setreuid07.c: Rewrite the test using new LTP API

diff --git a/testcases/kernel/syscalls/setreuid/setreuid07.c b/testcases/kernel/syscalls/setreuid/setreuid07.c
index ff222cd00..83559583e 100644
--- a/testcases/kernel/syscalls/setreuid/setreuid07.c
+++ b/testcases/kernel/syscalls/setreuid/setreuid07.c
@@ -1,192 +1,67 @@ 
+// SPDX-License-Identifier: GPL-2.0-later
 /*
  * Copyright (c) Kerlabs 2008.
  * Copyright (c) International Business Machines  Corp., 2008
- *
- * This program is free software;  you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY;  without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
- * the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program;  if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
  * Created by Renaud Lottiaux
+ * Copyright (c) 2023 SUSE LLC Avinesh Kumar <avinesh.kumar@suse.com>
  */
 
-/*
+/*\
+ * [Description]
+ *
  * Check if setreuid behaves correctly with file permissions.
  * The test creates a file as ROOT with permissions 0644, does a setreuid
  * and then tries to open the file with RDWR permissions.
  * The same test is done in a fork to check if new UIDs are correctly
- * passed to the son.
+ * passed to the child process.
  */
 
-#include <errno.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/wait.h>
-#include <fcntl.h>
-#include <unistd.h>
 #include <pwd.h>
+#include <stdlib.h>
 
-#include "test.h"
-#include "safe_macros.h"
-#include "compat_16.h"
+#include "tst_test.h"
+#include "compat_tst_16.h"
 
-TCID_DEFINE(setreuid07);
-int TST_TOTAL = 1;
+#define TEMPFILE "testfile"
 
-static char testfile[256] = "";
 static struct passwd *ltpuser;
 
-static int fd = -1;
-
-static void setup(void);
-static void cleanup(void);
-static void do_master_child(void);
-
-int main(int ac, char **av)
+static void setup(void)
 {
-	pid_t pid;
+	int fd;
 
-	tst_parse_opts(ac, av, NULL, NULL);
+	ltpuser = SAFE_GETPWNAM("nobody");
 
-	setup();
-
-	pid = FORK_OR_VFORK();
-	if (pid < 0)
-		tst_brkm(TBROK, cleanup, "Fork failed");
-
-	if (pid == 0)
-		do_master_child();
-
-	tst_record_childstatus(cleanup, pid);
-
-	cleanup();
-	tst_exit();
+	UID16_CHECK(ltpuser->pw_uid, setreuid);
+	fd = SAFE_OPEN(TEMPFILE, O_CREAT | O_RDWR, 0644);
+	SAFE_CLOSE(fd);
 }
 
-static void do_master_child(void)
+static void run(void)
 {
-	int lc;
-	int pid;
+	pid_t pid;
 	int status;
 
-	for (lc = 0; TEST_LOOPING(lc); lc++) {
-		int tst_fd;
-
-		tst_count = 0;
-
-		if (SETREUID(NULL, 0, ltpuser->pw_uid) == -1) {
-			perror("setreuid failed");
-			exit(TFAIL);
-		}
-
-		/* Test 1: Check the process with new uid cannot open the file
-		 *         with RDWR permissions.
-		 */
-		TEST(tst_fd = open(testfile, O_RDWR));
-
-		if (TEST_RETURN != -1) {
-			printf("open succeeded unexpectedly\n");
-			close(tst_fd);
-			exit(TFAIL);
-		}
-
-		if (TEST_ERRNO == EACCES) {
-			printf("open failed with EACCES as expected\n");
-		} else {
-			perror("open failed unexpectedly");
-			exit(TFAIL);
-		}
+	TST_EXP_PASS_SILENT(SETREUID(-1, ltpuser->pw_uid));
+	TST_EXP_FAIL2(open(TEMPFILE, O_RDWR), EACCES);
 
-		/* Test 2: Check a son process cannot open the file
-		 *         with RDWR permissions.
-		 */
-		pid = FORK_OR_VFORK();
-		if (pid < 0)
-			tst_brkm(TBROK, cleanup, "Fork failed");
-
-		if (pid == 0) {
-			int tst_fd2;
-
-			/* Test to open the file in son process */
-			TEST(tst_fd2 = open(testfile, O_RDWR));
-
-			if (TEST_RETURN != -1) {
-				printf("call succeeded unexpectedly\n");
-				close(tst_fd2);
-				exit(TFAIL);
-			}
-
-			if (TEST_ERRNO == EACCES) {
-				printf("open failed with EACCES as expected\n");
-				exit(TPASS);
-			} else {
-				printf("open failed unexpectedly\n");
-				exit(TFAIL);
-			}
-		} else {
-			/* Wait for son completion */
-			if (waitpid(pid, &status, 0) == -1) {
-				perror("waitpid failed");
-				exit(TFAIL);
-			}
-			if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
-				exit(WEXITSTATUS(status));
-		}
-
-		/* Test 3: Fallback to initial uid and check we can again open
-		 *         the file with RDWR permissions.
-		 */
-		tst_count++;
-		if (SETREUID(NULL, 0, 0) == -1) {
-			perror("setreuid failed");
-			exit(TFAIL);
-		}
-
-		TEST(tst_fd = open(testfile, O_RDWR));
-
-		if (TEST_RETURN == -1) {
-			perror("open failed unexpectedly");
-			exit(TFAIL);
-		} else {
-			printf("open call succeeded\n");
-			close(tst_fd);
-		}
+	pid = SAFE_FORK();
+	if (pid == 0) {
+		TST_EXP_FAIL2(open(TEMPFILE, O_RDWR), EACCES);
+		exit(0);
 	}
-	exit(TPASS);
-}
+	SAFE_WAITPID(pid, &status, 0);
+	if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
+		exit(WEXITSTATUS(status));
 
-static void setup(void)
-{
-	tst_require_root();
-
-	ltpuser = getpwnam("nobody");
-	if (ltpuser == NULL)
-		tst_brkm(TBROK, NULL, "nobody must be a valid user.");
-
-	tst_tmpdir();
-
-	sprintf(testfile, "setreuid07file%d.tst", getpid());
-
-	/* Create test file */
-	fd = SAFE_OPEN(cleanup, testfile, O_CREAT | O_RDWR, 0644);
-
-	tst_sig(FORK, DEF_HANDLER, cleanup);
-
-	TEST_PAUSE;
+	TST_EXP_PASS_SILENT(SETREUID(-1, 0));
+	TST_EXP_FD(open(TEMPFILE, O_RDWR));
+	SAFE_CLOSE(TST_RET);
 }
 
-static void cleanup(void)
-{
-	close(fd);
-
-	tst_rmdir();
-}
+static struct tst_test test = {
+	.setup = setup,
+	.test_all = run,
+	.needs_root = 1,
+	.forks_child = 1
+};