Module: VMWareSparseDisk

Defined in:
lib/disk/modules/VMWareSparseDisk.rb

Constant Summary collapse

SPARSE_EXTENT_HEADER = 
BinaryStruct.new([
  'L', 'magicNumber',
  'L', 'version',
  'L', 'flags',
  'Q', 'capacity',
  'Q', 'grainSize',
  'Q', 'descriptorOffset',
  'Q', 'descriptorSize',
  'L', 'numGTEsPerGT',
  'Q', 'rgdOffset',
  'Q', 'gdOffset',
  'Q', 'overHead',
  'C', 'uncleanShutdown'
])
SIZEOF_SPARSE_EXTENT_HEADER = 
SPARSE_EXTENT_HEADER.size
GTE_SIZE = 
4
GDE_SIZE = 
4

Instance Method Summary collapse

Instance Method Details

#d_close ⇒ Object 



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# File 'lib/disk/modules/VMWareSparseDisk.rb', line 131

def d_close
  @vmwareSparseDisk_file.close
end

#d_init ⇒ Object 



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# File 'lib/disk/modules/VMWareSparseDisk.rb', line 25

def d_init
  self.diskType = "VMWare Sparse"
  self.blockSize = 512
  fileMode = MiqDiskCommon.file_mode(dInfo)
  @vmwareSparseDisk_file = MiqLargeFile.open(dInfo.fileName, fileMode)
  buf = @vmwareSparseDisk_file.read(SIZEOF_SPARSE_EXTENT_HEADER)
  @sparseHeader = OpenStruct.new(SPARSE_EXTENT_HEADER.decode(buf))
  @grainSize = @sparseHeader.grainSize
  @grainBytes = @grainSize * blockSize
  @capacity = @sparseHeader.capacity * blockSize

  #
  # Seek to start of the grain directory.
  #
  @vmwareSparseDisk_file.seek(@sparseHeader.gdOffset * blockSize, IO::SEEK_SET)

  #
  # Read the first grain directory entry to get the offset to the start of
  # the grain tables.
  #
  buf = @vmwareSparseDisk_file.read(GDE_SIZE)
  @grainTableBase = buf.unpack('L')[0] * blockSize
  # dumpGT
end

#d_read(pos, len, offset = 0) ⇒ Object 



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# File 'lib/disk/modules/VMWareSparseDisk.rb', line 54

def d_read(pos, len, offset = 0)
  gnStart, goStart = grainPos(pos - offset)
  gnEnd, goEnd = grainPos(pos + len - offset)

  if gnStart == gnEnd
    grainPos = getGTE(gnStart)
    # Mods for parent link.
    if grainPos == 0
      return MemoryBuffer.create(len) if @dInfo.parent.nil?
      return @dInfo.parent.d_read(pos, len)
    else
      @vmwareSparseDisk_file.seek(grainPos + goStart, IO::SEEK_SET)
      return @vmwareSparseDisk_file.read(len)
    end
  end

  bytesRead = 0
  rv = ''
  (gnStart..gnEnd).each do |gn|
    so = 0
    l = @grainBytes

    if gn == gnStart
      so = goStart
      l -= so
    end
    l -= (@grainBytes - goEnd) if gn == gnEnd

    gp = getGTE(gn)
    # Mods for parent link.
    if gp == 0
      if @dInfo.parent.nil?
        rv << MemoryBuffer.create(l)
      else
        rv << @dInfo.parent.d_read(pos + bytesRead, l)
      end
    else
      @vmwareSparseDisk_file.seek(gp + so, IO::SEEK_SET)
      rv << @vmwareSparseDisk_file.read(l)
    end
    bytesRead += l
  end
  rv
end

#d_size ⇒ Object

Disk size in sectors.



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# File 'lib/disk/modules/VMWareSparseDisk.rb', line 136

def d_size
  @capacity / @blockSize
end

#d_write(pos, buf, len, offset = 0) ⇒ Object 



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# File 'lib/disk/modules/VMWareSparseDisk.rb', line 99

def d_write(pos, buf, len, offset = 0)
  gnStart, goStart = grainPos(pos - offset)
  gnEnd, goEnd = grainPos(pos + len - offset)

  if gnStart == gnEnd
    grainPos = getGTE(gnStart)
    grainPos = allocGrain(gnStart) if grainPos == 0
    @vmwareSparseDisk_file.seek(grainPos + goStart, IO::SEEK_SET)
    return @vmwareSparseDisk_file.write(buf, len)
  end

  bytesWritten = 0
  (gnStart..gnEnd).each do |gn|
    so = 0
    l = @grainBytes

    if gn == gnStart
      so = goStart
      l -= so
    end
    if gn == gnEnd
      l -= (@grainBytes - goEnd)
    end

    gp = getGTE(gn)
    gp = allocGrain(gn) if gp == 0
    @vmwareSparseDisk_file.seek(gp + so, IO::SEEK_SET)
    bytesWritten += @vmwareSparseDisk_file.write(buf[bytesWritten, l], l)
  end
  bytesWritten
end

#getBase ⇒ Object 



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# File 'lib/disk/modules/VMWareSparseDisk.rb', line 50

def getBase
  self
end