def record_big_endian(self):
'''
A method to generate a string representing the big endian version of
this Path Table Record.
Parameters:
None.
Returns:
A string representing the big endian version of this Path Table Record.
'''
if not self._initialized:
raise pycdlibexception.PyCdlibInternalError("Path Table Record not yet initialized")
return self._record(utils.swab_32bit(self.extent_location),
utils.swab_16bit(self.parent_directory_num))
def record_big_endian(self):
'''
A method to generate a string representing the big endian version of
this Path Table Record.
Parameters:
None.
Returns:
A string representing the big endian version of this Path Table Record.
'''
if not self._initialized:
raise pycdlibexception.PyCdlibInternalError("Path Table Record not yet initialized")
return self._record(utils.swab_32bit(self.extent_location),
utils.swab_16bit(self.parent_directory_num))
def new(self, platform_id):
'''
A method to create a new El Torito Validation Entry.
Parameters:
platform_id - The platform ID to set for this validation entry.
Returns:
Nothing.
'''
if self._initialized:
raise pycdlibexception.PyCdlibInternalError('El Torito Validation Entry already initialized')
self.platform_id = platform_id
self.id_string = b'\x00' * 24 # FIXME: let the user set this
self.checksum = 0
self.checksum = utils.swab_16bit(self._checksum(self._record()) - 1)
self._initialized = True
def record_big_endian(self):
# type: () -> bytes
"""
Generate a string representing the big endian version of
this Path Table Record.
Parameters:
None.
Returns:
A string representing the big endian version of this Path Table Record.
"""
if not self._initialized:
raise pycdlibexception.PyCdlibInternalError(
'Path Table Record not initialized')
return self._record(utils.swab_32bit(self.extent_location),
utils.swab_16bit(self.parent_directory_num))
def new(self, platform_id):
# type: (int) -> None
'''
A method to create a new El Torito Validation Entry.
Parameters:
platform_id - The platform ID to set for this validation entry.
Returns:
Nothing.
'''
if self._initialized:
raise pycdlibexception.PyCdlibInternalError('El Torito Validation Entry already initialized')
self.platform_id = platform_id
self.id_string = b'\x00' * 24 # FIXME: let the user set this
self.checksum = 0
self.checksum = utils.swab_16bit(self._checksum(self._record()) - 1)
self._initialized = True
def record(self):
'''
A method to generate the string representing this Directory Record.
Parameters:
None.
Returns:
String representing this Directory Record.
'''
if not self._initialized:
raise pycdlibexception.PyCdlibInternalError(
'Directory Record not yet initialized')
# Ecma-119 9.1.5 says the date should reflect the time when the
# record was written, so we make a new date now and use that to
# write out the record.
self.date = dates.DirectoryRecordDate()
self.date.new()
padlen = struct.calcsize(self.FMT) + self.len_fi
padstr = b'\x00' * (padlen % 2)
extent_loc = self._extent_location()
xa_rec = b''
if self.xa_record is not None:
xa_rec = b'\x00' * self.xa_pad_size + self.xa_record.record()
rr_rec = b''
if self.rock_ridge is not None:
rr_rec = self.rock_ridge.record_dr_entries()
outlist = [
struct.pack(self.FMT, self.dr_len, self.xattr_len, extent_loc,
utils.swab_32bit(extent_loc), self.data_length,
utils.swab_32bit(self.data_length), self.date.record(),
self.file_flags, self.file_unit_size,
self.interleave_gap_size, self.seqnum,
utils.swab_16bit(self.seqnum), self.len_fi) +
self.file_ident + padstr + xa_rec + rr_rec
]
outlist.append(b'\x00' * (len(outlist[0]) % 2))
return b''.join(outlist)
def new(self, platform_id):
'''
A method to create a new El Torito Validation Entry.
Parameters:
platform_id - The platform ID to set for this validation entry.
Returns:
Nothing.
'''
if self.initialized:
raise pycdlibexception.PyCdlibInternalError("El Torito Validation Entry already initialized")
self.header_id = 1
self.platform_id = platform_id
self.id_string = b"\x00" * 24 # FIXME: let the user set this
self.keybyte1 = 0x55
self.keybyte2 = 0xaa
self.checksum = 0
self.checksum = utils.swab_16bit(self._checksum(self._record()) - 1)
self.initialized = True
def record(self):
'''
A method to generate the string representing this Directory Record.
Parameters:
None.
Returns:
String representing this Directory Record.
