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. 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 int subdir(const char *, const char *); 61 static void usage(void) __dead2; 62 63 int 64 main(int argc, char *argv[]) 65 { 66 struct iovec *iov; 67 char *p, *val; 68 char source[MAXPATHLEN]; 69 char target[MAXPATHLEN]; 70 char errmsg[255]; 71 int ch, iovlen; 72 char nullfs[] = "nullfs"; 73 74 iov = NULL; 75 iovlen = 0; 76 errmsg[0] = '\0'; 77 while ((ch = getopt(argc, argv, "o:")) != -1) 78 switch(ch) { 79 case 'o': 80 val = strdup(""); 81 p = strchr(optarg, '='); 82 if (p != NULL) { 83 free(val); 84 *p = '\0'; 85 val = p + 1; 86 } 87 build_iovec(&iov, &iovlen, optarg, val, (size_t)-1); 88 break; 89 case '?': 90 default: 91 usage(); 92 } 93 argc -= optind; 94 argv += optind; 95 96 if (argc != 2) 97 usage(); 98 99 /* resolve target and source with realpath(3) */ 100 if (checkpath(argv[0], target) != 0) 101 err(EX_USAGE, "%s", target); 102 if (checkpath(argv[1], source) != 0) 103 err(EX_USAGE, "%s", source); 104 105 if (subdir(target, source) || subdir(source, target)) 106 errx(EX_USAGE, "%s (%s) and %s are not distinct paths", 107 argv[0], target, argv[1]); 108 109 build_iovec(&iov, &iovlen, "fstype", nullfs, (size_t)-1); 110 build_iovec(&iov, &iovlen, "fspath", source, (size_t)-1); 111 build_iovec(&iov, &iovlen, "target", target, (size_t)-1); 112 build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg)); 113 if (nmount(iov, iovlen, 0) < 0) { 114 if (errmsg[0] != 0) 115 err(1, "%s: %s", source, errmsg); 116 else 117 err(1, "%s", source); 118 } 119 exit(0); 120 } 121 122 int 123 subdir(const char *p, 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(void) 139 { 140 (void)fprintf(stderr, 141 "usage: mount_nullfs [-o options] target mount-point\n"); 142 exit(1); 143 } 144