source: trunk/kernel/syscalls/sys_open.c @ 457

Last change on this file since 457 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: 3.1 KB
Line 
1/*
2 * sys_open.c - open a file.
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_kernel_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 <remote_spinlock.h>
33#include <remote_rwlock.h>
34
35///////////////////////////////////
36int sys_open ( char     * pathname,
37               uint32_t   flags,
38               uint32_t   mode )
39{
40    error_t        error;
41    xptr_t         file_xp;                          // extended pointer on vfs_file_t
42    uint32_t       file_id;                          // file descriptor index
43    char           kbuf[CONFIG_VFS_MAX_PATH_LENGTH];
44
45    thread_t     * this     = CURRENT_THREAD;
46    process_t    * process  = this->process;
47
48    // check fd_array not full
49    if( process_fd_array_full() )
50    {
51        printk("\n[ERROR] in %s : file descriptor array full for process %x\n",
52               __FUNCTION__ , process->pid );
53        this->errno = ENFILE;
54        return -1;
55    }
56
57    // check pathname length
58    if( hal_strlen_from_uspace( pathname ) >= CONFIG_VFS_MAX_PATH_LENGTH )
59    {
60        printk("\n[ERROR] in %s : pathname too long\n", __FUNCTION__ );
61        this->errno = ENFILE;
62        return -1;
63    }
64
65    // copy pathname in kernel space
66    hal_strcpy_from_uspace( kbuf , pathname , CONFIG_VFS_MAX_PATH_LENGTH );
67
68    // get cluster and local pointer on reference process
69    xptr_t      ref_xp  = process->ref_xp;
70    process_t * ref_ptr = (process_t *)GET_PTR( ref_xp );
71    cxy_t       ref_cxy = GET_CXY( ref_xp );
72
73    // get the cwd lock in read mode from reference process
74    remote_rwlock_rd_lock( XPTR( ref_cxy , &ref_ptr->cwd_lock ) );
75
76    // call the relevant VFS function
77    error = vfs_open( process,
78                      kbuf,
79                      flags,
80                      mode,
81                      &file_xp,
82                      &file_id );
83
84    // release the cwd lock
85    remote_rwlock_rd_unlock( XPTR( ref_cxy , &ref_ptr->cwd_lock ) );
86
87    if( error )
88    {
89        printk("\n[ERROR] in %s : cannot create file descriptor\n", __FUNCTION__ );
90        this->errno = ENFILE;
91        return -1;
92    }
93
94    // update local fd_array
95    remote_spinlock_lock( XPTR( local_cxy , &process->fd_array.lock ) );
96    process->fd_array.array[file_id] = file_xp;
97    remote_spinlock_unlock( XPTR( local_cxy , &process->fd_array.lock ) );
98
99    return file_id;
100}
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