source: trunk/kernel/syscalls/sys_read.c @ 324

Last change on this file since 324 was 313, checked in by alain, 7 years ago

RSeveral modifs in the page-fault handling.

File size: 3.1 KB
RevLine 
[1]1/*
[23]2 * sys_read.c - read bytes from a file
[1]3 *
[23]4 * Author     Alain Greiner (2016,2017)
[1]5 *
[23]6 * Copyright (c) UPMC Sorbonne Universites
[1]7 *
[23]8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
[1]11 * under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; version 2.0 of the License.
13 *
[23]14 * ALMOS-MKH is distributed in the hope that it will be useful, but
[1]15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
[23]20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
[1]21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
[23]24#include <kernel_config.h>
25#include <hal_types.h>
26#include <hal_uspace.h>
27#include <hal_special.h>
[1]28#include <errno.h>
[23]29#include <vfs.h>
30#include <vmm.h>
[1]31#include <thread.h>
[23]32#include <printk.h>
33#include <process.h>
[1]34
[23]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 )
[1]41{
[23]42    error_t      error;
[313]43    paddr_t      paddr;       // required for user space checking
[23]44        xptr_t       file_xp;     // remote file extended pointer
[1]45
[23]46        thread_t  *  this    = CURRENT_THREAD;
47        process_t *  process = this->process;
48 
49    // check file_id argument
50        if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
[1]51        {
[23]52        printk("\n[ERROR] in %s : illegal file descriptor index = %d\n",
53               __FUNCTION__ , file_id );
54                this->errno = EBADFD;
[1]55                return -1;
56        }
57
[23]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 readable
85    uint32_t attr = hal_remote_lw( XPTR( file_cxy , &file_ptr->attr ) );
86    if( (attr & FD_ATTR_READ_ENABLE) == 0 )
[1]87        {
[23]88        printk("\n[ERROR] in %s : file %d not readable\n",
89               __FUNCTION__ , file_id );
90                this->errno = EBADFD;
[1]91                return -1;
92        }
[313]93   
94    // transfer count bytes directly from mapper to user buffer
95    error = vfs_user_move( true,               // to_buffer
96                           file_xp , 
97                           buf, 
98                           count );
99
100    if( error )
[23]101    {
[313]102        printk("\n[ERROR] in %s cannot read data from file %d\n",
103               __FUNCTION__ , file_id );
104        this->errno = error;
105        return -1;
[23]106    }
107
[124]108    hal_fence();
[23]109
110        return 0;
111
112}  // end sys_read()
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