/*
 * \brief  Virtualbox adjusted pthread_create implementation
 * \author Alexander Boettcher
 * \date   2014-04-09
 */

/*
 * Copyright (C) 2014 Genode Labs GmbH
 *
 * This file is distributed under the terms of the GNU General Public License
 * version 2.
 */

/* Genode */
#include <base/printf.h>
#include <base/thread.h>
#include <base/env.h>
#include <cpu_session/connection.h>

/* Genode libc pthread binding */
#include "thread.h"

/* libc */
#include <pthread.h>
#include <errno.h>

/* vbox */
#include <internal/thread.h>

static Genode::Cpu_session * get_cpu_session(RTTHREADTYPE type) {
	using namespace Genode;

	static Cpu_connection * con[RTTHREADTYPE_END - 1];
	static Lock lock;

	Assert(type && type < RTTHREADTYPE_END);

	Lock::Guard guard(lock);

	if (con[type - 1])
		return con[type - 1];

	long const prio = (RTTHREADTYPE_END - type) *
	                  (Cpu_session::PRIORITY_LIMIT / RTTHREADTYPE_END);

	char * data = new (env()->heap()) char[32];

	snprintf(data, 32, "vbox %u", type);

	con[type - 1] = new (env()->heap()) Cpu_connection(data, prio);

	return con[type - 1];
}


extern "C" {

	/**
	 * Returns true if a vCPU could be started. If false we run without
	 * hardware acceleration support.
	 */
	bool create_emt_vcpu(pthread_t * pthread, size_t stack,
	                     const pthread_attr_t *attr,
	                     void *(*start_routine) (void *), void *arg,
	                     Genode::Cpu_session *);

	int pthread_create(pthread_t *thread, const pthread_attr_t *attr,
	                   void *(*start_routine) (void *), void *arg)
	{
		PRTTHREADINT rtthread = reinterpret_cast<PRTTHREADINT>(arg);

		Assert(rtthread);

		size_t stack_size = Genode::Native_config::context_virtual_size() -
		                    sizeof(Genode::Native_utcb) - 2 * (1UL << 12);

		if (rtthread->cbStack < stack_size)
			stack_size = rtthread->cbStack;
		else
			PWRN("requested stack for thread '%s' of %zu Bytes is too large, "
			     "limit to %zu Bytes", rtthread->szName, rtthread->cbStack,
			     stack_size);

		/* sanity check - emt and vcpu thread have to have same prio class */
		if (!Genode::strcmp(rtthread->szName, "EMT"))
			Assert(rtthread->enmType == RTTHREADTYPE_EMULATION);

		if (rtthread->enmType == RTTHREADTYPE_EMULATION) {

			if (create_emt_vcpu(thread, stack_size, attr, start_routine, arg,
			                          get_cpu_session(RTTHREADTYPE_EMULATION)))
				return 0;
			/* no haredware support, create normal pthread thread */
		}

		pthread_t thread_obj = new (Genode::env()->heap())
		                           pthread(attr ? *attr : 0, start_routine,
		                           arg, stack_size, rtthread->szName,
		                           get_cpu_session(rtthread->enmType));

		if (!thread_obj)
			return EAGAIN;

		*thread = thread_obj;

		thread_obj->start();

		return 0;
	}
}