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 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static char sccsid[] = "@(#)mktemp.c	8.1 (Berkeley) 6/4/93";
32#endif /* LIBC_SCCS and not lint */
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: src/lib/libc/stdio/mktemp.c,v 1.32 2010/02/28 13:31:29 jh Exp $");
35
36#include "namespace.h"
37#include <sys/param.h>
38#include <sys/stat.h>
39#include <fcntl.h>
40#include <errno.h>
41#include <stdio.h>
42#include <stdlib.h>
43#include <string.h>
44#include <ctype.h>
45#include <unistd.h>
46#include "un-namespace.h"
47
48char *_mktemp(char *);
49
50static int _gettemp(char *, int *, int, int);
51
52static const char padchar[] =
53"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
54
55int
56mkstemps(path, slen)
57	char *path;
58	int slen;
59{
60	int fd;
61
62	return (_gettemp(path, &fd, 0, slen) ? fd : -1);
63}
64
65int
66mkstemp(path)
67	char *path;
68{
69	int fd;
70
71	return (_gettemp(path, &fd, 0, 0) ? fd : -1);
72}
73
74char *
75mkdtemp(path)
76	char *path;
77{
78	return (_gettemp(path, (int *)NULL, 1, 0) ? path : (char *)NULL);
79}
80
81char *
82_mktemp(path)
83	char *path;
84{
85	return (_gettemp(path, (int *)NULL, 0, 0) ? path : (char *)NULL);
86}
87
88__warn_references(mktemp,
89    "warning: mktemp() possibly used unsafely; consider using mkstemp()");
90
91char *
92mktemp(path)
93	char *path;
94{
95	return (_mktemp(path));
96}
97
98static int
99_gettemp(path, doopen, domkdir, slen)
100	char *path;
101	int *doopen;
102	int domkdir;
103	int slen;
104{
105	char *start, *trv, *suffp, *carryp;
106	char *pad;
107	struct stat sbuf;
108	int rval;
109	uint32_t rand;
110	char carrybuf[MAXPATHLEN];
111
112	if ((doopen != NULL && domkdir) || slen < 0) {
113		errno = EINVAL;
114		return (0);
115	}
116
117	for (trv = path; *trv != '\0'; ++trv)
118		;
119	if (trv - path >= MAXPATHLEN) {
120		errno = ENAMETOOLONG;
121		return (0);
122	}
123	trv -= slen;
124	suffp = trv;
125	--trv;
126	if (trv < path || NULL != strchr(suffp, '/')) {
127		errno = EINVAL;
128		return (0);
129	}
130
131	/* Fill space with random characters */
132	while (trv >= path && *trv == 'X') {
133		rand = arc4random_uniform(sizeof(padchar) - 1);
134		*trv-- = padchar[rand];
135	}
136	start = trv + 1;
137
138	/* save first combination of random characters */
139	memcpy(carrybuf, start, suffp - start);
140
141	/*
142	 * check the target directory.
143	 */
144	if (doopen != NULL || domkdir) {
145		for (; trv > path; --trv) {
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);
175
176		/* If we have a collision, cycle through the space of filenames */
177		for (trv = start, carryp = carrybuf;;) {
178			/* have we tried all possible permutations? */
179			if (trv == suffp)
180				return (0); /* yes - exit with EEXIST */
181			pad = strchr(padchar, *trv);
182			if (pad == NULL) {
183				/* this should never happen */
184				errno = EIO;
185				return (0);
186			}
187			/* increment character */
188			*trv = (*++pad == '\0') ? padchar[0] : *pad;
189			/* carry to next position? */
190			if (*trv == *carryp) {
191				/* increment position and loop */
192				++trv;
193				++carryp;
194			} else {
195				/* try with new name */
196				break;
197			}
198		}
199	}
200	/*NOTREACHED*/
201}
202