mktemp.c revision 92889 
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  "$FreeBSD: head/lib/libc/stdio/mktemp.c 92889 2002-03-21 18:49:23Z obrien $";
40#endif /* LIBC_SCCS and not lint */
41
42/* #include "namespace.h" */
43#include <sys/types.h>
44#include <sys/stat.h>
45#include <fcntl.h>
46#include <errno.h>
47#include <stdio.h>
48#include <stdlib.h>
49#include <string.h>
50#include <ctype.h>
51#include <unistd.h>
52/* #include "un-namespace.h" */
53
54char *_mktemp __P((char *));
55
56static int _gettemp __P((char *, int *, int, int));
57
58static const unsigned char padchar[] =
59"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
60
61int
62mkstemps(path, slen)
63	char *path;
64	int slen;
65{
66	int fd;
67
68	return (_gettemp(path, &fd, 0, slen) ? fd : -1);
69}
70
71int
72mkstemp(path)
73	char *path;
74{
75	int fd;
76
77	return (_gettemp(path, &fd, 0, 0) ? fd : -1);
78}
79
80char *
81mkdtemp(path)
82	char *path;
83{
84	return(_gettemp(path, (int *)NULL, 1, 0) ? path : (char *)NULL);
85}
86
87char *
88_mktemp(path)
89	char *path;
90{
91	return(_gettemp(path, (int *)NULL, 0, 0) ? path : (char *)NULL);
92}
93
94__warn_references(mktemp,
95    "warning: mktemp() possibly used unsafely; consider using mkstemp()");
96
97char *
98mktemp(path)
99	char *path;
100{
101	return(_mktemp(path));
102}
103
104static int
105_gettemp(path, doopen, domkdir, slen)
106	char *path;
107	int *doopen;
108	int domkdir;
109	int slen;
110{
111	char *start, *trv, *suffp;
112	char *pad;
113	struct stat sbuf;
114	int rval;
115	uint32_t rand;
116
117	if (doopen && domkdir) {
118		errno = EINVAL;
119		return(0);
120	}
121
122	for (trv = path; *trv; ++trv)
123		;
124	trv -= slen;
125	suffp = trv;
126	--trv;
127	if (trv < path) {
128		errno = EINVAL;
129		return (0);
130	}
131
132	/* Fill space with random characters */
133	while (*trv == 'X') {
134		rand = arc4random() % (sizeof(padchar) - 1);
135		*trv-- = padchar[rand];
136	}
137	start = trv + 1;
138
139	/*
140	 * check the target directory.
141	 */
142	if (doopen || domkdir) {
143		for (;; --trv) {
144			if (trv <= path)
145				break;
146			if (*trv == '/') {
147				*trv = '\0';
148				rval = stat(path, &sbuf);
149				*trv = '/';
150				if (rval != 0)
151					return(0);
152				if (!S_ISDIR(sbuf.st_mode)) {
153					errno = ENOTDIR;
154					return(0);
155				}
156				break;
157			}
158		}
159	}
160
161	for (;;) {
162		if (doopen) {
163			if ((*doopen =
164			    _open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
165				return(1);
166			if (errno != EEXIST)
167				return(0);
168		} else if (domkdir) {
169			if (mkdir(path, 0700) == 0)
170				return(1);
171			if (errno != EEXIST)
172				return(0);
173		} else if (lstat(path, &sbuf))
174			return(errno == ENOENT ? 1 : 0);
175
176		/* If we have a collision, cycle through the space of filenames */
177		for (trv = start;;) {
178			if (*trv == '\0' || trv == suffp)
179				return(0);
180			pad = strchr(padchar, *trv);
181			if (pad == NULL || !*++pad)
182				*trv++ = padchar[0];
183			else {
184				*trv++ = *pad;
185				break;
186			}
187		}
188	}
189	/*NOTREACHED*/
190}
191