util/iso.py: wip ISO creation tool
This commit is contained in:
K. Lange
parent
0f683d32de
commit
72f653f915
278
util/iso.py
Executable file
278
util/iso.py
Executable file
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#!/usr/bin/env python3
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"""
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Tool for creating ISO 9660 CD images.
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"""
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import array
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import struct
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class Structure(object):
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assert_size = -1
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def __init__(self):
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self.data = {}
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for field in self.fields:
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if len(field) > 2:
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f, s, d = field
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self.data[s] = d
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else:
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f, s = field
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if f.endswith('s'):
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self.data[s] = b""
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else:
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self.data[s] = 0
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if self.assert_size != -1:
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assert(len(self) == self.assert_size)
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def __len__(self):
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return sum([struct.calcsize(f[0]) for f in self.fields])
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def read(self, data, offset):
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def read_struct(fmt,buf,offset):
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out, = struct.unpack_from(fmt,buf,offset)
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return out, offset + struct.calcsize(fmt)
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o = offset
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for field in self.fields:
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if len(field) > 2:
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f, s, _ = field
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else:
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f, s = field
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self.data[s], o = read_struct(f, data, o)
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return o
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def write(self, data, offset):
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def write_struct(fmt, buf, offset, value):
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struct.pack_into(fmt, buf, offset, value)
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return offset + struct.calcsize(fmt)
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o = offset
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for field in self.fields:
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if len(field) > 2:
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f, s, _ = field
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else:
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f, s = field
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o = write_struct(f,data,o,self.data[s])
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return o
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def make_time():
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data = array.array('b',b'\0'*17)
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struct.pack_into(
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'4s2s2s2s2s2s2sb',
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data, 0,
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b'2018', b'11', b'14', # Year, Month, Day
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b'12', b'00', b'00', # Hour, Minute, Second
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b'00', # Hundreths
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0, # Offset
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)
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return bytes(data)
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class ISOBootRecord(Structure):
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assert_size = 2048
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fields = (
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('B', 'type_code', 0),
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('5s', 'cd001', b'CD001'),
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('B', 'version', 1),
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('32s', 'boot_system_identifier'),
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('32s', 'boot_identifier'),
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('1977s', 'boot_record_data'),
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)
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class ISOElToritoBootRecord(ISOBootRecord):
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assert_size = 2048
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fields = (
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('B', 'type_code', 0),
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('5s', 'cd001', b'CD001'),
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('B', 'version', 1),
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('32s', 'boot_system_identifier',b'EL TORITO SPECIFICATION'),
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('32s', 'boot_identifier'),
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('<I', 'catalog_lba'),
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('1973s', 'boot_record_data'),
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)
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def set_catalog(self, catalog_lba):
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self.data['catalog_lba'] = catalog_lba
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class ISOPrimaryVolumeDescriptor(Structure):
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assert_size = 2048
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fields = (
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('B', 'type_code', 1),
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('5s', 'cd001', b'CD001'),
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('B', 'version', 1),
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('B', 'unused_0', 0),
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('32s', 'system_id', b' '*32),
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('32s', 'volume_id', b'ToaruOS Boot CD'.ljust(32)),
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('8s', 'unused_1', b'\0'*8),
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('<I', 'volume_space_lsb'),
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('>I', 'volume_space_msb'),
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('32s', 'unused_2', b'\0'*32),
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('<H', 'volume_set_size_lsb', 1),
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('>H', 'volume_set_size_msb', 1),
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('<H', 'volume_sequence_lsb', 1),
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('>H', 'volume_sequence_msb', 1),
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('<H', 'logical_block_size_lsb', 2048),
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('>H', 'logical_block_size_msb', 2048),
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('<I', 'path_table_size_lsb'),
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('>I', 'path_table_size_msb'),
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('<I', 'type_l_table_lsb'),
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('<I', 'optional_type_l_table_lsb'),
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('>I', 'type_m_table_msb'),
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('>I', 'optional_type_m_table_msb'),
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('34s', 'root_entry_data'),
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('128s', 'volume_set_identifier', b' '*128),
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('128s', 'publisher_identifier', b' '*128),
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('128s', 'data_preparer_identifier', b' '*128),
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('128s', 'application_identifier',b' '*128),
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('38s', 'copyright_file_identifier',b' '*38),
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('36s', 'abstract_file_identifier',b' '*36),
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('37s', 'bibliographic_file_identifier',b' '*37),
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('17s', 'volume_creation_time',make_time()),
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('17s', 'volume_modification_time',make_time()),
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('17s', 'volume_expiration_time',make_time()),
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('17s', 'volume_effective_time',make_time()),
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('B', 'file_structure_version'),
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('B', 'unused_3', 0),
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('512s', 'application_data'),
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('653s', 'reserved', b'\0'*653),
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)
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class ISOVolumeDescriptorSetTerminator(Structure):
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assert_size = 2048
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fields = (
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('B', 'type_code', 0xFF),
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('5s', 'cd001', b'CD001'),
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('B', 'version', 1),
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('2041s', 'unused', b'\0'*2041)
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)
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class ArbitraryData(object):
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def __init__(self, path):
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with open(path,'rb') as f:
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tmp = f.read()
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self.data = array.array('b',tmp)
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self.size = len(self.data)
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while (self.size % 2048):
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self.size += 1
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def write(self, data, offset):
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struct.pack_into(str(self.size) + 's', data, offset, self.data.tobytes())
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return offset + self.size
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class ISO9660(object):
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def __init__(self, from_file=None):
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self.primary_volume_descriptor = ISOPrimaryVolumeDescriptor()
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self.boot_record = ISOElToritoBootRecord()
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self.volume_descriptor_set_terminator = ISOVolumeDescriptorSetTerminator()
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self.el_torito_catalog = ElToritoCatalog()
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if from_file:
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# Only for a file we produced.
