The metadata stored by Android at the beginning of a "super" partition, which is what it calls a disk partition that holds one or more Dynamic Partitions. Dynamic Partitions do more or less the same thing that LVM does on Linux, allowing Android to map ranges of non-contiguous extents to a single logical device. This metadata holds that mapping.
This page hosts a formal specification of Android Dynamic Partitions metadata using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for Python generated by Kaitai Struct depends on the Python runtime library. You have to install it before you can parse data.
The Python runtime library can be installed from PyPI:
python3 -m pip install kaitaistructParse a local file and get structure in memory:
data = AndroidSuper.from_file("path/to/local/file.img")
Or parse structure from a bytes:
from kaitaistruct import KaitaiStream, BytesIO
raw = b"\x00\x01\x02..."
data = AndroidSuper(KaitaiStream(BytesIO(raw)))
After that, one can get various attributes from the structure by invoking getter methods like:
data.root # => get root
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO
from enum import Enum
if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 9):
raise Exception("Incompatible Kaitai Struct Python API: 0.9 or later is required, but you have %s" % (kaitaistruct.__version__))
class AndroidSuper(KaitaiStruct):
"""The metadata stored by Android at the beginning of a "super" partition, which
is what it calls a disk partition that holds one or more Dynamic Partitions.
Dynamic Partitions do more or less the same thing that LVM does on Linux,
allowing Android to map ranges of non-contiguous extents to a single logical
device. This metadata holds that mapping.
.. seealso::
Source - https://source.android.com/docs/core/ota/dynamic_partitions
.. seealso::
Source - https://android.googlesource.com/platform/system/core/+/refs/tags/android-11.0.0_r8/fs_mgr/liblp/include/liblp/metadata_format.h
"""
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
pass
class Root(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self._raw_primary_geometry = self._io.read_bytes(4096)
_io__raw_primary_geometry = KaitaiStream(BytesIO(self._raw_primary_geometry))
self.primary_geometry = AndroidSuper.Geometry(_io__raw_primary_geometry, self, self._root)
self._raw_backup_geometry = self._io.read_bytes(4096)
_io__raw_backup_geometry = KaitaiStream(BytesIO(self._raw_backup_geometry))
self.backup_geometry = AndroidSuper.Geometry(_io__raw_backup_geometry, self, self._root)
self._raw_primary_metadata = []
self.primary_metadata = []
for i in range(self.primary_geometry.metadata_slot_count):
self._raw_primary_metadata.append(self._io.read_bytes(self.primary_geometry.metadata_max_size))
_io__raw_primary_metadata = KaitaiStream(BytesIO(self._raw_primary_metadata[i]))
self.primary_metadata.append(AndroidSuper.Metadata(_io__raw_primary_metadata, self, self._root))
self._raw_backup_metadata = []
self.backup_metadata = []
for i in range(self.primary_geometry.metadata_slot_count):
self._raw_backup_metadata.append(self._io.read_bytes(self.primary_geometry.metadata_max_size))
_io__raw_backup_metadata = KaitaiStream(BytesIO(self._raw_backup_metadata[i]))
self.backup_metadata.append(AndroidSuper.Metadata(_io__raw_backup_metadata, self, self._root))
class Geometry(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.magic = self._io.read_bytes(4)
if not self.magic == b"\x67\x44\x6C\x61":
raise kaitaistruct.ValidationNotEqualError(b"\x67\x44\x6C\x61", self.magic, self._io, u"/types/geometry/seq/0")
self.struct_size = self._io.read_u4le()
self.checksum = self._io.read_bytes(32)
self.metadata_max_size = self._io.read_u4le()
self.metadata_slot_count = self._io.read_u4le()
self.logical_block_size = self._io.read_u4le()
class Metadata(KaitaiStruct):
class TableKind(Enum):
partitions = 0
extents = 1
groups = 2
block_devices = 3
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.magic = self._io.read_bytes(4)
if not self.magic == b"\x30\x50\x4C\x41":
raise kaitaistruct.ValidationNotEqualError(b"\x30\x50\x4C\x41", self.magic, self._io, u"/types/metadata/seq/0")
self.major_version = self._io.read_u2le()
self.minor_version = self._io.read_u2le()
self.header_size = self._io.read_u4le()
self.header_checksum = self._io.read_bytes(32)
