xref: /freebsd/lib/libc/stdio/tempnam.c (revision 63a938566d524836885917d95bd491aa4400b181)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1988, 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 #if defined(LIBC_SCCS) && !defined(lint)
33 static char sccsid[] = "@(#)tempnam.c	8.1 (Berkeley) 6/4/93";
34 #endif /* LIBC_SCCS and not lint */
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include <sys/param.h>
39 #include <errno.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <unistd.h>
44 #include <paths.h>
45 
46 __warn_references(tempnam,
47     "warning: tempnam() possibly used unsafely; consider using mkstemp()");
48 
49 extern char *_mktemp(char *);
50 
51 char *
52 tempnam(const char *dir, const char *pfx)
53 {
54 	int sverrno;
55 	char *f, *name;
56 
57 	if (!(name = malloc(MAXPATHLEN)))
58 		return(NULL);
59 
60 	if (!pfx)
61 		pfx = "tmp.";
62 
63 	if (issetugid() == 0 && (f = getenv("TMPDIR"))) {
64 		(void)snprintf(name, MAXPATHLEN, "%s%s%sXXXXXX", f,
65 		    *(f + strlen(f) - 1) == '/'? "": "/", pfx);
66 		if ((f = _mktemp(name)))
67 			return(f);
68 	}
69 
70 	if ((f = (char *)dir)) {
71 		(void)snprintf(name, MAXPATHLEN, "%s%s%sXXXXXX", f,
72 		    *(f + strlen(f) - 1) == '/'? "": "/", pfx);
73 		if ((f = _mktemp(name)))
74 			return(f);
75 	}
76 
77 	f = P_tmpdir;
78 	(void)snprintf(name, MAXPATHLEN, "%s%sXXXXXX", f, pfx);
79 	if ((f = _mktemp(name)))
80 		return(f);
81 
82 	f = _PATH_TMP;
83 	(void)snprintf(name, MAXPATHLEN, "%s%sXXXXXX", f, pfx);
84 	if ((f = _mktemp(name)))
85 		return(f);
86 
87 	sverrno = errno;
88 	free(name);
89 	errno = sverrno;
90 	return(NULL);
91 }
92