source: trunk/kernel/syscalls/sys_open.c @ 566

Last change on this file since 566 was 566, checked in by alain, 3 years ago

Complete restructuration of kernel locks.

File size: 3.5 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_rwlock.h>
33
34#include <syscalls.h>
35
36///////////////////////////////////
37int sys_open ( char     * pathname,
38               uint32_t   flags,
39               uint32_t   mode )
40{
41    error_t        error;
42    xptr_t         file_xp;                          // extended pointer on vfs_file_t
43    uint32_t       file_id;                          // file descriptor index
44    char           kbuf[CONFIG_VFS_MAX_PATH_LENGTH];
45
46    thread_t     * this     = CURRENT_THREAD;
47    process_t    * process  = this->process;
48
49#if DEBUG_SYS_OPEN
50uint32_t     tm_start;
51uint32_t     tm_end;
52tm_start = hal_get_cycles();
53#endif
54 
55    // check fd_array not full
56    if( process_fd_array_full() )
57    {
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
63        this->errno = ENFILE;
64        return -1;
65    }
66
67    // check pathname length
68    if( hal_strlen_from_uspace( pathname ) >= CONFIG_VFS_MAX_PATH_LENGTH )
69    {
70
71#if DEBUG_SYSCALLS_ERROR
72printk("\n[ERROR] in %s : pathname too long\n", __FUNCTION__ );
73#endif
74        this->errno = ENFILE;
75        return -1;
76    }
77
78    // copy pathname in kernel space
79    hal_strcpy_from_uspace( kbuf , pathname , CONFIG_VFS_MAX_PATH_LENGTH );
80
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 
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
93    remote_rwlock_rd_acquire( XPTR( ref_cxy , &ref_ptr->cwd_lock ) );
94
95    // call the relevant VFS function
96    error = vfs_open( process,
97                      kbuf,
98                      flags,
99                      mode,
100                      &file_xp,
101                      &file_id );
102
103    // release the cwd lock
104    remote_rwlock_rd_release( XPTR( ref_cxy , &ref_ptr->cwd_lock ) );
105
106    if( error )
107    {
108        printk("\n[ERROR] in %s : cannot create file descriptor for %s\n",
109        __FUNCTION__ , kbuf );
110        this->errno = ENFILE;
111        return -1;
112    }
113
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 
121    return file_id;
122}
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