"""The EWF image file-like object."""
import pyewf
from dfvfs.file_io import file_object_io
from dfvfs.lib import errors
from dfvfs.lib import ewf_helper
from dfvfs.resolver import resolver
[docs]
class EWFFile(file_object_io.FileObjectIO):
"""File input/output (IO) object using pyewf."""
[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().__init__(resolver_context, path_spec)
self._file_objects = []
def _Close(self):
"""Closes the file-like object."""
# pylint: disable=protected-access
super()._Close()
self._file_objects = []
def _OpenFileObject(self, path_spec):
"""Opens the file-like object defined by path specification.
Args:
path_spec (PathSpec): path specification.
Returns:
pyewf.handle: a file-like object or None.
Raises:
PathSpecError: if the path specification is invalid.
"""
if not path_spec.HasParent():
raise errors.PathSpecError("Unsupported path specification without parent.")
parent_path_spec = path_spec.parent
parent_location = getattr(parent_path_spec, "location", None)
if parent_location and parent_path_spec.IsSystemLevel():
segment_file_paths = pyewf.glob(parent_location)
ewf_handle = pyewf.handle()
ewf_handle.open(segment_file_paths)
else:
# Note that we cannot use pyewf's glob function since it does not
# handle the file system abstraction dfvfs provides.
file_system = resolver.Resolver.OpenFileSystem(
parent_path_spec, resolver_context=self._resolver_context
)
segment_file_path_specs = ewf_helper.EWFGlobPathSpec(file_system, path_spec)
if not segment_file_path_specs:
return None
for segment_file_path_spec in segment_file_path_specs:
file_object = resolver.Resolver.OpenFileObject(
segment_file_path_spec, resolver_context=self._resolver_context
)
self._file_objects.append(file_object)
ewf_handle = pyewf.handle()
ewf_handle.open_file_objects(self._file_objects)
return ewf_handle
[docs]
def get_size(self):
"""Retrieves the size of the file-like object.
Returns:
int: size of the RAW storage media image inside the EWF container.
Raises:
OSError: if the file-like object has not been opened.
"""
if not self._is_open:
raise OSError("Not opened.")
return self._file_object.get_media_size()