1 /* $NetBSD: mount_null.c,v 1.9 2002/09/21 18:43:37 christos 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. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #ifndef lint 41 __COPYRIGHT("@(#) Copyright (c) 1992, 1993, 1994\n\ 42 The Regents of the University of California. All rights reserved.\n"); 43 #endif /* not lint */ 44 45 #ifndef lint 46 #if 0 47 static char sccsid[] = "@(#)mount_null.c 8.6 (Berkeley) 4/26/95"; 48 #else 49 __RCSID("$NetBSD: mount_null.c,v 1.9 2002/09/21 18:43:37 christos Exp $"); 50 #endif 51 #endif /* not lint */ 52 53 #include <sys/param.h> 54 #include <sys/mount.h> 55 #include <miscfs/nullfs/null.h> 56 57 #include <err.h> 58 #include <stdio.h> 59 #include <unistd.h> 60 #include <stdlib.h> 61 #include <string.h> 62 63 #include "mntopts.h" 64 65 static const struct mntopt mopts[] = { 66 MOPT_STDOPTS, 67 MOPT_GETARGS, 68 { NULL } 69 }; 70 71 int main __P((int, char *[])); 72 int mount_null __P((int argc, char **argv)); 73 static int subdir __P((const char *, const char *)); 74 static void usage __P((void)); 75 76 #ifndef MOUNT_NOMAIN 77 int 78 main(argc, argv) 79 int argc; 80 char **argv; 81 { 82 return mount_null(argc, argv); 83 } 84 #endif 85 86 int 87 mount_null(argc, argv) 88 int argc; 89 char *argv[]; 90 { 91 struct null_args args; 92 int ch, mntflags; 93 char target[MAXPATHLEN]; 94 95 mntflags = 0; 96 while ((ch = getopt(argc, argv, "o:")) != -1) 97 switch(ch) { 98 case 'o': 99 getmntopts(optarg, mopts, &mntflags, 0); 100 break; 101 case '?': 102 default: 103 usage(); 104 } 105 argc -= optind; 106 argv += optind; 107 108 if (argc != 2) 109 usage(); 110 111 if (realpath(argv[0], target) == 0) 112 err(1, "%s", target); 113 114 if (subdir(target, argv[1]) || subdir(argv[1], target)) 115 errx(1, "%s (%s) and %s are not distinct paths", 116 argv[0], target, argv[1]); 117 118 args.la.target = target; 119 120 if (mount(MOUNT_NULL, argv[1], mntflags, &args)) 121 err(1, "%s on %s", target, argv[1]); 122 exit(0); 123 } 124 125 static int 126 subdir(p, dir) 127 const char *p; 128 const char *dir; 129 { 130 int l; 131 132 l = strlen(dir); 133 if (l <= 1) 134 return (1); 135 136 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0')) 137 return (1); 138 139 return (0); 140 } 141 142 static void 143 usage() 144 { 145 (void)fprintf(stderr, 146 "usage: mount_null [-o options] target_fs mount_point\n"); 147 exit(1); 148 } 149