/**
 * ntfs_dir.c - devoptab directory routines for NTFS-based devices.
 *
 * Copyright (c) 2010 Dimok
 * Copyright (c) 2009 Rhys "Shareese" Koedijk
 * Copyright (c) 2006 Michael "Chishm" Chisholm
 *
 * This program/include file 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 of the License, or
 * (at your option) any later version.
 *
 * This program/include file 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 this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_SYS_STATVFS_H
#include <sys/statvfs.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif

#include "ntfsinternal.h"
#include "ntfsdir.h"
#include "device.h"
#include <sys/dir.h>

#define STATE(x)    ((ntfs_dir_state*)(x)->dirStruct)

void ntfsCloseDir ( ntfs_dir_state *dir )
{
    // Sanity check
    if ( !dir || !dir->vd )
        return;

    // Free the directory entries (if any)
    while ( dir->first )
    {
        ntfs_dir_entry *next = dir->first->next;
        ntfs_free( dir->first->name );
        ntfs_free( dir->first );
        dir->first = next;
    }

    // Close the directory (if open)
    if ( dir->ni )
        ntfsCloseEntry( dir->vd, dir->ni );

    // Reset the directory state
    dir->ni = NULL;
    dir->first = NULL;
    dir->current = NULL;

    return;
}

int ntfs_stat_r ( struct _reent *r, const char *path, struct stat *st )
{
    // Short circuit cases were we don't actually have to do anything
    if ( !st || !path )
        return 0;

    ntfs_log_trace( "path %s, st %p\n", path, st );

    ntfs_vd *vd = NULL;
    ntfs_inode *ni = NULL;

    // Get the volume descriptor for this path
    vd = ntfsGetVolume( path );
    if ( !vd )
    {
        r->_errno = ENODEV;
        return -1;
    }

    if ( strcmp( path, "." ) == 0 || strcmp( path, ".." ) == 0 )
    {
        memset( st, 0, sizeof( struct stat ) );
        st->st_mode = S_IFDIR;
        return 0;
    }

    // Lock
    ntfsLock( vd );

    // Find the entry
    ni = ntfsOpenEntry( vd, path );
    if ( !ni )
    {
        r->_errno = errno;
        ntfsUnlock( vd );
        return -1;
    }

    // Get the entry stats
    int ret = ntfsStat( vd, ni, st );
    if ( ret )
        r->_errno = errno;

    // Close the entry
    ntfsCloseEntry( vd, ni );

    ntfsUnlock( vd );

    return 0;
}

int ntfs_link_r ( struct _reent *r, const char *existing, const char *newLink )
{
    ntfs_log_trace( "existing %s, newLink %s\n", existing, newLink );

    ntfs_vd *vd = NULL;
    ntfs_inode *ni = NULL;

    // Get the volume descriptor for this path
    vd = ntfsGetVolume( existing );
    if ( !vd )
    {
        r->_errno = ENODEV;
        return -1;
    }

    // Lock
    ntfsLock( vd );

    // Create a symbolic link between the two paths
    ni = ntfsCreate( vd, existing, S_IFLNK, newLink );
    if ( !ni )
    {
        ntfsUnlock( vd );
        r->_errno = errno;
        return -1;
    }

    // Close the symbolic link
    ntfsCloseEntry( vd, ni );

    // Unlock
    ntfsUnlock( vd );

    return 0;
}

int ntfs_unlink_r ( struct _reent *r, const char *name )
{
    ntfs_log_trace( "name %s\n", name );

    // Unlink the entry
    int ret = ntfsUnlink( ntfsGetVolume( name ), name );
    if ( ret )
        r->_errno = errno;

    return ret;
}

int ntfs_chdir_r ( struct _reent *r, const char *name )
{
    ntfs_log_trace( "name %s\n", name );

    ntfs_vd *vd = NULL;
    ntfs_inode *ni = NULL;

    // Get the volume descriptor for this path
    vd = ntfsGetVolume( name );
    if ( !vd )
    {
        r->_errno = ENODEV;
        return -1;
    }

    // Lock
    ntfsLock( vd );

    // Find the directory
    ni = ntfsOpenEntry( vd, name );
    if ( !ni )
    {
        ntfsUnlock( vd );
        r->_errno = ENOENT;
        return -1;
    }

