source: trunk/kernel/syscalls/sys_getcwd.c @ 459

Last change on this file since 459 was 457, checked in by alain, 3 years ago

This version modifies the exec syscall and fixes a large number of small bugs.
The version number has been updated (0.1)

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