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gettemp.c revision 1.14.22.1 
      1 /*	$NetBSD: gettemp.c,v 1.14.22.1 2015/04/16 06:24:16 snj 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 1.14.22.1 2015/04/16 06:24:16 snj 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(path, doopen, domkdir)
     68 	char *path;
     69 	int *doopen;
     70 	int domkdir;
     71 {
     72 	char *start, *trv;
     73 	struct stat sbuf;
     74 	u_int pid;
     75 
     76 	/* To guarantee multiple calls generate unique names even if
     77 	   the file is not created. 676 different possibilities with 7
     78 	   or more X's, 26 with 6 or less. */
     79 	static char xtra[2] = "aa";
     80 	int xcnt = 0;
     81 
     82 	_DIAGASSERT(path != NULL);
     83 	/* doopen may be NULL */
     84 
     85 	pid = getpid();
     86 
     87 	/* Move to end of path and count trailing X's. */
     88 	for (trv = path; *trv; ++trv)
     89 		if (*trv == 'X')
     90 			xcnt++;
     91 		else
     92 			xcnt = 0;
     93 
     94 	/* Use at least one from xtra.  Use 2 if more than 6 X's. */
     95 	if (*(trv - 1) == 'X')
     96 		*--trv = xtra[0];
     97 	if (xcnt > 6 && *(trv - 1) == 'X')
     98 		*--trv = xtra[1];
     99 
    100 	/* Set remaining X's to pid digits with 0's to the left. */
    101 	while (*--trv == 'X') {
    102 		*trv = (pid % 10) + '0';
    103 		pid /= 10;
    104 	}
    105 
    106 	/* update xtra for next call. */
    107 	if (xtra[0] != 'z')
    108 		xtra[0]++;
    109 	else {
    110 		xtra[0] = 'a';
    111 		if (xtra[1] != 'z')
    112 			xtra[1]++;
    113 		else
    114 			xtra[1] = 'a';
    115 	}
    116 
    117 	/*
    118 	 * check the target directory; if you have six X's and it
    119 	 * doesn't exist this runs for a *very* long time.
    120 	 */
    121 	for (start = trv + 1;; --trv) {
    122 		if (trv <= path)
    123 			break;
    124 		if (*trv == '/') {
    125 			int e;
    126 			*trv = '\0';
    127 			e = stat(path, &sbuf);
    128 			*trv = '/';
    129 			if (e == -1)
    130 				return doopen == NULL && !domkdir;
    131 			if (!S_ISDIR(sbuf.st_mode)) {
    132 				errno = ENOTDIR;
    133 				return doopen == NULL && !domkdir;
    134 			}
    135 			break;
    136 		}
    137 	}
    138 
    139 	for (;;) {
    140 		if (doopen) {
    141 			if ((*doopen =
    142 			    open(path, O_CREAT | O_EXCL | O_RDWR, 0600)) >= 0)
    143 				return (1);
    144 			if (errno != EEXIST)
    145 				return (0);
    146 		} else if (domkdir) {
    147 			if (mkdir(path, 0700) >= 0)
    148 				return (1);
    149 			if (errno != EEXIST)
    150 				return (0);
    151 		} else if (lstat(path, &sbuf))
    152 			return (errno == ENOENT ? 1 : 0);
    153 
    154 		/* tricky little algorithm for backward compatibility */
    155 		for (trv = start;;) {
    156 			if (!*trv)
    157 				return (0);
    158 			if (*trv == 'z')
    159 				*trv++ = 'a';
    160 			else {
    161 				if (isdigit((unsigned char)*trv))
    162 					*trv = 'a';
    163 				else
    164 					++*trv;
    165 				break;
    166 			}
    167 		}
    168 	}
    169 	/*NOTREACHED*/
    170 }
    171 
    172 #endif /* !HAVE_NBTOOL_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP */
    173