1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1987, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #if defined(LIBC_SCCS) && !defined(lint) 33 static char sccsid[] = "@(#)mktemp.c 8.1 (Berkeley) 6/4/93"; 34 #endif /* LIBC_SCCS and not lint */ 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include "namespace.h" 39 #include <sys/param.h> 40 #include <sys/stat.h> 41 #include <fcntl.h> 42 #include <errno.h> 43 #include <stdio.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include <ctype.h> 47 #include <unistd.h> 48 #include "un-namespace.h" 49 50 char *_mktemp(char *); 51 52 static int _gettemp(int, char *, int *, int, int, int); 53 54 static const unsigned char padchar[] = 55 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; 56 57 int 58 mkostempsat(int dfd, char *path, int slen, int oflags) 59 { 60 int fd; 61 62 return (_gettemp(dfd, path, &fd, 0, slen, oflags) ? fd : -1); 63 } 64 65 int 66 mkostemps(char *path, int slen, int oflags) 67 { 68 int fd; 69 70 return (_gettemp(AT_FDCWD, path, &fd, 0, slen, oflags) ? fd : -1); 71 } 72 73 int 74 mkstemps(char *path, int slen) 75 { 76 int fd; 77 78 return (_gettemp(AT_FDCWD, path, &fd, 0, slen, 0) ? fd : -1); 79 } 80 81 int 82 mkostemp(char *path, int oflags) 83 { 84 int fd; 85 86 return (_gettemp(AT_FDCWD, path, &fd, 0, 0, oflags) ? fd : -1); 87 } 88 89 int 90 mkstemp(char *path) 91 { 92 int fd; 93 94 return (_gettemp(AT_FDCWD, path, &fd, 0, 0, 0) ? fd : -1); 95 } 96 97 char * 98 mkdtemp(char *path) 99 { 100 return (_gettemp(AT_FDCWD, path, (int *)NULL, 1, 0, 0) ? path : (char *)NULL); 101 } 102 103 char * 104 _mktemp(char *path) 105 { 106 return (_gettemp(AT_FDCWD, path, (int *)NULL, 0, 0, 0) ? path : (char *)NULL); 107 } 108 109 __warn_references(mktemp, 110 "warning: mktemp() possibly used unsafely; consider using mkstemp()"); 111 112 char * 113 mktemp(char *path) 114 { 115 return (_mktemp(path)); 116 } 117 118 static int 119 _gettemp(int dfd, char *path, int *doopen, int domkdir, int slen, int oflags) 120 { 121 char *start, *trv, *suffp, *carryp; 122 char *pad; 123 struct stat sbuf; 124 uint32_t rand; 125 char carrybuf[MAXPATHLEN]; 126 int saved; 127 128 if ((doopen != NULL && domkdir) || slen < 0 || 129 (oflags & ~(O_APPEND | O_DIRECT | O_SHLOCK | O_EXLOCK | O_SYNC | 130 O_CLOEXEC)) != 0) { 131 errno = EINVAL; 132 return (0); 133 } 134 135 trv = path + strlen(path); 136 if (trv - path >= MAXPATHLEN) { 137 errno = ENAMETOOLONG; 138 return (0); 139 } 140 trv -= slen; 141 suffp = trv; 142 --trv; 143 if (trv < path || NULL != strchr(suffp, '/')) { 144 errno = EINVAL; 145 return (0); 146 } 147 148 /* Fill space with random characters */ 149 while (trv >= path && *trv == 'X') { 150 rand = arc4random_uniform(sizeof(padchar) - 1); 151 *trv-- = padchar[rand]; 152 } 153 start = trv + 1; 154 155 saved = 0; 156 oflags |= O_CREAT | O_EXCL | O_RDWR; 157 for (;;) { 158 if (doopen) { 159 *doopen = _openat(dfd, path, oflags, 0600); 160 if (*doopen >= 0) 161 return (1); 162 if (errno != EEXIST) 163 return (0); 164 } else if (domkdir) { 165 if (mkdir(path, 0700) == 0) 166 return (1); 167 if (errno != EEXIST) 168 return (0); 169 } else if (lstat(path, &sbuf)) 170 return (errno == ENOENT); 171 172 /* save first combination of random characters */ 173 if (!saved) { 174 memcpy(carrybuf, start, suffp - start); 175 saved = 1; 176 } 177 178 /* If we have a collision, cycle through the space of filenames */ 179 for (trv = start, carryp = carrybuf;;) { 180 /* have we tried all possible permutations? */ 181 if (trv == suffp) 182 return (0); /* yes - exit with EEXIST */ 183 pad = strchr(padchar, *trv); 184 if (pad == NULL) { 185 /* this should never happen */ 186 errno = EIO; 187 return (0); 188 } 189 /* increment character */ 190 *trv = (*++pad == '\0') ? padchar[0] : *pad; 191 /* carry to next position? */ 192 if (*trv == *carryp) { 193 /* increment position and loop */ 194 ++trv; 195 ++carryp; 196 } else { 197 /* try with new name */ 198 break; 199 } 200 } 201 } 202 /*NOTREACHED*/ 203 } 204