APM (Apple Partition Map) partition table: Python parsing library

This page hosts a formal specification of APM (Apple Partition Map) partition table using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime 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 kaitaistruct

Code

Parse a local file and get structure in memory:

data = ApmPartitionTable.from_file("path/to/local/file.bin")

Or parse structure from a bytes:

from kaitaistruct import KaitaiStream, BytesIO

raw = b"\x00\x01\x02..."
data = ApmPartitionTable(KaitaiStream(BytesIO(raw)))

After that, one can get various attributes from the structure by invoking getter methods like:

data.sector_size # => 0x200 (512) bytes for disks, 0x1000 (4096) bytes is not supported by APM
0x800 (2048) bytes for CDROM

Python source code to parse APM (Apple Partition Map) partition table

apm_partition_table.py

# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
# type: ignore

import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO


if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 11):
    raise Exception("Incompatible Kaitai Struct Python API: 0.11 or later is required, but you have %s" % (kaitaistruct.__version__))

class ApmPartitionTable(KaitaiStruct):
    """
    .. seealso::
       Source - https://en.wikipedia.org/wiki/Apple_Partition_Map
    """
    def __init__(self, _io, _parent=None, _root=None):
        super(ApmPartitionTable, self).__init__(_io)
        self._parent = _parent
        self._root = _root or self
        self._read()

    def _read(self):
        pass


    def _fetch_instances(self):
        pass
        _ = self.partition_entries
        if hasattr(self, '_m_partition_entries'):
            pass
            for i in range(len(self._m_partition_entries)):
                pass
                self._m_partition_entries[i]._fetch_instances()


        _ = self.partition_lookup
        if hasattr(self, '_m_partition_lookup'):
            pass
            self._m_partition_lookup._fetch_instances()


    class PartitionEntry(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(ApmPartitionTable.PartitionEntry, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.magic = self._io.read_bytes(2)
            if not self.magic == b"\x50\x4D":
                raise kaitaistruct.ValidationNotEqualError(b"\x50\x4D", self.magic, self._io, u"/types/partition_entry/seq/0")
            self.reserved_1 = self._io.read_bytes(2)
            self.number_of_partitions = self._io.read_u4be()
            self.partition_start = self._io.read_u4be()
            self.partition_size = self._io.read_u4be()
            self.partition_name = (KaitaiStream.bytes_terminate(self._io.read_bytes(32), 0, False)).decode(u"ASCII")
            self.partition_type = (KaitaiStream.bytes_terminate(self._io.read_bytes(32), 0, False)).decode(u"ASCII")
            self.data_start = self._io.read_u4be()
            self.data_size = self._io.read_u4be()
            self.partition_status = self._io.read_u4be()
            self.boot_code_start = self._io.read_u4be()
            self.boot_code_size = self._io.read_u4be()
            self.boot_loader_address = self._io.read_u4be()
            self.reserved_2 = self._io.read_bytes(4)
            self.boot_code_entry = self._io.read_u4be()
            self.reserved_3 = self._io.read_bytes(4)
            self.boot_code_cksum = self._io.read_u4be()
            self.processor_type = (KaitaiStream.bytes_terminate(self._io.read_bytes(16), 0, False)).decode(u"ASCII")


        def _fetch_instances(self):
            pass
            _ = self.boot_code
            if hasattr(self, '_m_boot_code'):
                pass

            _ = self.data
            if hasattr(self, '_m_data'):
                pass

            _ = self.partition
            if hasattr(self, '_m_partition'):
                pass


        @property
        def boot_code(self):
            if hasattr(self, '_m_boot_code'):
                return self._m_boot_code

            io = self._root._io
            _pos = io.pos()
            io.seek(self.boot_code_start * self._root.sector_size)
            self._m_boot_code = io.read_bytes(self.boot_code_size)
            io.seek(_pos)
            return getattr(self, '_m_boot_code', None)

        @property
        def data(self):
            if hasattr(self, '_m_data'):
                return self._m_data

            io = self._root._io
            _pos = io.pos()
            io.seek(self.data_start * self._root.sector_size)
            self._m_data = io.read_bytes(self.data_size * self._root.sector_size)
            io.seek(_pos)
            return getattr(self, '_m_data', None)

        @property
        def partition(self):
            if hasattr(self, '_m_partition'):
                return self._m_partition

            if self.partition_status & 1 != 0:
                pass
                io = self._root._io
                _pos = io.pos()
                io.seek(self.partition_start * self._root.sector_size)
                self._m_partition = io.read_bytes(self.partition_size * self._root.sector_size)
                io.seek(_pos)

            return getattr(self, '_m_partition', None)


    @property
    def partition_entries(self):
        if hasattr(self, '_m_partition_entries'):
            return self._m_partition_entries

        io = self._root._io
        _pos = io.pos()
        io.seek(self._root.sector_size)
        self._raw__m_partition_entries = []
        self._m_partition_entries = []
        for i in range(self._root.partition_lookup.number_of_partitions):
            self._raw__m_partition_entries.append(io.read_bytes(self.sector_size))
            _io__raw__m_partition_entries = KaitaiStream(BytesIO(self._raw__m_partition_entries[i]))
            self._m_partition_entries.append(ApmPartitionTable.PartitionEntry(_io__raw__m_partition_entries, self, self._root))

        io.seek(_pos)
        return getattr(self, '_m_partition_entries', None)

    @property
    def partition_lookup(self):
        """Every partition entry contains the number of partition entries.
        We parse the first entry, to know how many to parse, including the first one.
        No logic is given what to do if other entries have a different number.
        """
        if hasattr(self, '_m_partition_lookup'):
            return self._m_partition_lookup

        io = self._root._io
        _pos = io.pos()
        io.seek(self._root.sector_size)
        self._raw__m_partition_lookup = io.read_bytes(self.sector_size)
        _io__raw__m_partition_lookup = KaitaiStream(BytesIO(self._raw__m_partition_lookup))
        self._m_partition_lookup = ApmPartitionTable.PartitionEntry(_io__raw__m_partition_lookup, self, self._root)
        io.seek(_pos)
        return getattr(self, '_m_partition_lookup', None)

    @property
    def sector_size(self):
        """0x200 (512) bytes for disks, 0x1000 (4096) bytes is not supported by APM
        0x800 (2048) bytes for CDROM
        """
        if hasattr(self, '_m_sector_size'):
            return self._m_sector_size

        self._m_sector_size = 512
        return getattr(self, '_m_sector_size', None)