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mktemp.c revision 1.5.2.1 
      1 /*	$NetBSD: mktemp.c,v 1.5.2.1 1995/03/02 20:24:01 jtc 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 1.5.2.1 1995/03/02 20:24:01 jtc Exp $";
     41 #endif /* LIBC_SCCS and not lint */
     42 
     43 #include "namespace.h"
     44 #include <sys/types.h>
     45 #include <sys/stat.h>
     46 #include <fcntl.h>
     47 #include <errno.h>
     48 #include <stdio.h>
     49 #include <ctype.h>
     50 #include <unistd.h>
     51 
     52 static int _gettemp();
     53 
     54 int
     55 mkstemp(path)
     56 	char *path;
     57 {
     58 	int fd;
     59 
     60 	return (_gettemp(path, &fd) ? fd : -1);
     61 }
     62 
     63 char *
     64 mktemp(path)
     65 	char *path;
     66 {
     67 	return(_gettemp(path, (int *)NULL) ? path : (char *)NULL);
     68 }
     69 
     70 static int
     71 _gettemp(path, doopen)
     72 	char *path;
     73 	register int *doopen;
     74 {
     75 	extern int errno;
     76 	register char *start, *trv;
     77 	struct stat sbuf;
     78 	u_int pid;
     79 
     80 	pid = getpid();
     81 	for (trv = path; *trv; ++trv);		/* extra X's get set to 0's */
     82 	while (*--trv == 'X') {
     83 		*trv = (pid % 10) + '0';
     84 		pid /= 10;
     85 	}
     86 
     87 	/*
     88 	 * check the target directory; if you have six X's and it
     89 	 * doesn't exist this runs for a *very* long time.
     90 	 */
     91 	for (start = trv + 1;; --trv) {
     92 		if (trv <= path)
     93 			break;
     94 		if (*trv == '/') {
     95 			*trv = '\0';
     96 			if (stat(path, &sbuf))
     97 				return(0);
     98 			if (!S_ISDIR(sbuf.st_mode)) {
     99 				errno = ENOTDIR;
    100 				return(0);
    101 			}
    102 			*trv = '/';
    103 			break;
    104 		}
    105 	}
    106 
    107 	for (;;) {
    108 		if (doopen) {
    109 			if ((*doopen =
    110 			    open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
    111 				return(1);
    112 			if (errno != EEXIST)
    113 				return(0);
    114 		}
    115 		else if (stat(path, &sbuf))
    116 			return(errno == ENOENT ? 1 : 0);
    117 
    118 		/* tricky little algorithm for backward compatibility */
    119 		for (trv = start;;) {
    120 			if (!*trv)
    121 				return(0);
    122 			if (*trv == 'z')
    123 				*trv++ = 'a';
    124 			else {
    125 				if (isdigit(*trv))
    126 					*trv = 'a';
    127 				else
    128 					++*trv;
    129 				break;
    130 			}
    131 		}
    132 	}
    133 	/*NOTREACHED*/
    134 }
    135