1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #ifndef lint 36 static const char copyright[] = 37 "@(#) Copyright (c) 1992, 1993, 1994\n\ 38 The Regents of the University of California. All rights reserved.\n"; 39 #endif /* not lint */ 40 41 #ifndef lint 42 #if 0 43 static char sccsid[] = "@(#)mount_null.c 8.6 (Berkeley) 4/26/95"; 44 #endif 45 static const char rcsid[] = 46 "$FreeBSD$"; 47 #endif /* not lint */ 48 49 #include <sys/param.h> 50 #include <sys/mount.h> 51 #include <sys/uio.h> 52 53 #include <err.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <sysexits.h> 58 #include <unistd.h> 59 60 #include "mntopts.h" 61 62 int subdir(const char *, const char *); 63 static void usage(void) __dead2; 64 65 int 66 main(int argc, char *argv[]) 67 { 68 struct iovec *iov; 69 char *p, *val; 70 char source[MAXPATHLEN]; 71 char target[MAXPATHLEN]; 72 char errmsg[255]; 73 int ch, iovlen; 74 char nullfs[] = "nullfs"; 75 76 iov = NULL; 77 iovlen = 0; 78 errmsg[0] = '\0'; 79 while ((ch = getopt(argc, argv, "o:")) != -1) 80 switch(ch) { 81 case 'o': 82 val = strdup(""); 83 p = strchr(optarg, '='); 84 if (p != NULL) { 85 free(val); 86 *p = '\0'; 87 val = p + 1; 88 } 89 build_iovec(&iov, &iovlen, optarg, val, (size_t)-1); 90 break; 91 case '?': 92 default: 93 usage(); 94 } 95 argc -= optind; 96 argv += optind; 97 98 if (argc != 2) 99 usage(); 100 101 /* resolve target and source with realpath(3) */ 102 if (checkpath(argv[0], target) != 0) 103 err(EX_USAGE, "%s", target); 104 if (checkpath(argv[1], source) != 0) 105 err(EX_USAGE, "%s", source); 106 107 if (subdir(target, source) || subdir(source, target)) 108 errx(EX_USAGE, "%s (%s) and %s are not distinct paths", 109 argv[0], target, argv[1]); 110 111 build_iovec(&iov, &iovlen, "fstype", nullfs, (size_t)-1); 112 build_iovec(&iov, &iovlen, "fspath", source, (size_t)-1); 113 build_iovec(&iov, &iovlen, "target", target, (size_t)-1); 114 build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg)); 115 if (nmount(iov, iovlen, 0) < 0) { 116 if (errmsg[0] != 0) 117 err(1, "%s: %s", source, errmsg); 118 else 119 err(1, "%s", source); 120 } 121 exit(0); 122 } 123 124 int 125 subdir(const char *p, const char *dir) 126 { 127 int l; 128 129 l = strlen(dir); 130 if (l <= 1) 131 return (1); 132 133 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0')) 134 return (1); 135 136 return (0); 137 } 138 139 static void 140 usage(void) 141 { 142 (void)fprintf(stderr, 143 "usage: mount_nullfs [-o options] target mount-point\n"); 144 exit(1); 145 } 146