devfs.cxx

eCos操作系统源码

//==========================================================================
//
//      devfs.cxx
//
//      Fileio device filesystem
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
// Copyright (C) 2003 Gary Thomas
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. However the source code for this file must still be made available
// in accordance with section (3) of the GNU General Public License.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):           nickg
// Contributors:        nickg, gthomas
// Date:                2000-05-25
// Purpose:             Fileio device filesystem
// Description:         This file implements a simple filesystem that interfaces
//                      to the existing device IO subsystem.
//                      
//              
//              
//
//####DESCRIPTIONEND####
//
//==========================================================================

#include <pkgconf/hal.h>
#include <pkgconf/kernel.h>
#include <pkgconf/io_fileio.h>

#include <cyg/kernel/ktypes.h>         // base kernel types
#include <cyg/infra/cyg_trac.h>        // tracing macros
#include <cyg/infra/cyg_ass.h>         // assertion macros

#include "fio.h"                       // Private header

#include <cyg/io/devtab.h>              // device subsystem
#include <cyg/io/config_keys.h>         // CYG_IO_GET_CONFIG_SERIAL_OUTPUT_DRAIN

//==========================================================================
// Forward definitions

// Filesystem operations
static int dev_mount    ( cyg_fstab_entry *fste, cyg_mtab_entry *mte );
static int dev_umount   ( cyg_mtab_entry *mte );
static int dev_open     ( cyg_mtab_entry *mte, cyg_dir dir, const char *name,
                          int mode,  cyg_file *fte );
static int dev_unlink   ( cyg_mtab_entry *mte, cyg_dir dir, const char *name );
static int dev_mkdir    ( cyg_mtab_entry *mte, cyg_dir dir, const char *name );
static int dev_rmdir    ( cyg_mtab_entry *mte, cyg_dir dir, const char *name );
static int dev_rename   ( cyg_mtab_entry *mte, cyg_dir dir1, const char *name1,
                          cyg_dir dir2, const char *name2 );
static int dev_link     ( cyg_mtab_entry *mte, cyg_dir dir1, const char *name1,
                          cyg_dir dir2, const char *name2, int type );
static int dev_opendir  ( cyg_mtab_entry *mte, cyg_dir dir, const char *name,
                          cyg_file *fte );
static int dev_chdir    ( cyg_mtab_entry *mte, cyg_dir dir, const char *name,
                          cyg_dir *dir_out );
static int dev_stat     ( cyg_mtab_entry *mte, cyg_dir dir, const char *name,
                          struct stat *buf);
static int dev_getinfo  ( cyg_mtab_entry *mte, cyg_dir dir, const char *name,
                          int key, void *buf, int len );
static int dev_setinfo  ( cyg_mtab_entry *mte, cyg_dir dir, const char *name,
                          int key, void *buf, int len );

// File operations
static int dev_fo_read      (struct CYG_FILE_TAG *fp, struct CYG_UIO_TAG *uio);
static int dev_fo_write     (struct CYG_FILE_TAG *fp, struct CYG_UIO_TAG *uio);
static int dev_fo_lseek     (struct CYG_FILE_TAG *fp, off_t *pos, int whence );
static int dev_fo_ioctl     (struct CYG_FILE_TAG *fp, CYG_ADDRWORD com,
                             CYG_ADDRWORD data);
static cyg_bool dev_fo_select (struct CYG_FILE_TAG *fp, int which, CYG_ADDRWORD info);
static int dev_fo_fsync     (struct CYG_FILE_TAG *fp, int mode );        
static int dev_fo_close     (struct CYG_FILE_TAG *fp);
static int dev_fo_fstat     (struct CYG_FILE_TAG *fp, struct stat *buf );
static int dev_fo_getinfo   (struct CYG_FILE_TAG *fp, int key, void *buf, int len );
static int dev_fo_setinfo   (struct CYG_FILE_TAG *fp, int key, void *buf, int len );


//==========================================================================
// Filesystem table entries

FSTAB_ENTRY( dev_fste, "devfs", 0,
             CYG_SYNCMODE_NONE,         // dev system has its own sync mechanism
             dev_mount,
             dev_umount,
             dev_open,
             dev_unlink,
             dev_mkdir,
             dev_rmdir,
             dev_rename,
             dev_link,
             dev_opendir,
             dev_chdir,
             dev_stat,
             dev_getinfo,
             dev_setinfo);

MTAB_ENTRY( dev_mte,
                   "/dev",
                   "devfs",
                   "",
                   0);

static cyg_fileops dev_fileops =
{
    dev_fo_read,
    dev_fo_write,
    dev_fo_lseek,
    dev_fo_ioctl,
    dev_fo_select,
    dev_fo_fsync,
    dev_fo_close,
    dev_fo_fstat,
    dev_fo_getinfo,
    dev_fo_setinfo
};

//==========================================================================
// Filesystem operations

// -------------------------------------------------------------------------

static int dev_mount    ( cyg_fstab_entry *fste, cyg_mtab_entry *mte )
{
    // Nothing to do here. The device IO subsystem has already initialized
    // iteslf, and the fileio infrastructure will do the rest.
    
    return 0;
}

// -------------------------------------------------------------------------

static int dev_umount   ( cyg_mtab_entry *mte )
{
    // Nothing to do here.
    
    return 0;
}

// -------------------------------------------------------------------------

static int dev_open     ( cyg_mtab_entry *mte, cyg_dir dir, const char *name,
                          int mode,  cyg_file *file )
{
    Cyg_ErrNo err;
    cyg_io_handle_t handle;

    // The name we are passed will point to the first character after
    // "/dev/". We know that the full string contains the prefix string,
    // so we back the pointer up by 5 chars.
    // A better approach would be for the device table entries to only
    // contain the part of the string after the prefix.

    name -= 5;
    
    err = cyg_io_lookup( name, &handle );

    if( err < 0 )
        return -err;

    // If we want non-blocking mode, configure the device for it.
    if( (mode & (O_NONBLOCK|O_RDONLY)) == (O_NONBLOCK|O_RDONLY) )
    {
        cyg_uint32 f = 0;
        cyg_uint32 fsize = sizeof(f);
        err = cyg_io_set_config( handle, CYG_IO_SET_CONFIG_READ_BLOCKING,
                                 (void *)&f, &fsize);
        if( err < 0 )
            return -err;
    }

    if( (mode & (O_NONBLOCK|O_WRONLY)) == (O_NONBLOCK|O_WRONLY) )
    {
        cyg_uint32 f = 0;
        cyg_uint32 fsize = sizeof(f);        
        err = cyg_io_set_config( handle, CYG_IO_SET_CONFIG_WRITE_BLOCKING,
                                 (void *)&f, &fsize);
        if( err < 0 )
            return -err;
    }
    
    // Initialize the file object
    
    file->f_flag |= mode & CYG_FILE_MODE_MASK;
    file->f_type = CYG_FILE_TYPE_FILE;
    file->f_ops = &dev_fileops;
    file->f_offset = 0;
    file->f_data = (CYG_ADDRWORD)handle;
    file->f_xops = 0;

    return 0;
}

// -------------------------------------------------------------------------

static int dev_unlink   ( cyg_mtab_entry *mte, cyg_dir dir, const char *name )
{
    return EROFS;
}

// -------------------------------------------------------------------------

static int dev_mkdir    ( cyg_mtab_entry *mte, cyg_dir dir, const char *name )
{
    return EROFS;
}

// -------------------------------------------------------------------------

static int dev_rmdir    ( cyg_mtab_entry *mte, cyg_dir dir, const char *name )
{
    return EROFS;
}

// -------------------------------------------------------------------------