/*
 * sys_write.c - Kernel function implementing the "write" system call.
 * 
 * Author        Alain Greiner (2016,2017,2018)
 *
 * 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_kernel_types.h>
#include <hal_uspace.h>
#include <hal_irqmask.h>
#include <hal_special.h>
#include <errno.h>
#include <vfs.h>
#include <vmm.h>
#include <thread.h>
#include <printk.h>
#include <process.h>


extern uint32_t enter_sys_write;
extern uint32_t enter_devfs_write;
extern uint32_t enter_txt_write;
extern uint32_t enter_chdev_cmd_write;
extern uint32_t enter_chdev_server_write;
extern uint32_t enter_tty_cmd_write;
extern uint32_t enter_tty_isr_write;
extern uint32_t exit_tty_isr_write;
extern uint32_t exit_tty_cmd_write;
extern uint32_t exit_chdev_server_write;
extern uint32_t exit_chdev_cmd_write;
extern uint32_t exit_txt_write;
extern uint32_t exit_devfs_write;
extern uint32_t exit_sys_write;

//////////////////////////////////
int sys_write( uint32_t   file_id,
               void     * vaddr,
               uint32_t   count )
{
    error_t      error;
    vseg_t     * vseg;            // required for user space checking
	xptr_t       file_xp;         // remote file extended pointer
    uint32_t     nbytes;          // number of bytes actually written
    reg_t        save_sr;         // required to enable IRQs during syscall

	thread_t   * this = CURRENT_THREAD;
	process_t  * process = this->process;

#if (DEBUG_SYS_WRITE || CONFIG_INSTRUMENTATION_SYSCALLS)
uint64_t     tm_start = hal_get_cycles();
#endif

#if DEBUG_SYS_WRITE
tm_start = hal_get_cycles();
if( DEBUG_SYS_WRITE < tm_start )
printk("\n[DBG] %s : thread[%x,%x] enter / vaddr %x / count %d / cycle %d\n",
__FUNCTION__, process->pid, this->trdid, vaddr, count, (uint32_t)tm_start );
#endif
 
#if (DEBUG_SYS_WRITE & 1)
enter_sys_write = (uint32_t)tm_start;
#endif

    // check file_id argument
	if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
	{

#if DEBUG_SYSCALLS_ERROR
printk("\n[ERROR] in %s : thread[%x,%x] illegal file descriptor index %d\n",
__FUNCTION__, process->pid, this->trdid, file_id );
#endif
        this->errno = EBADFD;
		return -1;
	}

    // check user buffer in user space
    error = vmm_get_vseg( process , (intptr_t)vaddr , &vseg );

    if ( error )
    {

#if DEBUG_SYSCALLS_ERROR
printk("\n[ERROR] in %s : thread[%x,%x] user buffer unmapped %x\n",
__FUNCTION__ , process->pid, this->trdid, (intptr_t)vaddr );
vmm_display( process , false );
#endif
		this->errno = EINVAL;
		return -1;
    }

    // get extended pointer on remote file descriptor
    file_xp = process_fd_get_xptr( process , file_id );

    if( file_xp == XPTR_NULL )
    {

#if DEBUG_SYSCALLS_ERROR
printk("\n[ERROR] in %s : thread[%x,%x] undefined file descriptor index = %d\n",
__FUNCTION__, process->pid, this->trdid, file_id );
#endif
		this->errno = EBADFD;
		return -1;
    }

    // get file descriptor cluster and local pointer
    vfs_file_t * file_ptr = (vfs_file_t *)GET_PTR( file_xp );
    cxy_t        file_cxy = GET_CXY( file_xp );

 
    // get file type
    vfs_inode_type_t type = hal_remote_l32( XPTR( file_cxy , &file_ptr->type ) );

    // enable IRQs
    hal_enable_irq( &save_sr );

   // action depend on file type
    if( type == INODE_TYPE_FILE )  // check file writable & write to mapper 
    {
        // check file writable
        uint32_t attr = hal_remote_l32( XPTR( file_cxy , &file_ptr->attr ) );
        if( (attr & FD_ATTR_WRITE_ENABLE) == 0 )
	    {

#if DEBUG_SYSCALLS_ERROR
printk("\n[ERROR] in %s : thread[%x,%x] file %d not writable\n",
__FUNCTION__ , process->pid, this->trdid, file_id );
#endif
		    this->errno = EBADFD;
		    return -1;
	    }

