1 /* $NetBSD: mktemp.c,v 1.10 1997/11/04 23:52:58 thorpej 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char sccsid[] = "@(#)mktemp.c 8.1 (Berkeley) 6/4/93"; 40 #else 41 __RCSID("$NetBSD: mktemp.c,v 1.10 1997/11/04 23:52:58 thorpej Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include <sys/types.h> 46 #include <sys/stat.h> 47 #include <fcntl.h> 48 #include <errno.h> 49 #include <stdio.h> 50 #include <ctype.h> 51 #include <unistd.h> 52 #include <errno.h> 53 #include "local.h" 54 55 static int _gettemp __P((char *, int *)); 56 57 int 58 mkstemp(path) 59 char *path; 60 { 61 int fd; 62 63 return (_gettemp(path, &fd) ? fd : -1); 64 } 65 66 char * 67 _mktemp(path) 68 char *path; 69 { 70 return (_gettemp(path, (int *)NULL) ? path : (char *)NULL); 71 } 72 73 __warn_references(mktemp, 74 "warning: mktemp() possibly used unsafely, consider using mkstemp()") 75 76 char * 77 mktemp(path) 78 char *path; 79 { 80 return (_gettemp(path, (int *)NULL) ? path : (char *)NULL); 81 } 82 83 static int 84 _gettemp(path, doopen) 85 char *path; 86 register int *doopen; 87 { 88 register char *start, *trv; 89 struct stat sbuf; 90 u_int pid; 91 92 /* To guarantee multiple calls generate unique names even if 93 the file is not created. 676 different possibilities with 7 94 or more X's, 26 with 6 or less. */ 95 static char xtra[2] = "aa"; 96 int xcnt = 0; 97 98 pid = getpid(); 99 100 /* Move to end of path and count trailing X's. */ 101 for (trv = path; *trv; ++trv) 102 if (*trv == 'X') 103 xcnt++; 104 else 105 xcnt = 0; 106 107 /* Use at least one from xtra. Use 2 if more than 6 X's. */ 108 if (*(trv-1) == 'X') 109 *--trv = xtra[0]; 110 if (xcnt > 6 && *(trv-1) == 'X') 111 *--trv = xtra[1]; 112 113 /* Set remaining X's to pid digits with 0's to the left. */ 114 while (*--trv == 'X') { 115 *trv = (pid % 10) + '0'; 116 pid /= 10; 117 } 118 119 /* update xtra for next call. */ 120 if (xtra[0] != 'z') 121 xtra[0]++; 122 else { 123 xtra[0] = 'a'; 124 if (xtra[1] != 'z') 125 xtra[1]++; 126 else 127 xtra[1] = 'a'; 128 } 129 130 /* 131 * check the target directory; if you have six X's and it 132 * doesn't exist this runs for a *very* long time. 133 */ 134 for (start = trv + 1;; --trv) { 135 if (trv <= path) 136 break; 137 if (*trv == '/') { 138 *trv = '\0'; 139 if (stat(path, &sbuf)) 140 return (0); 141 if (!S_ISDIR(sbuf.st_mode)) { 142 errno = ENOTDIR; 143 return (0); 144 } 145 *trv = '/'; 146 break; 147 } 148 } 149 150 for (;;) { 151 if (doopen) { 152 if ((*doopen = 153 open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0) 154 return (1); 155 if (errno != EEXIST) 156 return (0); 157 } 158 else if (lstat(path, &sbuf)) 159 return (errno == ENOENT ? 1 : 0); 160 161 /* tricky little algorithm for backward compatibility */ 162 for (trv = start;;) { 163 if (!*trv) 164 return (0); 165 if (*trv == 'z') 166 *trv++ = 'a'; 167 else { 168 if (isdigit(*trv)) 169 *trv = 'a'; 170 else 171 ++*trv; 172 break; 173 } 174 } 175 } 176 /*NOTREACHED*/ 177 } 178