This page hosts a formal specification of ext2 filesystem 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 = Ext2.from_file("path/to/local/file.bin")
Or parse structure from a bytes:
from kaitaistruct import KaitaiStream, BytesIO
raw = b"\x00\x01\x02..."
data = Ext2(KaitaiStream(BytesIO(raw)))
After that, one can get various attributes from the structure by invoking getter methods like:
data.bg1 # => get bg1
# 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 Ext2(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):
pass
class SuperBlockStruct(KaitaiStruct):
class StateEnum(Enum):
valid_fs = 1
error_fs = 2
class ErrorsEnum(Enum):
act_continue = 1
act_ro = 2
act_panic = 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.inodes_count = self._io.read_u4le()
self.blocks_count = self._io.read_u4le()
self.r_blocks_count = self._io.read_u4le()
self.free_blocks_count = self._io.read_u4le()
self.free_inodes_count = self._io.read_u4le()
self.first_data_block = self._io.read_u4le()
self.log_block_size = self._io.read_u4le()
self.log_frag_size = self._io.read_u4le()
self.blocks_per_group = self._io.read_u4le()
self.frags_per_group = self._io.read_u4le()
self.inodes_per_group = self._io.read_u4le()
self.mtime = self._io.read_u4le()
self.wtime = self._io.read_u4le()
self.mnt_count = self._io.read_u2le()
self.max_mnt_count = self._io.read_u2le()
self.magic = self._io.read_bytes(2)
if not self.magic == b"\x53\xEF":
raise kaitaistruct.ValidationNotEqualError(b"\x53\xEF", self.magic, self._io, u"/types/super_block_struct/seq/15")
self.state = KaitaiStream.resolve_enum(Ext2.SuperBlockStruct.StateEnum, self._io.read_u2le())
self.errors = KaitaiStream.resolve_enum(Ext2.SuperBlockStruct.ErrorsEnum, self._io.read_u2le())
self.minor_rev_level = self._io.read_u2le()
self.lastcheck = self._io.read_u4le()
self.checkinterval = self._io.read_u4le()
self.creator_os = self._io.read_u4le()
self.rev_level = self._io.read_u4le()
self.def_resuid = self._io.read_u2le()
self.def_resgid = self._io.read_u2le()
self.first_ino = self._io.read_u4le()
self.inode_size = self._io.read_u2le()
self.block_group_nr = self._io.read_u2le()
self.feature_compat = self._io.read_u4le()
self.feature_incompat = self._io.read_u4le()
self.feature_ro_compat = self._io.read_u4le()
self.uuid = self._io.read_bytes(16)
self.volume_name = self._io.read_bytes(16)
self.last_mounted = self._io.read_bytes(64)
self.algo_bitmap = self._io.read_u4le()
self.prealloc_blocks = self._io.read_u1()
self.prealloc_dir_blocks = self._io.read_u1()
self.padding1 = self._io.read_bytes(2)
self.journal_uuid = self._io.read_bytes(16)
self.journal_inum = self._io.read_u4le()
self.journal_dev = self._io.read_u4le()
self.last_orphan = self._io.read_u4le()
self.hash_seed = []
for i in range(4):
self.hash_seed.append(self._io.read_u4le())
self.def_hash_version = self._io.read_u1()
@property
def block_size(self):
if hasattr(self, '_m_block_size'):
return self._m_block_size
self._m_block_size = (1024 << self.log_block_size)
return getattr(self, '_m_block_size', None)
@property
def block_group_count(self):
if hasattr(self, '_m_block_group_count'):
return self._m_block_group_count
self._m_block_group_count = self.blocks_count // self.blocks_per_group
return getattr(self, '_m_block_group_count', None)
class DirEntry(KaitaiStruct):
class FileTypeEnum(Enum):
unknown = 0
reg_file = 1
dir = 2
chrdev = 3
blkdev = 4
fifo = 5
sock = 6
symlink = 7
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.inode_ptr = self._io.read_u4le()
self.rec_len = self._io.read_u2le()
self.name_len = self._io.read_u1()
self.file_type = KaitaiStream.resolve_enum(Ext2.DirEntry.FileTypeEnum, self._io.read_u1())
self.name = (self._io.read_bytes(self.name_len)).decode(u"UTF-8")
self.padding = self._io.read_bytes(((self.rec_len - self.name_len) - 8))
@property
def inode(self):
if hasattr(self, '_m_inode'):
return self._m_inode
self._m_inode = self._root.bg1.block_groups[(self.inode_ptr - 1) // self._root.bg1.super_block.inodes_per_group].inodes[((self.inode_ptr - 1) % self._root.bg1.super_block.inodes_per_group)]
