mount_unionfs.c revision 25275
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 44static char sccsid[] = "@(#)mount_union.c 8.5 (Berkeley) 3/27/94"; 45#endif /* not lint */ 46 47#include <sys/param.h> 48#include <sys/mount.h> 49 50#include <miscfs/union/union.h> 51 52#include <err.h> 53#include <stdio.h> 54#include <stdlib.h> 55#include <string.h> 56#include <sysexits.h> 57#include <unistd.h> 58 59#include "mntopts.h" 60 61static struct mntopt mopts[] = { 62 MOPT_STDOPTS, 63 { NULL } 64}; 65 66static int subdir __P((const char *, const char *)); 67static void usage __P((void)) __dead2; 68 69int 70main(argc, argv) 71 int argc; 72 char *argv[]; 73{ 74 struct union_args args; 75 int ch, mntflags; 76 char source[MAXPATHLEN]; 77 char target[MAXPATHLEN]; 78 struct vfsconf vfc; 79 int error; 80 81 mntflags = 0; 82 args.mntflags = UNMNT_ABOVE; 83 while ((ch = getopt(argc, argv, "bo:r")) != -1) 84 switch (ch) { 85 case 'b': 86 args.mntflags &= ~UNMNT_OPMASK; 87 args.mntflags |= UNMNT_BELOW; 88 break; 89 case 'o': 90 getmntopts(optarg, mopts, &mntflags, 0); 91 break; 92 case 'r': 93 args.mntflags &= ~UNMNT_OPMASK; 94 args.mntflags |= UNMNT_REPLACE; 95 break; 96 case '?': 97 default: 98 usage(); 99 /* NOTREACHED */ 100 } 101 argc -= optind; 102 argv += optind; 103 104 if (argc != 2) 105 usage(); 106 107 if (realpath(argv[0], target) == 0) 108 err(EX_OSERR, "%s", target); 109 110 if (realpath(argv[1], source) == 0) 111 err(EX_OSERR, "%s", target); 112 113 if (subdir(target, source) || subdir(source, target)) 114 errx(EX_USAGE, "%s (%s) and %s (%s) are not distinct paths", 115 argv[0], target, argv[1], source); 116 117 args.target = target; 118 119 error = getvfsbyname("union", &vfc); 120 if (error && vfsisloadable("union")) { 121 if (vfsload("union")) 122 err(EX_OSERR, "vfsload(union)"); 123 endvfsent(); /* flush cache */ 124 error = getvfsbyname("union", &vfc); 125 } 126 if (error) 127 errx(EX_OSERR, "union filesystem is not available"); 128 129 if (mount(vfc.vfc_name, source, mntflags, &args)) 130 err(EX_OSERR, target); 131 exit(0); 132} 133 134int 135subdir(p, dir) 136 const char *p; 137 const char *dir; 138{ 139 int l; 140 141 l = strlen(dir); 142 if (l <= 1) 143 return (1); 144 145 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0')) 146 return (1); 147 148 return (0); 149} 150 151void 152usage() 153{ 154 (void)fprintf(stderr, 155 "usage: mount_union [-br] [-o options] target_fs mount_point\n"); 156 exit(EX_USAGE); 157} 158