source: trunk/kernel/syscalls/sys_readdir.c @ 23

Last change on this file since 23 was 23, checked in by alain, 5 years ago

Introduce syscalls.

File size: 2.6 KB
Line 
1/*
2 * sys_readdir.c - Read one entry from an open directory.
3 *
4 * Author    Alain Greiner (2016,2017)
5 *
6 * Copyright (c) UPMC Sorbonne Universites
7 *
8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
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 *
14 * ALMOS-MKH is distributed in the hope that it will be useful, but
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
20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#include <kernel_config.h>
25#include <hal_types.h>
26#include <hal_uspace.h>
27#include <errno.h>
28#include <thread.h>
29#include <printk.h>
30#include <vfs.h>
31#include <process.h>
32#include <syscalls.h>
33
34//////////////////////////////////////////
35int sys_readdir ( uint32_t       file_id,
36                  vfs_dirent_t * dirent )
37{
38        error_t        error;
39    paddr_t        paddr;
40        xptr_t         file_xp;    // extended pointer on searched directory file descriptor
41    vfs_dirent_t   k_dirent;   // kernel copy of dirent
42
43        thread_t     * this     = CURRENT_THREAD;
44        process_t    * process  = this->process;
45
46    // check file_id argument
47        if( file_id >= CONFIG_PROCESS_FILE_MAX_NR )
48        {
49        printk("\n[ERROR] in %s : illegal file descriptor index\n", __FUNCTION__ );
50        this->errno = EBADFD;
51                return -1;
52        }
53
54    // check dirent structure in user space
55    error = vmm_v2p_translate( false , dirent , &paddr );
56
57    if ( error )
58    {
59        printk("\n[ERROR] in %s : user buffer for dirent unmapped = %x\n",
60               __FUNCTION__ , (intptr_t)dirent );
61                this->errno = EFAULT;
62                return -1;
63    }
64
65    // get extended pointer on remote file descriptor
66    file_xp = process_fd_get_xptr( process , file_id );
67
68    if( file_xp == XPTR_NULL )
69    {
70        printk("\n[ERROR] in %s : undefined file descriptor index = %d\n",
71               __FUNCTION__ , file_id );
72            this->errno = EBADFD;
73        return -1;
74    }
75 
76    // call the relevant VFS function
77        error = vfs_readdir( file_xp , &k_dirent );
78
79        if( error )
80        {
81        printk("\n[ERROR] in %s : cannot access directory %d\n",
82               __FUNCTION__ , file_id );
83                this->errno = error;
84                return -1;
85        }
86   
87    // copy dirent to user space
88    hal_copy_to_uspace( dirent , &k_dirent , sizeof(vfs_dirent_t) );
89
90        return 0;
91
92}  // end sys_readdir()
Note: See TracBrowser for help on using the repository browser.