1/* $Id: compat_mkdtemp.c,v 1.4 2021/09/19 15:02:55 schwarze Exp $ */
2/*
3 * Copyright (c) 2015, 2021 Ingo Schwarze <schwarze@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 *
17 * The algorithm of this function is inspired by OpenBSD mkdtemp(3)
18 * by Theo de Raadt and Todd Miller, but the code differs.
19 */
20#include "config.h"
21
22#include <sys/stat.h>
23#include <errno.h>
24#include <limits.h>
25#include <stdlib.h>
26#include <string.h>
27
28char *
29mkdtemp(char *path)
30{
31	char		*start, *cp;
32	unsigned	 int tries;
33
34	start = strchr(path, '\0');
35	while (start > path && start[-1] == 'X')
36		start--;
37
38	for (tries = INT_MAX; tries; tries--) {
39		if (mktemp(path) == NULL)
40			return NULL;
41		if (mkdir(path, S_IRUSR | S_IWUSR | S_IXUSR) == 0)
42			return path;
43		for (cp = start; *cp != '\0'; cp++)
44			*cp = 'X';
45		if (errno != EEXIST)
46			return NULL;
47	}
48	errno = EEXIST;
49	return NULL;
50}
51