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 1.3 2003/08/08 04:18:40 dillon 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 __P((const char *, const char *)); 61 static void usage __P((void)) __dead2; 62 63 int 64 main(argc, argv) 65 int argc; 66 char *argv[]; 67 { 68 struct null_args args; 69 int ch, mntflags; 70 char source[MAXPATHLEN]; 71 char target[MAXPATHLEN]; 72 struct vfsconf vfc; 73 int error; 74 75 mntflags = 0; 76 while ((ch = getopt(argc, argv, "o:")) != -1) 77 switch(ch) { 78 case 'o': 79 getmntopts(optarg, mopts, &mntflags, 0); 80 break; 81 case '?': 82 default: 83 usage(); 84 } 85 argc -= optind; 86 argv += optind; 87 88 if (argc != 2) 89 usage(); 90 91 /* resolve target and source with realpath(3) */ 92 (void)checkpath(argv[0], target); 93 (void)checkpath(argv[1], source); 94 95 if (subdir(target, source) || subdir(source, target)) 96 errx(EX_USAGE, "%s (%s) and %s are not distinct paths", 97 argv[0], target, argv[1]); 98 99 args.target = target; 100 101 error = getvfsbyname("null", &vfc); 102 if (error && vfsisloadable("null")) { 103 if(vfsload("null")) 104 err(EX_OSERR, "vfsload(null)"); 105 endvfsent(); 106 error = getvfsbyname("null", &vfc); 107 } 108 if (error) 109 errx(EX_OSERR, "null/loopback filesystem is not available"); 110 111 if (mount(vfc.vfc_name, source, mntflags, &args)) 112 err(1, NULL); 113 exit(0); 114 } 115 116 int 117 subdir(p, dir) 118 const char *p; 119 const char *dir; 120 { 121 int l; 122 123 l = strlen(dir); 124 if (l <= 1) 125 return (1); 126 127 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0')) 128 return (1); 129 130 return (0); 131 } 132 133 static void 134 usage() 135 { 136 (void)fprintf(stderr, 137 "usage: mount_null [-o options] target_fs mount_point\n"); 138 exit(1); 139 } 140