tmpfile.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#if defined(LIBC_SCCS) && !defined(lint)
36static char sccsid[] = "@(#)tmpfile.c	8.1 (Berkeley) 6/4/93";
37#endif /* LIBC_SCCS and not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: stable/11/lib/libc/stdio/tmpfile.c 330897 2018-03-14 03:19:51Z eadler $");
40
41#include "namespace.h"
42#include <sys/types.h>
43#include <signal.h>
44#include <unistd.h>
45#include <errno.h>
46#include <stdio.h>
47#include <stdlib.h>
48#include <string.h>
49#include <paths.h>
50#include "un-namespace.h"
51#include "libc_private.h"
52
53FILE *
54tmpfile(void)
55{
56	sigset_t set, oset;
57	FILE *fp;
58	int fd, sverrno;
59#define	TRAILER	"tmp.XXXXXX"
60	char *buf;
61	const char *tmpdir;
62
63	tmpdir = NULL;
64	if (issetugid() == 0)
65		tmpdir = getenv("TMPDIR");
66	if (tmpdir == NULL)
67		tmpdir = _PATH_TMP;
68
69	(void)asprintf(&buf, "%s%s%s", tmpdir,
70	    (tmpdir[strlen(tmpdir) - 1] == '/') ? "" : "/", TRAILER);
71	if (buf == NULL)
72		return (NULL);
73
74	sigfillset(&set);
75	(void)__libc_sigprocmask(SIG_BLOCK, &set, &oset);
76
77	fd = mkstemp(buf);
78	if (fd != -1)
79		(void)unlink(buf);
80
81	free(buf);
82
83	(void)__libc_sigprocmask(SIG_SETMASK, &oset, NULL);
84
85	if (fd == -1)
86		return (NULL);
87
88	if ((fp = fdopen(fd, "w+")) == NULL) {
89		sverrno = errno;
90		(void)_close(fd);
91		errno = sverrno;
92		return (NULL);
93	}
94	return (fp);
95}
96