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 "namespace.h" 36 #include <sys/param.h> 37 #include <sys/stat.h> 38 #include <fcntl.h> 39 #include <errno.h> 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <ctype.h> 44 #include <unistd.h> 45 #include "un-namespace.h" 46 47 char *_mktemp(char *); 48 49 static int _gettemp(int, char *, int *, int, int, int); 50 51 static const unsigned char padchar[] = 52 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; 53 54 int 55 mkostempsat(int dfd, char *path, int slen, int oflags) 56 { 57 int fd; 58 59 return (_gettemp(dfd, path, &fd, 0, slen, oflags) ? fd : -1); 60 } 61 62 int 63 mkostemps(char *path, int slen, int oflags) 64 { 65 int fd; 66 67 return (_gettemp(AT_FDCWD, path, &fd, 0, slen, oflags) ? fd : -1); 68 } 69 70 int 71 mkstemps(char *path, int slen) 72 { 73 int fd; 74 75 return (_gettemp(AT_FDCWD, path, &fd, 0, slen, 0) ? fd : -1); 76 } 77 78 int 79 mkostemp(char *path, int oflags) 80 { 81 int fd; 82 83 return (_gettemp(AT_FDCWD, path, &fd, 0, 0, oflags) ? fd : -1); 84 } 85 86 int 87 mkstemp(char *path) 88 { 89 int fd; 90 91 return (_gettemp(AT_FDCWD, path, &fd, 0, 0, 0) ? fd : -1); 92 } 93 94 char * 95 mkdtemp(char *path) 96 { 97 return (_gettemp(AT_FDCWD, path, (int *)NULL, 1, 0, 0) ? path : (char *)NULL); 98 } 99 100 char * 101 _mktemp(char *path) 102 { 103 return (_gettemp(AT_FDCWD, path, (int *)NULL, 0, 0, 0) ? path : (char *)NULL); 104 } 105 106 __warn_references(mktemp, 107 "warning: mktemp() possibly used unsafely; consider using mkstemp()"); 108 109 char * 110 mktemp(char *path) 111 { 112 return (_mktemp(path)); 113 } 114 115 static int 116 _gettemp(int dfd, char *path, int *doopen, int domkdir, int slen, int oflags) 117 { 118 char *start, *trv, *suffp, *carryp; 119 char *pad; 120 struct stat sbuf; 121 uint32_t rand; 122 char carrybuf[MAXPATHLEN]; 123 int saved; 124 125 if ((doopen != NULL && domkdir) || slen < 0 || 126 (oflags & ~(O_APPEND | O_DIRECT | O_SHLOCK | O_EXLOCK | O_SYNC | 127 O_CLOEXEC)) != 0) { 128 errno = EINVAL; 129 return (0); 130 } 131 132 trv = path + strlen(path); 133 if (trv - path >= MAXPATHLEN) { 134 errno = ENAMETOOLONG; 135 return (0); 136 } 137 trv -= slen; 138 suffp = trv; 139 --trv; 140 if (trv < path || NULL != strchr(suffp, '/')) { 141 errno = EINVAL; 142 return (0); 143 } 144 145 /* Fill space with random characters */ 146 while (trv >= path && *trv == 'X') { 147 rand = arc4random_uniform(sizeof(padchar) - 1); 148 *trv-- = padchar[rand]; 149 } 150 start = trv + 1; 151 152 saved = 0; 153 oflags |= O_CREAT | O_EXCL | O_RDWR; 154 for (;;) { 155 if (doopen) { 156 *doopen = _openat(dfd, path, oflags, 0600); 157 if (*doopen >= 0) 158 return (1); 159 if (errno != EEXIST) 160 return (0); 161 } else if (domkdir) { 162 if (mkdir(path, 0700) == 0) 163 return (1); 164 if (errno != EEXIST) 165 return (0); 166 } else if (lstat(path, &sbuf)) 167 return (errno == ENOENT); 168 169 /* save first combination of random characters */ 170 if (!saved) { 171 memcpy(carrybuf, start, suffp - start); 172 saved = 1; 173 } 174 175 /* If we have a collision, cycle through the space of filenames */ 176 for (trv = start, carryp = carrybuf;;) { 177 /* have we tried all possible permutations? */ 178 if (trv == suffp) 179 return (0); /* yes - exit with EEXIST */ 180 pad = strchr(padchar, *trv); 181 if (pad == NULL) { 182 /* this should never happen */ 183 errno = EIO; 184 return (0); 185 } 186 /* increment character */ 187 *trv = (*++pad == '\0') ? padchar[0] : *pad; 188 /* carry to next position? */ 189 if (*trv == *carryp) { 190 /* increment position and loop */ 191 ++trv; 192 ++carryp; 193 } else { 194 /* try with new name */ 195 break; 196 } 197 } 198 } 199 /*NOTREACHED*/ 200 } 201