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gettemp.c revision 1.14.20.2 
      1 /*	$NetBSD: gettemp.c,v 1.14.20.2 2014/05/22 11:36:54 yamt 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 #if HAVE_NBTOOL_CONFIG_H
     33 #include "nbtool_config.h"
     34 #endif
     35 
     36 #if !HAVE_NBTOOL_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP
     37 
     38 #include <sys/cdefs.h>
     39 #if defined(LIBC_SCCS) && !defined(lint)
     40 #if 0
     41 static char sccsid[] = "@(#)mktemp.c	8.1 (Berkeley) 6/4/93";
     42 #else
     43 __RCSID("$NetBSD: gettemp.c,v 1.14.20.2 2014/05/22 11:36:54 yamt Exp $");
     44 #endif
     45 #endif /* LIBC_SCCS and not lint */
     46 
     47 #include <sys/types.h>
     48 #include <sys/stat.h>
     49 
     50 #include <assert.h>
     51 #include <ctype.h>
     52 #include <errno.h>
     53 #include <fcntl.h>
     54 #include <stdio.h>
     55 #include <stdlib.h>
     56 #include <unistd.h>
     57 
     58 #if HAVE_NBTOOL_CONFIG_H
     59 #define	GETTEMP		__nbcompat_gettemp
     60 #else
     61 #include "reentrant.h"
     62 #include "local.h"
     63 #define	GETTEMP		__gettemp
     64 #endif
     65 
     66 int
     67 GETTEMP(char *path, int *doopen, int domkdir)
     68 {
     69 	char *start, *trv;
     70 	struct stat sbuf;
     71 	u_int pid;
     72 
     73 	/* To guarantee multiple calls generate unique names even if
     74 	   the file is not created. 676 different possibilities with 7
     75 	   or more X's, 26 with 6 or less. */
     76 	static char xtra[2] = "aa";
     77 	int xcnt = 0;
     78 
     79 	_DIAGASSERT(path != NULL);
     80 	/* doopen may be NULL */
     81 
     82 	pid = getpid();
     83 
     84 	/* Move to end of path and count trailing X's. */
     85 	for (trv = path; *trv; ++trv)
     86 		if (*trv == 'X')
     87 			xcnt++;
     88 		else
     89 			xcnt = 0;
     90 
     91 	/* Use at least one from xtra.  Use 2 if more than 6 X's. */
     92 	if (xcnt > 0) {
     93 		*--trv = xtra[0];
     94 		xcnt--;
     95 	}
     96 	if (xcnt > 5) {
     97 		*--trv = xtra[1];
     98 		xcnt--;
     99 	}
    100 
    101 	/* Set remaining X's to pid digits with 0's to the left. */
    102 	for (; xcnt > 0; xcnt--) {
    103 		*--trv = (pid % 10) + '0';
    104 		pid /= 10;
    105 	}
    106 
    107 	/* update xtra for next call. */
    108 	if (xtra[0] != 'z')
    109 		xtra[0]++;
    110 	else {
    111 		xtra[0] = 'a';
    112 		if (xtra[1] != 'z')
    113 			xtra[1]++;
    114 		else
    115 			xtra[1] = 'a';
    116 	}
    117 
    118 	/*
    119 	 * check the target directory; if you have six X's and it
    120 	 * doesn't exist this runs for a *very* long time.
    121 	 */
    122 	for (start = trv + 1;; --trv) {
    123 		if (trv <= path)
    124 			break;
    125 		if (*trv == '/') {
    126 			int e;
    127 			*trv = '\0';
    128 			e = stat(path, &sbuf);
    129 			*trv = '/';
    130 			if (e == -1)
    131 				return doopen == NULL && !domkdir;
    132 			if (!S_ISDIR(sbuf.st_mode)) {
    133 				errno = ENOTDIR;
    134 				return doopen == NULL && !domkdir;
    135 			}
    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_NBTOOL_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP */
    174