xref: /dragonfly/lib/libc/stdio/mktemp.c (revision 2cd2d2b5)
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. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * @(#)mktemp.c	8.1 (Berkeley) 6/4/93
34  * $FreeBSD: src/lib/libc/stdio/mktemp.c,v 1.19.2.3 2002/06/18 09:53:07 robert Exp $
35  * $DragonFly: src/lib/libc/stdio/mktemp.c,v 1.5 2004/06/07 20:35:41 hmp Exp $
36  */
37 
38 #include <sys/types.h>
39 #include <sys/stat.h>
40 #include <fcntl.h>
41 #include <errno.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <ctype.h>
46 #include <unistd.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
56 mkstemps(char *path, int slen)
57 {
58 	int fd;
59 
60 	return (_gettemp(path, &fd, 0, slen) ? fd : -1);
61 }
62 
63 int
64 mkstemp(char *path)
65 {
66 	int fd;
67 
68 	return (_gettemp(path, &fd, 0, 0) ? fd : -1);
69 }
70 
71 char *
72 mkdtemp(char *path)
73 {
74 	return (_gettemp(path, (int *)NULL, 1, 0) ? path : (char *)NULL);
75 }
76 
77 char *
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 *
87 mktemp(char *path)
88 {
89 	return (_mktemp(path));
90 }
91 
92 static int
93 _gettemp(char *path, int *doopen, int domkdir, int slen)
94 {
95 	char *start, *trv, *suffp;
96 	char *pad;
97 	struct stat sbuf;
98 	int rval;
99 	uint32_t rand;
100 
101 	if (doopen != NULL && domkdir) {
102 		errno = EINVAL;
103 		return (0);
104 	}
105 
106 	for (trv = path; *trv != '\0'; ++trv)
107 		;
108 	trv -= slen;
109 	suffp = trv;
110 	--trv;
111 	if (trv < path) {
112 		errno = EINVAL;
113 		return (0);
114 	}
115 
116 	/* Fill space with random characters */
117 	while (trv >= path && *trv == 'X') {
118 		rand = arc4random() % (sizeof(padchar) - 1);
119 		*trv-- = padchar[rand];
120 	}
121 	start = trv + 1;
122 
123 	/*
124 	 * check the target directory.
125 	 */
126 	if (doopen != NULL || domkdir) {
127 		for (; trv > path; --trv) {
128 			if (*trv == '/') {
129 				*trv = '\0';
130 				rval = stat(path, &sbuf);
131 				*trv = '/';
132 				if (rval != 0)
133 					return (0);
134 				if (!S_ISDIR(sbuf.st_mode)) {
135 					errno = ENOTDIR;
136 					return (0);
137 				}
138 				break;
139 			}
140 		}
141 	}
142 
143 	for (;;) {
144 		if (doopen) {
145 			if ((*doopen =
146 			    _open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
147 				return (1);
148 			if (errno != EEXIST)
149 				return (0);
150 		} else if (domkdir) {
151 			if (mkdir(path, 0700) == 0)
152 				return (1);
153 			if (errno != EEXIST)
154 				return (0);
155 		} else if (lstat(path, &sbuf))
156 			return (errno == ENOENT);
157 
158 		/* If we have a collision, cycle through the space of filenames */
159 		for (trv = start;;) {
160 			if (*trv == '\0' || trv == suffp)
161 				return (0);
162 			pad = strchr(padchar, *trv);
163 			if (pad == NULL || *++pad == '\0')
164 				*trv++ = padchar[0];
165 			else {
166 				*trv++ = *pad;
167 				break;
168 			}
169 		}
170 	}
171 	/*NOTREACHED*/
172 }
173