source: trunk/kernel/syscalls/sys_getcwd.c @ 506

Last change on this file since 506 was 506, checked in by viala@…, 3 years ago

[syscalls] add interface in implementation.

Add const where possible, fix protoypes to follow interface.

File size: 2.7 KB
Line 
1/*
2 * sys_getcwd.c - get process current work directory
3 *
4 * Author    Alain Greiner (2016,2017,2018)
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_kernel_types.h>
26#include <hal_uspace.h>
27#include <hal_special.h>
28#include <errno.h>
29#include <vfs.h>
30#include <vmm.h>
31#include <process.h>
32#include <thread.h>
33#include <printk.h>
34
35#include <syscalls.h>
36
37/* TODO: user page(s) need to be locked  [AG] */
38
39////////////////////////////////
40int sys_getcwd ( char     * buf, 
41                 uint32_t   nbytes )
42{
43        error_t    error;
44    vseg_t   * vseg;
45    char       kbuf[CONFIG_VFS_MAX_PATH_LENGTH];
46 
47        thread_t  * this    = CURRENT_THREAD;
48    process_t * process = this->process;
49
50    // check buffer size
51        if( nbytes < CONFIG_VFS_MAX_PATH_LENGTH )
52        {
53
54#if DEBUG_SYSCALLS_ERROR
55printk("\n[ERROR] in %s : buffer too small / thread %x / process %x\n",
56__FUNCTION__ , this->trdid , process->pid );
57#endif
58                this->errno = EINVAL;
59        return -1;
60        }
61
62    // check buffer in user space
63    error = vmm_get_vseg( process, (intptr_t)buf , &vseg );
64
65        if( error )
66        {
67
68#if DEBUG_SYSCALLS_ERROR
69printk("\n[ERROR] in %s : user buffer unmapped %x / thread %x / process %x\n",
70__FUNCTION__ , (intptr_t)buf , this->trdid , process->pid );
71#endif
72                this->errno = EINVAL;
73        return -1;
74        }
75
76    // get reference process cluster and local pointer
77    xptr_t      ref_xp  = process->ref_xp;
78    cxy_t       ref_cxy = GET_CXY( ref_xp );
79    process_t * ref_ptr = (process_t *)GET_PTR( ref_xp );
80
81    // get CWD lock in read mode
82        remote_rwlock_rd_lock( XPTR( ref_cxy , &ref_ptr->cwd_lock ) );
83
84    // call relevant VFS function
85        error = vfs_get_path( XPTR( ref_cxy , &ref_ptr->vfs_cwd_xp ) ,
86                          kbuf , CONFIG_VFS_MAX_PATH_LENGTH );
87
88    // release CWD lock
89        remote_rwlock_rd_unlock( XPTR( ref_cxy , &ref_ptr->cwd_lock ) );
90
91    // copy kernel buffer to user space
92    hal_copy_to_uspace( buf , kbuf , CONFIG_VFS_MAX_PATH_LENGTH );
93
94    hal_fence();
95
96        return 0;
97
98}  // end sys_getcwd()
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