This page hosts a formal specification of Android Boot Image 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 = AndroidImg.from_file("path/to/local/file.img")
Or parse structure from a bytes:
from kaitaistruct import KaitaiStream, BytesIO
raw = b"\x00\x01\x02..."
data = AndroidImg(KaitaiStream(BytesIO(raw)))
After that, one can get various attributes from the structure by invoking getter methods like:
data.base # => base loading address
# 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 AndroidImg(KaitaiStruct):
"""
.. seealso::
Source - https://source.android.com/docs/core/architecture/bootloader/boot-image-header
"""
def __init__(self, _io, _parent=None, _root=None):
super(AndroidImg, self).__init__(_io)
self._parent = _parent
self._root = _root or self
self._read()
def _read(self):
self.magic = self._io.read_bytes(8)
if not self.magic == b"\x41\x4E\x44\x52\x4F\x49\x44\x21":
raise kaitaistruct.ValidationNotEqualError(b"\x41\x4E\x44\x52\x4F\x49\x44\x21", self.magic, self._io, u"/seq/0")
self.kernel = AndroidImg.Load(self._io, self, self._root)
self.ramdisk = AndroidImg.Load(self._io, self, self._root)
self.second = AndroidImg.Load(self._io, self, self._root)
self.tags_load = self._io.read_u4le()
self.page_size = self._io.read_u4le()
self.header_version = self._io.read_u4le()
self.os_version = AndroidImg.OsVersion(self._io, self, self._root)
self.name = (KaitaiStream.bytes_terminate(self._io.read_bytes(16), 0, False)).decode(u"ASCII")
self.cmdline = (KaitaiStream.bytes_terminate(self._io.read_bytes(512), 0, False)).decode(u"ASCII")
self.sha = self._io.read_bytes(32)
self.extra_cmdline = (KaitaiStream.bytes_terminate(self._io.read_bytes(1024), 0, False)).decode(u"ASCII")
if self.header_version > 0:
pass
self.recovery_dtbo = AndroidImg.SizeOffset(self._io, self, self._root)
if self.header_version > 0:
pass
self.boot_header_size = self._io.read_u4le()
if self.header_version > 1:
pass
self.dtb = AndroidImg.LoadLong(self._io, self, self._root)
def _fetch_instances(self):
pass
self.kernel._fetch_instances()
self.ramdisk._fetch_instances()
self.second._fetch_instances()
self.os_version._fetch_instances()
if self.header_version > 0:
pass
self.recovery_dtbo._fetch_instances()
if self.header_version > 0:
pass
if self.header_version > 1:
pass
self.dtb._fetch_instances()
_ = self.dtb_img
if hasattr(self, '_m_dtb_img'):
pass
_ = self.kernel_img
if hasattr(self, '_m_kernel_img'):
pass
_ = self.ramdisk_img
if hasattr(self, '_m_ramdisk_img'):
pass
_ = self.recovery_dtbo_img
if hasattr(self, '_m_recovery_dtbo_img'):
pass
_ = self.second_img
if hasattr(self, '_m_second_img'):
pass
class Load(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
super(AndroidImg.Load, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.size = self._io.read_u4le()
self.addr = self._io.read_u4le()
def _fetch_instances(self):
pass
class LoadLong(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
super(AndroidImg.LoadLong, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.size = self._io.read_u4le()
self.addr = self._io.read_u8le()
def _fetch_instances(self):
pass
class OsVersion(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
super(AndroidImg.OsVersion, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.version = self._io.read_u4le()
def _fetch_instances(self):
pass
@property
def major(self):
if hasattr(self, '_m_major'):
return self._m_major
self._m_major = self.version >> 25 & 127
return getattr(self, '_m_major', None)
@property
def minor(self):
if hasattr(self, '_m_minor'):
return self._m_minor
self._m_minor = self.version >> 18 & 127
return getattr(self, '_m_minor', None)
@property
def month(self):
if hasattr(self, '_m_month'):
return self._m_month
self._m_month = self.version & 15
return getattr(self, '_m_month', None)
@property
def patch(self):
if hasattr(self, '_m_patch'):
return self._m_patch
self._m_patch = self.version >> 11 & 127
return getattr(self, '_m_patch', None)
@property
def year(self):
if hasattr(self, '_m_year'):
return self._m_year
self._m_year = (self.version >> 4 & 127) + 2000
return getattr(self, '_m_year', None)
class SizeOffset(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
super(AndroidImg.SizeOffset, self).__init__(_io)
self._parent = _parent
self._root = _root
self._read()
def _read(self):
self.size = self._io.read_u4le()
self.offset = self._io.read_u8le()
def _fetch_instances(self):
pass
@property
def base(self):
"""base loading address."""
