xref: /openbsd-src/lib/libc/stdio/tmpfile.c (revision c5f4fad510dd427c0c20c0f4d164f60ce24651b6)
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 rcsid[] = "$OpenBSD: tmpfile.c,v 1.8 2004/09/28 18:12:44 otto Exp $";
35 #endif /* LIBC_SCCS and not lint */
36 
37 #include <sys/types.h>
38 #include <sys/stat.h>
39 #include <unistd.h>
40 #include <signal.h>
41 #include <errno.h>
42 #include <stdio.h>
43 #include <string.h>
44 #include <paths.h>
45 
46 FILE *
47 tmpfile(void)
48 {
49 	sigset_t set, oset;
50 	FILE *fp;
51 	int fd, sverrno;
52 #define	TRAILER	"tmp.XXXXXXXXXX"
53 	char buf[sizeof(_PATH_TMP) + sizeof(TRAILER)];
54 
55 	(void)memcpy(buf, _PATH_TMP, sizeof(_PATH_TMP) - 1);
56 	(void)memcpy(buf + sizeof(_PATH_TMP) - 1, TRAILER, sizeof(TRAILER));
57 
58 	sigfillset(&set);
59 	(void)sigprocmask(SIG_BLOCK, &set, &oset);
60 
61 	fd = mkstemp(buf);
62 	if (fd != -1) {
63 		mode_t u;
64 
65 		(void)unlink(buf);
66 		u = umask(0);
67 		(void)umask(u);
68 		(void)fchmod(fd, 0666 & ~u);
69 	}
70 
71 	(void)sigprocmask(SIG_SETMASK, &oset, NULL);
72 
73 	if (fd == -1)
74 		return (NULL);
75 
76 	if ((fp = fdopen(fd, "w+")) == NULL) {
77 		sverrno = errno;
78 		(void)close(fd);
79 		errno = sverrno;
80 		return (NULL);
81 	}
82 	return (fp);
83 }
84