//==========================================================================
//
//      misc.cxx
//
//      Fileio miscellaneous functions
//
//==========================================================================
//####COPYRIGHTBEGIN####
//                                                                          
// -------------------------------------------                              
// The contents of this file are subject to the Red Hat eCos Public License 
// Version 1.1 (the "License"); you may not use this file except in         
// compliance with the License.  You may obtain a copy of the License at    
// http://www.redhat.com/                                                   
//                                                                          
// Software distributed under the License is distributed on an "AS IS"      
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the 
// License for the specific language governing rights and limitations under 
// the License.                                                             
//                                                                          
// The Original Code is eCos - Embedded Configurable Operating System,      
// released September 30, 1998.                                             
//                                                                          
// The Initial Developer of the Original Code is Red Hat.                   
// Portions created by Red Hat are                                          
// Copyright (C) 1998, 1999, 2000 Red Hat, Inc.                             
// All Rights Reserved.                                                     
// -------------------------------------------                              
//                                                                          
//####COPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):           nickg
// Contributors:        nickg
// Date:                2000-05-25
// Purpose:             Fileio miscellaneous functions
// Description:         This file contains various miscellaneous functions
//                      for use with the fileio system. These include startup,
//                      table management, and other service routines.
//
//####DESCRIPTIONEND####
//
//==========================================================================

#include <pkgconf/system.h>
#include <pkgconf/hal.h>
#include <pkgconf/kernel.h>
#include <pkgconf/io_fileio.h>
#ifdef CYGPKG_LIBC_TIME
#include <pkgconf/libc_time.h>
#endif


#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 <string.h>                    // strcmp()
#include <time.h>                      // time()

#ifdef CYGPKG_IO_WALLCLOCK
# include <cyg/io/wallclock.hxx>       // Wallclock class
#endif

#include "fio.h"                       // Private header

//==========================================================================
// forward definitions

static void cyg_mtab_init();

__externC int chdir( const char *path );

//==========================================================================
// Filesystem tables

// -------------------------------------------------------------------------
// Filesystem table.

// This array contains entries for all filesystem that are installed in
// the system.
__externC cyg_fstab_entry fstab[];
CYG_HAL_TABLE_BEGIN( fstab, fstab );

// end of filesystem table, set in linker script.
__externC cyg_fstab_entry fstab_end;
CYG_HAL_TABLE_END( fstab_end, fstab );

// Array of mutexes for locking the fstab entries
Cyg_Mutex fstab_lock[CYGNUM_FILEIO_FSTAB_MAX];

// -------------------------------------------------------------------------
// Mount table.

// This array contains entries for all valid running filesystems.
__externC cyg_mtab_entry mtab[];
CYG_HAL_TABLE_BEGIN( mtab, mtab );

// Extra entries at end of mtab for dynamic mount points.
cyg_mtab_entry mtab_extra[CYGNUM_FILEIO_MTAB_EXTRA] CYG_HAL_TABLE_EXTRA(mtab) = { { NULL } };

// End of mount table, set in the linker script.
__externC cyg_mtab_entry mtab_end;
CYG_HAL_TABLE_END( mtab_end, mtab );

// Array of mutexes for locking the mtab entries
Cyg_Mutex mtab_lock[CYGNUM_FILEIO_MTAB_MAX];

//==========================================================================
// Current directory

cyg_mtab_entry *cdir_mtab_entry = NULL;
cyg_dir cdir_dir = CYG_DIR_NULL;

//==========================================================================
// Initialization object

class Cyg_Fileio_Init_Class
{
public:    
    Cyg_Fileio_Init_Class();
};

static Cyg_Fileio_Init_Class fileio_initializer CYGBLD_ATTRIB_INIT_PRI(CYG_INIT_IO);

Cyg_Fileio_Init_Class::Cyg_Fileio_Init_Class()
{
    cyg_fd_init();

    cyg_mtab_init();

    chdir("/");
}

//==========================================================================
// Mount table initializer

static void cyg_mtab_init()
{
    cyg_mtab_entry *m;
    
    for( m = &mtab[0]; m != &mtab_end; m++ )
    {
        const char *fsname = m->fsname;
        cyg_fstab_entry *f;

        // Ignore empty entries
        if( m->name == NULL )
            continue;
        
        // stop if there are more than the configured maximum
        if( m-&mtab[0] >= CYGNUM_FILEIO_MTAB_MAX )
            break;
        
        for( f = &fstab[0]; f != &fstab_end; f++ )
        {
            // stop if there are more than the configured maximum
            if( f-&fstab[0] >= CYGNUM_FILEIO_FSTAB_MAX )
                break;
            
            if( strcmp( fsname, f->name) == 0 )
            {
                // We have a match.

                if( f->mount( f, m ) == 0 )
                {
                    m->valid    = true;
                    m->fs       = f;
                    // m->root installed by fs.
                }
                else
                {
                    m->valid = false;
                }
                
                break;
            }
        }
    }
}

//==========================================================================
// Mount table matching

// -------------------------------------------------------------------------
// matchlen() compares two strings and returns the number of bytes by which
// they match.

static int matchlen( const char *s1, const char *s2 )
{
    int len = 0;
    while( s1[len] == s2[len] && s1[len] && s2[len] ) len++;

    // Return length only if s2 is an initial substring of s1,
    // and it terminates in s1 at end-of-string or a '/'.

    // Special case for s2 == "/"
    if( len == 1 && s2[0] == '/' && s2[1] == 0 )
        return len;
    
    if( (s2[len] == 0) && (s1[len] == 0 || s1[len] == '/'))
         return len;
    else return 0;
}

// -------------------------------------------------------------------------
// Search the mtab for the entry that matches the longest substring of
// **name. 

