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 * @(#) Copyright (c) 1992, 1993, 1994 The Regents of the University of California. All rights reserved. 37 * @(#)mount_null.c 8.6 (Berkeley) 4/26/95 38 * $FreeBSD: src/sbin/mount_null/mount_null.c,v 1.13 1999/10/09 11:54:11 phk Exp $ 39 * $DragonFly: src/sbin/mount_null/mount_null.c,v 1.5 2003/11/01 17:16:00 drhodus Exp $ 40 */ 41 42 #include <sys/param.h> 43 #include <sys/mount.h> 44 #include <vfs/nullfs/null.h> 45 46 #include <err.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <sysexits.h> 51 #include <unistd.h> 52 53 #include "mntopts.h" 54 55 struct mntopt mopts[] = { 56 MOPT_STDOPTS, 57 { NULL } 58 }; 59 60 int subdir(const char *, const char *); 61 static void usage(void) __dead2; 62 63 int 64 main(int argc, char **argv) 65 { 66 struct null_args args; 67 int ch, mntflags; 68 char source[MAXPATHLEN]; 69 char target[MAXPATHLEN]; 70 struct vfsconf vfc; 71 int error; 72 73 mntflags = 0; 74 while ((ch = getopt(argc, argv, "o:")) != -1) 75 switch(ch) { 76 case 'o': 77 getmntopts(optarg, mopts, &mntflags, 0); 78 break; 79 case '?': 80 default: 81 usage(); 82 } 83 argc -= optind; 84 argv += optind; 85 86 if (argc != 2) 87 usage(); 88 89 /* resolve target and source with realpath(3) */ 90 (void)checkpath(argv[0], target); 91 (void)checkpath(argv[1], source); 92 93 if (subdir(target, source) || subdir(source, target)) 94 errx(EX_USAGE, "%s (%s) and %s are not distinct paths", 95 argv[0], target, argv[1]); 96 97 args.target = target; 98 99 error = getvfsbyname("null", &vfc); 100 if (error && vfsisloadable("null")) { 101 if(vfsload("null")) 102 err(EX_OSERR, "vfsload(null)"); 103 endvfsent(); 104 error = getvfsbyname("null", &vfc); 105 } 106 if (error) 107 errx(EX_OSERR, "null/loopback filesystem is not available"); 108 109 if (mount(vfc.vfc_name, source, mntflags, &args)) 110 err(1, NULL); 111 exit(0); 112 } 113 114 int 115 subdir(const char *p, const char *dir) 116 { 117 int l; 118 119 l = strlen(dir); 120 if (l <= 1) 121 return (1); 122 123 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0')) 124 return (1); 125 126 return (0); 127 } 128 129 static void 130 usage(void) 131 { 132 (void)fprintf(stderr, 133 "usage: mount_null [-o options] target_fs mount_point\n"); 134 exit(1); 135 } 136