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Revision 1.4, Sun Sep 19 15:02:55 2021 UTC (4 weeks, 1 day ago) by schwarze
Branch: MAIN
CVS Tags: VERSION_1_14_6, HEAD
Changes since 1.3: +5 -7 lines

Two minor improvements:
1. If mktemp(3) fails, do not overwrite the errno because
all errors mktemp(3) might return are also valid for mkdtemp(3).
2. If mkdir(2) fails, always put back the Xes, even if
the error is fatal and the function is about to return NULL.

/* $Id: compat_mkdtemp.c,v 1.4 2021/09/19 15:02:55 schwarze Exp $ */
/*
 * Copyright (c) 2015, 2021 Ingo Schwarze <schwarze@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * The algorithm of this function is inspired by OpenBSD mkdtemp(3)
 * by Theo de Raadt and Todd Miller, but the code differs.
 */
#include "config.h"

#include <sys/stat.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>

char *
mkdtemp(char *path)
{
	char		*start, *cp;
	unsigned	 int tries;

	start = strchr(path, '\0');
	while (start > path && start[-1] == 'X')
		start--;

	for (tries = INT_MAX; tries; tries--) {
		if (mktemp(path) == NULL)
			return NULL;
		if (mkdir(path, S_IRUSR | S_IWUSR | S_IXUSR) == 0)
			return path;
		for (cp = start; *cp != '\0'; cp++)
			*cp = 'X';
		if (errno != EEXIST)
			return NULL;
	}
	errno = EEXIST;
	return NULL;
}