'''
if not self._initialized:
raise pycdlibexception.PyCdlibInternalError("Directory Record not yet initialized")
# Ecma-119 9.1.5 says the date should reflect the time when the
# record was written, so we make a new date now and use that to
# write out the record.
self.date = dates.DirectoryRecordDate()
self.date.new()
padlen = struct.calcsize(self.FMT) + self.len_fi
padstr = b'\x00' * (padlen % 2)
extent_loc = self._extent_location()
xa_rec = b""
if self.xa_record is not None:
xa_rec = b'\x00' * self.xa_pad_size + self.xa_record.record()
rr_rec = b""
if self.rock_ridge is not None:
rr_rec = self.rock_ridge.record_dr_entries()
outlist = [struct.pack(self.FMT, self.dr_len, self.xattr_len,
extent_loc, utils.swab_32bit(extent_loc),
self.data_length, utils.swab_32bit(self.data_length),
self.date.record(), self.file_flags,
self.file_unit_size, self.interleave_gap_size,
self.seqnum, utils.swab_16bit(self.seqnum),
self.len_fi) + self.file_ident + padstr + xa_rec + rr_rec]
outlist.append(b'\x00' * (len(outlist[0]) % 2))
return b"".join(outlist)
def equal_to_be(self, be_record):
'''
A method to compare a little-endian path table record to its
big-endian counterpart. This is used to ensure that the ISO is sane.
Parameters:
be_record - The big-endian object to compare with the little-endian
object.
Returns:
Nothing.
'''
if not self._initialized:
raise pycdlibexception.PyCdlibInternalError("This Path Table Record is not yet initialized")
if be_record.len_di != self.len_di or \
be_record.xattr_length != self.xattr_length or \
utils.swab_32bit(be_record.extent_location) != self.extent_location or \
utils.swab_16bit(be_record.parent_directory_num) != self.parent_directory_num or \
be_record.directory_identifier != self.directory_identifier:
return False
return True
def equal_to_be(self, be_record):
'''
A method to compare a little-endian path table record to its
big-endian counterpart. This is used to ensure that the ISO is sane.
Parameters:
be_record - The big-endian object to compare with the little-endian
object.
Returns:
Nothing.
'''
if not self._initialized:
raise pycdlibexception.PyCdlibInternalError("This Path Table Record is not yet initialized")
if be_record.len_di != self.len_di or \
be_record.xattr_length != self.xattr_length or \
utils.swab_32bit(be_record.extent_location) != self.extent_location or \
utils.swab_16bit(be_record.parent_directory_num) != self.parent_directory_num or \
be_record.directory_identifier != self.directory_identifier:
return False
return True
def equal_to_be(self, be_record):
# type: (PathTableRecord) -> bool
'''
Compare a little-endian path table record to its big-endian counterpart.
This is used to ensure that the ISO is sane.
Parameters:
be_record - The big-endian object to compare with the little-endian
object.
Returns:
True if this record is equal to the big-endian record passed in,
False otherwise.
'''
if not self._initialized:
raise pycdlibexception.PyCdlibInternalError(
'Path Table Record not initialized')
if be_record.len_di != self.len_di or \
be_record.xattr_length != self.xattr_length or \
utils.swab_32bit(be_record.extent_location) != self.extent_location or \
utils.swab_16bit(be_record.parent_directory_num) != self.parent_directory_num or \
be_record.directory_identifier != self.directory_identifier:
return False
return True
def parse(self, vd, record, parent):
'''
Parse a directory record out of a string.
Parameters:
vd - The Volume Descriptor this record is part of.
record - The string to parse for this record.
parent - The parent of this record.
Returns:
True if this Directory Record has Rock Ridge extensions, False otherwise.
'''
if self._initialized:
raise pycdlibexception.PyCdlibInternalError(
'Directory Record already initialized')
if len(record) > 255:
# Since the length is supposed to be 8 bits, this should never
# happen.
raise pycdlibexception.PyCdlibInvalidISO(
'Directory record longer than 255 bytes!')
(self.dr_len, self.xattr_len, extent_location_le, extent_location_be,
data_length_le, data_length_be_unused, dr_date, self.file_flags,
self.file_unit_size, self.interleave_gap_size, seqnum_le, seqnum_be,
self.len_fi) = struct.unpack_from(self.FMT, record[:33], 0)
