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_read.c

    r1 r23  
    11/*
    2  * kern/sys_read.c - read bytes from an opened file
     2 * sys_read.c - read bytes from 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>
     29#include <vfs.h>
     30#include <vmm.h>
    2431#include <thread.h>
    25 #include <vfs.h>
    26 #include <sys-vfs.h>
    27 #include <task.h>
     32#include <printk.h>
     33#include <process.h>
    2834
    29 int sys_read (uint_t fd, void *buf, size_t count)
     35/* TODO: user page(s) need to be locked  [AG] */
     36
     37/////////////////////////////////
     38int sys_read( uint32_t   file_id,
     39              void     * buf,
     40              uint32_t   count )
    3041{
    31         struct ku_obj kub;
    32         ssize_t err;
    33         struct thread_s *this;
    34         struct task_s *task;
    35         struct vfs_file_s *file;
     42    error_t      error;
     43    paddr_t      paddr;
     44    char         kbuf[CONFIG_VFS_KBUF_SIZE];
    3645
    37         file = NULL;
    38         this = current_thread;
    39         task = current_task;
     46        xptr_t       file_xp;     // remote file extended pointer
     47    uint32_t     nbytes;      // number of bytes in one iteration
    4048
    41         if((fd >= CONFIG_TASK_FILE_MAX_NR) || (task_fd_lookup(task, fd, &file)))
     49        thread_t  *  this    = CURRENT_THREAD;
     50        process_t *  process = this->process;
     51 
     52    // check file_id argument
     53        if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
    4254        {
    43                 this->info.errno = EBADFD;
     55        printk("\n[ERROR] in %s : illegal file descriptor index = %d\n",
     56               __FUNCTION__ , file_id );
     57                this->errno = EBADFD;
    4458                return -1;
    4559        }
    4660
    47         KU_SLICE_BUFF(kub, buf, count);
    48         if((err = vfs_read(file, &kub)) < 0)
     61    // check user buffer in user space
     62    error = vmm_v2p_translate( false , buf , &paddr );
     63
     64    if ( error )
     65    {
     66        printk("\n[ERROR] in %s : user buffer unmapped = %x\n",
     67               __FUNCTION__ , (intptr_t)buf );
     68                this->errno = EINVAL;
     69                return -1;
     70    }
     71
     72    // get extended pointer on remote file descriptor
     73    file_xp = process_fd_get_xptr( process , file_id );
     74
     75    if( file_xp == XPTR_NULL )
     76    {
     77        printk("\n[ERROR] in %s : undefined file descriptor index = %d\n",
     78               __FUNCTION__ , file_id );
     79        this->errno = EBADFD;
     80        return -1;
     81    }
     82
     83    // get file descriptor cluster and local pointer
     84    vfs_file_t * file_ptr = (vfs_file_t *)GET_PTR( file_xp );
     85    cxy_t        file_cxy = GET_CXY( file_xp );
     86
     87    // check file readable
     88    uint32_t attr = hal_remote_lw( XPTR( file_cxy , &file_ptr->attr ) );
     89    if( (attr & FD_ATTR_READ_ENABLE) == 0 )
    4990        {
    50                 this->info.errno = -err;
    51                 printk(INFO, "INFO: sys_read: Error %d\n", this->info.errno);
     91        printk("\n[ERROR] in %s : file %d not readable\n",
     92               __FUNCTION__ , file_id );
     93                this->errno = EBADFD;
    5294                return -1;
    5395        }
    5496   
    55         return err;
    56 }
     97    // transfer at most CONFIG_VFS_KBUF_SIZE bytes per iteration
     98    while( count )
     99    {
     100        if( count <= CONFIG_VFS_KBUF_SIZE )
     101        {
     102            nbytes = count;
     103            count  = 0;
     104        }
     105        else
     106        {
     107            nbytes = CONFIG_VFS_KBUF_SIZE;
     108            count  = count - CONFIG_VFS_KBUF_SIZE;
     109        }
     110
     111        // transfer nbytes to kernel buffer
     112        error = vfs_move( true,               // read => (to_buffer = true)
     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        // copy kernel buffer to user space
     126        hal_copy_to_uspace( buf , kbuf , nbytes );
     127    }
     128
     129    hal_wbflush();
     130
     131        return 0;
     132
     133}  // end sys_read()
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