/*
 * Copyright (c) 2002, Intel Corporation. All rights reserved.
 * This file is licensed under the GPL license.  For the full content
 * of this license, see the COPYING file at the top level of this
 * source tree.

 * Test that pthread_rwlock_timedwrlock(pthread_rwlock_t *rwlock)
 *
 *	pthread_rwlock_timedwrlock() function shall apply a write lock to the
 *	read-write lock referenced by rwlock as in the pthread_rwlock_wrlock() function.
 *	However, if the lock cannot be acquired without waiting for other threads to
 *	unlock the lock, this wait shall be terminate when the specified timeout expires.
 *
 * Steps:
 * 1.  Initialize rwlock
 * 2.  Main creats thread0.
 * 3.  Thread0 does pthread_rwlock_timedwrlock(), should get the lock successfully then unlock.
 * 4.  Main thread locks 'rwlock' for reading with pthread_rwlock_rdlock()
 * 5.  Create a child thread, the thread time-locks 'rwlock' for writing,
 *	using pthread_rwlock_timedwrlock(), should block, but when the timer expires,
 *	that wait will be terminated.
 * 6.  Main thread unlocks 'rwlock'
 * 7.  Main thread locks 'rwlock' for writing.
 * 8.  Create child thread to lock 'rwlock' for writing, using pthread_rwlock_timedwrlock,
 *	 it should block but when the timer expires, the wait will be terminated
 * 8.  Main thread unlocks 'rwlock'
 */

/* Test with CLOCK_REALTIME */

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/time.h>
#include "posixtest.h"

#define TIMEOUT 3

static pthread_rwlock_t rwlock;
static int thread_state;
static struct timeval currsec1, currsec2;
static int expired;

/* thread_state indicates child thread state:
	1: not in child thread yet;
	2: just enter child thread ;
	3: just before child thread exit;
*/

#define NOT_CREATED_THREAD 1
#define ENTERED_THREAD 2
#define EXITING_THREAD 3

static void *fn_wr(void *arg PTS_ATTRIBUTE_UNUSED)
{
	struct timespec timeout, ts;
	int rc;
	thread_state = ENTERED_THREAD;
#ifdef CLOCK_REALTIME
	rc = clock_gettime(CLOCK_REALTIME, &ts);
	if (rc != 0) {
		perror("clock_gettime()");
		exit(PTS_UNRESOLVED);
	}
	currsec1.tv_sec = ts.tv_sec;
	currsec1.tv_usec = ts.tv_nsec / 1000;
#else
	gettimeofday(&currsec1, NULL);
#endif
	/* Absolute time, not relative. */
	timeout.tv_sec = currsec1.tv_sec + TIMEOUT;
	timeout.tv_nsec = currsec1.tv_usec * 1000;

	printf("thread: attempt timed write lock, %d secs\n", TIMEOUT);
	rc = pthread_rwlock_timedwrlock(&rwlock, &timeout);
	if (rc == ETIMEDOUT) {
		printf("thread: timer expired\n");
		expired = 1;
	} else if (rc == 0) {
		printf("thread: acquired write lock\n");
		expired = 0;
		printf("thread: unlock write lock\n");
		if (pthread_rwlock_unlock(&rwlock) != 0) {
			printf("thread: error release write lock\n");
			exit(PTS_UNRESOLVED);
		}
	} else {
		printf("thread: Error in pthread_rwlock_timedrdlock().\n");
		exit(PTS_UNRESOLVED);
	}

	/* Get time after the mutex timed out in locking. */
#ifdef CLOCK_REALTIME
	rc = clock_gettime(CLOCK_REALTIME, &ts);
	if (rc != 0) {
		perror("clock_gettime()");
		exit(PTS_UNRESOLVED);
	}
	currsec2.tv_sec = ts.tv_sec;
	currsec2.tv_usec = ts.tv_nsec / 1000;
#else
	gettimeofday(&currsec2, NULL);
#endif
	thread_state = EXITING_THREAD;
	pthread_exit(0);
	return NULL;
}

int main(void)
{
	int cnt = 0;
	pthread_t thread0, thread1, thread2;

	if (pthread_rwlock_init(&rwlock, NULL) != 0) {
		printf("Error at pthread_rwlock_init()\n");
		return PTS_UNRESOLVED;
	}

	printf("main: create thread0\n");
	thread_state = NOT_CREATED_THREAD;
	if (pthread_create(&thread0, NULL, fn_wr, NULL) != 0) {
		printf("Error creating thread0\n");
		return PTS_UNRESOLVED;
	}

