1 /* $NetBSD: gettemp.c,v 1.22 2024/01/20 14:52:49 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 1.22 2024/01/20 14:52:49 christos Exp $");
42 #endif
43 #endif /* LIBC_SCCS and not lint */
44
45 #include <sys/param.h>
46 #include <sys/stat.h>
47 #include <fcntl.h>
48 #include <string.h>
49
50 static const unsigned char padchar[] =
51 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
52
53 int
GETTEMP(char * path,int * doopen,int domkdir,int slen,int oflags)54 GETTEMP(char *path, int *doopen, int domkdir, int slen, int oflags)
55 {
56 char *start, *trv, *suffp, *carryp;
57 const char *pad;
58 struct stat sbuf;
59 int rval;
60 uint32_t r;
61 char carrybuf[MAXPATHLEN];
62
63 _DIAGASSERT(path != NULL);
64 /* doopen may be NULL */
65 if ((doopen != NULL && domkdir) || slen < 0 ||
66 (oflags & ~(O_APPEND | O_DIRECT | O_SHLOCK | O_EXLOCK | O_SYNC |
67 O_CLOEXEC)) != 0) {
68 errno = EINVAL;
69 return 0;
70 }
71
72 for (trv = path; *trv != '\0'; ++trv)
73 continue;
74
75 if (trv - path >= MAXPATHLEN) {
76 errno = ENAMETOOLONG;
77 return 0;
78 }
79 trv -= slen;
80 suffp = trv;
81 --trv;
82 if (trv < path || NULL != strchr(suffp, '/')) {
83 errno = EINVAL;
84 return 0;
85 }
86
87 /* Fill space with random characters */
88 while (trv >= path && *trv == 'X') {
89 r = arc4random_uniform((unsigned int)(sizeof(padchar) - 1));
90 *trv-- = padchar[r];
91 }
92 start = trv + 1;
93
94 /* save first combination of random characters */
95 memcpy(carrybuf, start, (size_t)(suffp - start));
96
97 /*
98 * check the target directory.
99 */
100 if (doopen != NULL || domkdir) {
101 for (; trv > path; --trv) {
102 if (*trv == '/') {
103 *trv = '\0';
104 rval = stat(path, &sbuf);
105 *trv = '/';
106 if (rval != 0)
107 return 0;
108 if (!S_ISDIR(sbuf.st_mode)) {
109 errno = ENOTDIR;
110 return 0;
111 }
112 break;
113 }
114 }
115 }
116
117 for (;;) {
118 if (doopen) {
119 if ((*doopen = open(path, O_CREAT|O_EXCL|O_RDWR|oflags,
120 0600)) != -1)
121 return 1;
122 if (errno != EEXIST)
123 return 0;
124 } else if (domkdir) {
125 if (mkdir(path, 0700) != -1)
126 return 1;
127 if (errno != EEXIST)
128 return 0;
129 } else if (lstat(path, &sbuf))
130 return errno == ENOENT;
131
132 /*
133 * If we have a collision,
134 * cycle through the space of filenames
135 */
136 for (trv = start, carryp = carrybuf;;) {
137 /* have we tried all possible permutations? */
138 if (trv == suffp)
139 return 0; /* yes - exit with EEXIST */
140 pad = strchr((const char *)padchar, *trv);
141 if (pad == NULL) {
142 /* this should never happen */
143 errno = EIO;
144 return 0;
145 }
146 /* increment character */
147 *trv = (*++pad == '\0') ? padchar[0] : *pad;
148 /* carry to next position? */
149 if (*trv == *carryp) {
150 /* increment position and loop */
151 ++trv;
152 ++carryp;
153 } else {
154 /* try with new name */
155 break;
156 }
157 }
158 }
159 /*NOTREACHED*/
160 }
161
162 #endif /* !HAVE_NBTOOL_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP */
163