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gettemp.c revision 1.8 
      1 /*	$NetBSD: gettemp.c,v 1.8 2002/09/14 04:27:21 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 #if HAVE_CONFIG_H
     37 #include "config.h"
     38 #endif
     39 
     40 #if !HAVE_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP
     41 
     42 #include <sys/cdefs.h>
     43 #if defined(LIBC_SCCS) && !defined(lint)
     44 #if 0
     45 static char sccsid[] = "@(#)mktemp.c	8.1 (Berkeley) 6/4/93";
     46 #else
     47 __RCSID("$NetBSD: gettemp.c,v 1.8 2002/09/14 04:27:21 thorpej Exp $");
     48 #endif
     49 #endif /* LIBC_SCCS and not lint */
     50 
     51 #include <sys/types.h>
     52 #include <sys/stat.h>
     53 
     54 #include <assert.h>
     55 #include <ctype.h>
     56 #include <errno.h>
     57 #include <fcntl.h>
     58 #include <stdio.h>
     59 #include <stdlib.h>
     60 #include <unistd.h>
     61 
     62 #if HAVE_CONFIG_H
     63 #define	GETTEMP		gettemp
     64 #else
     65 #include "local.h"
     66 #define	GETTEMP		__gettemp
     67 #endif
     68 
     69 int
     70 GETTEMP(path, doopen, domkdir)
     71 	char *path;
     72 	int *doopen;
     73 	int domkdir;
     74 {
     75 	char *start, *trv;
     76 	struct stat sbuf;
     77 	u_int pid;
     78 
     79 	/* To guarantee multiple calls generate unique names even if
     80 	   the file is not created. 676 different possibilities with 7
     81 	   or more X's, 26 with 6 or less. */
     82 	static char xtra[2] = "aa";
     83 	int xcnt = 0;
     84 
     85 	_DIAGASSERT(path != NULL);
     86 	/* doopen may be NULL */
     87 
     88 	pid = getpid();
     89 
     90 	/* Move to end of path and count trailing X's. */
     91 	for (trv = path; *trv; ++trv)
     92 		if (*trv == 'X')
     93 			xcnt++;
     94 		else
     95 			xcnt = 0;
     96 
     97 	/* Use at least one from xtra.  Use 2 if more than 6 X's. */
     98 	if (*(trv-1) == 'X')
     99 		*--trv = xtra[0];
    100 	if (xcnt > 6 && *(trv-1) == 'X')
    101 		*--trv = xtra[1];
    102 
    103 	/* Set remaining X's to pid digits with 0's to the left. */
    104 	while (*--trv == 'X') {
    105 		*trv = (pid % 10) + '0';
    106 		pid /= 10;
    107 	}
    108 
    109 	/* update xtra for next call. */
    110 	if (xtra[0] != 'z')
    111 		xtra[0]++;
    112 	else {
    113 		xtra[0] = 'a';
    114 		if (xtra[1] != 'z')
    115 			xtra[1]++;
    116 		else
    117 			xtra[1] = 'a';
    118 	}
    119 
    120 	/*
    121 	 * check the target directory; if you have six X's and it
    122 	 * doesn't exist this runs for a *very* long time.
    123 	 */
    124 	for (start = trv + 1;; --trv) {
    125 		if (trv <= path)
    126 			break;
    127 		if (*trv == '/') {
    128 			*trv = '\0';
    129 			if (stat(path, &sbuf))
    130 				return (0);
    131 			if (!S_ISDIR(sbuf.st_mode)) {
    132 				errno = ENOTDIR;
    133 				return (0);
    134 			}
    135 			*trv = '/';
    136 			break;
    137 		}
    138 	}
    139 
    140 	for (;;) {
    141 		if (doopen) {
    142 			if ((*doopen =
    143 			    open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
    144 				return (1);
    145 			if (errno != EEXIST)
    146 				return (0);
    147 		} else if (domkdir) {
    148 			if (mkdir(path, 0700) >= 0)
    149 				return (1);
    150 			if (errno != EEXIST)
    151 				return (0);
    152 		} else if (lstat(path, &sbuf))
    153 			return (errno == ENOENT ? 1 : 0);
    154 
    155 		/* tricky little algorithm for backward compatibility */
    156 		for (trv = start;;) {
    157 			if (!*trv)
    158 				return (0);
    159 			if (*trv == 'z')
    160 				*trv++ = 'a';
    161 			else {
    162 				if (isdigit((unsigned char)*trv))
    163 					*trv = 'a';
    164 				else
    165 					++*trv;
    166 				break;
    167 			}
    168 		}
    169 	}
    170 	/*NOTREACHED*/
    171 }
    172 
    173 #endif /* !HAVE_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP */
    174