    // Ensure that this directory is indeed a directory
    if ( !( ni->mrec->flags && MFT_RECORD_IS_DIRECTORY ) )
    {
        ntfsCloseEntry( vd, ni );
        ntfsUnlock( vd );
        r->_errno = ENOTDIR;
        return -1;
    }

    // Close the old current directory (if any)
    if ( vd->cwd_ni )
        ntfsCloseEntry( vd, vd->cwd_ni );

    // Set the new current directory
    vd->cwd_ni = ni;

    // Unlock
    ntfsUnlock( vd );

    return 0;
}

int ntfs_rename_r ( struct _reent *r, const char *oldName, const char *newName )
{
    ntfs_log_trace( "oldName %s, newName %s\n", oldName, newName );

    ntfs_vd *vd = NULL;
    ntfs_inode *ni = NULL;

    // Get the volume descriptor for this path
    vd = ntfsGetVolume( oldName );
    if ( !vd )
    {
        r->_errno = ENODEV;
        return -1;
    }

    // Lock
    ntfsLock( vd );

    // You cannot rename between devices
    if ( vd != ntfsGetVolume( newName ) )
    {
        ntfsUnlock( vd );
        r->_errno = EXDEV;
        return -1;
    }

    // Check that there is no existing entry with the new name
    ni = ntfsOpenEntry( vd, newName );
    if ( ni )
    {
        ntfsCloseEntry( vd, ni );
        ntfsUnlock( vd );
        r->_errno = EEXIST;
        return -1;
    }

    // Link the old entry with the new one
    if ( ntfsLink( vd, oldName, newName ) )
    {
        ntfsUnlock( vd );
        return -1;
    }

    // Unlink the old entry
    if ( ntfsUnlink( vd, oldName ) )
    {
        if ( ntfsUnlink( vd, newName ) )
        {
            ntfsUnlock( vd );
            return -1;
        }
        ntfsUnlock( vd );
        return -1;
    }

    // Unlock
    ntfsUnlock( vd );

    return 0;
}

int ntfs_mkdir_r ( struct _reent *r, const char *path, int mode )
{
    ntfs_log_trace( "path %s, mode %i\n", path, mode );

    ntfs_vd *vd = NULL;
    ntfs_inode *ni = NULL;

    // Get the volume descriptor for this path
    vd = ntfsGetVolume( path );
    if ( !vd )
    {
        r->_errno = ENODEV;
        return -1;
    }

    // Lock
    ntfsLock( vd );

    // Create the directory
    ni = ntfsCreate( vd, path, S_IFDIR, NULL );
    if ( !ni )
    {
        ntfsUnlock( vd );
        r->_errno = errno;
        return -1;
    }

    // Close the directory
    ntfsCloseEntry( vd, ni );

    // Unlock
    ntfsUnlock( vd );

    return 0;
}

int ntfs_statvfs_r ( struct _reent *r, const char *path, struct statvfs *buf )
{
    ntfs_log_trace( "path %s, buf %p\n", path, buf );

    ntfs_vd *vd = NULL;
    s64 size;
    int delta_bits;

    // Get the volume descriptor for this path
    vd = ntfsGetVolume( path );
    if ( !vd )
    {
        r->_errno = ENODEV;
        return -1;
    }

    // Short circuit cases were we don't actually have to do anything
    if ( !buf )
        return 0;

    // Lock
    ntfsLock( vd );

    // Zero out the stat buffer
    memset( buf, 0, sizeof( struct statvfs ) );

    if ( ntfs_volume_get_free_space( vd->vol ) < 0 )
    {
        ntfsUnlock( vd );
        return -1;
    }

    // File system block size
    buf->f_bsize = vd->vol->cluster_size;

    // Fundamental file system block size
    buf->f_frsize = vd->vol->cluster_size;

    // Total number of blocks on file system in units of f_frsize
    buf->f_blocks = vd->vol->nr_clusters;

    // Free blocks available for all and for non-privileged processes
    size = MAX( vd->vol->free_clusters, 0 );
    buf->f_bfree = buf->f_bavail = size;

    // Free inodes on the free space
    delta_bits = vd->vol->cluster_size_bits - vd->vol->mft_record_size_bits;
    if ( delta_bits >= 0 )
        size <<= delta_bits;
    else
        size >>= -delta_bits;