# In theory we should have a check here that checks to make sure that
# the length of the record we were passed in matches the data record
# length. However, we have seen ISOs in the wild where this is
# incorrect, so we elide the check here.
if extent_location_le != utils.swab_32bit(extent_location_be):
raise pycdlibexception.PyCdlibInvalidISO(
'Little-endian (%d) and big-endian (%d) extent location disagree'
% (extent_location_le, utils.swab_32bit(extent_location_be)))
self.orig_extent_loc = extent_location_le
# Theoretically, we should check to make sure that the little endian
# data length is the same as the big endian data length. In practice,
# though, we've seen ISOs where this is wrong. Skip the check, and just
# pick the little-endian as the 'actual' size, and hope for the best.
self.data_length = data_length_le
if seqnum_le != utils.swab_16bit(seqnum_be):
raise pycdlibexception.PyCdlibInvalidISO(
'Little-endian and big-endian seqnum disagree')
self.seqnum = seqnum_le
self.date = dates.DirectoryRecordDate()
self.date.parse(dr_date)
# OK, we've unpacked what we can from the beginning of the string. Now
# we have to use the len_fi to get the rest.
self.parent = parent
self.vd = vd
if self.parent is None:
self.is_root = True
# A root directory entry should always be exactly 34 bytes.
# However, we have seen ISOs in the wild that get this wrong, so we
# elide a check for it.
self.file_ident = bytes(bytearray([record[33]]))
# A root directory entry should always have 0 as the identifier.
# However, we have seen ISOs in the wild that don't have this set
# properly to 0. In that case, we override what we parsed out from
# the original with the correct value (\x00), and hope for the best.
if self.file_ident != b'\x00':
self.file_ident = b'\x00'
self.isdir = True
else:
record_offset = 33
self.file_ident = record[record_offset:record_offset + self.len_fi]
record_offset += self.len_fi
if self.file_flags & (1 << self.FILE_FLAG_DIRECTORY_BIT):
self.isdir = True
if self.len_fi % 2 == 0:
record_offset += 1
if len(record[record_offset:]) >= XARecord.length():
xa_rec = XARecord()
try:
xa_rec.parse(record[record_offset:record_offset +
XARecord.length()])
self.xa_record = xa_rec
record_offset += XARecord.length()
except pycdlibexception.PyCdlibInvalidISO:
# We've seen some ISOs in the wild (Windows 98 SE) that
# put the XA record all the way at the back, with some
# padding. Try again from the back.
try:
xa_rec.parse(record[-XARecord.length():])
self.xa_record = xa_rec
self.xa_pad_size = len(
record) - record_offset - XARecord.length()
record_offset = len(record)
except pycdlibexception.PyCdlibInvalidISO:
pass
if len(record[record_offset:]
) >= 2 and record[record_offset:record_offset + 2] in (
b'SP', b'RR', b'CE', b'PX', b'ER', b'ES', b'PN', b'SL',
b'NM', b'CL', b'PL', b'TF', b'SF', b'RE'):
self.rock_ridge = rockridge.RockRidge()
is_first_dir_record_of_root = self.file_ident == b'\x00' and parent.parent is None
if is_first_dir_record_of_root:
bytes_to_skip = 0
elif parent.parent is None:
bytes_to_skip = parent.children[0].rock_ridge.bytes_to_skip
else:
bytes_to_skip = parent.rock_ridge.bytes_to_skip
self.rock_ridge.parse(record[record_offset:],
is_first_dir_record_of_root,
bytes_to_skip, False)
if self.xattr_len != 0:
if self.file_flags & (1 << self.FILE_FLAG_RECORD_BIT):
raise pycdlibexception.PyCdlibInvalidISO(
'Record Bit not allowed with Extended Attributes')
if self.file_flags & (1 << self.FILE_FLAG_PROTECTION_BIT):
raise pycdlibexception.PyCdlibInvalidISO(
'Protection Bit not allowed with Extended Attributes')
if self.rock_ridge is None:
ret = None
else:
ret = self.rock_ridge.rr_version
if self.is_root:
self._printable_name = b'/'
elif self.file_ident == b'\x00':
self._printable_name = b'.'
elif self.file_ident == b'\x01':
self._printable_name = b'..'
else:
self._printable_name = self.file_ident
self._initialized = True
return ret
def parse(self, record, data_fp, parent):
'''
Parse a directory record out of a string.
Parameters:
record - The string to parse for this record.
data_fp - The file object to associate with this record.
parent - The parent of this record.
Returns:
True if this Directory Record has Rock Ridge extensions, False otherwise.
'''
if self._initialized:
raise pycdlibexception.PyCdlibInternalError("Directory Record already initialized")
if len(record) > 255:
# Since the length is supposed to be 8 bits, this should never
# happen.
raise pycdlibexception.PyCdlibInvalidISO("Directory record longer than 255 bytes!")