__externC int cyg_mtab_lookup( cyg_dir *dir, const char **name, cyg_mtab_entry **mte)
{
    cyg_mtab_entry *m, *best = NULL;
    int best_len = 0;

    // Unrooted file names go straight to current dir
    if( **name != '/' ) return 0;

    // Otherwise search the mount table.
    for( m = &mtab[0]; m != &mtab_end; m++ )
    {
        if( m->name != NULL )
        {
            int len = matchlen(*name,m->name);
            if( len > best_len )
                best = m, best_len = len;
        }
    }

    // No match found, bad path name...
    if( best_len == 0 ) return -1;
    
    *name += best_len;
    if( **name == '/' )
        (*name)++;
    *mte = best;
    *dir = best->root;

    return 0;
}

//==========================================================================
// mount filesystem

__externC int mount( const char *devname,
                     const char *dir,
                     const char *fsname)
{

    FILEIO_ENTRY();
    
    cyg_mtab_entry *m;
    cyg_fstab_entry *f;
    
    // Search the mount table for an empty entry
    for( m = &mtab[0]; m != &mtab_end; m++ )
    {
        // stop if there are more than the configured maximum
        if( m-&mtab[0] >= CYGNUM_FILEIO_MTAB_MAX )
        {
            m = &mtab_end;
            break;
        }

         if( m->name == NULL ) break;
    }

    if( m == &mtab_end )
        FILEIO_RETURN(ENOMEM);

    // Now search the fstab for the filesystem implementation
    for( f = &fstab[0]; f != &fstab_end; f++ )
    {
        // stop if there are more than the configured maximum
        if( f-&fstab[0] >= CYGNUM_FILEIO_FSTAB_MAX )
            break;
            
        if( strcmp( fsname, f->name) == 0 )
            break;
    }

    if( f == &fstab_end )
        FILEIO_RETURN(ENODEV);
            
    // We have a match.

    m->name = dir;
    m->fsname = fsname;
    m->devname = devname;
    
    if( f->mount( f, m ) == 0 )
    {
        m->valid    = true;
        m->fs       = f;
        // m->root installed by fs.
    }
    else
    {
        m->valid = false;
        m->name = NULL;
    }
                
    FILEIO_RETURN(ENOERR);
}

//==========================================================================
// unmount filesystem

__externC int umount( const char *name)
{
    int err = ENOERR;
    
    FILEIO_ENTRY();
    
    cyg_mtab_entry *m;

    // Search the mount table for a matching entry
    for( m = &mtab[0]; m != &mtab_end; m++ )
    {
        // stop if there are more than the configured maximum
        if( m-&mtab[0] >= CYGNUM_FILEIO_MTAB_MAX )
        {
            m = &mtab_end;
            break;
        }

        // Ignore empty entries
         if( m->name == NULL ) continue;

         // match names.
         if( strcmp(name,m->name) == 0 ) break;

         // Match device name too?
    }

    if( m == &mtab_end )
        FILEIO_RETURN(EINVAL);

    // We have a match, call the umount function

    err = m->fs->umount( m );

    if( err == ENOERR )
    {
        m->valid        = false;
        m->name         = NULL;
    }
    
    FILEIO_RETURN(err);
}

//==========================================================================
// Implement filesystem locking protocol. 

void cyg_fs_lock( cyg_mtab_entry *mte, cyg_uint32 syncmode )
{
    if( syncmode & CYG_SYNCMODE_FILE_FILESYSTEM )
        fstab_lock[mte->fs-&fstab[0]].lock();

    if( syncmode & CYG_SYNCMODE_FILE_MOUNTPOINT )
        mtab_lock[mte-&mtab[0]].lock();
}

void cyg_fs_unlock( cyg_mtab_entry *mte, cyg_uint32 syncmode )
{
    if( syncmode & CYG_SYNCMODE_FILE_FILESYSTEM )
        fstab_lock[mte->fs-&fstab[0]].unlock();

    if( syncmode & CYG_SYNCMODE_FILE_MOUNTPOINT )
        mtab_lock[mte-&mtab[0]].unlock();
}

//==========================================================================
// Timestamp support
// This provides access to the current time/date, expressed as a
// time_t.  It uses a number of mechanisms to do this, selecting
// whichever is available in the current configuration.

__externC time_t cyg_timestamp()
{
#if defined(CYGPKG_IO_WALLCLOCK)

    // First, try to get the time from the wallclock device.
    
    return (time_t) Cyg_WallClock::wallclock->get_current_time();

#elif CYGINT_ISO_POSIX_TIMERS

    // If POSIX is present, use the current value of the realtime
    // clock.
    
    struct timespec tp;

    clock_gettime( CLOCK_REALTIME, &tp );

    return (time_t) tp.tv_sec;
    
#else    

    // If all else fails, get the current realtime clock value and
    // convert it to seconds ourself.
    
    static struct Cyg_Clock::converter sec_converter;
    struct cyg_bool initialized = false;
    cyg_tick_count ticks;
    
    if( !initialized )
    {
        Cyg_Clock::real_time_clock->get_clock_to_other_converter( 1000000000, &sec_converter );
        initialized = true;
    }

    ticks = Cyg_Clock::real_time_clock->current_value();
    
    return (time_t) Cyg_Clock::convert( ticks, &sec_converter )
        
#endif    
    
}

//==========================================================================
// Default functions

__externC int cyg_fileio_enosys() { return ENOSYS; }
__externC int cyg_fileio_erofs() { return EROFS; }
__externC int cyg_fileio_enoerr() { return ENOERR; }
__externC int cyg_fileio_enotdir() { return ENOTDIR; }

__externC int cyg_fileio_seltrue (struct CYG_FILE_TAG *fp, int which, CYG_ADDRWORD info)
{ return 1; }

// -------------------------------------------------------------------------
// EOF misc.cxx