    // Number of inodes at this point in time
    buf->f_files = ( vd->vol->mftbmp_na->allocated_size << 3 ) + size;

    // Free inodes available for all and for non-privileged processes
    size += vd->vol->free_mft_records;
    buf->f_ffree = buf->f_favail = MAX( size, 0 );

    // File system id
    buf->f_fsid = vd->id;

    // Bit mask of f_flag values.
    buf->f_flag = ( NVolReadOnly( vd->vol ) ? ST_RDONLY : 0 );

    // Maximum length of filenames
    buf->f_namemax = NTFS_MAX_NAME_LEN;

    // Unlock
    ntfsUnlock( vd );

    return 0;
}

/**
 * PRIVATE: Callback for directory walking
 */
int ntfs_readdir_filler ( DIR_ITER *dirState, const ntfschar *name, const int name_len, const int name_type,
                          const s64 pos, const MFT_REF mref, const unsigned dt_type )
{
    ntfs_dir_state *dir = STATE( dirState );
    ntfs_dir_entry *entry = NULL;
    char *entry_name = NULL;

    // Sanity check
    if ( !dir || !dir->vd )
    {
        errno = EINVAL;
        return -1;
    }

    // Ignore DOS file names
    if ( name_type == FILE_NAME_DOS )
    {
        return 0;
    }

    // Preliminary check that this entry can be enumerated (as described by the volume descriptor)
    if ( MREF( mref ) == FILE_root || MREF( mref ) >= FILE_first_user || dir->vd->showSystemFiles )
    {

        // Convert the entry name to our current local
        if ( ntfsUnicodeToLocal( name, name_len, &entry_name, 0 ) < 0 )
        {
            return -1;
        }

        if ( dir->first && dir->first->mref == FILE_root &&
                MREF( mref ) == FILE_root && strcmp( entry_name, ".." ) == 0 )
        {
            return 0;
        }

        // If this is not the parent or self directory reference
        if ( ( strcmp( entry_name, "." ) != 0 ) && ( strcmp( entry_name, ".." ) != 0 ) )
        {

            // Open the entry
            ntfs_inode *ni = ntfs_pathname_to_inode( dir->vd->vol, dir->ni, entry_name );
            if ( !ni )
                return -1;

            // Double check that this entry can be emuerated (as described by the volume descriptor)
            if ( ( ( ni->flags & FILE_ATTR_HIDDEN ) && !dir->vd->showHiddenFiles ) ||
                    ( ( ni->flags & FILE_ATTR_SYSTEM ) && !dir->vd->showSystemFiles ) )
            {
                ntfs_inode_close( ni );
                return 0;
            }

            // Close the entry
            ntfs_inode_close( ni );

        }

        // Allocate a new directory entry
        entry = ( ntfs_dir_entry * ) ntfs_alloc( sizeof( ntfs_dir_entry ) );
        if ( !entry )
            return -1;

        // Setup the entry
        entry->name = entry_name;
        entry->next = NULL;
        entry->mref = MREF( mref );

        // Link the entry to the directory
        if ( !dir->first )
        {
            dir->first = entry;
        }
        else
        {
            ntfs_dir_entry *last = dir->first;
            while ( last->next ) last = last->next;
            last->next = entry;
        }

    }

    return 0;
}

DIR_ITER *ntfs_diropen_r ( struct _reent *r, DIR_ITER *dirState, const char *path )
{
    ntfs_log_trace( "dirState %p, path %s\n", dirState, path );

    ntfs_dir_state* dir = STATE( dirState );
    s64 position = 0;

    // Get the volume descriptor for this path
    dir->vd = ntfsGetVolume( path );
    if ( !dir->vd )
    {
        r->_errno = ENODEV;
        return NULL;
    }

    // Lock
    ntfsLock( dir->vd );

    // Find the directory
    dir->ni = ntfsOpenEntry( dir->vd, path );
    if ( !dir->ni )
    {
        ntfsUnlock( dir->vd );
        r->_errno = ENOENT;
        return NULL;
    }

    // Ensure that this directory is indeed a directory
    if ( !( dir->ni->mrec->flags && MFT_RECORD_IS_DIRECTORY ) )
    {
        ntfsCloseEntry( dir->vd, dir->ni );
        ntfsUnlock( dir->vd );
        r->_errno = ENOTDIR;
        return NULL;
    }

