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 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 _new(self, vd, name, parent, seqnum, isdir, length, xa):
'''
Internal method to create a new Directory Record.
Parameters:
vd - The Volume Descriptor this record is part of.
name - The name for this directory record.
parent - The parent of this directory record.
seqnum - The sequence number to associate with this directory record.
isdir - Whether this directory record represents a directory.
length - The length of the data for this directory record.
xa - True if this is an Extended Attribute record.
Returns:
Nothing.
'''
# Adding a new time should really be done when we are going to write
# the ISO (in record()). Ecma-119 9.1.5 says:
#
# 'This field shall indicate the date and the time of the day at which
# the information in the Extent described by the Directory Record was
# recorded.'
#
# We create it here just to have something in the field, but we'll
# redo the whole thing when we are mastering.
self.date = dates.DirectoryRecordDate()
self.date.new()
if length > 2**32 - 1:
raise pycdlibexception.PyCdlibInvalidInput(
'Maximum supported file length is 2^32-1')
self.data_length = length
self.file_ident = name
self.isdir = isdir
self.seqnum = seqnum
# For a new directory record entry, there is no original_extent_loc,
# so we leave it at None.
self.orig_extent_loc = None
self.len_fi = len(self.file_ident)
self.dr_len = struct.calcsize(self.FMT) + self.len_fi
# From Ecma-119, 9.1.6, the file flag bits are:
#
# Bit 0 - Existence - 0 for existence known, 1 for hidden
# Bit 1 - Directory - 0 for file, 1 for directory
# Bit 2 - Associated File - 0 for not associated, 1 for associated
# Bit 3 - Record - 0=structure not in xattr, 1=structure in xattr
# Bit 4 - Protection - 0=no owner and group, 1=owner and group in xattr
# Bit 5 - Reserved
# Bit 6 - Reserved
# Bit 7 - Multi-extent - 0=final directory record, 1=not final directory record
self.file_flags = 0
if self.isdir:
self.file_flags |= (1 << self.FILE_FLAG_DIRECTORY_BIT)
self.file_unit_size = 0 # FIXME: we don't support setting file unit size for now
self.interleave_gap_size = 0 # FIXME: we don't support setting interleave gap size for now
self.xattr_len = 0 # FIXME: we don't support xattrs for now
self.parent = parent
if parent is None:
# If no parent, then this is the root
self.is_root = True
if xa:
self.xa_record = XARecord()
self.xa_record.new()
self.dr_len += XARecord.length()
self.dr_len += (self.dr_len % 2)
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.vd = vd
self._initialized = True
def _new(self, mangledname, parent, seqnum, isdir, length, xa):
'''
Internal method to create a new Directory Record.
Parameters:
mangledname - The ISO9660 name for this directory record.
parent - The parent of this directory record.
seqnum - The sequence number to associate with this directory record.
isdir - Whether this directory record represents a directory.
length - The length of the data for this directory record.
xa - True if this is an Extended Attribute record.
Returns:
Nothing.
'''
# Adding a new time should really be done when we are going to write
# the ISO (in record()). Ecma-119 9.1.5 says:
#
# "This field shall indicate the date and the time of the day at which
# the information in the Extent described by the Directory Record was
# recorded."
#
# We create it here just to have something in the field, but we'll
# redo the whole thing when we are mastering.
self.date = dates.DirectoryRecordDate()
self.date.new()
if length > 2**32 - 1:
raise pycdlibexception.PyCdlibInvalidInput(
"Maximum supported file length is 2^32-1")
self.data_length = length
# FIXME: if the length of the item is more than 2^32 - 1, and the
# interchange level is 3, we should make duplicate directory record
# entries so we can represent the whole file (see
# http://wiki.osdev.org/ISO_9660, Size Limitations for a discussion of
# this).
self.file_ident = mangledname
self.isdir = isdir
self.seqnum = seqnum
# For a new directory record entry, there is no original_extent_loc,
# so we leave it at None.
self.orig_extent_loc = None
self.len_fi = len(self.file_ident)
self.dr_len = struct.calcsize(self.FMT) + self.len_fi
# From Ecma-119, 9.1.6, the file flag bits are:
#
# Bit 0 - Existence - 0 for existence known, 1 for hidden
# Bit 1 - Directory - 0 for file, 1 for directory
# Bit 2 - Associated File - 0 for not associated, 1 for associated
# Bit 3 - Record - 0 for structure not in xattr, 1 for structure in xattr
# Bit 4 - Protection - 0 for no owner and group in xattr, 1 for owner and group in xattr
# Bit 5 - Reserved
# Bit 6 - Reserved
# Bit 7 - Multi-extent - 0 for final directory record, 1 for not final directory record
# FIXME: We probably want to allow the existence, associated file, xattr
# record, and multi-extent bits to be set by the caller.
self.file_flags = 0
if self.isdir:
self.file_flags |= (1 << self.FILE_FLAG_DIRECTORY_BIT)
self.file_unit_size = 0 # FIXME: we don't support setting file unit size for now
self.interleave_gap_size = 0 # FIXME: we don't support setting interleave gap size for now
self.xattr_len = 0 # FIXME: we don't support xattrs for now
self.children = []
self.parent = parent
self.is_root = False
if parent is None:
# If no parent, then this is the root
self.is_root = True
self.xa_record = None
if xa:
self.xa_record = XARecord()
self.xa_record.new()
self.dr_len += XARecord.length()
self.dr_len += (self.dr_len % 2)
self.rock_ridge = None
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