mktemp.c revision 1573 
1/*
2 * Copyright (c) 1987, 1993
3 *	The Regents of the University of California.  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)
35static char sccsid[] = "@(#)mktemp.c	8.1 (Berkeley) 6/4/93";
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#include <ctype.h>
44
45static int _gettemp();
46
47mkstemp(path)
48	char *path;
49{
50	int fd;
51
52	return (_gettemp(path, &fd) ? fd : -1);
53}
54
55char *
56mktemp(path)
57	char *path;
58{
59	return(_gettemp(path, (int *)NULL) ? path : (char *)NULL);
60}
61
62static
63_gettemp(path, doopen)
64	char *path;
65	register int *doopen;
66{
67	extern int errno;
68	register char *start, *trv;
69	struct stat sbuf;
70	u_int pid;
71
72	pid = getpid();
73	for (trv = path; *trv; ++trv);		/* extra X's get set to 0's */
74	while (*--trv == 'X') {
75		*trv = (pid % 10) + '0';
76		pid /= 10;
77	}
78
79	/*
80	 * check the target directory; if you have six X's and it
81	 * doesn't exist this runs for a *very* long time.
82	 */
83	for (start = trv + 1;; --trv) {
84		if (trv <= path)
85			break;
86		if (*trv == '/') {
87			*trv = '\0';
88			if (stat(path, &sbuf))
89				return(0);
90			if (!S_ISDIR(sbuf.st_mode)) {
91				errno = ENOTDIR;
92				return(0);
93			}
94			*trv = '/';
95			break;
96		}
97	}
98
99	for (;;) {
100		if (doopen) {
101			if ((*doopen =
102			    open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
103				return(1);
104			if (errno != EEXIST)
105				return(0);
106		}
107		else if (stat(path, &sbuf))
108			return(errno == ENOENT ? 1 : 0);
109
110		/* tricky little algorithm for backward compatibility */
111		for (trv = start;;) {
112			if (!*trv)
113				return(0);
114			if (*trv == 'z')
115				*trv++ = 'a';
116			else {
117				if (isdigit(*trv))
118					*trv = 'a';
119				else
120					++*trv;
121				break;
122			}
123		}
124	}
125	/*NOTREACHED*/
126}
127