/*************************************************************************
* (C) 2011 AITNET ltd - Sofia/Bulgaria - <misho@aitbg.com>
*  by Michael Pounov <misho@openbsd-bg.org>
*
* $Author: misho $
* $Id: aitsched.c,v 1.7 2012/05/14 12:09:13 misho Exp $
*
**************************************************************************
The ELWIX and AITNET software is distributed under the following
terms:

All of the documentation and software included in the ELWIX and AITNET
Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>

Copyright 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
	by Michael Pounov <misho@elwix.org>.  All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. All advertising materials mentioning features or use of this software
   must display the following acknowledgement:
This product includes software developed by Michael Pounov <misho@elwix.org>
ELWIX - Embedded LightWeight unIX and its contributors.
4. Neither the name of AITNET nor the names of its contributors
   may be used to endorse or promote products derived from this software
   without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY AITNET AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
*/
#include "global.h"
#include "hooks.h"


#pragma GCC visibility push(hidden)

int sched_Errno;
char sched_Error[STRSIZ];

#pragma GCC visibility pop


// sched_GetErrno() Get error code of last operation
inline int
sched_GetErrno()
{
	return sched_Errno;
}

// sched_GetError() Get error text of last operation
inline const char *
sched_GetError()
{
	return sched_Error;
}

// sched_SetErr() Set error to variables for internal use!!!
inline void
sched_SetErr(int eno, char *estr, ...)
{
	va_list lst;

	sched_Errno = eno;
	memset(sched_Error, 0, sizeof sched_Error);
	va_start(lst, estr);
	vsnprintf(sched_Error, sizeof sched_Error, estr, lst);
	va_end(lst);
}

/* Init and prepare scheduler functions */

/*
 * schedRegisterHooks() - Register IO handles and bind tasks to it
 *
 * @root = root task
 * return: -1 error or 0 ok
 */
int
schedRegisterHooks(sched_root_task_t * __restrict root)
{
	assert(root);

	if (root->root_hooks.hook_root.fini)
		root->root_hooks.hook_root.fini(root, NULL);
	memset(&root->root_hooks, 0, sizeof root->root_hooks);

	root->root_hooks.hook_add.read = sched_hook_read;
	root->root_hooks.hook_add.write = sched_hook_write;

	root->root_hooks.hook_exec.cancel = sched_hook_cancel;
	root->root_hooks.hook_exec.fetch = sched_hook_fetch;
	root->root_hooks.hook_exec.exception = sched_hook_exception;

	root->root_hooks.hook_root.init = sched_hook_init;
	root->root_hooks.hook_root.fini = sched_hook_fini;
	return 0;
}

/*
 * schedInit() - Init scheduler
 *
 * @data = optional data if !=NULL
 * @datlen = data len if data is set
 * return: allocated root task if ok or NULL error
 */
sched_root_task_t *
schedInit(void ** __restrict data, size_t datlen)
{
	sched_root_task_t *root = NULL;
	int (*func)(sched_root_task_t *);
#ifdef HAVE_LIBPTHREAD
	register int i;
#endif

	root = malloc(sizeof(sched_root_task_t));
	if (!root) {
		LOGERR;
	} else {
		memset(root, 0, sizeof(sched_root_task_t));

		/* INFINIT polling period by default */
		sched_timespecinf(&root->root_poll);

#ifdef HAVE_LIBPTHREAD
		for (i = 0; i < taskMAX; i++)
			if (pthread_mutex_init(&root->root_mtx[i], NULL)) {
				LOGERR;
				while (i)
					pthread_mutex_destroy(&root->root_mtx[--i]);
				free(root);
				return NULL;
			}

		for (i = 0; i < taskMAX; i++)
			pthread_mutex_lock(&root->root_mtx[i]);
#endif

		TAILQ_INIT(&root->root_read);
		TAILQ_INIT(&root->root_write);
		TAILQ_INIT(&root->root_timer);
		TAILQ_INIT(&root->root_event);
		TAILQ_INIT(&root->root_eventlo);
		TAILQ_INIT(&root->root_ready);
		TAILQ_INIT(&root->root_unuse);

