Ignore:
Timestamp:
Jun 18, 2017, 10:06:41 PM (5 years ago)
Author:
alain
Message:

Introduce syscalls.

File:
1 edited

Legend:

Unmodified
Added
Removed
  • trunk/kernel/syscalls/sys_write.c

    r1 r23  
    11/*
    2  * kern/sys_write.c - write bytes to a file
     2 * sys_write.c - write bytes to a file
    33 *
    4  * Copyright (c) 2008,2009,2010,2011,2012 Ghassan Almaless
    5  * Copyright (c) 2011,2012 UPMC Sorbonne Universites
     4 * Author        Alain Greiner (2016,2017)
    65 *
    7  * This file is part of ALMOS-kernel.
     6 * Copyright (c) UPMC Sorbonne Universites
    87 *
    9  * ALMOS-kernel is free software; you can redistribute it and/or modify it
     8 * This file is part of ALMOS-MKH.
     9 *
     10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
    1011 * under the terms of the GNU General Public License as published by
    1112 * the Free Software Foundation; version 2.0 of the License.
    1213 *
    13  * ALMOS-kernel is distributed in the hope that it will be useful, but
     14 * ALMOS-MKH is distributed in the hope that it will be useful, but
    1415 * WITHOUT ANY WARRANTY; without even the implied warranty of
    1516 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     
    1718 *
    1819 * You should have received a copy of the GNU General Public License
    19  * along with ALMOS-kernel; if not, write to the Free Software Foundation,
     20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
    2021 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
    2122 */
    2223
     24#include <kernel_config.h>
     25#include <hal_types.h>
     26#include <hal_uspace.h>
     27#include <hal_special.h>
    2328#include <errno.h>
    24 #include <thread.h>
    2529#include <vfs.h>
    2630#include <thread.h>
    27 #include <sys-vfs.h>
    28 #include <task.h>
     31#include <printk.h>
     32#include <process.h>
    2933
    30 int sys_write (uint_t fd, void *buf, size_t count)
     34/* TODO: user page(s) need to be locked  [AG] */
     35
     36//////////////////////////////////
     37int sys_write( uint32_t   file_id,
     38               void     * buf,
     39               uint32_t   count )
    3140{
    32         ssize_t err = 0;
    33         struct thread_s *this;
    34         struct task_s *task;
    35         struct vfs_file_s *file;
    36         struct ku_obj kub;
     41    error_t      error;
     42    paddr_t      paddr;
     43    char         kbuf[CONFIG_VFS_KBUF_SIZE];
     44        xptr_t       file_xp;                       // remote file extended pointer
     45    uint32_t     nbytes;                        // number of bytes in one iteration
    3746
    38         file = NULL;
    39         this = current_thread;
    40         task = current_task;
     47        thread_t   * this = CURRENT_THREAD;
     48        process_t  * process = this->process;
    4149 
    42         if((fd >= CONFIG_TASK_FILE_MAX_NR) || (task_fd_lookup(task, fd, &file)))
     50    // check file_id argument
     51        if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
    4352        {
    44                 this->info.errno = EBADFD;
     53        printk("\n[ERROR] in %s : illegal file descriptor index\n", __FUNCTION__ );
     54        this->errno = EBADFD;
    4555                return -1;
    4656        }
    4757
    48         KU_SLICE_BUFF(kub, buf, count);
    49         if((err = vfs_write(file, &kub)) < 0)
     58    // check user buffer in user space
     59    error = vmm_v2p_translate( false , buf , &paddr );
     60
     61    if ( error )
     62    {
     63        printk("\n[ERROR] in %s : user buffer unmapped = %x\n",
     64               __FUNCTION__ , (intptr_t)buf );
     65                this->errno = EINVAL;
     66                return -1;
     67    }
     68
     69    // get extended pointer on remote file descriptor
     70    file_xp = process_fd_get_xptr( process , file_id );
     71
     72    if( file_xp == XPTR_NULL )
     73    {
     74        printk("\n[ERROR] in %s : undefined file descriptor index = %d\n",
     75               __FUNCTION__ , file_id );
     76                this->errno = EBADFD;
     77                return -1;
     78    }
     79
     80    // get file descriptor cluster and local pointer
     81    vfs_file_t * file_ptr = (vfs_file_t *)GET_PTR( file_xp );
     82    cxy_t        file_cxy = GET_CXY( file_xp );
     83
     84    // check file writable
     85    uint32_t attr = hal_remote_lw( XPTR( file_cxy , &file_ptr->attr ) );
     86    if( (attr & FD_ATTR_WRITE_ENABLE) == 0 )
    5087        {
    51                 this->info.errno = (err < 0) ? -err : err;
     88        printk("\n[ERROR] in %s : file %d not writable\n",
     89               __FUNCTION__ , file_id );
     90                this->errno = EBADFD;
    5291                return -1;
    5392        }
    5493   
    55         return err;
    56 }
     94    // transfer at most CONFIG_VFS_KBUF_SIZE bytes per iteration
     95    while( count )
     96    {
     97        if( count <= CONFIG_VFS_KBUF_SIZE )
     98        {
     99            nbytes = count;
     100            count  = 0;
     101        }
     102        else
     103        {
     104            nbytes = CONFIG_VFS_KBUF_SIZE;
     105            count  = count - CONFIG_VFS_KBUF_SIZE;
     106        }
     107
     108        // copy user buffer to kernel buffer
     109        hal_copy_to_uspace( buf , kbuf , nbytes );
     110
     111        // transfer nbytes from kernel buffer
     112        error = vfs_move( false,               // write => (to_buffer = false)
     113                          file_xp,
     114                          kbuf ,
     115                          nbytes );
     116
     117        if( error )
     118        {
     119            printk("\n[ERROR] in %s cannot read data from file %d\n",
     120                   __FUNCTION__ , file_id );
     121            this->errno = error;
     122            return -1;
     123        }
     124    }
     125
     126    hal_wbflush();
     127
     128        return 0;
     129
     130}  // end sys_write()
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