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with open(from_file, 'rb') as f:
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tmp = f.read()
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data = array.array('b', tmp)
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self.primary_volume_descriptor.read(data, 0x10 * 2048)
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self.boot_record.read(data, 0x11 * 2048)
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self.volume_descriptor_set_terminator.read(data, 0x12 * 2048)
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self.el_torito_catalog.read(data, self.boot_record.data['catalog_lba'] * 2048)
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else:
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self.boot_payload = ArbitraryData('cdrom/boot.sys')
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self.boot_record.set_catalog(0x13)
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self.el_torito_catalog.initial_entry.data['sector_count'] = 24
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self.el_torito_catalog.initial_entry.data['load_rba'] = 0x14
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def write(self, file_name):
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with open(file_name, 'wb') as f:
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data = array.array('b',b'\0'*(2048*0x14 + self.boot_payload.size))
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print(len(data))
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self.primary_volume_descriptor.write(data,0x10 * 2048)
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self.boot_record.write(data,0x11 * 2048)
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self.volume_descriptor_set_terminator.write(data,0x12 * 2048)
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self.el_torito_catalog.write(data,0x13 * 2048)
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self.boot_payload.write(data,0x14 * 2048)
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data.tofile(f)
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class ElToritoValidationEntry(Structure):
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assert_size = 0x20
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fields = (
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('B','header_id',1),
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('B','platform_id',0),
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('<H','reserved_0'),
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('24s','id_str',b'\0'*24),
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('<H','checksum',0x55aa),
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('B','key_55',0x55),
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('B','key_aa',0xaa),
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)
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class ElToritoInitialEntry(Structure):
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assert_size = 0x20
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fields = (
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('B','bootable',0x88),
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('B','media_type'),
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('<H','load_segment'),
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('B','system_type'),
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('B','unused_0'),
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('<H','sector_count'),
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('<I','load_rba'),
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('20s','unused_1',b'\0'*20),
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)
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class ElToritoSectionHeader(Structure):
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assert_size = 0x20
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fields = (
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('B','header_id',0x91),
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('B','platform_id',0xEF),
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('<H','sections',1),
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('28s','id_str',b'\0'*28)
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)
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class ElToritoSectionEntry(Structure):
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assert_size = 0x20
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fields = (
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('B','bootable',0x88),
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('B','media_type'),
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('<H','load_segment'),
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('B','system_type'),
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('B','unused_0'),
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('<H','sector_count'),
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('<I','load_rba'),
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('B','selection_criteria'),
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('19s','vendor'),
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)
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class ElToritoCatalog(object):
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def __init__(self):
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self.validation_entry = ElToritoValidationEntry()
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self.initial_entry = ElToritoInitialEntry()
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self.section_header = ElToritoSectionHeader()
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self.section = ElToritoSectionEntry()
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def read(self, data, offset):
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o = offset
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o = self.validation_entry.read(data, o)
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o = self.initial_entry.read(data, o)
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o = self.section_header.read(data, o)
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o = self.section.read(data, o)
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def write(self, data, offset):
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o = offset
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o = self.validation_entry.write(data, o)
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o = self.initial_entry.write(data, o)
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o = self.section_header.write(data, o)
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o = self.section.write(data, o)
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iso = ISO9660()
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#print(iso.el_torito_catalog.validation_entry.data)
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#print(iso.el_torito_catalog.initial_entry.data)
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#print(iso.el_torito_catalog.section_header.data)
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#print(iso.el_torito_catalog.section.data)
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iso.write('test.iso')
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