1/*	$OpenBSD: tempnam.c,v 1.17 2013/09/30 12:02:35 millert 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
42extern char *_mktemp(char *);
43
44char *
45tempnam(const char *dir, const char *pfx)
46{
47	int sverrno, len;
48	char *f, *name;
49
50	if (!(name = malloc(PATH_MAX)))
51		return(NULL);
52
53	if (!pfx)
54		pfx = "tmp.";
55
56	if (issetugid() == 0 && (f = getenv("TMPDIR")) && *f != '\0') {
57		len = snprintf(name, PATH_MAX, "%s%s%sXXXXXXXXXX", f,
58		    f[strlen(f) - 1] == '/' ? "" : "/", pfx);
59		if (len < 0 || len >= PATH_MAX) {
60			errno = ENAMETOOLONG;
61			return(NULL);
62		}
63		if ((f = _mktemp(name)))
64			return(f);
65	}
66
67	if (dir != NULL) {
68		f = *dir ? (char *)dir : ".";
69		len = snprintf(name, PATH_MAX, "%s%s%sXXXXXXXXXX", f,
70		    f[strlen(f) - 1] == '/' ? "" : "/", pfx);
71		if (len < 0 || len >= PATH_MAX) {
72			errno = ENAMETOOLONG;
73			return(NULL);
74		}
75		if ((f = _mktemp(name)))
76			return(f);
77	}
78
79	f = P_tmpdir;
80	len = snprintf(name, PATH_MAX, "%s%sXXXXXXXXX", f, pfx);
81	if (len < 0 || len >= PATH_MAX) {
82		errno = ENAMETOOLONG;
83		return(NULL);
84	}
85	if ((f = _mktemp(name)))
86		return(f);
87
88	f = _PATH_TMP;
89	len = snprintf(name, PATH_MAX, "%s%sXXXXXXXXX", f, pfx);
90	if (len < 0 || len >= PATH_MAX) {
91		errno = ENAMETOOLONG;
92		return(NULL);
93	}
94	if ((f = _mktemp(name)))
95		return(f);
96
97	sverrno = errno;
98	free(name);
99	errno = sverrno;
100	return(NULL);
101}
102