xref: /freebsd/crypto/openssh/openbsd-compat/mktemp.c (revision 6b3455a7665208c366849f0b2b3bc916fb97516e)
1 /* OPENBSD ORIGINAL: lib/libc/stdio/mktemp.c */
2 
3 /* THIS FILE HAS BEEN MODIFIED FROM THE ORIGINAL OPENBSD SOURCE */
4 /* Changes: Removed mktemp */
5 
6 /*
7  * Copyright (c) 1987, 1993
8  *	The Regents of the University of California.  All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include "includes.h"
36 
37 #if !defined(HAVE_MKDTEMP) || defined(HAVE_STRICT_MKSTEMP)
38 
39 #if defined(LIBC_SCCS) && !defined(lint)
40 static char rcsid[] = "$OpenBSD: mktemp.c,v 1.17 2003/06/02 20:18:37 millert Exp $";
41 #endif /* LIBC_SCCS and not lint */
42 
43 #ifdef HAVE_CYGWIN
44 #define open binary_open
45 extern int binary_open();
46 #endif
47 
48 static int _gettemp(char *, int *, int, int);
49 
50 int
51 mkstemps(path, slen)
52 	char *path;
53 	int slen;
54 {
55 	int fd;
56 
57 	return (_gettemp(path, &fd, 0, slen) ? fd : -1);
58 }
59 
60 int
61 mkstemp(path)
62 	char *path;
63 {
64 	int fd;
65 
66 	return (_gettemp(path, &fd, 0, 0) ? fd : -1);
67 }
68 
69 char *
70 mkdtemp(path)
71 	char *path;
72 {
73 	return(_gettemp(path, (int *)NULL, 1, 0) ? path : (char *)NULL);
74 }
75 
76 static int
77 _gettemp(path, doopen, domkdir, slen)
78 	char *path;
79 	register int *doopen;
80 	int domkdir;
81 	int slen;
82 {
83 	register char *start, *trv, *suffp;
84 	struct stat sbuf;
85 	int rval;
86 	pid_t pid;
87 
88 	if (doopen && domkdir) {
89 		errno = EINVAL;
90 		return(0);
91 	}
92 
93 	for (trv = path; *trv; ++trv)
94 		;
95 	trv -= slen;
96 	suffp = trv;
97 	--trv;
98 	if (trv < path) {
99 		errno = EINVAL;
100 		return (0);
101 	}
102 	pid = getpid();
103 	while (trv >= path && *trv == 'X' && pid != 0) {
104 		*trv-- = (pid % 10) + '0';
105 		pid /= 10;
106 	}
107 	while (trv >= path && *trv == 'X') {
108 		char c;
109 
110 		pid = (arc4random() & 0xffff) % (26+26);
111 		if (pid < 26)
112 			c = pid + 'A';
113 		else
114 			c = (pid - 26) + 'a';
115 		*trv-- = c;
116 	}
117 	start = trv + 1;
118 
119 	/*
120 	 * check the target directory; if you have six X's and it
121 	 * doesn't exist this runs for a *very* long time.
122 	 */
123 	if (doopen || domkdir) {
124 		for (;; --trv) {
125 			if (trv <= path)
126 				break;
127 			if (*trv == '/') {
128 				*trv = '\0';
129 				rval = stat(path, &sbuf);
130 				*trv = '/';
131 				if (rval != 0)
132 					return(0);
133 				if (!S_ISDIR(sbuf.st_mode)) {
134 					errno = ENOTDIR;
135 					return(0);
136 				}
137 				break;
138 			}
139 		}
140 	}
141 
142 	for (;;) {
143 		if (doopen) {
144 			if ((*doopen =
145 			    open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
146 				return(1);
147 			if (errno != EEXIST)
148 				return(0);
149 		} else if (domkdir) {
150 			if (mkdir(path, 0700) == 0)
151 				return(1);
152 			if (errno != EEXIST)
153 				return(0);
154 		} else if (lstat(path, &sbuf))
155 			return(errno == ENOENT ? 1 : 0);
156 
157 		/* tricky little algorithm for backward compatibility */
158 		for (trv = start;;) {
159 			if (!*trv)
160 				return (0);
161 			if (*trv == 'Z') {
162 				if (trv == suffp)
163 					return (0);
164 				*trv++ = 'a';
165 			} else {
166 				if (isdigit(*trv))
167 					*trv = 'a';
168 				else if (*trv == 'z')	/* inc from z to A */
169 					*trv = 'A';
170 				else {
171 					if (trv == suffp)
172 						return (0);
173 					++*trv;
174 				}
175 				break;
176 			}
177 		}
178 	}
179 	/*NOTREACHED*/
180 }
181 
182 #endif /* !defined(HAVE_MKDTEMP) || defined(HAVE_STRICT_MKSTEMP) */
183