xref: /freebsd/lib/libc/stdio/mktemp.c (revision 8ab2f5ecc596131f6ca790d6ae35540c06ed7985)
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 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "@(#)mktemp.c	8.1 (Berkeley) 6/4/93";
36 #endif /* LIBC_SCCS and not lint */
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include "namespace.h"
41 #include <sys/types.h>
42 #include <sys/stat.h>
43 #include <fcntl.h>
44 #include <errno.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <ctype.h>
49 #include <unistd.h>
50 #include "un-namespace.h"
51 
52 char *_mktemp(char *);
53 
54 static int _gettemp(char *, int *, int, int);
55 
56 static const unsigned char padchar[] =
57 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
58 
59 int
60 mkstemps(path, slen)
61 	char *path;
62 	int slen;
63 {
64 	int fd;
65 
66 	return (_gettemp(path, &fd, 0, slen) ? fd : -1);
67 }
68 
69 int
70 mkstemp(path)
71 	char *path;
72 {
73 	int fd;
74 
75 	return (_gettemp(path, &fd, 0, 0) ? fd : -1);
76 }
77 
78 char *
79 mkdtemp(path)
80 	char *path;
81 {
82 	return (_gettemp(path, (int *)NULL, 1, 0) ? path : (char *)NULL);
83 }
84 
85 char *
86 _mktemp(path)
87 	char *path;
88 {
89 	return (_gettemp(path, (int *)NULL, 0, 0) ? path : (char *)NULL);
90 }
91 
92 __warn_references(mktemp,
93     "warning: mktemp() possibly used unsafely; consider using mkstemp()");
94 
95 char *
96 mktemp(path)
97 	char *path;
98 {
99 	return (_mktemp(path));
100 }
101 
102 static int
103 _gettemp(path, doopen, domkdir, slen)
104 	char *path;
105 	int *doopen;
106 	int domkdir;
107 	int slen;
108 {
109 	char *start, *trv, *suffp;
110 	char *pad;
111 	struct stat sbuf;
112 	int rval;
113 	uint32_t rand;
114 
115 	if (doopen != NULL && domkdir) {
116 		errno = EINVAL;
117 		return (0);
118 	}
119 
120 	for (trv = path; *trv != '\0'; ++trv)
121 		;
122 	trv -= slen;
123 	suffp = trv;
124 	--trv;
125 	if (trv < path) {
126 		errno = EINVAL;
127 		return (0);
128 	}
129 
130 	/* Fill space with random characters */
131 	while (trv >= path && *trv == 'X') {
132 		rand = arc4random() % (sizeof(padchar) - 1);
133 		*trv-- = padchar[rand];
134 	}
135 	start = trv + 1;
136 
137 	/*
138 	 * check the target directory.
139 	 */
140 	if (doopen != NULL || domkdir) {
141 		for (; trv > path; --trv) {
142 			if (*trv == '/') {
143 				*trv = '\0';
144 				rval = stat(path, &sbuf);
145 				*trv = '/';
146 				if (rval != 0)
147 					return (0);
148 				if (!S_ISDIR(sbuf.st_mode)) {
149 					errno = ENOTDIR;
150 					return (0);
151 				}
152 				break;
153 			}
154 		}
155 	}
156 
157 	for (;;) {
158 		if (doopen) {
159 			if ((*doopen =
160 			    _open(path, O_CREAT|O_EXCL|O_RDWR, 0600)) >= 0)
161 				return (1);
162 			if (errno != EEXIST)
163 				return (0);
164 		} else if (domkdir) {
165 			if (mkdir(path, 0700) == 0)
166 				return (1);
167 			if (errno != EEXIST)
168 				return (0);
169 		} else if (lstat(path, &sbuf))
170 			return (errno == ENOENT);
171 
172 		/* If we have a collision, cycle through the space of filenames */
173 		for (trv = start;;) {
174 			if (*trv == '\0' || trv == suffp)
175 				return (0);
176 			pad = strchr(padchar, *trv);
177 			if (pad == NULL || *++pad == '\0')
178 				*trv++ = padchar[0];
179 			else {
180 				*trv++ = *pad;
181 				break;
182 			}
183 		}
184 	}
185 	/*NOTREACHED*/
186 }
187