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. 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("$FreeBSD$");
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, int);
51
52static const unsigned char padchar[] =
53"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
54
55int
56mkostemps(char *path, int slen, int oflags)
57{
58	int fd;
59
60	return (_gettemp(path, &fd, 0, slen, oflags) ? fd : -1);
61}
62
63int
64mkstemps(char *path, int slen)
65{
66	int fd;
67
68	return (_gettemp(path, &fd, 0, slen, 0) ? fd : -1);
69}
70
71int
72mkostemp(char *path, int oflags)
73{
74	int fd;
75
76	return (_gettemp(path, &fd, 0, 0, oflags) ? fd : -1);
77}
78
79int
80mkstemp(char *path)
81{
82	int fd;
83
84	return (_gettemp(path, &fd, 0, 0, 0) ? fd : -1);
85}
86
87char *
88mkdtemp(char *path)
89{
90	return (_gettemp(path, (int *)NULL, 1, 0, 0) ? path : (char *)NULL);
91}
92
93char *
94_mktemp(char *path)
95{
96	return (_gettemp(path, (int *)NULL, 0, 0, 0) ? path : (char *)NULL);
97}
98
99__warn_references(mktemp,
100    "warning: mktemp() possibly used unsafely; consider using mkstemp()");
101
102char *
103mktemp(char *path)
104{
105	return (_mktemp(path));
106}
107
108static int
109_gettemp(char *path, int *doopen, int domkdir, int slen, int oflags)
110{
111	char *start, *trv, *suffp, *carryp;
112	char *pad;
113	struct stat sbuf;
114	int rval;
115	uint32_t rand;
116	char carrybuf[MAXPATHLEN];
117
118	if ((doopen != NULL && domkdir) || slen < 0 ||
119	    (oflags & ~(O_APPEND | O_DIRECT | O_SHLOCK | O_EXLOCK | O_SYNC |
120	    O_CLOEXEC)) != 0) {
121		errno = EINVAL;
122		return (0);
123	}
124
125	for (trv = path; *trv != '\0'; ++trv)
126		;
127	if (trv - path >= MAXPATHLEN) {
128		errno = ENAMETOOLONG;
129		return (0);
130	}
131	trv -= slen;
132	suffp = trv;
133	--trv;
134	if (trv < path || NULL != strchr(suffp, '/')) {
135		errno = EINVAL;
136		return (0);
137	}
138
139	/* Fill space with random characters */
140	while (trv >= path && *trv == 'X') {
141		rand = arc4random_uniform(sizeof(padchar) - 1);
142		*trv-- = padchar[rand];
143	}
144	start = trv + 1;
145
146	/* save first combination of random characters */
147	memcpy(carrybuf, start, suffp - start);
148
149	/*
150	 * check the target directory.
151	 */
152	if (doopen != NULL || domkdir) {
153		for (; trv > path; --trv) {
154			if (*trv == '/') {
155				*trv = '\0';
156				rval = stat(path, &sbuf);
157				*trv = '/';
158				if (rval != 0)
159					return (0);
160				if (!S_ISDIR(sbuf.st_mode)) {
161					errno = ENOTDIR;
162					return (0);
163				}
164				break;
165			}
166		}
167	}
168
169	for (;;) {
170		if (doopen) {
171			if ((*doopen =
172			    _open(path, O_CREAT|O_EXCL|O_RDWR|oflags, 0600)) >=
173			    0)
174				return (1);
175			if (errno != EEXIST)
176				return (0);
177		} else if (domkdir) {
178			if (mkdir(path, 0700) == 0)
179				return (1);
180			if (errno != EEXIST)
181				return (0);
182		} else if (lstat(path, &sbuf))
183			return (errno == ENOENT);
184
185		/* If we have a collision, cycle through the space of filenames */
186		for (trv = start, carryp = carrybuf;;) {
187			/* have we tried all possible permutations? */
188			if (trv == suffp)
189				return (0); /* yes - exit with EEXIST */
190			pad = strchr(padchar, *trv);
191			if (pad == NULL) {
192				/* this should never happen */
193				errno = EIO;
194				return (0);
195			}
196			/* increment character */
197			*trv = (*++pad == '\0') ? padchar[0] : *pad;
198			/* carry to next position? */
199			if (*trv == *carryp) {
200				/* increment position and loop */
201				++trv;
202				++carryp;
203			} else {
204				/* try with new name */
205				break;
206			}
207		}
208	}
209	/*NOTREACHED*/
210}
211