1 /* $NetBSD: mktemp.c,v 1.8 1997/07/07 17:47:00 phil 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 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)mktemp.c 8.1 (Berkeley) 6/4/93"; 39 #endif 40 static char rcsid[] = "$NetBSD: mktemp.c,v 1.8 1997/07/07 17:47:00 phil Exp $"; 41 #endif /* LIBC_SCCS and not lint */ 42 43 #include <sys/types.h> 44 #include <sys/stat.h> 45 #include <fcntl.h> 46 #include <errno.h> 47 #include <stdio.h> 48 #include <ctype.h> 49 #include <unistd.h> 50 51 static int _gettemp(); 52 53 int 54 mkstemp(path) 55 char *path; 56 { 57 int fd; 58 59 return (_gettemp(path, &fd) ? fd : -1); 60 } 61 62 char * 63 _mktemp(path) 64 char *path; 65 { 66 return (_gettemp(path, (int *)NULL) ? path : (char *)NULL); 67 } 68 69 __warn_references(mktemp, 70 "warning: mktemp() possibly used unsafely, consider using mkstemp()"); 71 72 char * 73 mktemp(path) 74 char *path; 75 { 76 return (_gettemp(path, (int *)NULL) ? path : (char *)NULL); 77 } 78 79 static int 80 _gettemp(path, doopen) 81 char *path; 82 register int *doopen; 83 { 84 extern int errno; 85 register char *start, *trv; 86 struct stat sbuf; 87 u_int pid; 88 89 /* To guarantee multiple calls generate unique names even if 90 the file is not created. 676 different possibilities with 7 91 or more X's, 26 with 6 or less. */ 92 static char xtra[2] = "aa"; 93 int xcnt = 0; 94 95 pid = getpid(); 96 97 /* Move to end of path and count trailing X's. */ 98 for (trv = path; *trv; ++trv) 99 if (*trv == 'X') 100 xcnt++; 101 else 102 xcnt = 0; 103 104 /* Use at least one from xtra. Use 2 if more than 6 X's. */ 105 if (*(trv-1) == 'X') 106 *--trv = xtra[0]; 107 if (xcnt > 6 && *(trv-1) == 'X') 108 *--trv = xtra[1]; 109 110 /* Set remaining X's to pid digits with 0's to the left. */ 111 while (*--trv == 'X') { 112 *trv = (pid % 10) + '0'; 113 pid /= 10; 114 } 115 116 /* update xtra for next call. */ 117 if (xtra[0] != 'z') 118 xtra[0]++; 119 else { 120 xtra[0] = 'a'; 121 if (xtra[1] != 'z') 122 xtra[1]++; 123 else 124 xtra[1] = 'a'; 125 } 126 127 /* 128 * check the target directory; if you have six X's and it 129 * doesn't exist this runs for a *very* long time. 130 */ 131 for (start = trv + 1;; --trv) { 132 if (trv <= path) 133 break; 134 if (*trv == '/') { 135 *trv = '\0'; 136 if (stat(path, &sbuf)) 137 return (0); 138 if (!S_ISDIR(sbuf.st_mode)) { 139 errno = ENOTDIR; 140 return (0); 141 } 142 *trv = '/'; 143 break; 144 } 145 } 146 147 for (;;) { 148 if (doopen) { 149 if ((*doopen = 150 open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0) 151 return (1); 152 if (errno != EEXIST) 153 return (0); 154 } 155 else if (lstat(path, &sbuf)) 156 return (errno == ENOENT ? 1 : 0); 157 158 /* tricky little algorithm for backward compatibility */ 159 for (trv = start;;) { 160 if (!*trv) 161 return (0); 162 if (*trv == 'z') 163 *trv++ = 'a'; 164 else { 165 if (isdigit(*trv)) 166 *trv = 'a'; 167 else 168 ++*trv; 169 break; 170 } 171 } 172 } 173 /*NOTREACHED*/ 174 } 175