source: trunk/kernel/syscalls/sys_open.c @ 569

Last change on this file since 569 was 566, checked in by alain, 6 years ago

Complete restructuration of kernel locks.

File size: 3.5 KB
RevLine 
[1]1/*
[23]2 * sys_open.c - open a file.
[305]3 *
[23]4 * Author        Alain Greiner (2016,2017)
[1]5 *
[23]6 * Copyright (c) UPMC Sorbonne Universites
[1]7 *
[23]8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
[1]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 *
[23]14 * ALMOS-MKH is distributed in the hope that it will be useful, but
[1]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
[23]20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
[1]21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
[23]24#include <kernel_config.h>
[457]25#include <hal_kernel_types.h>
[23]26#include <hal_uspace.h>
[1]27#include <errno.h>
28#include <thread.h>
[23]29#include <printk.h>
[1]30#include <vfs.h>
31#include <process.h>
[23]32#include <remote_rwlock.h>
[1]33
[506]34#include <syscalls.h>
35
[1]36///////////////////////////////////
[566]37int sys_open ( char     * pathname,
38               uint32_t   flags,
39               uint32_t   mode )
[1]40{
[305]41    error_t        error;
42    xptr_t         file_xp;                          // extended pointer on vfs_file_t
43    uint32_t       file_id;                          // file descriptor index
[23]44    char           kbuf[CONFIG_VFS_MAX_PATH_LENGTH];
[1]45
[305]46    thread_t     * this     = CURRENT_THREAD;
47    process_t    * process  = this->process;
[1]48
[459]49#if DEBUG_SYS_OPEN
50uint32_t     tm_start;
51uint32_t     tm_end;
52tm_start = hal_get_cycles();
53#endif
54 
[23]55    // check fd_array not full
[305]56    if( process_fd_array_full() )
57    {
[566]58
59#if DEBUG_SYSCALLS_ERROR
60printk("\n[ERROR] in %s : file descriptor array full for process %x\n",
61__FUNCTION__ , process->pid );
62#endif
[305]63        this->errno = ENFILE;
[23]64        return -1;
[305]65    }
[1]66
[407]67    // check pathname length
68    if( hal_strlen_from_uspace( pathname ) >= CONFIG_VFS_MAX_PATH_LENGTH )
[23]69    {
[566]70
71#if DEBUG_SYSCALLS_ERROR
72printk("\n[ERROR] in %s : pathname too long\n", __FUNCTION__ );
73#endif
[305]74        this->errno = ENFILE;
[23]75        return -1;
76    }
[1]77
[407]78    // copy pathname in kernel space
79    hal_strcpy_from_uspace( kbuf , pathname , CONFIG_VFS_MAX_PATH_LENGTH );
80
[459]81#if DEBUG_SYS_OPEN
82if( DEBUG_SYS_OPEN < tm_start )
83printk("\n[DBG] %s : thread %x in process %x enter / path %s / flags %x / cycle %d\n",
84__FUNCTION__, this->trdid, process->pid, kbuf, flags, (uint32_t)tm_start );
85#endif
86 
[23]87    // get cluster and local pointer on reference process
88    xptr_t      ref_xp  = process->ref_xp;
89    process_t * ref_ptr = (process_t *)GET_PTR( ref_xp );
90    cxy_t       ref_cxy = GET_CXY( ref_xp );
91
92    // get the cwd lock in read mode from reference process
[566]93    remote_rwlock_rd_acquire( XPTR( ref_cxy , &ref_ptr->cwd_lock ) );
[23]94
95    // call the relevant VFS function
[407]96    error = vfs_open( process,
[23]97                      kbuf,
98                      flags,
99                      mode,
100                      &file_xp,
101                      &file_id );
102
103    // release the cwd lock
[566]104    remote_rwlock_rd_release( XPTR( ref_cxy , &ref_ptr->cwd_lock ) );
[23]105
[305]106    if( error )
107    {
[459]108        printk("\n[ERROR] in %s : cannot create file descriptor for %s\n",
109        __FUNCTION__ , kbuf );
[305]110        this->errno = ENFILE;
111        return -1;
112    }
[1]113
[459]114#if DEBUG_SYS_OPEN
115tm_end = hal_get_cycles();
116if( DEBUG_SYS_OPEN < tm_start )
117printk("\n[DBG] %s : thread %x in process %x exit / cost %d / cycle %d\n",
118__FUNCTION__, this->trdid, process->pid, (uint32_t)(tm_end - tm_start), (uint32_t)tm_start );
119#endif
120 
[305]121    return file_id;
[1]122}
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