    // Read the directory
    dir->first = dir->current = NULL;
    if ( ntfs_readdir( dir->ni, &position, dirState, ( ntfs_filldir_t )ntfs_readdir_filler ) )
    {
        ntfsCloseDir( dir );
        ntfsUnlock( dir->vd );
        r->_errno = errno;
        return NULL;
    }

    // Move to the first entry in the directory
    dir->current = dir->first;

    // Update directory times
    ntfsUpdateTimes( dir->vd, dir->ni, NTFS_UPDATE_ATIME );

    // Insert the directory into the double-linked FILO list of open directories
    if ( dir->vd->firstOpenDir )
    {
        dir->nextOpenDir = dir->vd->firstOpenDir;
        dir->vd->firstOpenDir->prevOpenDir = dir;
    }
    else
    {
        dir->nextOpenDir = NULL;
    }
    dir->prevOpenDir = NULL;
    dir->vd->cwd_ni = dir->ni;
    dir->vd->firstOpenDir = dir;
    dir->vd->openDirCount++;

    // Unlock
    ntfsUnlock( dir->vd );

    return dirState;
}

int ntfs_dirreset_r ( struct _reent *r, DIR_ITER *dirState )
{
    ntfs_log_trace( "dirState %p\n", dirState );

    ntfs_dir_state* dir = STATE( dirState );

    // Sanity check
    if ( !dir || !dir->vd || !dir->ni )
    {
        r->_errno = EBADF;
        return -1;
    }

    // Lock
    ntfsLock( dir->vd );

    // Move to the first entry in the directory
    dir->current = dir->first;

    // Update directory times
    ntfsUpdateTimes( dir->vd, dir->ni, NTFS_UPDATE_ATIME );

    // Unlock
    ntfsUnlock( dir->vd );

    return 0;
}

int ntfs_dirnext_r ( struct _reent *r, DIR_ITER *dirState, char *filename, struct stat *filestat )
{
    ntfs_log_trace( "dirState %p, filename %p, filestat %p\n", dirState, filename, filestat );

    ntfs_dir_state* dir = STATE( dirState );
    ntfs_inode *ni = NULL;

    // Sanity check
    if ( !dir || !dir->vd || !dir->ni )
    {
        r->_errno = EBADF;
        return -1;
    }

    // Lock
    ntfsLock( dir->vd );

    // Check that there is a entry waiting to be fetched
    if ( !dir->current )
    {
        ntfsUnlock( dir->vd );
        r->_errno = ENOENT;
        return -1;
    }

    // Fetch the current entry
    strcpy( filename, dir->current->name );
    if ( filestat != NULL )
    {
        if ( strcmp( dir->current->name, "." ) == 0 || strcmp( dir->current->name, ".." ) == 0 )
        {
            memset( filestat, 0, sizeof( struct stat ) );
            filestat->st_mode = S_IFDIR;
        }
        else
        {
            ni = ntfsOpenEntry( dir->vd, dir->current->name );
            if ( ni )
            {
                ntfsStat( dir->vd, ni, filestat );
                ntfsCloseEntry( dir->vd, ni );
            }
        }
    }

    // Move to the next entry in the directory
    dir->current = dir->current->next;

    // Update directory times
    ntfsUpdateTimes( dir->vd, dir->ni, NTFS_UPDATE_ATIME );

    // Unlock
    ntfsUnlock( dir->vd );

    return 0;
}

int ntfs_dirclose_r ( struct _reent *r, DIR_ITER *dirState )
{
    ntfs_log_trace( "dirState %p\n", dirState );

    ntfs_dir_state* dir = STATE( dirState );

    // Sanity check
    if ( !dir || !dir->vd )
    {
        r->_errno = EBADF;
        return -1;
    }

    // Lock
    ntfsLock( dir->vd );

    // Close the directory
    ntfsCloseDir( dir );

    // Remove the directory from the double-linked FILO list of open directories
    dir->vd->openDirCount--;
    if ( dir->nextOpenDir )
        dir->nextOpenDir->prevOpenDir = dir->prevOpenDir;
    if ( dir->prevOpenDir )
        dir->prevOpenDir->nextOpenDir = dir->nextOpenDir;
    else
        dir->vd->firstOpenDir = dir->nextOpenDir;

    // Unlock
    ntfsUnlock( dir->vd );

    return 0;
}