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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #ifndef lint 34 static const char copyright[] = 35 "@(#) Copyright (c) 1992, 1993, 1994\n\ 36 The Regents of the University of California. All rights reserved.\n"; 37 #endif /* not lint */ 38 39 #ifndef lint 40 #if 0 41 static char sccsid[] = "@(#)mount_null.c 8.6 (Berkeley) 4/26/95"; 42 #endif 43 static const char rcsid[] = 44 "$FreeBSD$"; 45 #endif /* not lint */ 46 47 #include <sys/param.h> 48 #include <sys/mount.h> 49 #include <sys/uio.h> 50 51 #include <err.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <sysexits.h> 56 #include <unistd.h> 57 58 #include "mntopts.h" 59 60 struct mntopt mopts[] = { 61 MOPT_STDOPTS, 62 { NULL } 63 }; 64 65 int subdir(const char *, const char *); 66 static void usage(void) __dead2; 67 68 int 69 main(argc, argv) 70 int argc; 71 char *argv[]; 72 { 73 struct iovec iov[6]; 74 int ch, mntflags; 75 char source[MAXPATHLEN]; 76 char target[MAXPATHLEN]; 77 78 mntflags = 0; 79 while ((ch = getopt(argc, argv, "o:")) != -1) 80 switch(ch) { 81 case 'o': 82 getmntopts(optarg, mopts, &mntflags, 0); 83 break; 84 case '?': 85 default: 86 usage(); 87 } 88 argc -= optind; 89 argv += optind; 90 91 if (argc != 2) 92 usage(); 93 94 /* resolve target and source with realpath(3) */ 95 (void)checkpath(argv[0], target); 96 (void)checkpath(argv[1], source); 97 98 if (subdir(target, source) || subdir(source, target)) 99 errx(EX_USAGE, "%s (%s) and %s are not distinct paths", 100 argv[0], target, argv[1]); 101 102 iov[0].iov_base = "fstype"; 103 iov[0].iov_len = sizeof("fstype"); 104 iov[1].iov_base = "nullfs"; 105 iov[1].iov_len = strlen(iov[1].iov_base) + 1; 106 iov[2].iov_base = "fspath"; 107 iov[2].iov_len = sizeof("fspath"); 108 iov[3].iov_base = source; 109 iov[3].iov_len = strlen(source) + 1; 110 iov[4].iov_base = "target"; 111 iov[4].iov_len = sizeof("target"); 112 iov[5].iov_base = target; 113 iov[5].iov_len = strlen(target) + 1; 114 115 if (nmount(iov, 6, mntflags)) 116 err(1, NULL); 117 exit(0); 118 } 119 120 int 121 subdir(p, dir) 122 const char *p; 123 const char *dir; 124 { 125 int l; 126 127 l = strlen(dir); 128 if (l <= 1) 129 return (1); 130 131 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0')) 132 return (1); 133 134 return (0); 135 } 136 137 static void 138 usage() 139 { 140 (void)fprintf(stderr, 141 "usage: mount_nullfs [-o options] target_fs mount_point\n"); 142 exit(1); 143 } 144