testcases/kernel/syscalls/open/open02.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) International Business Machines Corp., 2001
 * Ported to LTP: Wayne Boyer
 *	06/2017 Modified by Guangwen Feng <fenggw-fnst@cn.fujitsu.com>
 */

/*\
 * [Description]
 *
 * 1. open a new file without O_CREAT, ENOENT should be returned.
 * 2. open a file with O_RDONLY | O_NOATIME and the caller was not
 * privileged, EPERM should be returned.
 */

#define _GNU_SOURCE

#include <pwd.h>
#include "tst_test.h"

#define TEST_FILE	"test_file"
#define TEST_FILE2	"test_file2"

static struct tcase {
	const char *filename;
	int flag;
	int exp_errno;
	const char *desc;
} tcases[] = {
	{TEST_FILE, O_RDWR, ENOENT, "new file without O_CREAT"},
	{TEST_FILE2, O_RDONLY | O_NOATIME, EPERM, "unprivileged O_RDONLY | O_NOATIME"},
};

void setup(void)
{
	struct passwd *ltpuser;

	SAFE_TOUCH(TEST_FILE2, 0644, NULL);

	ltpuser = SAFE_GETPWNAM("nobody");

	SAFE_SETEUID(ltpuser->pw_uid);
}

static void verify_open(unsigned int n)
{
	struct tcase *tc = &tcases[n];

	TST_EXP_FAIL2(open(tc->filename, tc->flag, 0444),
	             tc->exp_errno, "open() %s", tc->desc);
}

void cleanup(void)
{
	SAFE_SETEUID(0);
}

static struct tst_test test = {
	.tcnt = ARRAY_SIZE(tcases),
	.needs_root = 1,
	.needs_tmpdir = 1,
	.setup = setup,
	.cleanup = cleanup,
	.test = verify_open,
};