#ifdef HAVE_LIBPTHREAD
		for (i = 0; i < taskMAX; i++)
			pthread_mutex_unlock(&root->root_mtx[i]);
#endif

		if (data && *data) {
			if (datlen) {
				root->root_data.iov_base = *data;
				root->root_data.iov_len = datlen;
			} else { /* if datlen == 0, switch to callbacks init mode */
				 /* little hack :) for correct initialization of scheduler */
				func = (int(*)(sched_root_task_t*)) data;
				func(root);
			}
		}

		if (root->root_hooks.hook_root.init)
			root->root_hooks.hook_root.init(root, NULL);
	}

	return root;
}

/*
 * schedEnd() - End scheduler & free all resources
 *
 * @root = root task
 * return: -1 error or 0 ok
 */
int
schedEnd(sched_root_task_t ** __restrict root)
{
	sched_task_t *task, *tmp;
#ifdef HAVE_LIBPTHREAD
	register int i;
#endif

	if (!root || !*root)
		return -1;

	TAILQ_FOREACH_SAFE(task, &(*root)->root_read, task_node, tmp) {
		schedCancel(task);
	}
	TAILQ_FOREACH_SAFE(task, &(*root)->root_write, task_node, tmp) {
		schedCancel(task);
	}
	TAILQ_FOREACH_SAFE(task, &(*root)->root_timer, task_node, tmp) {
		schedCancel(task);
	}
	TAILQ_FOREACH_SAFE(task, &(*root)->root_event, task_node, tmp) {
		schedCancel(task);
	}
	TAILQ_FOREACH_SAFE(task, &(*root)->root_eventlo, task_node, tmp) {
		schedCancel(task);
	}
	TAILQ_FOREACH_SAFE(task, &(*root)->root_ready, task_node, tmp) {
		schedCancel(task);
	}

#ifdef HAVE_LIBPTHREAD
	pthread_mutex_lock(&(*root)->root_mtx[taskUNUSE]);
#endif
	while ((task = TAILQ_FIRST(&(*root)->root_unuse))) {
		TAILQ_REMOVE(&(*root)->root_unuse, task, task_node);
		free(task);
	}
#ifdef HAVE_LIBPTHREAD
	pthread_mutex_unlock(&(*root)->root_mtx[taskUNUSE]);
#endif

	if ((*root)->root_hooks.hook_root.fini)
		(*root)->root_hooks.hook_root.fini(*root, NULL);

#ifdef HAVE_LIBPTHREAD
	for (i = 0; i < taskMAX; i++)
		pthread_mutex_destroy(&(*root)->root_mtx[i]);
#endif

	free(*root);
	*root = NULL;
	return 0;
}

/*
 * schedCall() - Call task execution function
 *
 * @task = current task
 * return: !=NULL error or =NULL ok
 */
inline void *
schedCall(sched_task_t * __restrict task)
{
	void *ptr = (void*) -1;

	if (!task)
		return ptr;

	if (!TASK_ISLOCKED(task))
		TASK_LOCK(task);

	task->task_id++;
	ptr = task->task_func(task);

	TASK_UNLOCK(task);
	return ptr;
}

/*
 * schedFetch() - Fetch ready task
 *
 * @root = root task
 * return: =NULL error or !=NULL ready task
 */
inline void *
schedFetch(sched_root_task_t * __restrict root)
{
	void *ptr;

	if (!root)
		return NULL;

	if (root->root_hooks.hook_exec.fetch)
		ptr = root->root_hooks.hook_exec.fetch(root, NULL);
	else
		ptr = NULL;

	return ptr;
}

/*
 * schedCancel() - Cancel task from scheduler
 *
 * @task = task
 * return: -1 error or 0 ok
 */
int
schedCancel(sched_task_t * __restrict task)
{
	sched_queue_t *queue;