(self.dr_len, self.xattr_len, extent_location_le, extent_location_be,
data_length_le, data_length_be_unused, dr_date, self.file_flags,
self.file_unit_size, self.interleave_gap_size, seqnum_le, seqnum_be,
self.len_fi) = struct.unpack_from(self.FMT, record[:33], 0)
# In theory we should have a check here that checks to make sure that
# the length of the record we were passed in matches the data record
# length. However, we have seen ISOs in the wild where this is
# incorrect, so we elide the check here.
if extent_location_le != utils.swab_32bit(extent_location_be):
raise pycdlibexception.PyCdlibInvalidISO("Little-endian (%d) and big-endian (%d) extent location disagree" % (extent_location_le, utils.swab_32bit(extent_location_be)))
self.orig_extent_loc = extent_location_le
self.new_extent_loc = None
# Theoretically, we should check to make sure that the little endian
# data length is the same as the big endian data length. In practice,
# though, we've seen ISOs where this is wrong. Skip the check, and just
# pick the little-endian as the "actual" size, and hope for the best.
self.data_length = data_length_le
if seqnum_le != utils.swab_16bit(seqnum_be):
raise pycdlibexception.PyCdlibInvalidISO("Little-endian and big-endian seqnum disagree")
self.seqnum = seqnum_le
self.date = dates.DirectoryRecordDate()
self.date.parse(dr_date)
# OK, we've unpacked what we can from the beginning of the string. Now
# we have to use the len_fi to get the rest.
self.children = []
self.is_root = False
self.isdir = False
self.parent = parent
self.data_fp = data_fp
self.rock_ridge = None
self.xa_record = None
if self.parent is None:
self.is_root = True
# A root directory entry should always be exactly 34 bytes.
# However, we have seen ISOs in the wild that get this wrong, so we
# elide a check for it.
self.file_ident = bytes(bytearray([record[33]]))
# A root directory entry should always have 0 as the identifier.
if self.file_ident != b'\x00':
raise pycdlibexception.PyCdlibInvalidISO("Invalid root directory entry identifier")
self.isdir = True
else:
record_offset = 33
self.file_ident = record[record_offset:record_offset + self.len_fi]
record_offset += self.len_fi
if self.file_flags & (1 << self.FILE_FLAG_DIRECTORY_BIT):
self.isdir = True
else:
self.original_data_location = self.DATA_ON_ORIGINAL_ISO
if self.len_fi % 2 == 0:
record_offset += 1
if len(record[record_offset:]) >= XARecord.length():
xa_rec = XARecord()
try:
xa_rec.parse(record[record_offset:record_offset + XARecord.length()])
self.xa_record = xa_rec
record_offset += XARecord.length()
except pycdlibexception.PyCdlibInvalidISO:
# We've seen some ISOs in the wild (Windows 98 SE) that
# put the XA record all the way at the back, with some
# padding. Try again from the back.
try:
xa_rec.parse(record[-XARecord.length():])
self.xa_record = xa_rec
self.xa_pad_size = len(record) - record_offset - XARecord.length()
record_offset = len(record)
except pycdlibexception.PyCdlibInvalidISO:
pass
if len(record[record_offset:]) >= 2 and record[record_offset:record_offset + 2] in [b'SP', b'RR', b'CE', b'PX', b'ER', b'ES', b'PN', b'SL', b'NM', b'CL', b'PL', b'TF', b'SF', b'RE']:
self.rock_ridge = rockridge.RockRidge()
is_first_dir_record_of_root = self.file_ident == b'\x00' and parent.parent is None
if is_first_dir_record_of_root:
bytes_to_skip = 0
elif parent.parent is None:
bytes_to_skip = parent.children[0].rock_ridge.bytes_to_skip
else:
bytes_to_skip = parent.rock_ridge.bytes_to_skip
self.rock_ridge.parse(record[record_offset:],
is_first_dir_record_of_root,
bytes_to_skip,
False)
if self.xattr_len != 0:
if self.file_flags & (1 << self.FILE_FLAG_RECORD_BIT):
raise pycdlibexception.PyCdlibInvalidISO("Record Bit not allowed with Extended Attributes")
if self.file_flags & (1 << self.FILE_FLAG_PROTECTION_BIT):
raise pycdlibexception.PyCdlibInvalidISO("Protection Bit not allowed with Extended Attributes")
self._initialized = True
if self.rock_ridge is None:
ret = None
else:
ret = self.rock_ridge.rr_version
if self.is_root:
self._printable_name = b'/'
elif self.file_ident == b'\x00':
self._printable_name = b'.'
elif self.file_ident == b'\x01':
self._printable_name = b'..'
else:
self._printable_name = self.file_ident
return ret
