1/* $NetBSD: gettemp.c,v 1.22 2024/01/20 14:52:49 christos Exp $ */ 2 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#include "gettemp.h" 33 34#if !HAVE_NBTOOL_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP 35 36#include <sys/cdefs.h> 37#if defined(LIBC_SCCS) && !defined(lint) 38#if 0 39static char sccsid[] = "@(#)mktemp.c 8.1 (Berkeley) 6/4/93"; 40#else 41__RCSID("$NetBSD: gettemp.c,v 1.22 2024/01/20 14:52:49 christos Exp $"); 42#endif 43#endif /* LIBC_SCCS and not lint */ 44 45#include <sys/param.h> 46#include <sys/stat.h> 47#include <fcntl.h> 48#include <string.h> 49 50static const unsigned char padchar[] = 51"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; 52 53int 54GETTEMP(char *path, int *doopen, int domkdir, int slen, int oflags) 55{ 56 char *start, *trv, *suffp, *carryp; 57 const char *pad; 58 struct stat sbuf; 59 int rval; 60 uint32_t r; 61 char carrybuf[MAXPATHLEN]; 62 63 _DIAGASSERT(path != NULL); 64 /* doopen may be NULL */ 65 if ((doopen != NULL && domkdir) || slen < 0 || 66 (oflags & ~(O_APPEND | O_DIRECT | O_SHLOCK | O_EXLOCK | O_SYNC | 67 O_CLOEXEC)) != 0) { 68 errno = EINVAL; 69 return 0; 70 } 71 72 for (trv = path; *trv != '\0'; ++trv) 73 continue; 74 75 if (trv - path >= MAXPATHLEN) { 76 errno = ENAMETOOLONG; 77 return 0; 78 } 79 trv -= slen; 80 suffp = trv; 81 --trv; 82 if (trv < path || NULL != strchr(suffp, '/')) { 83 errno = EINVAL; 84 return 0; 85 } 86 87 /* Fill space with random characters */ 88 while (trv >= path && *trv == 'X') { 89 r = arc4random_uniform((unsigned int)(sizeof(padchar) - 1)); 90 *trv-- = padchar[r]; 91 } 92 start = trv + 1; 93 94 /* save first combination of random characters */ 95 memcpy(carrybuf, start, (size_t)(suffp - start)); 96 97 /* 98 * check the target directory. 99 */ 100 if (doopen != NULL || domkdir) { 101 for (; trv > path; --trv) { 102 if (*trv == '/') { 103 *trv = '\0'; 104 rval = stat(path, &sbuf); 105 *trv = '/'; 106 if (rval != 0) 107 return 0; 108 if (!S_ISDIR(sbuf.st_mode)) { 109 errno = ENOTDIR; 110 return 0; 111 } 112 break; 113 } 114 } 115 } 116 117 for (;;) { 118 if (doopen) { 119 if ((*doopen = open(path, O_CREAT|O_EXCL|O_RDWR|oflags, 120 0600)) != -1) 121 return 1; 122 if (errno != EEXIST) 123 return 0; 124 } else if (domkdir) { 125 if (mkdir(path, 0700) != -1) 126 return 1; 127 if (errno != EEXIST) 128 return 0; 129 } else if (lstat(path, &sbuf)) 130 return errno == ENOENT; 131 132 /* 133 * If we have a collision, 134 * cycle through the space of filenames 135 */ 136 for (trv = start, carryp = carrybuf;;) { 137 /* have we tried all possible permutations? */ 138 if (trv == suffp) 139 return 0; /* yes - exit with EEXIST */ 140 pad = strchr((const char *)padchar, *trv); 141 if (pad == NULL) { 142 /* this should never happen */ 143 errno = EIO; 144 return 0; 145 } 146 /* increment character */ 147 *trv = (*++pad == '\0') ? padchar[0] : *pad; 148 /* carry to next position? */ 149 if (*trv == *carryp) { 150 /* increment position and loop */ 151 ++trv; 152 ++carryp; 153 } else { 154 /* try with new name */ 155 break; 156 } 157 } 158 } 159 /*NOTREACHED*/ 160} 161 162#endif /* !HAVE_NBTOOL_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP */ 163