self.tables_size = self._io.read_u4le()
self.tables_checksum = self._io.read_bytes(32)
self.partitions = AndroidSuper.Metadata.TableDescriptor(AndroidSuper.Metadata.TableKind.partitions, self._io, self, self._root)
self.extents = AndroidSuper.Metadata.TableDescriptor(AndroidSuper.Metadata.TableKind.extents, self._io, self, self._root)
self.groups = AndroidSuper.Metadata.TableDescriptor(AndroidSuper.Metadata.TableKind.groups, self._io, self, self._root)
self.block_devices = AndroidSuper.Metadata.TableDescriptor(AndroidSuper.Metadata.TableKind.block_devices, self._io, self, self._root)
class BlockDevice(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.first_logical_sector = self._io.read_u8le()
self.alignment = self._io.read_u4le()
self.alignment_offset = self._io.read_u4le()
self.size = self._io.read_u8le()
self.partition_name = (KaitaiStream.bytes_terminate(self._io.read_bytes(36), 0, False)).decode(u"UTF-8")
self.flag_slot_suffixed = self._io.read_bits_int_le(1) != 0
self.flags_reserved = self._io.read_bits_int_le(31)
class Extent(KaitaiStruct):
class TargetType(Enum):
linear = 0
zero = 1
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.num_sectors = self._io.read_u8le()
self.target_type = KaitaiStream.resolve_enum(AndroidSuper.Metadata.Extent.TargetType, self._io.read_u4le())
self.target_data = self._io.read_u8le()
self.target_source = self._io.read_u4le()
class TableDescriptor(KaitaiStruct):
def __init__(self, kind, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self.kind = kind
self._read()
def _read(self):
self.offset = self._io.read_u4le()
self.num_entries = self._io.read_u4le()
self.entry_size = self._io.read_u4le()
@property
def table(self):
if hasattr(self, '_m_table'):
return self._m_table
_pos = self._io.pos()
self._io.seek((self._parent.header_size + self.offset))
self._raw__m_table = []
self._m_table = []
for i in range(self.num_entries):
_on = self.kind
if _on == AndroidSuper.Metadata.TableKind.partitions:
self._raw__m_table.append(self._io.read_bytes(self.entry_size))
_io__raw__m_table = KaitaiStream(BytesIO(self._raw__m_table[i]))
self._m_table.append(AndroidSuper.Metadata.Partition(_io__raw__m_table, self, self._root))
elif _on == AndroidSuper.Metadata.TableKind.extents:
self._raw__m_table.append(self._io.read_bytes(self.entry_size))
_io__raw__m_table = KaitaiStream(BytesIO(self._raw__m_table[i]))
self._m_table.append(AndroidSuper.Metadata.Extent(_io__raw__m_table, self, self._root))
elif _on == AndroidSuper.Metadata.TableKind.groups:
self._raw__m_table.append(self._io.read_bytes(self.entry_size))
_io__raw__m_table = KaitaiStream(BytesIO(self._raw__m_table[i]))
self._m_table.append(AndroidSuper.Metadata.Group(_io__raw__m_table, self, self._root))
elif _on == AndroidSuper.Metadata.TableKind.block_devices:
self._raw__m_table.append(self._io.read_bytes(self.entry_size))
_io__raw__m_table = KaitaiStream(BytesIO(self._raw__m_table[i]))
self._m_table.append(AndroidSuper.Metadata.BlockDevice(_io__raw__m_table, self, self._root))
else:
self._m_table.append(self._io.read_bytes(self.entry_size))
self._io.seek(_pos)
return getattr(self, '_m_table', None)
class Partition(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.name = (KaitaiStream.bytes_terminate(self._io.read_bytes(36), 0, False)).decode(u"UTF-8")
self.attr_readonly = self._io.read_bits_int_le(1) != 0
self.attr_slot_suffixed = self._io.read_bits_int_le(1) != 0
self.attr_updated = self._io.read_bits_int_le(1) != 0
self.attr_disabled = self._io.read_bits_int_le(1) != 0
self.attrs_reserved = self._io.read_bits_int_le(28)
self._io.align_to_byte()
self.first_extent_index = self._io.read_u4le()
self.num_extents = self._io.read_u4le()
self.group_index = self._io.read_u4le()
class Group(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.name = (KaitaiStream.bytes_terminate(self._io.read_bytes(36), 0, False)).decode(u"UTF-8")
self.flag_slot_suffixed = self._io.read_bits_int_le(1) != 0
self.flags_reserved = self._io.read_bits_int_le(31)
self._io.align_to_byte()
self.maximum_size = self._io.read_u8le()
@property
def root(self):
if hasattr(self, '_m_root'):
return self._m_root
_pos = self._io.pos()
self._io.seek(4096)
self._m_root = AndroidSuper.Root(self._io, self, self._root)
self._io.seek(_pos)
return getattr(self, '_m_root', None)