	if (!task || !TASK_ROOT(task))
		return -1;

	if (TASK_ROOT(task)->root_hooks.hook_exec.cancel)
		if (TASK_ROOT(task)->root_hooks.hook_exec.cancel(task, NULL))
			return -1;

	switch (TASK_TYPE(task)) {
		case taskREAD:
			queue = &TASK_ROOT(task)->root_read;
			break;
		case taskWRITE:
			queue = &TASK_ROOT(task)->root_write;
			break;
		case taskTIMER:
			queue = &TASK_ROOT(task)->root_timer;
			break;
		case taskEVENT:
			queue = &TASK_ROOT(task)->root_event;
			break;
		case taskEVENTLO:
			queue = &TASK_ROOT(task)->root_eventlo;
			break;
		case taskREADY:
			queue = &TASK_ROOT(task)->root_ready;
			break;
		default:
			queue = NULL;
	}
	if (queue) {
#ifdef HAVE_LIBPTHREAD
		pthread_mutex_lock(&TASK_ROOT(task)->root_mtx[TASK_TYPE(task)]);
#endif
		TAILQ_REMOVE(queue, task, task_node);
#ifdef HAVE_LIBPTHREAD
		pthread_mutex_unlock(&TASK_ROOT(task)->root_mtx[TASK_TYPE(task)]);
#endif
	}
	if (TASK_TYPE(task) != taskUNUSE)
		_sched_unuseTask(task);

	return 0;
}

/*
 * schedCancelby() - Cancel task from scheduler by criteria
 *
 * @root = root task
 * @type = cancel from queue type, if =taskMAX cancel same task from all queues
 * @criteria = find task by criteria [CRITERIA_CALL|CRITERIA_ARG|CRITERIA_FD|CRITERIA_VAL|CRITERIA_TV]
 * @param = search parameter
 * @hook = custom cleanup hook function, may be NULL
 * return: -1 error, -2 error in sub-stage cancel execution, -3 error from custom hook or 0 ok
 */
int
schedCancelby(sched_root_task_t * __restrict root, sched_task_type_t type, 
		u_char criteria, void *param, sched_hook_func_t hook)
{
	sched_task_t *task;
	sched_queue_t *queue;
	int flg = 0;

	if (!root)
		return -1;
	if (type == taskMAX) {
		if (schedCancelby(root, taskREAD, criteria, param, hook))
			return -2;
		if (schedCancelby(root, taskWRITE, criteria, param, hook))
			return -2;
		if (schedCancelby(root, taskTIMER, criteria, param, hook))
			return -2;
		if (schedCancelby(root, taskEVENT, criteria, param, hook))
			return -2;
		if (schedCancelby(root, taskEVENTLO, criteria, param, hook))
			return -2;
		if (schedCancelby(root, taskREADY, criteria, param, hook))
			return -2;
		return 0;
	}
	switch (type) {
		case taskREAD:
			queue = &root->root_read;
			break;
		case taskWRITE:
			queue = &root->root_write;
			break;
		case taskTIMER:
			queue = &root->root_timer;
			break;
		case taskEVENT:
			queue = &root->root_event;
			break;
		case taskEVENTLO:
			queue = &root->root_eventlo;
			break;
		case taskREADY:
			queue = &root->root_ready;
			break;
		default:
			return 0;
	}

