# -*- coding: utf-8 -*-
"""The SleuthKit (TSK) partition file-like object implementation."""
from dfvfs.file_io import data_range_io
from dfvfs.lib import errors
from dfvfs.lib import tsk_partition
from dfvfs.resolver import resolver
[docs]
class TSKPartitionFile(data_range_io.DataRange):
"""File input/output (IO) object using pytsk3."""
[docs]
def __init__(self, resolver_context, path_spec):
"""Initializes a file input/output (IO) object.
Args:
resolver_context (Context): resolver context.
path_spec (PathSpec): a path specification.
"""
super(TSKPartitionFile, self).__init__(resolver_context, path_spec)
self._file_system = None
def _Close(self):
"""Closes the file-like object."""
self._file_system = None
def _Open(self, mode='rb'):
"""Opens the file-like object defined by path specification.
Args:
mode (Optional[str]): file access mode.
Raises:
AccessError: if the access to open the file was denied.
IOError: if the file-like object could not be opened.
OSError: if the file-like object could not be opened.
PathSpecError: if the path specification is incorrect.
"""
if not self._path_spec.HasParent():
raise errors.PathSpecError(
'Unsupported path specification without parent.')
self._file_system = resolver.Resolver.OpenFileSystem(
self._path_spec, resolver_context=self._resolver_context)
tsk_volume = self._file_system.GetTSKVolume()
tsk_vs, _ = tsk_partition.GetTSKVsPartByPathSpec(
tsk_volume, self._path_spec)
if tsk_vs is None:
raise errors.PathSpecError(
'Unable to retrieve TSK volume system part from path '
'specification.')
range_offset = tsk_partition.TSKVsPartGetStartSector(tsk_vs)
range_size = tsk_partition.TSKVsPartGetNumberOfSectors(tsk_vs)
if range_offset is None or range_size is None:
raise errors.PathSpecError(
'Unable to retrieve TSK volume system part data range from path '
'specification.')
bytes_per_sector = tsk_partition.TSKVolumeGetBytesPerSector(tsk_volume)
range_offset *= bytes_per_sector
range_size *= bytes_per_sector
self._SetRange(range_offset, range_size)
self._file_object = resolver.Resolver.OpenFileObject(
self._path_spec.parent, resolver_context=self._resolver_context)