1 /* $NetBSD: gettemp.c,v 1.7 2002/04/01 13:59:34 bjh21 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: gettemp.c,v 1.7 2002/04/01 13:59:34 bjh21 Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include <sys/types.h> 46 #include <sys/stat.h> 47 48 #include <assert.h> 49 #include <ctype.h> 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <unistd.h> 55 56 #include "local.h" 57 58 int 59 __gettemp(path, doopen, domkdir) 60 char *path; 61 int *doopen; 62 int domkdir; 63 { 64 char *start, *trv; 65 struct stat sbuf; 66 u_int pid; 67 68 /* To guarantee multiple calls generate unique names even if 69 the file is not created. 676 different possibilities with 7 70 or more X's, 26 with 6 or less. */ 71 static char xtra[2] = "aa"; 72 int xcnt = 0; 73 74 _DIAGASSERT(path != NULL); 75 /* doopen may be NULL */ 76 77 pid = getpid(); 78 79 /* Move to end of path and count trailing X's. */ 80 for (trv = path; *trv; ++trv) 81 if (*trv == 'X') 82 xcnt++; 83 else 84 xcnt = 0; 85 86 /* Use at least one from xtra. Use 2 if more than 6 X's. */ 87 if (*(trv-1) == 'X') 88 *--trv = xtra[0]; 89 if (xcnt > 6 && *(trv-1) == 'X') 90 *--trv = xtra[1]; 91 92 /* Set remaining X's to pid digits with 0's to the left. */ 93 while (*--trv == 'X') { 94 *trv = (pid % 10) + '0'; 95 pid /= 10; 96 } 97 98 /* update xtra for next call. */ 99 if (xtra[0] != 'z') 100 xtra[0]++; 101 else { 102 xtra[0] = 'a'; 103 if (xtra[1] != 'z') 104 xtra[1]++; 105 else 106 xtra[1] = 'a'; 107 } 108 109 /* 110 * check the target directory; if you have six X's and it 111 * doesn't exist this runs for a *very* long time. 112 */ 113 for (start = trv + 1;; --trv) { 114 if (trv <= path) 115 break; 116 if (*trv == '/') { 117 *trv = '\0'; 118 if (stat(path, &sbuf)) 119 return (0); 120 if (!S_ISDIR(sbuf.st_mode)) { 121 errno = ENOTDIR; 122 return (0); 123 } 124 *trv = '/'; 125 break; 126 } 127 } 128 129 for (;;) { 130 if (doopen) { 131 if ((*doopen = 132 open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0) 133 return (1); 134 if (errno != EEXIST) 135 return (0); 136 } else if (domkdir) { 137 if (mkdir(path, 0700) >= 0) 138 return (1); 139 if (errno != EEXIST) 140 return (0); 141 } else if (lstat(path, &sbuf)) 142 return (errno == ENOENT ? 1 : 0); 143 144 /* tricky little algorithm for backward compatibility */ 145 for (trv = start;;) { 146 if (!*trv) 147 return (0); 148 if (*trv == 'z') 149 *trv++ = 'a'; 150 else { 151 if (isdigit((unsigned char)*trv)) 152 *trv = 'a'; 153 else 154 ++*trv; 155 break; 156 } 157 } 158 } 159 /*NOTREACHED*/ 160 } 161