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 #include <sys/param.h> 36 #include <sys/mount.h> 37 #include <sys/stat.h> 38 #include <sys/uio.h> 39 40 #include <err.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <sysexits.h> 45 #include <unistd.h> 46 47 #include "mntopts.h" 48 49 static void usage(void) __dead2; 50 51 static int 52 stat_realpath(const char *path, char *resolved, struct stat *sbp) 53 { 54 if (realpath(path, resolved) == NULL || stat(resolved, sbp) != 0) 55 return (1); 56 return (0); 57 } 58 59 int 60 main(int argc, char *argv[]) 61 { 62 struct iovec *iov; 63 char *p, *val; 64 char mountpoint[MAXPATHLEN]; 65 char target[MAXPATHLEN]; 66 char errmsg[255]; 67 int ch, iovlen; 68 char nullfs[] = "nullfs"; 69 struct stat target_stat; 70 struct stat mountpoint_stat; 71 72 iov = NULL; 73 iovlen = 0; 74 errmsg[0] = '\0'; 75 while ((ch = getopt(argc, argv, "o:")) != -1) 76 switch(ch) { 77 case 'o': 78 val = strdup(""); 79 p = strchr(optarg, '='); 80 if (p != NULL) { 81 free(val); 82 *p = '\0'; 83 val = p + 1; 84 } 85 build_iovec(&iov, &iovlen, optarg, val, (size_t)-1); 86 break; 87 case '?': 88 default: 89 usage(); 90 } 91 argc -= optind; 92 argv += optind; 93 94 if (argc != 2) 95 usage(); 96 97 /* resolve target and mountpoint with realpath(3) */ 98 if (stat_realpath(argv[0], target, &target_stat) != 0) 99 err(EX_USAGE, "%s", target); 100 if (stat_realpath(argv[1], mountpoint, &mountpoint_stat) != 0) 101 err(EX_USAGE, "%s", mountpoint); 102 if (!S_ISDIR(target_stat.st_mode) && !S_ISREG(target_stat.st_mode)) 103 errx(EX_USAGE, "%s: must be either a file or directory", 104 target); 105 if ((target_stat.st_mode & S_IFMT) != 106 (mountpoint_stat.st_mode & S_IFMT)) 107 errx(EX_USAGE, 108 "%s: must be same type as %s (file or directory)", 109 mountpoint, target); 110 111 build_iovec(&iov, &iovlen, "fstype", nullfs, (size_t)-1); 112 build_iovec(&iov, &iovlen, "fspath", mountpoint, (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", mountpoint, errmsg); 118 else 119 err(1, "%s", mountpoint); 120 } 121 exit(0); 122 } 123 124 static void 125 usage(void) 126 { 127 (void)fprintf(stderr, 128 "usage: mount_nullfs [-o options] target mount-point\n"); 129 exit(1); 130 } 131