/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or https://opensource.org/licenses/CDDL-1.0.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2019 by Tomohiro Kusumi. All rights reserved.
 */

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <err.h>

/* backward compat in case it's not defined */
#ifndef O_TMPFILE
#define	O_TMPFILE	(020000000|O_DIRECTORY)
#endif

/*
 * DESCRIPTION:
 *	Verify fstat(2) for O_TMPFILE file considers umask.
 *
 * STRATEGY:
 *	1. open(2) with O_TMPFILE.
 *	2. linkat(2).
 *	3. fstat(2) and verify .st_mode value.
 */

static void
test_stat_mode(mode_t mask)
{
	struct stat fst;
	int i, fd;
	char spath[1024], dpath[1024];
	const char *penv[] = {"TESTDIR", "TESTFILE0"};
	mode_t masked = 0777 & ~mask;
	mode_t mode;

	/*
	 * Get the environment variable values.
	 */
	for (i = 0; i < ARRAY_SIZE(penv); i++)
		if ((penv[i] = getenv(penv[i])) == NULL)
			errx(1, "getenv(penv[%d])", i);

	umask(mask);
	fd = open(penv[0], O_RDWR|O_TMPFILE, 0777);
	if (fd == -1)
		err(2, "open(%s)", penv[0]);

	if (fstat(fd, &fst) == -1)
		err(3, "fstat(%s)", penv[0]);

	snprintf(spath, sizeof (spath), "/proc/self/fd/%d", fd);
	snprintf(dpath, sizeof (dpath), "%s/%s", penv[0], penv[1]);

	unlink(dpath);
	if (linkat(AT_FDCWD, spath, AT_FDCWD, dpath, AT_SYMLINK_FOLLOW) == -1)
		err(4, "linkat");
	close(fd);

	/* Verify fstat(2) result at old path */
	mode = fst.st_mode & 0777;
	if (mode != masked)
		errx(5, "fstat(2) %o != %o\n", mode, masked);

	fd = open(dpath, O_RDWR);
	if (fd == -1)
		err(6, "open(%s)", dpath);

	if (fstat(fd, &fst) == -1)
		err(7, "fstat(%s)", dpath);

	/* Verify fstat(2) result at new path */
	mode = fst.st_mode & 0777;
	if (mode != masked)
		errx(8, "fstat(2) %o != %o\n", mode, masked);
	close(fd);
}

int
main(void)
{
	fprintf(stdout, "Verify stat(2) for O_TMPFILE file considers umask.\n");

	test_stat_mode(0022);
	test_stat_mode(0077);

	return (0);
}
