/*
 * sys_fg.c - Kernel function implementing the "fg" system call.
 * 
 * Author    Alain Greiner (2016,2017)
 *
 * 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 <kernel_config.h>
#include <hal_types.h>
#include <hal_irqmask.h>
#include <errno.h>
#include <thread.h>
#include <printk.h>
#include <process.h>
#include <shared_syscalls.h>
#include <cluster.h>
#include <rpc.h>

//////////////////////////
int sys_fg( pid_t    pid )
{
    xptr_t      process_xp;
    process_t * process_ptr;
    cxy_t       process_cxy;
    xptr_t      chdev_xp;
    chdev_t   * chdev_ptr;
    cxy_t       chdev_cxy;

    thread_t  * this    = CURRENT_THREAD;

#if CONFIG_SYSCALL_DEBUG
uint64_t    tm_start;
uint64_t    tm_end;
tm_start = hal_get_cycles();
printk("\n[DBG] %s : core[%x,%d] enter / process %x / cycle %d\n",
__FUNCTION__ , local_cxy , this->core->lid , pid, (uint32_t)tm_start );
#endif

    // check process existence
    process_xp = cluster_get_reference_process_from_pid( pid );

    if( process_xp == XPTR_NULL )
    {
        syscall_dmsg("\n[ERROR] in %s : process %x not found\n",
        __FUNCTION__ , pid );
        this->errno = EINVAL;
        return -1;
    }
    
    // get reference process cluster and local pointer
    process_ptr = (process_t *)GET_PTR( process_xp );
    process_cxy = GET_CXY( process_xp );
 
    // get extended pointer on TXT_RX chdev
    chdev_xp = chdev_from_file( XPTR( process_cxy , &process_ptr->fd_array.array[0] ) );

    // get chdev cluster and local pointer
    chdev_ptr = (chdev_t *)GET_PTR( chdev_xp );
    chdev_cxy = GET_CXY( chdev_xp );

    // set reference process owner in TXT_RX chdev
    hal_remote_swd( XPTR( chdev_cxy , &chdev_ptr->ext.txt.owner_xp ) , process_xp );

    hal_fence();

#if CONFIG_SYSCALL_DEBUG 
tm_end = hal_get_cycles();
printk("\n[DBG] %s : core[%x,%d] exit / process %x / cost = %d\n",
__FUNCTION__ , local_cxy , this->core->lid , pid, (uint32_t)(tm_end - tm_start) );
#endif
 
	return 0;

}  // end sys_kill()