &mntflags, 0); 100 if (mp == NULL) 101 err(1, "getmntopts"); 102 freemntopts(mp); 103 break; 104 case '?': 105 default: 106 usage(); 107 /* NOTREACHED */ 108 } 109 argc -= optind; 110 argv += optind; 111 112 if (argc != 2) 113 usage(); 114 115 if (realpath(argv[0], target) == NULL) /* Check device path */ 116 err(1, "realpath %s", argv[0]); 117 if (strncmp(argv[0], target, MAXPATHLEN)) { 118 warnx("\"%s\" is a relative path.", argv[0]); 119 warnx("using \"%s\" instead.", target); 120 } 121 122 if (realpath(argv[1], canon_dir) == NULL) /* Check mounton path */ 123 err(1, "realpath %s", argv[1]); 124 if (strncmp(argv[1], canon_dir, MAXPATHLEN)) { 125 warnx("\"%s\" is a relative path.", argv[1]); 126 warnx("using \"%s\" instead.", canon_dir); 127 } 128 129 if (subdir(target, canon_dir) || subdir(canon_dir, target)) 130 errx(1, "%s (%s) and %s are not distinct paths", 131 argv[0], target, canon_dir); 132 133 args.target = target; 134 135 if (mount(MOUNT_UNION, canon_dir, mntflags, &args, sizeof args) == -1) 136 err(1, "%s on %s", target, canon_dir); 137 if (mntflags & MNT_GETARGS) { 138 char buf[1024]; 139 (void)snprintb(buf, sizeof(buf), UNMNT_BITS, args.mntflags); 140 printf("flags=%s\n", buf); 141 } 142 exit(0); 143 } 144 145 static int 146 subdir(const char *p, const char *dir) 147 { 148 int l; 149 150 l = strlen(dir); 151 if (l <= 1) 152 return (1); 153 154 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0')) 155 return (1); 156 157 return (0); 158 } 159 160 static void 161 usage(void) 162 { 163 (void)fprintf(stderr, 164 "usage: mount_union [-br] [-o options] target_fs mount_point\n"); 165 exit(1); 166 } 167