1 /* $NetBSD: gettemp.c,v 1.20 2015/02/05 16:05:20 christos Exp $ */
2
3 /*
4 * Copyright (c) 1987, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include "gettemp.h"
33
34 #if !HAVE_NBTOOL_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP
35
36 #include <sys/cdefs.h>
37 #if defined(LIBC_SCCS) && !defined(lint)
38 #if 0
39 static char sccsid[] = "@(#)mktemp.c 8.1 (Berkeley) 6/4/93";
40 #else
41 __RCSID("$NetBSD: gettemp.c,v 1.20 2015/02/05 16:05:20 christos Exp $");
42 #endif
43 #endif /* LIBC_SCCS and not lint */
44
45 #include <sys/param.h>
46 #include <fcntl.h>
47 #include <string.h>
48
49 static const unsigned char padchar[] =
50 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
51
52 int
GETTEMP(char * path,int * doopen,int domkdir,int slen,int oflags)53 GETTEMP(char *path, int *doopen, int domkdir, int slen, int oflags)
54 {
55 char *start, *trv, *suffp, *carryp;
56 char *pad;
57 struct stat sbuf;
58 int rval;
59 uint32_t r;
60 char carrybuf[MAXPATHLEN];
61
62 _DIAGASSERT(path != NULL);
63 /* doopen may be NULL */
64 if ((doopen != NULL && domkdir) || slen < 0 ||
65 (oflags & ~(O_APPEND | O_DIRECT | O_SHLOCK | O_EXLOCK | O_SYNC |
66 O_CLOEXEC)) != 0) {
67 errno = EINVAL;
68 return 0;
69 }
70
71 for (trv = path; *trv != '\0'; ++trv)
72 continue;
73
74 if (trv - path >= MAXPATHLEN) {
75 errno = ENAMETOOLONG;
76 return 0;
77 }
78 trv -= slen;
79 suffp = trv;
80 --trv;
81 if (trv < path || NULL != strchr(suffp, '/')) {
82 errno = EINVAL;
83 return 0;
84 }
85
86 /* Fill space with random characters */
87 while (trv >= path && *trv == 'X') {
88 r = arc4random_uniform((unsigned int)(sizeof(padchar) - 1));
89 *trv-- = padchar[r];
90 }
91 start = trv + 1;
92
93 /* save first combination of random characters */
94 memcpy(carrybuf, start, (size_t)(suffp - start));
95
96 /*
97 * check the target directory.
98 */
99 if (doopen != NULL || domkdir) {
100 for (; trv > path; --trv) {
101 if (*trv == '/') {
102 *trv = '\0';
103 rval = stat(path, &sbuf);
104 *trv = '/';
105 if (rval != 0)
106 return 0;
107 if (!S_ISDIR(sbuf.st_mode)) {
108 errno = ENOTDIR;
109 return 0;
110 }
111 break;
112 }
113 }
114 }
115
116 for (;;) {
117 if (doopen) {
118 if ((*doopen = open(path, O_CREAT|O_EXCL|O_RDWR|oflags,
119 0600)) != -1)
120 return 1;
121 if (errno != EEXIST)
122 return 0;
123 } else if (domkdir) {
124 if (mkdir(path, 0700) != -1)
125 return 1;
126 if (errno != EEXIST)
127 return 0;
128 } else if (lstat(path, &sbuf))
129 return errno == ENOENT;
130
131 /*
132 * If we have a collision,
133 * cycle through the space of filenames
134 */
135 for (trv = start, carryp = carrybuf;;) {
136 /* have we tried all possible permutations? */
137 if (trv == suffp)
138 return 0; /* yes - exit with EEXIST */
139 pad = strchr((const char *)padchar, *trv);
140 if (pad == NULL) {
141 /* this should never happen */
142 errno = EIO;
143 return 0;
144 }
145 /* increment character */
146 *trv = (*++pad == '\0') ? padchar[0] : *pad;
147 /* carry to next position? */
148 if (*trv == *carryp) {
149 /* increment position and loop */
150 ++trv;
151 ++carryp;
152 } else {
153 /* try with new name */
154 break;
155 }
156 }
157 }
158 /*NOTREACHED*/
159 }
160
161 #endif /* !HAVE_NBTOOL_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP */
162