	/* thread0 should not block at all since no one else has locked rwlock */

	cnt = 0;
	expired = 0;
	do {
		sleep(1);
	} while (thread_state != EXITING_THREAD && cnt++ < 2 * TIMEOUT);

	if (thread_state == EXITING_THREAD) {
		if (expired == 1) {
			printf("Test FAILED: the timer expired\n");
			exit(PTS_FAIL);
		} else
			printf("thread0 correctly acquired the write lock.\n");
	} else if (thread_state == ENTERED_THREAD) {
		printf
		    ("Test FAILED: thread0 incorrectly blocked on timedwrlock\n");
		exit(PTS_FAIL);
	} else {
		printf("Unexpected state for thread0 %d\n", thread_state);
		exit(PTS_UNRESOLVED);
	}

	if (pthread_join(thread0, NULL) != 0) {
		printf("Error when joining thread0\n");
		return PTS_UNRESOLVED;
	}

	printf("main: attempt read lock\n");
	/* We have no lock, this read lock should succeed */
	if (pthread_rwlock_rdlock(&rwlock) != 0) {
		printf("Error at pthread_rwlock_rdlock()\n");
		return PTS_UNRESOLVED;
	}
	printf("main: acquired read lock\n");

	thread_state = NOT_CREATED_THREAD;

	printf("main: create thread1\n");
	if (pthread_create(&thread1, NULL, fn_wr, NULL) != 0) {
		printf("Error when creating thread1\n");
		return PTS_UNRESOLVED;
	}

	/* If the shared data is not altered by child after TIMEOUT*2 seconds,
	   we regard it as blocked */

	/* we expect the thread to expire blocking after timeout */
	cnt = 0;
	do {
		sleep(1);
	} while (thread_state != EXITING_THREAD && cnt++ < 2 * TIMEOUT);

	if (thread_state == EXITING_THREAD) {
		/* the child thread does not block, check the time interval */
		struct timeval time_diff;
		time_diff.tv_sec = currsec2.tv_sec - currsec1.tv_sec;
		time_diff.tv_usec = currsec2.tv_usec - currsec1.tv_usec;
		if (time_diff.tv_usec < 0) {
			--time_diff.tv_sec;
			time_diff.tv_usec += 1000000;
		}
		if (time_diff.tv_sec < TIMEOUT) {
			printf("Test FAILED: the timer expired and blocking "
			       "was terminated, but the timeout is not correct: "
			       "expected to wait for %d, but waited for %ld.%06ld\n",
			       TIMEOUT, (long)time_diff.tv_sec,
			       (long)time_diff.tv_usec);
			exit(PTS_FAIL);
		} else
			printf("thread1 correctly expired at timeout.\n");
	} else if (thread_state == ENTERED_THREAD) {
		printf("Test FAILED: wait is not terminated even "
		       "when the timer expired\n");
		exit(PTS_FAIL);
	} else {
		printf("Unexpected state for thread1 %d\n", thread_state);
		exit(PTS_UNRESOLVED);
	}

	printf("main: unlock read lock\n");
	if (pthread_rwlock_unlock(&rwlock) != 0) {
		printf("Error when release read lock\n");
		exit(PTS_UNRESOLVED);
	}

	if (pthread_join(thread1, NULL) != 0) {
		printf("Error when joining thread1\n");
		return PTS_UNRESOLVED;
	}

	printf("main: attempt write lock\n");
	if (pthread_rwlock_wrlock(&rwlock) != 0) {
		printf("Error at pthread_rwlock_wrlock()\n");
		return PTS_UNRESOLVED;
	}
	printf("main: acquired write lock\n");

	thread_state = NOT_CREATED_THREAD;
	cnt = 0;
	printf("main: create thread2\n");
	if (pthread_create(&thread2, NULL, fn_wr, NULL) != 0) {
		printf("Error when creating thread2\n");
		return PTS_UNRESOLVED;
	}

	/* we expect thread2 to expire blocking after timeout */
	do {
		sleep(1);
	} while (thread_state != EXITING_THREAD && cnt++ < 2 * TIMEOUT);

	if (thread_state == EXITING_THREAD) {
		/* the child thread does not block, check the time interval */
		struct timeval time_diff;
		time_diff.tv_sec = currsec2.tv_sec - currsec1.tv_sec;
		time_diff.tv_usec = currsec2.tv_usec - currsec1.tv_usec;
		if (time_diff.tv_usec < 0) {
			--time_diff.tv_sec;
			time_diff.tv_usec += 1000000;
		}
		if (time_diff.tv_sec < TIMEOUT) {
			printf("Test FAILED: for thread 2, the timer expired "
			       "and waiter terminated, but the timeout is not correct\n");
			exit(PTS_FAIL);
		} else
			printf("thread2 correctly expired at timeout.\n");

	} else if (thread_state == ENTERED_THREAD) {
		printf("Test FAILED: for thread2, wait is not terminated "
		       "even when the timer expired\n");
		exit(PTS_FAIL);
	} else {
		printf("Unexpected state for thread2 %d\n", thread_state);
		exit(PTS_UNRESOLVED);
	}

	printf("main: unlock write lock\n");
	thread_state = NOT_CREATED_THREAD;
	if (pthread_rwlock_unlock(&rwlock) != 0) {
		printf("Error releasing write lock\n");
		exit(PTS_UNRESOLVED);
	}

	if (pthread_rwlock_destroy(&rwlock) != 0) {
		printf("Error at pthread_rwlockattr_destroy()\n");
		return PTS_UNRESOLVED;
	}

	printf("Test PASSED\n");
	return PTS_PASS;
}