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

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

Introduce syscalls.

File size: 2.7 KB
Line 
1/*
2 * sys_chdir: change process current working directory
3 *
4 * Author    Alain Greiner (2016,2017)
5 *
6 * Copyright (c) 2011,2012 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 <hal_types.h>
25#include <hal_uspace.h>
26#include <chdev.h>
27#include <rwlock.h>
28#include <vfs.h>
29#include <errno.h>
30#include <thread.h>
31#include <printk.h>
32#include <process.h>
33
34/////////////////////////////////
35int sys_chdir ( char * pathname )
36{
37        error_t   error;
38    paddr_t   paddr;
39    uint32_t  length;
40    char      kbuf[CONFIG_VFS_MAX_PATH_LENGTH];
41
42        thread_t  * this    = CURRENT_THREAD;
43    process_t * process = this->process;
44
45    // check pathname in user space
46    error = vmm_v2p_translate( false , pathname , &paddr );
47
48        if( error )
49        {
50        printk("\n[ERROR] in %s : user buffer unmapped  for thread %x in process %x\n",
51               __FUNCTION__ , this->trdid , process->pid );
52                this->errno = EINVAL;
53                return -1;
54        }       
55     
56    // get pathname length
57    length = hal_strlen_from_uspace( pathname );
58
59    if( length >= CONFIG_VFS_MAX_PATH_LENGTH )
60    {
61        printk("\n[ERROR] in %s : pathname too long for thread %x in process %x\n",
62               __FUNCTION__ , this->trdid , process->pid );
63                this->errno = ENFILE;
64        return -1;
65    }
66 
67        // get pathname copy in kernel space
68    hal_copy_from_uspace( kbuf, pathname, length );
69
70    // get cluster and local pointer on reference process
71    xptr_t      ref_xp  = process->ref_xp;
72    process_t * ref_ptr = (process_t *)GET_PTR( ref_xp );
73    cxy_t       ref_cxy = GET_CXY( ref_xp );
74
75    // get extended pointer on cwd lock in reference process
76    xptr_t lock_xp = hal_remote_lwd( XPTR( ref_cxy , &ref_ptr->cwd_lock ) );
77       
78    // get cwd lock in read mode
79        remote_rwlock_rd_lock( lock_xp );
80
81    // call relevant VFS function
82        error = vfs_chdir( process->vfs_cwd_xp , kbuf );
83
84    // release cwd lock
85        remote_rwlock_rd_unlock( lock_xp );
86
87        if( error )
88        {
89        printk("\n[ERROR] in %s : cannot change current directory\n", __FUNCTION__ );
90                this->errno = error;
91                return -1;
92        }
93   
94        return 0;
95}
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