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 * @(#)mktemp.c 8.1 (Berkeley) 6/4/93
30 * $FreeBSD: src/lib/libc/stdio/mktemp.c,v 1.31 2008/07/28 21:18:59 jhb Exp $
31 * $DragonFly: src/lib/libc/stdio/mktemp.c,v 1.7 2005/11/20 11:07:30 swildner Exp $
32 */
33
34 #include "namespace.h"
35 #include <sys/param.h>
36 #include <sys/stat.h>
37 #include <fcntl.h>
38 #include <errno.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <ctype.h>
43 #include <unistd.h>
44 #include "un-namespace.h"
45
46 char *_mktemp(char *);
47
48 static int _gettemp(char *, int *, int, int, int);
49
50 static const unsigned char padchar[] =
51 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
52
53 int
mkstemps(char * path,int slen)54 mkstemps(char *path, int slen)
55 {
56 int fd;
57
58 return (_gettemp(path, &fd, 0, slen, 0) ? fd : -1);
59 }
60
61 int
mkostemps(char * path,int slen,int oflags)62 mkostemps(char *path, int slen, int oflags)
63 {
64 int fd;
65
66 return (_gettemp(path, &fd, 0, slen, oflags) ? fd : -1);
67 }
68
69 int
mkstemp(char * path)70 mkstemp(char *path)
71 {
72 int fd;
73
74 return (_gettemp(path, &fd, 0, 0, 0) ? fd : -1);
75 }
76
77 int
mkostemp(char * path,int oflags)78 mkostemp(char *path, int oflags)
79 {
80 int fd;
81
82 return (_gettemp(path, &fd, 0, 0, oflags) ? fd : -1);
83 }
84
85 char *
mkdtemp(char * path)86 mkdtemp(char *path)
87 {
88 return (_gettemp(path, NULL, 1, 0, 0) ? path : NULL);
89 }
90
91 char *
_mktemp(char * path)92 _mktemp(char *path)
93 {
94 return (_gettemp(path, NULL, 0, 0, 0) ? path : NULL);
95 }
96
97 __warn_references(mktemp,
98 "warning: mktemp() possibly used unsafely; consider using mkstemp()");
99
100 char *
mktemp(char * path)101 mktemp(char *path)
102 {
103 return (_mktemp(path));
104 }
105
106 static int
_gettemp(char * path,int * doopen,int domkdir,int slen,int oflags)107 _gettemp(char *path, int *doopen, int domkdir, int slen, int oflags)
108 {
109 char *start, *trv, *suffp, *carryp;
110 char *pad;
111 struct stat sbuf;
112 int rval;
113 uint32_t rand;
114 char carrybuf[MAXPATHLEN];
115
116 if ((oflags & ~(O_APPEND | O_DIRECT | O_SHLOCK |
117 O_EXLOCK | O_SYNC | O_CLOEXEC)) != 0) {
118 errno = EINVAL;
119 return (0);
120 }
121 if ((doopen != NULL && domkdir) || slen < 0) {
122 errno = EINVAL;
123 return (0);
124 }
125
126 for (trv = path; *trv != '\0'; ++trv)
127 ;
128 trv -= slen;
129 suffp = trv;
130 --trv;
131 if (trv < path || NULL != strchr(suffp, '/')) {
132 errno = EINVAL;
133 return (0);
134 }
135
136 /* Fill space with random characters */
137 while (trv >= path && *trv == 'X') {
138 rand = arc4random_uniform(sizeof(padchar) - 1);
139 *trv-- = padchar[rand];
140 }
141 start = trv + 1;
142
143 /* save first combination of random characters */
144 memcpy(carrybuf, start, suffp - start);
145
146 /*
147 * check the target directory.
148 */
149 if (doopen != NULL || domkdir) {
150 for (; trv > path; --trv) {
151 if (*trv == '/') {
152 *trv = '\0';
153 rval = stat(path, &sbuf);
154 *trv = '/';
155 if (rval != 0)
156 return (0);
157 if (!S_ISDIR(sbuf.st_mode)) {
158 errno = ENOTDIR;
159 return (0);
160 }
161 break;
162 }
163 }
164 }
165
166 for (;;) {
167 if (doopen) {
168 if ((*doopen = _open(path, O_CREAT|O_EXCL|O_RDWR|oflags,
169 0600)) >= 0) {
170 return (1);
171 }
172 if (errno != EEXIST)
173 return (0);
174 } else if (domkdir) {
175 if (mkdir(path, 0700) == 0)
176 return (1);
177 if (errno != EEXIST)
178 return (0);
179 } else if (lstat(path, &sbuf))
180 return (errno == ENOENT);
181
182 /* If we have a collision, cycle through the space of filenames */
183 for (trv = start, carryp = carrybuf;;) {
184 /* have we tried all possible permutations? */
185 if (trv == suffp)
186 return (0); /* yes - exit with EEXIST */
187 pad = strchr(padchar, *trv);
188 if (pad == NULL) {
189 /* this should never happen */
190 errno = EIO;
191 return (0);
192 }
193 /* increment character */
194 *trv = (*++pad == '\0') ? padchar[0] : *pad;
195 /* carry to next position? */
196 if (*trv == *carryp) {
197 /* increment position and loop */
198 ++trv;
199 ++carryp;
200 } else {
201 /* try with new name */
202 break;
203 }
204 }
205 }
206 /*NOTREACHED*/
207 }
208