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)
31 static 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
48 char *_mktemp(char *);
49
50 static int _gettemp(char *, int *, int, int);
51
52 static const unsigned char padchar[] =
53 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
54
55 int
mkstemps(char * path,int slen)56 mkstemps(char *path, int slen)
57 {
58 int fd;
59
60 return (_gettemp(path, &fd, 0, slen) ? fd : -1);
61 }
62
63 int
mkstemp(char * path)64 mkstemp(char *path)
65 {
66 int fd;
67
68 return (_gettemp(path, &fd, 0, 0) ? fd : -1);
69 }
70
71 char *
mkdtemp(char * path)72 mkdtemp(char *path)
73 {
74 return (_gettemp(path, (int *)NULL, 1, 0) ? path : (char *)NULL);
75 }
76
77 char *
_mktemp(char * path)78 _mktemp(char *path)
79 {
80 return (_gettemp(path, (int *)NULL, 0, 0) ? path : (char *)NULL);
81 }
82
83 __warn_references(mktemp,
84 "warning: mktemp() possibly used unsafely; consider using mkstemp()");
85
86 char *
mktemp(char * path)87 mktemp(char *path)
88 {
89 return (_mktemp(path));
90 }
91
92 static int
_gettemp(char * path,int * doopen,int domkdir,int slen)93 _gettemp(char *path, int *doopen, int domkdir, int slen)
94 {
95 char *start, *trv, *suffp, *carryp;
96 char *pad;
97 struct stat sbuf;
98 int rval;
99 uint32_t rand;
100 char carrybuf[MAXPATHLEN];
101
102 if ((doopen != NULL && domkdir) || slen < 0) {
103 errno = EINVAL;
104 return (0);
105 }
106
107 for (trv = path; *trv != '\0'; ++trv)
108 ;
109 if (trv - path >= MAXPATHLEN) {
110 errno = ENAMETOOLONG;
111 return (0);
112 }
113 trv -= slen;
114 suffp = trv;
115 --trv;
116 if (trv < path || NULL != strchr(suffp, '/')) {
117 errno = EINVAL;
118 return (0);
119 }
120
121 /* Fill space with random characters */
122 while (trv >= path && *trv == 'X') {
123 rand = arc4random_uniform(sizeof(padchar) - 1);
124 *trv-- = padchar[rand];
125 }
126 start = trv + 1;
127
128 /* save first combination of random characters */
129 memcpy(carrybuf, start, suffp - start);
130
131 /*
132 * check the target directory.
133 */
134 if (doopen != NULL || domkdir) {
135 for (; trv > path; --trv) {
136 if (*trv == '/') {
137 *trv = '\0';
138 rval = stat(path, &sbuf);
139 *trv = '/';
140 if (rval != 0)
141 return (0);
142 if (!S_ISDIR(sbuf.st_mode)) {
143 errno = ENOTDIR;
144 return (0);
145 }
146 break;
147 }
148 }
149 }
150
151 for (;;) {
152 if (doopen) {
153 if ((*doopen =
154 _open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
155 return (1);
156 if (errno != EEXIST)
157 return (0);
158 } else if (domkdir) {
159 if (mkdir(path, 0700) == 0)
160 return (1);
161 if (errno != EEXIST)
162 return (0);
163 } else if (lstat(path, &sbuf))
164 return (errno == ENOENT);
165
166 /* If we have a collision, cycle through the space of filenames */
167 for (trv = start, carryp = carrybuf;;) {
168 /* have we tried all possible permutations? */
169 if (trv == suffp)
170 return (0); /* yes - exit with EEXIST */
171 pad = strchr(padchar, *trv);
172 if (pad == NULL) {
173 /* this should never happen */
174 errno = EIO;
175 return (0);
176 }
177 /* increment character */
178 *trv = (*++pad == '\0') ? padchar[0] : *pad;
179 /* carry to next position? */
180 if (*trv == *carryp) {
181 /* increment position and loop */
182 ++trv;
183 ++carryp;
184 } else {
185 /* try with new name */
186 break;
187 }
188 }
189 }
190 /*NOTREACHED*/
191 }
192