return getattr(self, '_m_inode', None)
class Inode(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.mode = self._io.read_u2le()
self.uid = self._io.read_u2le()
self.size = self._io.read_u4le()
self.atime = self._io.read_u4le()
self.ctime = self._io.read_u4le()
self.mtime = self._io.read_u4le()
self.dtime = self._io.read_u4le()
self.gid = self._io.read_u2le()
self.links_count = self._io.read_u2le()
self.blocks = self._io.read_u4le()
self.flags = self._io.read_u4le()
self.osd1 = self._io.read_u4le()
self.block = []
for i in range(15):
self.block.append(Ext2.BlockPtr(self._io, self, self._root))
self.generation = self._io.read_u4le()
self.file_acl = self._io.read_u4le()
self.dir_acl = self._io.read_u4le()
self.faddr = self._io.read_u4le()
self.osd2 = self._io.read_bytes(12)
@property
def as_dir(self):
if hasattr(self, '_m_as_dir'):
return self._m_as_dir
io = self.block[0].body._io
_pos = io.pos()
io.seek(0)
self._m_as_dir = Ext2.Dir(io, self, self._root)
io.seek(_pos)
return getattr(self, '_m_as_dir', None)
class BlockPtr(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.ptr = self._io.read_u4le()
@property
def body(self):
if hasattr(self, '_m_body'):
return self._m_body
_pos = self._io.pos()
self._io.seek((self.ptr * self._root.bg1.super_block.block_size))
self._raw__m_body = self._io.read_bytes(self._root.bg1.super_block.block_size)
_io__raw__m_body = KaitaiStream(BytesIO(self._raw__m_body))
self._m_body = Ext2.RawBlock(_io__raw__m_body, self, self._root)
self._io.seek(_pos)
return getattr(self, '_m_body', None)
class Dir(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.entries = []
i = 0
while not self._io.is_eof():
self.entries.append(Ext2.DirEntry(self._io, self, self._root))
i += 1
class BlockGroup(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_super_block = self._io.read_bytes(1024)
_io__raw_super_block = KaitaiStream(BytesIO(self._raw_super_block))
self.super_block = Ext2.SuperBlockStruct(_io__raw_super_block, self, self._root)
self.block_groups = []
for i in range(self.super_block.block_group_count):
self.block_groups.append(Ext2.Bgd(self._io, self, self._root))
class Bgd(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.block_bitmap_block = self._io.read_u4le()
self.inode_bitmap_block = self._io.read_u4le()
self.inode_table_block = self._io.read_u4le()
self.free_blocks_count = self._io.read_u2le()
self.free_inodes_count = self._io.read_u2le()
self.used_dirs_count = self._io.read_u2le()
self.pad_reserved = self._io.read_bytes((2 + 12))
@property
def block_bitmap(self):
if hasattr(self, '_m_block_bitmap'):
return self._m_block_bitmap
_pos = self._io.pos()
self._io.seek((self.block_bitmap_block * self._root.bg1.super_block.block_size))
self._m_block_bitmap = self._io.read_bytes(1024)
self._io.seek(_pos)
return getattr(self, '_m_block_bitmap', None)
@property
def inode_bitmap(self):
if hasattr(self, '_m_inode_bitmap'):
return self._m_inode_bitmap
_pos = self._io.pos()
self._io.seek((self.inode_bitmap_block * self._root.bg1.super_block.block_size))
self._m_inode_bitmap = self._io.read_bytes(1024)
self._io.seek(_pos)
return getattr(self, '_m_inode_bitmap', None)
@property
def inodes(self):
if hasattr(self, '_m_inodes'):
return self._m_inodes
_pos = self._io.pos()
self._io.seek((self.inode_table_block * self._root.bg1.super_block.block_size))
self._m_inodes = []
for i in range(self._root.bg1.super_block.inodes_per_group):
self._m_inodes.append(Ext2.Inode(self._io, self, self._root))
self._io.seek(_pos)
return getattr(self, '_m_inodes', None)
class RawBlock(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.body = self._io.read_bytes(self._root.bg1.super_block.block_size)
@property
def bg1(self):
if hasattr(self, '_m_bg1'):
return self._m_bg1
_pos = self._io.pos()
self._io.seek(1024)
self._m_bg1 = Ext2.BlockGroup(self._io, self, self._root)
self._io.seek(_pos)
return getattr(self, '_m_bg1', None)
@property
def root_dir(self):
if hasattr(self, '_m_root_dir'):
return self._m_root_dir
self._m_root_dir = self.bg1.block_groups[0].inodes[1].as_dir
return getattr(self, '_m_root_dir', None)