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 #include "namespace.h" 37 #include <sys/param.h> 38 #include <sys/stat.h> 39 #include <fcntl.h> 40 #include <errno.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <ctype.h> 45 #include <unistd.h> 46 #include "un-namespace.h" 47 48 char *_mktemp(char *); 49 50 static int _gettemp(int, char *, int *, int, int, int); 51 52 static const unsigned char padchar[] = 53 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; 54 55 int 56 mkostempsat(int dfd, char *path, int slen, int oflags) 57 { 58 int fd; 59 60 return (_gettemp(dfd, path, &fd, 0, slen, oflags) ? fd : -1); 61 } 62 63 int 64 mkostemps(char *path, int slen, int oflags) 65 { 66 int fd; 67 68 return (_gettemp(AT_FDCWD, path, &fd, 0, slen, oflags) ? fd : -1); 69 } 70 71 int 72 mkstemps(char *path, int slen) 73 { 74 int fd; 75 76 return (_gettemp(AT_FDCWD, path, &fd, 0, slen, 0) ? fd : -1); 77 } 78 79 int 80 mkostemp(char *path, int oflags) 81 { 82 int fd; 83 84 return (_gettemp(AT_FDCWD, path, &fd, 0, 0, oflags) ? fd : -1); 85 } 86 87 int 88 mkstemp(char *path) 89 { 90 int fd; 91 92 return (_gettemp(AT_FDCWD, path, &fd, 0, 0, 0) ? fd : -1); 93 } 94 95 char * 96 mkdtemp(char *path) 97 { 98 return (_gettemp(AT_FDCWD, path, (int *)NULL, 1, 0, 0) ? path : (char *)NULL); 99 } 100 101 char * 102 _mktemp(char *path) 103 { 104 return (_gettemp(AT_FDCWD, path, (int *)NULL, 0, 0, 0) ? path : (char *)NULL); 105 } 106 107 __warn_references(mktemp, 108 "warning: mktemp() possibly used unsafely; consider using mkstemp()"); 109 110 char * 111 mktemp(char *path) 112 { 113 return (_mktemp(path)); 114 } 115 116 static int 117 _gettemp(int dfd, char *path, int *doopen, int domkdir, int slen, int oflags) 118 { 119 char *start, *trv, *suffp, *carryp; 120 char *pad; 121 struct stat sbuf; 122 uint32_t rand; 123 char carrybuf[MAXPATHLEN]; 124 int saved; 125 126 if ((doopen != NULL && domkdir) || slen < 0 || 127 (oflags & ~(O_APPEND | O_DIRECT | O_SHLOCK | O_EXLOCK | O_SYNC | 128 O_CLOEXEC)) != 0) { 129 errno = EINVAL; 130 return (0); 131 } 132 133 trv = path + strlen(path); 134 if (trv - path >= MAXPATHLEN) { 135 errno = ENAMETOOLONG; 136 return (0); 137 } 138 trv -= slen; 139 suffp = trv; 140 --trv; 141 if (trv < path || NULL != strchr(suffp, '/')) { 142 errno = EINVAL; 143 return (0); 144 } 145 146 /* Fill space with random characters */ 147 while (trv >= path && *trv == 'X') { 148 rand = arc4random_uniform(sizeof(padchar) - 1); 149 *trv-- = padchar[rand]; 150 } 151 start = trv + 1; 152 153 saved = 0; 154 oflags |= O_CREAT | O_EXCL | O_RDWR; 155 for (;;) { 156 if (doopen) { 157 *doopen = _openat(dfd, path, oflags, 0600); 158 if (*doopen >= 0) 159 return (1); 160 if (errno != EEXIST) 161 return (0); 162 } else if (domkdir) { 163 if (mkdir(path, 0700) == 0) 164 return (1); 165 if (errno != EEXIST) 166 return (0); 167 } else if (lstat(path, &sbuf)) 168 return (errno == ENOENT); 169 170 /* save first combination of random characters */ 171 if (!saved) { 172 memcpy(carrybuf, start, suffp - start); 173 saved = 1; 174 } 175 176 /* If we have a collision, cycle through the space of filenames */ 177 for (trv = start, carryp = carrybuf;;) { 178 /* have we tried all possible permutations? */ 179 if (trv == suffp) 180 return (0); /* yes - exit with EEXIST */ 181 pad = strchr(padchar, *trv); 182 if (pad == NULL) { 183 /* this should never happen */ 184 errno = EIO; 185 return (0); 186 } 187 /* increment character */ 188 *trv = (*++pad == '\0') ? padchar[0] : *pad; 189 /* carry to next position? */ 190 if (*trv == *carryp) { 191 /* increment position and loop */ 192 ++trv; 193 ++carryp; 194 } else { 195 /* try with new name */ 196 break; 197 } 198 } 199 } 200 /*NOTREACHED*/ 201 } 202