mktemp.c revision 40539 
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)
35#if 0
36static char sccsid[] = "@(#)mktemp.c	8.1 (Berkeley) 6/4/93";
37#endif
38static const char rcsid[] =
39		"$Id: mktemp.c,v 1.10 1998/04/14 07:25:05 peter Exp $";
40#endif /* LIBC_SCCS and not lint */
41
42#include <sys/types.h>
43#include <sys/stat.h>
44#include <fcntl.h>
45#include <errno.h>
46#include <stdio.h>
47#include <stdlib.h>
48#include <ctype.h>
49#include <unistd.h>
50
51char *_mktemp __P((char *));
52
53static int _gettemp __P((char *, int *, int));
54
55int
56mkstemp(path)
57	char *path;
58{
59	int fd, rval;
60	mode_t oldumask;
61
62	oldumask = umask(077);
63	rval = (_gettemp(path, &fd, 0) ? fd : -1);
64	umask(oldumask);
65	return rval;
66}
67
68char *
69mkdtemp(path)
70	char *path;
71{
72	char *rval;
73	mode_t oldumask;
74
75	oldumask = umask(077);
76	rval = (_gettemp(path, (int *)NULL, 1) ? path : (char *)NULL);
77	umask(oldumask);
78	return rval;
79}
80
81char *
82_mktemp(path)
83	char *path;
84{
85	char *rval;
86	mode_t oldumask;
87
88	oldumask = umask(077);
89	rval = (_gettemp(path, (int *)NULL, 0) ? path : (char *)NULL);
90	umask(oldumask);
91	return rval;
92}
93
94#ifdef UNSAFE_WARN
95__warn_references(mktemp,
96    "warning: mktemp() possibly used unsafely; consider using mkstemp()");
97#endif
98
99char *
100mktemp(path)
101	char *path;
102{
103	return(_mktemp(path));
104}
105
106static int
107_gettemp(path, doopen, domkdir)
108	char *path;
109	register int *doopen;
110	int domkdir;
111{
112	register char *start, *trv;
113	struct stat sbuf;
114	int pid, rval;
115
116	if (doopen && domkdir) {
117		errno = EINVAL;
118		return(0);
119	}
120
121	pid = getpid();
122	for (trv = path; *trv; ++trv)
123		;
124	--trv;
125	while (*trv == 'X' && pid != 0) {
126		*trv-- = (pid % 10) + '0';
127		pid /= 10;
128	}
129	while (*trv == 'X') {
130		char c;
131
132		pid = (arc4random() & 0xffff) % (26+26);
133		if (pid < 26)
134			c = pid + 'A';
135		else
136			c = (pid - 26) + 'a';
137		*trv-- = c;
138	}
139	start = trv + 1;
140
141	/*
142	 * check the target directory; if you have six X's and it
143	 * doesn't exist this runs for a *very* long time.
144	 */
145	if (doopen || domkdir) {
146		for (;; --trv) {
147			if (trv <= path)
148				break;
149			if (*trv == '/') {
150				*trv = '\0';
151				rval = stat(path, &sbuf);
152				*trv = '/';
153				if (rval != 0)
154					return(0);
155				if (!S_ISDIR(sbuf.st_mode)) {
156					errno = ENOTDIR;
157					return(0);
158				}
159				break;
160			}
161		}
162	}
163
164	for (;;) {
165		if (doopen) {
166			if ((*doopen =
167			    open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
168				return(1);
169			if (errno != EEXIST)
170				return(0);
171		} else if (domkdir) {
172			if (mkdir(path, 0700) == 0)
173				return(1);
174			if (errno != EEXIST)
175				return(0);
176		} else if (lstat(path, &sbuf))
177			return(errno == ENOENT ? 1 : 0);
178
179		/* tricky little algorithm for backward compatibility */
180		for (trv = start;;) {
181			if (!*trv)
182				return(0);
183			if (*trv == 'Z')
184				*trv++ = 'a';
185			else {
186				if (isdigit(*trv))
187					*trv = 'a';
188				else if (*trv == 'z')	/* inc from z to A */
189					*trv = 'A';
190				else
191					++*trv;
192				break;
193			}
194		}
195	}
196	/*NOTREACHED*/
197}
198