/*
 * sys_thread_create.c - creates a new user thread
 * 
 * Author  Ghassan Almaless (2008,2009,2010,2011,2012)
 *         Mohamed lamine Karaoui (2015)
 *         Alain Greiner (2016)
 *
 * Copyright (c) UPMC Sorbonne Universites
 *
 * This file is part of ALMOS-MKH.
 *
 * ALMOS-MKH 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; version 2.0 of the License.
 *
 * ALMOS-MKH 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 ALMOS-MKH; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <almos_config.h>
#include <hal_types.h>
#include <printk.h>
#include <errno.h>
#include <core.h>
#include <cluster.h>
#include <list.h>
#include <xlist.h>
#include <thread.h>
#include <scheduler.h>
#include <kmem.h>
#include <process.h>
#include <spinlock.h>
#include <dqdt.h>


//////////////////////////////////////////////////////////////////////////////////////////
// This function implements the pthread_create system call
//////////////////////////////////////////////////////////////////////////////////////////
int sys_thread_create ( thread_t       * new_thread,    // [out] argument
                        pthread_attr_t * user_attr,     // [in] argument
                        void           * start_func,    // [in] argument
                        void           * start_args )   // [in] argument
{
	pthread_attr_t   attr;             // copy of pthread attributes in kernel space
	thread_t       * parent;           // pointer on thread executing the pthread_create
    xptr_t           xp_parent;        // extended pointer on created thread
    thread_t       * child;            // pointer on created child thread
    xptr_t           xp_child;         // extended pointer on created thread
    trdid_t          trdid;            // created thread identifier
    process_t      * process;          // pointer on local process descriptor
    error_t          error;

	uint32_t         tm_start;
	uint32_t         tm_end;

	tm_start = hal_time_stamp();

    // get parent thead pointer, extended pointer, and process pointer
	parent     = CURRENT_THREAD;
    xp_parent  = XPTR( local_cxy , parent );    
	process    = parent->process;

    // check user_attr & start_func arguments
	if( user_attr == NULL )
	{
		printk("\n[ERROR] in %s : user_attr is NULL\n", __FUNCTION__ );
		return EINVAL;
	}
	if( start_func== NULL )
	{
		printk("\n[ERROR] in %s : start_func is NULL\n", __FUNCTION__ );
		return EINVAL;
	}

    // copy user_attr structure to kernel space
	hal_copy_from_uspace( &attr , user_attr , sizeof(pthread_attr_t) );

    // check/set "cxy" attribute
	if( attr.flags & PT_FLAG_CLUSTER_DEFINED ) 
    {
        if( cluster_is_undefined( attr.cxy ) )
        {
		    printk("\n[ERROR] in %s : illegal target cluster = %x\n",
                   __FUNCTION__ , attr.cxy );
		    return = EINVAL;
        } 
    }
    else
    {
        attr.cxy = dqdt_get_cluster_for_process();
    }

    // set "pid", "start_func" & "start_args" attributes
    attr.pid        = process->pid;
    attr.start_func = start_func;
    attr.start_args = start_args;

    // create the thread, using a RPC if required
    // this returns "error", "child", and "xp_child" 
    if( attr.cxy == local_cxy )                 // target cluster is local 
    {
        // allocate a stack from local VMM 
        vseg_t * vseg = vmm_create_vseg( process, 
                                         0,
                                         0,
                                         VSEG_TYPE_STACK,
                                         local_cxy );
        if( vseg == NULL )
        {
		    printk("\n[ERROR] in %s for : cannot create stack vseg\n", __FUNCTION__ );
		    return = EINVAL;
        } 

        // create thread in local cluster
        error = thread_user_create( &child,
                                    &attr,
                                    vseg->min,
                                    vseg->max - vseg->min );

        xp_child = XPTR( local_cxy , thread );
    }
    else                                                 // target cluster is remote
    {
        rpc_thread_user_create( attr.cxy , &attr , &error , &xp_child );
        child = (thread_t *)GET_PTR( xp_child );
    }

    // check successful thread creation
    if( error ) 
    {
		printk("\n[ERROR] in %s : cannot create thread\n", __FUNCTION__ );
        return ENOMEM;
    }

    // returns trdid to user space 
    trdid = hal_remote_lw( XPTR( attr.cxy , &child->trdid ) );   
	hal_copy_to_uspace( new_thread , &trdid , sizeof(pthread_t) );
    
    // register new-thread in parent-thread children list if required
    if( attr.flags & PT_FLAG_DETACH == 0 ) thread_child_parent_link( xp_parent , xp_child );

	tm_end = hal_time_stamp();

	thread_dmsg("\n[INFO] %s created thread %x for process %x in cluster %x\n"
                "  start_cycle = %d / end_cycle = %d\n",
                   trdid , process->pid , attr.cxy , tm_start , tm_end );
	return 0;

}  // end sys_thread_create()