if hasattr(self, '_m_base'):
return self._m_base
self._m_base = self.kernel.addr - 32768
return getattr(self, '_m_base', None)
@property
def dtb_img(self):
if hasattr(self, '_m_dtb_img'):
return self._m_dtb_img
if ((self.header_version > 1) and (self.dtb.size > 0)) :
pass
_pos = self._io.pos()
self._io.seek((((((((self.page_size + self.kernel.size) + self.ramdisk.size) + self.second.size) + self.recovery_dtbo.size) + self.page_size) - 1) // self.page_size) * self.page_size)
self._m_dtb_img = self._io.read_bytes(self.dtb.size)
self._io.seek(_pos)
return getattr(self, '_m_dtb_img', None)
@property
def dtb_offset(self):
"""dtb offset from base."""
if hasattr(self, '_m_dtb_offset'):
return self._m_dtb_offset
if self.header_version > 1:
pass
self._m_dtb_offset = (self.dtb.addr - self.base if self.dtb.addr > 0 else 0)
return getattr(self, '_m_dtb_offset', None)
@property
def kernel_img(self):
if hasattr(self, '_m_kernel_img'):
return self._m_kernel_img
_pos = self._io.pos()
self._io.seek(self.page_size)
self._m_kernel_img = self._io.read_bytes(self.kernel.size)
self._io.seek(_pos)
return getattr(self, '_m_kernel_img', None)
@property
def kernel_offset(self):
"""kernel offset from base."""
if hasattr(self, '_m_kernel_offset'):
return self._m_kernel_offset
self._m_kernel_offset = self.kernel.addr - self.base
return getattr(self, '_m_kernel_offset', None)
@property
def ramdisk_img(self):
if hasattr(self, '_m_ramdisk_img'):
return self._m_ramdisk_img
if self.ramdisk.size > 0:
pass
_pos = self._io.pos()
self._io.seek(((((self.page_size + self.kernel.size) + self.page_size) - 1) // self.page_size) * self.page_size)
self._m_ramdisk_img = self._io.read_bytes(self.ramdisk.size)
self._io.seek(_pos)
return getattr(self, '_m_ramdisk_img', None)
@property
def ramdisk_offset(self):
"""ramdisk offset from base."""
if hasattr(self, '_m_ramdisk_offset'):
return self._m_ramdisk_offset
self._m_ramdisk_offset = (self.ramdisk.addr - self.base if self.ramdisk.addr > 0 else 0)
return getattr(self, '_m_ramdisk_offset', None)
@property
def recovery_dtbo_img(self):
if hasattr(self, '_m_recovery_dtbo_img'):
return self._m_recovery_dtbo_img
if ((self.header_version > 0) and (self.recovery_dtbo.size > 0)) :
pass
_pos = self._io.pos()
self._io.seek(self.recovery_dtbo.offset)
self._m_recovery_dtbo_img = self._io.read_bytes(self.recovery_dtbo.size)
self._io.seek(_pos)
return getattr(self, '_m_recovery_dtbo_img', None)
@property
def second_img(self):
if hasattr(self, '_m_second_img'):
return self._m_second_img
if self.second.size > 0:
pass
_pos = self._io.pos()
self._io.seek((((((self.page_size + self.kernel.size) + self.ramdisk.size) + self.page_size) - 1) // self.page_size) * self.page_size)
self._m_second_img = self._io.read_bytes(self.second.size)
self._io.seek(_pos)
return getattr(self, '_m_second_img', None)
@property
def second_offset(self):
"""2nd bootloader offset from base."""
if hasattr(self, '_m_second_offset'):
return self._m_second_offset
self._m_second_offset = (self.second.addr - self.base if self.second.addr > 0 else 0)
return getattr(self, '_m_second_offset', None)
@property
def tags_offset(self):
"""tags offset from base."""
if hasattr(self, '_m_tags_offset'):
return self._m_tags_offset
self._m_tags_offset = self.tags_load - self.base
return getattr(self, '_m_tags_offset', None)