xref: /freebsd/lib/libc/stdio/tmpfile.c (revision 3416500aef140042c64bc149cb1ec6620483bc44)
1 /*-
2  * Copyright (c) 1990, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Chris Torek.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char sccsid[] = "@(#)tmpfile.c	8.1 (Berkeley) 6/4/93";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 
39 #include "namespace.h"
40 #include <sys/types.h>
41 #include <signal.h>
42 #include <unistd.h>
43 #include <errno.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <paths.h>
48 #include "un-namespace.h"
49 #include "libc_private.h"
50 
51 FILE *
52 tmpfile(void)
53 {
54 	sigset_t set, oset;
55 	FILE *fp;
56 	int fd, sverrno;
57 #define	TRAILER	"tmp.XXXXXX"
58 	char *buf;
59 	const char *tmpdir;
60 
61 	tmpdir = NULL;
62 	if (issetugid() == 0)
63 		tmpdir = getenv("TMPDIR");
64 	if (tmpdir == NULL)
65 		tmpdir = _PATH_TMP;
66 
67 	(void)asprintf(&buf, "%s%s%s", tmpdir,
68 	    (tmpdir[strlen(tmpdir) - 1] == '/') ? "" : "/", TRAILER);
69 	if (buf == NULL)
70 		return (NULL);
71 
72 	sigfillset(&set);
73 	(void)__libc_sigprocmask(SIG_BLOCK, &set, &oset);
74 
75 	fd = mkstemp(buf);
76 	if (fd != -1)
77 		(void)unlink(buf);
78 
79 	free(buf);
80 
81 	(void)__libc_sigprocmask(SIG_SETMASK, &oset, NULL);
82 
83 	if (fd == -1)
84 		return (NULL);
85 
86 	if ((fp = fdopen(fd, "w+")) == NULL) {
87 		sverrno = errno;
88 		(void)_close(fd);
89 		errno = sverrno;
90 		return (NULL);
91 	}
92 	return (fp);
93 }
94