1/*	$OpenBSD: tempnam.c,v 1.19 2015/08/31 02:53:57 guenther Exp $ */
2/*
3 * Copyright (c) 1988, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <errno.h>
32#include <limits.h>
33#include <paths.h>
34#include <stdio.h>
35#include <stdlib.h>
36#include <string.h>
37#include <unistd.h>
38
39__warn_references(tempnam,
40    "warning: tempnam() possibly used unsafely; consider using mkstemp()");
41
42char *
43tempnam(const char *dir, const char *pfx)
44{
45	int sverrno, len;
46	char *f, *name;
47
48	if (!(name = malloc(PATH_MAX)))
49		return(NULL);
50
51	if (!pfx)
52		pfx = "tmp.";
53
54	if (issetugid() == 0 && (f = getenv("TMPDIR")) && *f != '\0') {
55		len = snprintf(name, PATH_MAX, "%s%s%sXXXXXXXXXX", f,
56		    f[strlen(f) - 1] == '/' ? "" : "/", pfx);
57		if (len < 0 || len >= PATH_MAX) {
58			errno = ENAMETOOLONG;
59			goto fail;
60		}
61		if ((f = _mktemp(name)))
62			return(f);
63	}
64
65	if (dir != NULL) {
66		f = *dir ? (char *)dir : ".";
67		len = snprintf(name, PATH_MAX, "%s%s%sXXXXXXXXXX", f,
68		    f[strlen(f) - 1] == '/' ? "" : "/", pfx);
69		if (len < 0 || len >= PATH_MAX) {
70			errno = ENAMETOOLONG;
71			goto fail;
72		}
73		if ((f = _mktemp(name)))
74			return(f);
75	}
76
77	f = P_tmpdir;
78	len = snprintf(name, PATH_MAX, "%s%sXXXXXXXXX", f, pfx);
79	if (len < 0 || len >= PATH_MAX) {
80		errno = ENAMETOOLONG;
81		goto fail;
82	}
83	if ((f = _mktemp(name)))
84		return(f);
85
86	f = _PATH_TMP;
87	len = snprintf(name, PATH_MAX, "%s%sXXXXXXXXX", f, pfx);
88	if (len < 0 || len >= PATH_MAX) {
89		errno = ENAMETOOLONG;
90		goto fail;
91	}
92	if ((f = _mktemp(name)))
93		return(f);
94
95fail:
96	sverrno = errno;
97	free(name);
98	errno = sverrno;
99	return(NULL);
100}
101