#ifdef HAVE_LIBPTHREAD
	pthread_mutex_lock(&root->root_mtx[type]);
#endif
	TAILQ_FOREACH(task, queue, task_node)
		if (criteria == CRITERIA_CALL) {
			if (task->task_func == (sched_task_func_t) param) {
				flg++;
				break;
			}
		} else if (criteria == CRITERIA_ARG) {
			if (task->task_arg == param) {
				flg++;
				break;
			}
		} else if (criteria == CRITERIA_FD) {
			if (TASK_FD(task) == (intptr_t) param) {
				flg++;
				break;
			}
		} else if (criteria == CRITERIA_VAL) {
			if (TASK_VAL(task) == (u_long) param) {
				flg++;
				break;
			}
		} else if (criteria == CRITERIA_TV) {
			if (!sched_timespeccmp(&TASK_TS(task), (struct timespec*) param, -)) {
				flg++;
				break;
			}
		} else {
#ifdef HAVE_LIBPTHREAD
			pthread_mutex_unlock(&root->root_mtx[type]);
#endif
			sched_SetErr(EINVAL, "Invalid parameter criteria %d", criteria);
			return -1;
		}
#ifdef HAVE_LIBPTHREAD
	pthread_mutex_unlock(&root->root_mtx[type]);
#endif
	if (!flg || !task)	/* task not found */
		return 0;

	if (TASK_ROOT(task)->root_hooks.hook_exec.cancel)
		if (TASK_ROOT(task)->root_hooks.hook_exec.cancel(task, NULL))
			return -1;
	if (hook)
		if (hook(task, NULL))
			return -3;

#ifdef HAVE_LIBPTHREAD
	pthread_mutex_lock(&TASK_ROOT(task)->root_mtx[type]);
#endif
	TAILQ_REMOVE(queue, task, task_node);
#ifdef HAVE_LIBPTHREAD
	pthread_mutex_unlock(&TASK_ROOT(task)->root_mtx[type]);
#endif

	if (TASK_TYPE(task) != taskUNUSE)
		_sched_unuseTask(task);
	return 0;
}

/*
 * schedRun() - Scheduler *run loop*
 *
 * @root = root task
 * @killState = kill condition variable, if !=0 stop scheduler loop
 * return: -1 error or 0 ok
 */
int
schedRun(sched_root_task_t *root, volatile intptr_t * __restrict killState)
{
	sched_task_t *task;

	if (!root)
		return -1;

	if (root->root_hooks.hook_exec.run)
		if (root->root_hooks.hook_exec.run(root, NULL))
			return -1;

	if (killState) {
		if (root->root_hooks.hook_exec.condition)
			/* condition scheduler loop */
			while (root && root->root_hooks.hook_exec.fetch && 
					root->root_hooks.hook_exec.condition && 
					root->root_hooks.hook_exec.condition(root, (void*) killState)) {
				if ((task = root->root_hooks.hook_exec.fetch(root, NULL)))
					schedCall(task);
			}
		else
			/* trigger scheduler loop */
			while (!*killState && root && root->root_hooks.hook_exec.fetch) {
				if ((task = root->root_hooks.hook_exec.fetch(root, NULL)))
					schedCall(task);
			}
	} else
		/* infinite scheduler loop */
		while (root && root->root_hooks.hook_exec.fetch)
			if ((task = root->root_hooks.hook_exec.fetch(root, NULL)))
				schedCall(task);

	return 0;
}

/*
 * schedPolling() - Polling timeout period if no timer task is present
 *
 * @root = root task
 * @ts = timeout polling period, if ==NULL INFINIT timeout
 * @tsold = old timeout polling if !=NULL
 * return: -1 error or 0 ok
 */
inline int
schedPolling(sched_root_task_t * __restrict root, struct timespec * __restrict ts, 
		struct timespec * __restrict tsold)
{
	if (!root)
		return -1;

	if (tsold)
		*tsold = root->root_poll;

	if (!ts)
		sched_timespecinf(&root->root_poll);
	else
		root->root_poll = *ts;

	return 0;
}

/*
 * schedTermCondition() - Activate hook for scheduler condition kill
 *
 * @root = root task
 * @condValue = condition value, kill schedRun() if condValue == killState
 * return: -1 error ok 0 ok
 */
inline int
schedTermCondition(sched_root_task_t * __restrict root, intptr_t condValue)
{
	if (!root)
		return -1;

	root->root_cond = condValue;
	root->root_hooks.hook_exec.condition = sched_hook_condition;
	return 0;
}