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mktemp.c revision 1.1.1.1 
      1 /*
      2  * Copyright (c) 1987 Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #if defined(LIBC_SCCS) && !defined(lint)
     35 static char sccsid[] = "@(#)mktemp.c	5.10 (Berkeley) 2/24/91";
     36 #endif /* LIBC_SCCS and not lint */
     37 
     38 #include <sys/types.h>
     39 #include <sys/stat.h>
     40 #include <fcntl.h>
     41 #include <errno.h>
     42 #include <stdio.h>
     43 
     44 static int _gettemp();
     45 
     46 mkstemp(path)
     47 	char *path;
     48 {
     49 	int fd;
     50 
     51 	return (_gettemp(path, &fd) ? fd : -1);
     52 }
     53 
     54 char *
     55 mktemp(path)
     56 	char *path;
     57 {
     58 	return(_gettemp(path, (int *)NULL) ? path : (char *)NULL);
     59 }
     60 
     61 static
     62 _gettemp(path, doopen)
     63 	char *path;
     64 	register int *doopen;
     65 {
     66 	extern int errno;
     67 	register char *start, *trv;
     68 	struct stat sbuf;
     69 	u_int pid;
     70 
     71 	pid = getpid();
     72 	for (trv = path; *trv; ++trv);		/* extra X's get set to 0's */
     73 	while (*--trv == 'X') {
     74 		*trv = (pid % 10) + '0';
     75 		pid /= 10;
     76 	}
     77 
     78 	/*
     79 	 * check the target directory; if you have six X's and it
     80 	 * doesn't exist this runs for a *very* long time.
     81 	 */
     82 	for (start = trv + 1;; --trv) {
     83 		if (trv <= path)
     84 			break;
     85 		if (*trv == '/') {
     86 			*trv = '\0';
     87 			if (stat(path, &sbuf))
     88 				return(0);
     89 			if (!S_ISDIR(sbuf.st_mode)) {
     90 				errno = ENOTDIR;
     91 				return(0);
     92 			}
     93 			*trv = '/';
     94 			break;
     95 		}
     96 	}
     97 
     98 	for (;;) {
     99 		if (doopen) {
    100 			if ((*doopen =
    101 			    open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
    102 				return(1);
    103 			if (errno != EEXIST)
    104 				return(0);
    105 		}
    106 		else if (stat(path, &sbuf))
    107 			return(errno == ENOENT ? 1 : 0);
    108 
    109 		/* tricky little algorithm for backward compatibility */
    110 		for (trv = start;;) {
    111 			if (!*trv)
    112 				return(0);
    113 			if (*trv == 'z')
    114 				*trv++ = 'a';
    115 			else {
    116 				if (isdigit(*trv))
    117 					*trv = 'a';
    118 				else
    119 					++*trv;
    120 				break;
    121 			}
    122 		}
    123 	}
    124 	/*NOTREACHED*/
    125 }
    126