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 MOPT_END 63 }; 64 65 int subdir(const char *, const char *); 66 static void usage(void) __dead2; 67 68 int 69 main(int argc, char *argv[]) 70 { 71 struct iovec iov[6]; 72 int ch, mntflags; 73 char source[MAXPATHLEN]; 74 char target[MAXPATHLEN]; 75 76 mntflags = 0; 77 while ((ch = getopt(argc, argv, "o:")) != -1) 78 switch(ch) { 79 case 'o': 80 getmntopts(optarg, mopts, &mntflags, 0); 81 break; 82 case '?': 83 default: 84 usage(); 85 } 86 argc -= optind; 87 argv += optind; 88 89 if (argc != 2) 90 usage(); 91 92 /* resolve target and source with realpath(3) */ 93 (void)checkpath(argv[0], target); 94 (void)checkpath(argv[1], source); 95 96 if (subdir(target, source) || subdir(source, target)) 97 errx(EX_USAGE, "%s (%s) and %s are not distinct paths", 98 argv[0], target, argv[1]); 99 100 iov[0].iov_base = strdup("fstype"); 101 iov[0].iov_len = sizeof("fstype"); 102 iov[1].iov_base = strdup("nullfs"); 103 iov[1].iov_len = strlen(iov[1].iov_base) + 1; 104 iov[2].iov_base = strdup("fspath"); 105 iov[2].iov_len = sizeof("fspath"); 106 iov[3].iov_base = source; 107 iov[3].iov_len = strlen(source) + 1; 108 iov[4].iov_base = strdup("target"); 109 iov[4].iov_len = sizeof("target"); 110 iov[5].iov_base = target; 111 iov[5].iov_len = strlen(target) + 1; 112 113 if (nmount(iov, 6, mntflags)) 114 err(1, NULL); 115 exit(0); 116 } 117 118 int 119 subdir(p, dir) 120 const char *p; 121 const char *dir; 122 { 123 int l; 124 125 l = strlen(dir); 126 if (l <= 1) 127 return (1); 128 129 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0')) 130 return (1); 131 132 return (0); 133 } 134 135 static void 136 usage() 137 { 138 (void)fprintf(stderr, 139 "usage: mount_nullfs [-o options] target mount-point\n"); 140 exit(1); 141 } 142