# -*- coding: utf-8 -*-
"""The APFS file system implementation."""
from dfvfs.lib import apfs_helper
from dfvfs.lib import definitions
from dfvfs.lib import errors
from dfvfs.path import apfs_path_spec
from dfvfs.resolver import resolver
from dfvfs.vfs import file_system
from dfvfs.vfs import apfs_file_entry
[docs]
class APFSFileSystem(file_system.FileSystem):
"""File system that uses pyfsapfs."""
ROOT_DIRECTORY_IDENTIFIER = 2
TYPE_INDICATOR = definitions.TYPE_INDICATOR_APFS
[docs]
def __init__(self, resolver_context, path_spec):
"""Initializes an APFS file system.
Args:
resolver_context (Context): resolver context.
path_spec (PathSpec): a path specification.
"""
super(APFSFileSystem, self).__init__(resolver_context, path_spec)
self._fsapfs_volume = None
def _Close(self):
"""Closes the file system.
Raises:
IOError: if the close failed.
"""
self._fsapfs_volume = None
def _Open(self, mode='rb'):
"""Opens the file system 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 APFS volume could not be retrieved or unlocked.
OSError: if the APFS volume could not be retrieved or unlocked.
PathSpecError: if the path specification is incorrect.
ValueError: if the path specification is invalid.
"""
if not self._path_spec.HasParent():
raise errors.PathSpecError(
'Unsupported path specification without parent.')
if self._path_spec.parent.type_indicator != (
definitions.TYPE_INDICATOR_APFS_CONTAINER):
raise errors.PathSpecError(
'Unsupported path specification not type APFS container.')
apfs_container_file_system = resolver.Resolver.OpenFileSystem(
self._path_spec.parent, resolver_context=self._resolver_context)
fsapfs_volume = apfs_container_file_system.GetAPFSVolumeByPathSpec(
self._path_spec.parent)
if not fsapfs_volume:
raise IOError('Unable to retrieve APFS volume')
try:
is_locked = not apfs_helper.APFSUnlockVolume(
fsapfs_volume, self._path_spec.parent, resolver.Resolver.key_chain)
except IOError as exception:
raise IOError(f'Unable to unlock volume with error: {exception!s}')
if is_locked:
raise IOError('Unable to unlock volume.')
self._fsapfs_volume = fsapfs_volume
[docs]
def FileEntryExistsByPathSpec(self, path_spec):
"""Determines if a file entry for a path specification exists.
Args:
path_spec (PathSpec): path specification.
Returns:
bool: True if the file entry exists.
Raises:
BackEndError: if the file entry cannot be opened.
"""
# Opening a file by location will ensure added time is provided when
# available.
fsapfs_file_entry = None
location = getattr(path_spec, 'location', None)
identifier = getattr(path_spec, 'identifier', None)
try:
if location is not None:
fsapfs_file_entry = self._fsapfs_volume.get_file_entry_by_path(location)
elif identifier is not None:
fsapfs_file_entry = self._fsapfs_volume.get_file_entry_by_identifier(
identifier)
except IOError as exception:
raise errors.BackEndError(exception)
return fsapfs_file_entry is not None
[docs]
def GetFileEntryByPathSpec(self, path_spec):
"""Retrieves a file entry for a path specification.
Args:
path_spec (PathSpec): path specification.
Returns:
APFSFileEntry: file entry or None if not available.
Raises:
BackEndError: if the file entry cannot be opened.
"""
# Opening a file by location will ensure added time is provided when
# available.
fsapfs_file_entry = None
location = getattr(path_spec, 'location', None)
identifier = getattr(path_spec, 'identifier', None)
if (location == self.LOCATION_ROOT or
identifier == self.ROOT_DIRECTORY_IDENTIFIER):
is_root = True
# Note that APFS can have a volume without a root directory.
fsapfs_file_entry = self._fsapfs_volume.get_root_directory()
else:
is_root = False
try:
if location is not None:
fsapfs_file_entry = self._fsapfs_volume.get_file_entry_by_path(
location)
elif identifier is not None:
fsapfs_file_entry = self._fsapfs_volume.get_file_entry_by_identifier(
identifier)
except IOError as exception:
raise errors.BackEndError(exception)
if fsapfs_file_entry is None:
return None
return apfs_file_entry.APFSFileEntry(
self._resolver_context, self, path_spec,
fsapfs_file_entry=fsapfs_file_entry, is_root=is_root)
[docs]
def GetAPFSFileEntryByPathSpec(self, path_spec):
"""Retrieves the APFS file entry for a path specification.
Args:
path_spec (PathSpec): a path specification.
Returns:
pyfsapfs.file_entry: file entry.
Raises:
PathSpecError: if the path specification is missing location and
identifier.
"""
# Opening a file by location will ensure added time is provided when
# available.
location = getattr(path_spec, 'location', None)
identifier = getattr(path_spec, 'identifier', None)
if location is not None:
fsapfs_file_entry = self._fsapfs_volume.get_file_entry_by_path(location)
elif identifier is not None:
fsapfs_file_entry = self._fsapfs_volume.get_file_entry_by_identifier(
identifier)
else:
raise errors.PathSpecError(
'Path specification missing location and identifier.')
return fsapfs_file_entry
[docs]
def GetRootFileEntry(self):
"""Retrieves the root file entry.
Returns:
APFSFileEntry: file entry or None if not available.
"""
path_spec = apfs_path_spec.APFSPathSpec(
location=self.LOCATION_ROOT, identifier=self.ROOT_DIRECTORY_IDENTIFIER,
parent=self._path_spec.parent)
return self.GetFileEntryByPathSpec(path_spec)