        // move count bytes to mapper
        nbytes = vfs_user_move( false,               // from buffer to mapper
                                file_xp,
                                vaddr, 
                                count );
    }
    else if( type == INODE_TYPE_DEV )  // check ownership & write to device
    {
        // check user buffer size for TXT_TX
        if( (type == INODE_TYPE_DEV) && (count >= CONFIG_TXT_KBUF_SIZE) )
        {

#if DEBUG_SYSCALLS_ERROR
printk("\n[ERROR] in %s : thread[%x,%x] user buffer size %x too large\n",
__FUNCTION__ , process->pid, this->trdid, count );
#endif
		    this->errno = EINVAL;
		    return -1;
        }

        // move count bytes to device
        nbytes = devfs_user_move( false,             // from buffer to device
                                 file_xp,
                                 vaddr,
                                 count );
    }
    else  // not FILE and not DEV
    {
        nbytes = 0;
        assert( false , "file type %d non supported\n", type );
    }

    if( nbytes != count )
    {

#if DEBUG_SYSCALLS_ERROR
printk("\n[ERROR] in %s : thread[%x,‰x] cannot write data to file %d\n",
__FUNCTION__ , process->pid, this->trdid, file_id );
#endif
        this->errno = error;
        return -1;
    }

    // restore IRQs
    hal_restore_irq( save_sr );

    hal_fence();

#if (DEBUG_SYS_WRITE || CONFIG_INSTRUMENTATION_SYSCALLS)
uint64_t     tm_end = hal_get_cycles();
#endif

#if DEBUG_SYS_WRITE
if( DEBUG_SYS_WRITE < tm_end )
printk("\n[DBG] %s : thread[%x,%x] exit / cycle %d\n",
__FUNCTION__, process->pid, this->trdid, (uint32_t)tm_end );
#endif
 
#if CONFIG_INSTRUMENTATION_SYSCALLS
hal_atomic_add( &syscalls_cumul_cost[SYS_WRITE] , tm_end - tm_start );
hal_atomic_add( &syscalls_occurences[SYS_WRITE] , 1 );
#endif

#if (DEBUG_SYS_WRITE & 1) 
exit_sys_write = (uint32_t)tm_end;

printk("\n***** timing to write a string *****\n"
" - enter_sys_write          = %d / delta %d\n"
" - enter_devfs_write        = %d / delta %d\n"
" - enter_txt_write          = %d / delta %d\n"
" - enter_chdev_cmd_write    = %d / delta %d\n"
" - enter_chdev_server_write = %d / delta %d\n"
" - enter_tty_cmd_write      = %d / delta %d\n"
" - enter_tty_isr_write      = %d / delta %d\n"
" - exit_tty_isr_write       = %d / delta %d\n"
" - exit_tty_cmd_write       = %d / delta %d\n"
" - exit_chdev_server_write  = %d / delta %d\n"
" - exit_chdev_cmd_write     = %d / delta %d\n"
" - exit_txt_write           = %d / delta %d\n"
" - exit_devfs_write         = %d / delta %d\n"
" - exit_sys_write           = %d / delta %d\n",
enter_sys_write          , 0 ,
enter_devfs_write        , enter_devfs_write        - enter_sys_write          ,
enter_txt_write          , enter_txt_write          - enter_devfs_write        ,
enter_chdev_cmd_write    , enter_chdev_cmd_write    - enter_txt_write          ,
enter_chdev_server_write , enter_chdev_server_write - enter_chdev_cmd_write    ,
enter_tty_cmd_write      , enter_tty_cmd_write      - enter_chdev_server_write ,
enter_tty_isr_write      , enter_tty_isr_write      - enter_tty_cmd_write      ,
exit_tty_isr_write       , exit_tty_isr_write       - enter_tty_isr_write      ,
exit_tty_cmd_write       , exit_tty_cmd_write       - exit_tty_isr_write       ,
exit_chdev_server_write  , exit_chdev_server_write  - exit_tty_cmd_write       ,
exit_chdev_cmd_write     , exit_chdev_cmd_write     - exit_chdev_server_write  ,
exit_txt_write           , exit_txt_write           - exit_chdev_cmd_write     ,
exit_devfs_write         , exit_devfs_write         - exit_txt_write           ,
exit_sys_write           , exit_sys_write           - exit_devfs_write         );
#endif
 
	return nbytes;

}  // end sys_write()
