mktemp.c revision 180696 
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: head/lib/libc/stdio/mktemp.c 180696 2008-07-22 15:08:50Z ache $");
35
36#include "namespace.h"
37#include <sys/types.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 unsigned 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;
106	char *pad;
107	struct stat sbuf;
108	int rval;
109	uint32_t rand;
110
111	if (doopen != NULL && domkdir) {
112		errno = EINVAL;
113		return (0);
114	}
115
116	for (trv = path; *trv != '\0'; ++trv)
117		;
118	trv -= slen;
119	suffp = trv;
120	--trv;
121	if (trv < path) {
122		errno = EINVAL;
123		return (0);
124	}
125
126	/* Fill space with random characters */
127	while (trv >= path && *trv == 'X') {
128		rand = arc4random_uniform(sizeof(padchar) - 1);
129		*trv-- = padchar[rand];
130	}
131	start = trv + 1;
132
133	/*
134	 * check the target directory.
135	 */
136	if (doopen != NULL || domkdir) {
137		for (; trv > path; --trv) {
138			if (*trv == '/') {
139				*trv = '\0';
140				rval = stat(path, &sbuf);
141				*trv = '/';
142				if (rval != 0)
143					return (0);
144				if (!S_ISDIR(sbuf.st_mode)) {
145					errno = ENOTDIR;
146					return (0);
147				}
148				break;
149			}
150		}
151	}
152
153	for (;;) {
154		if (doopen) {
155			if ((*doopen =
156			    _open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
157				return (1);
158			if (errno != EEXIST)
159				return (0);
160		} else if (domkdir) {
161			if (mkdir(path, 0700) == 0)
162				return (1);
163			if (errno != EEXIST)
164				return (0);
165		} else if (lstat(path, &sbuf))
166			return (errno == ENOENT);
167
168		/* If we have a collision, cycle through the space of filenames */
169		for (trv = start;;) {
170			if (*trv == '\0' || trv == suffp)
171				return (0);
172			pad = strchr(padchar, *trv);
173			if (pad == NULL || *++pad == '\0')
174				*trv++ = padchar[0];
175			else {
176				*trv++ = *pad;
177				break;
178			}
179		}
180	}
181	/*NOTREACHED*/
182}
183