xref: /freebsd/lib/libc/stdio/tmpfile.c (revision a35d88931c87cfe6bd38f01d7bad22140b3b38f3)
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. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)tmpfile.c	8.1 (Berkeley) 6/4/93";
39 #endif /* LIBC_SCCS and not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include "namespace.h"
44 #include <sys/types.h>
45 #include <signal.h>
46 #include <unistd.h>
47 #include <errno.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <paths.h>
52 #include "un-namespace.h"
53 
54 FILE *
55 tmpfile()
56 {
57 	sigset_t set, oset;
58 	FILE *fp;
59 	int fd, sverrno;
60 #define	TRAILER	"tmp.XXXXXX"
61 	char *buf;
62 	const char *tmpdir;
63 
64 	tmpdir = NULL;
65 	if (issetugid() == 0)
66 		tmpdir = getenv("TMPDIR");
67 	if (tmpdir == NULL)
68 		tmpdir = _PATH_TMP;
69 
70 	(void)asprintf(&buf, "%s%s%s", tmpdir,
71 	    (tmpdir[strlen(tmpdir) - 1] == '/') ? "" : "/", TRAILER);
72 	if (buf == NULL)
73 		return (NULL);
74 
75 	sigfillset(&set);
76 	(void)_sigprocmask(SIG_BLOCK, &set, &oset);
77 
78 	fd = mkstemp(buf);
79 	if (fd != -1)
80 		(void)unlink(buf);
81 
82 	free(buf);
83 
84 	(void)_sigprocmask(SIG_SETMASK, &oset, NULL);
85 
86 	if (fd == -1)
87 		return (NULL);
88 
89 	if ((fp = fdopen(fd, "w+")) == NULL) {
90 		sverrno = errno;
91 		(void)_close(fd);
92 		errno = sverrno;
93 		return (NULL);
94 	}
95 	return (fp);
96 }
97