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/stat.h> 52 #include <sys/uio.h> 53 54 #include <err.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <sysexits.h> 59 #include <unistd.h> 60 61 #include "mntopts.h" 62 63 static void usage(void) __dead2; 64 65 static int 66 stat_realpath(const char *path, char *resolved, struct stat *sbp) 67 { 68 if (realpath(path, resolved) == NULL || stat(resolved, sbp) != 0) 69 return (1); 70 return (0); 71 } 72 73 int 74 main(int argc, char *argv[]) 75 { 76 struct iovec *iov; 77 char *p, *val; 78 char mountpoint[MAXPATHLEN]; 79 char target[MAXPATHLEN]; 80 char errmsg[255]; 81 int ch, iovlen; 82 char nullfs[] = "nullfs"; 83 struct stat target_stat; 84 struct stat mountpoint_stat; 85 86 iov = NULL; 87 iovlen = 0; 88 errmsg[0] = '\0'; 89 while ((ch = getopt(argc, argv, "o:")) != -1) 90 switch(ch) { 91 case 'o': 92 val = strdup(""); 93 p = strchr(optarg, '='); 94 if (p != NULL) { 95 free(val); 96 *p = '\0'; 97 val = p + 1; 98 } 99 build_iovec(&iov, &iovlen, optarg, val, (size_t)-1); 100 break; 101 case '?': 102 default: 103 usage(); 104 } 105 argc -= optind; 106 argv += optind; 107 108 if (argc != 2) 109 usage(); 110 111 /* resolve target and mountpoint with realpath(3) */ 112 if (stat_realpath(argv[0], target, &target_stat) != 0) 113 err(EX_USAGE, "%s", target); 114 if (stat_realpath(argv[1], mountpoint, &mountpoint_stat) != 0) 115 err(EX_USAGE, "%s", mountpoint); 116 if (!S_ISDIR(target_stat.st_mode) && !S_ISREG(target_stat.st_mode)) 117 errx(EX_USAGE, "%s: must be either a file or directory", 118 target); 119 if ((target_stat.st_mode & S_IFMT) != 120 (mountpoint_stat.st_mode & S_IFMT)) 121 errx(EX_USAGE, 122 "%s: must be same type as %s (file or directory)", 123 mountpoint, target); 124 125 build_iovec(&iov, &iovlen, "fstype", nullfs, (size_t)-1); 126 build_iovec(&iov, &iovlen, "fspath", mountpoint, (size_t)-1); 127 build_iovec(&iov, &iovlen, "target", target, (size_t)-1); 128 build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg)); 129 if (nmount(iov, iovlen, 0) < 0) { 130 if (errmsg[0] != 0) 131 err(1, "%s: %s", mountpoint, errmsg); 132 else 133 err(1, "%s", mountpoint); 134 } 135 exit(0); 136 } 137 138 static void 139 usage(void) 140 { 141 (void)fprintf(stderr, 142 "usage: mount_nullfs [-o options] target mount-point\n"); 143 exit(1); 144 } 145