source: trunk/kernel/syscalls/sys_write.c @ 433

/*
 * sys_write.c - write bytes to a file
 * 
 * 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_uspace.h>
#include <hal_irqmask.h>
#include <hal_special.h>
#include <errno.h>
#include <vfs.h>
#include <thread.h>
#include <printk.h>
#include <process.h>

/* TODO: concurrent user page(s) unmap need to be handled [AG] */

//////////////////////////////////
int sys_write( uint32_t   file_id,
               void     * vaddr,
               uint32_t   count )
{
    error_t      error;
    paddr_t      paddr;           // unused, but 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 CONFIG_DEBUG_SYS_WRITE
uint32_t     tm_start;
uint32_t     tm_end;
tm_start = hal_get_cycles();
if( CONFIG_DEBUG_SYS_WRITE < tm_start )
printk("\n[DBG] %s : thread %x / process %x / vaddr %x / count %d / cycle %d\n",
__FUNCTION__, this, process->pid, vaddr, count, (uint32_t)tm_start );
#endif
 
    // check file_id argument
        if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
        {

#if CONFIG_DEBUG_SYSCALLS_ERROR
printk("\n[ERROR] in %s : illegal file descriptor index\n", __FUNCTION__ );
#endif
        this->errno = EBADFD;
                return -1;
        }

    // check user buffer in user space
    error = vmm_v2p_translate( false , vaddr , &paddr );

    if ( error )
    {

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

    // enable IRQs
    hal_enable_irq( &save_sr );

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

    if( file_xp == XPTR_NULL )
    {

#if CONFIG_DEBUG_SYSCALLS_ERROR
printk("\n[ERROR] in %s : undefined file descriptor index = %d in process %x\n",
__FUNCTION__ , file_id , process->pid );
#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_lw( XPTR( file_cxy , &file_ptr->type ) );

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

#if CONFIG_DEBUG_SYSCALLS_ERROR
printk("\n[ERROR] in %s : file %d not writable in process %x\n",
__FUNCTION__ , file_id , process->pid );
#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
    {
        // move count bytes to device
        nbytes = devfs_user_move( false,             // from buffer to device
                                 file_xp,
                                 vaddr,
                                 count );
    }
    else
    {
        nbytes = 0;
        assert( false , __FUNCTION__ , "file type %d non supported\n", type );
    }

    if( nbytes != count )
    {

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

    // restore IRQs
    hal_restore_irq( save_sr );

    hal_fence();

#if CONFIG_DEBUG_SYS_WRITE
tm_end = hal_get_cycles();
if( CONFIG_DEBUG_SYS_WRITE < tm_end )
printk("\n[DBG] %s : thread %x in process %x / cycle %d\n"
"nbytes = %d / first byte = %c / file_id = %d / cost = %d\n",
__FUNCTION__, this, process->pid, (uint32_t)tm_start,
nbytes, *((char *)(intptr_t)paddr) , file_id , (uint32_t)(tm_end - tm_start) );
#endif
 
        return nbytes;

}  // end sys_write()