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 #endif /* not lint */ 46 47 #include <sys/param.h> 48 #include <sys/mount.h> 49 #include <sys/stat.h> 50 #include <sys/uio.h> 51 52 #include <err.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <sysexits.h> 57 #include <unistd.h> 58 59 #include "mntopts.h" 60 61 static void usage(void) __dead2; 62 63 static int 64 stat_realpath(const char *path, char *resolved, struct stat *sbp) 65 { 66 if (realpath(path, resolved) == NULL || stat(resolved, sbp) != 0) 67 return (1); 68 return (0); 69 } 70 71 int 72 main(int argc, char *argv[]) 73 { 74 struct iovec *iov; 75 char *p, *val; 76 char mountpoint[MAXPATHLEN]; 77 char target[MAXPATHLEN]; 78 char errmsg[255]; 79 int ch, iovlen; 80 char nullfs[] = "nullfs"; 81 struct stat target_stat; 82 struct stat mountpoint_stat; 83 84 iov = NULL; 85 iovlen = 0; 86 errmsg[0] = '\0'; 87 while ((ch = getopt(argc, argv, "o:")) != -1) 88 switch(ch) { 89 case 'o': 90 val = strdup(""); 91 p = strchr(optarg, '='); 92 if (p != NULL) { 93 free(val); 94 *p = '\0'; 95 val = p + 1; 96 } 97 build_iovec(&iov, &iovlen, optarg, val, (size_t)-1); 98 break; 99 case '?': 100 default: 101 usage(); 102 } 103 argc -= optind; 104 argv += optind; 105 106 if (argc != 2) 107 usage(); 108 109 /* resolve target and mountpoint with realpath(3) */ 110 if (stat_realpath(argv[0], target, &target_stat) != 0) 111 err(EX_USAGE, "%s", target); 112 if (stat_realpath(argv[1], mountpoint, &mountpoint_stat) != 0) 113 err(EX_USAGE, "%s", mountpoint); 114 if (!S_ISDIR(target_stat.st_mode) && !S_ISREG(target_stat.st_mode)) 115 errx(EX_USAGE, "%s: must be either a file or directory", 116 target); 117 if ((target_stat.st_mode & S_IFMT) != 118 (mountpoint_stat.st_mode & S_IFMT)) 119 errx(EX_USAGE, 120 "%s: must be same type as %s (file or directory)", 121 mountpoint, target); 122 123 build_iovec(&iov, &iovlen, "fstype", nullfs, (size_t)-1); 124 build_iovec(&iov, &iovlen, "fspath", mountpoint, (size_t)-1); 125 build_iovec(&iov, &iovlen, "target", target, (size_t)-1); 126 build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg)); 127 if (nmount(iov, iovlen, 0) < 0) { 128 if (errmsg[0] != 0) 129 err(1, "%s: %s", mountpoint, errmsg); 130 else 131 err(1, "%s", mountpoint); 132 } 133 exit(0); 134 } 135 136 static void 137 usage(void) 138 { 139 (void)fprintf(stderr, 140 "usage: mount_nullfs [-o options] target mount-point\n"); 141 exit(1); 142 } 143