ISO9660 is standard filesystem used on read-only optical discs (mostly CD-ROM). The standard was based on earlier High Sierra Format (HSF), proposed for CD-ROMs in 1985, and, after several revisions, it was accepted as ISO9960:1998.
The format emphasizes portability (thus having pretty minimal features and very conservative file names standards) and sequential access (which favors disc devices with relatively slow rotation speed).
This page hosts a formal specification of ISO9660 CD 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 Ruby generated by Kaitai Struct depends on the Ruby runtime library. You have to install it before you can parse data.
The Ruby runtime library can be installed from RubyGems:
gem install kaitai-structParse a local file and get structure in memory:
data = Iso9660.from_file("path/to/local/file.iso")
Or parse structure from a string of bytes:
bytes = "\x00\x01\x02..."
data = Iso9660.new(Kaitai::Struct::Stream.new(bytes))
After that, one can get various attributes from the structure by invoking getter methods like:
data.sector_size # => get sector size
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
require 'kaitai/struct/struct'
unless Gem::Version.new(Kaitai::Struct::VERSION) >= Gem::Version.new('0.9')
raise "Incompatible Kaitai Struct Ruby API: 0.9 or later is required, but you have #{Kaitai::Struct::VERSION}"
end
##
# ISO9660 is standard filesystem used on read-only optical discs
# (mostly CD-ROM). The standard was based on earlier High Sierra
# Format (HSF), proposed for CD-ROMs in 1985, and, after several
# revisions, it was accepted as ISO9960:1998.
#
# The format emphasizes portability (thus having pretty minimal
# features and very conservative file names standards) and sequential
# access (which favors disc devices with relatively slow rotation
# speed).
class Iso9660 < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
self
end
##
# @see https://wiki.osdev.org/ISO_9660#The_Primary_Volume_Descriptor Source
class VolDescPrimary < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@unused1 = @_io.read_bytes(1)
raise Kaitai::Struct::ValidationNotEqualError.new([0].pack('C*'), unused1, _io, "/types/vol_desc_primary/seq/0") if not unused1 == [0].pack('C*')
@system_id = (@_io.read_bytes(32)).force_encoding("UTF-8")
@volume_id = (@_io.read_bytes(32)).force_encoding("UTF-8")
@unused2 = @_io.read_bytes(8)
raise Kaitai::Struct::ValidationNotEqualError.new([0, 0, 0, 0, 0, 0, 0, 0].pack('C*'), unused2, _io, "/types/vol_desc_primary/seq/3") if not unused2 == [0, 0, 0, 0, 0, 0, 0, 0].pack('C*')
@vol_space_size = U4bi.new(@_io, self, @_root)
@unused3 = @_io.read_bytes(32)
raise Kaitai::Struct::ValidationNotEqualError.new([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0].pack('C*'), unused3, _io, "/types/vol_desc_primary/seq/5") if not unused3 == [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0].pack('C*')
@vol_set_size = U2bi.new(@_io, self, @_root)
@vol_seq_num = U2bi.new(@_io, self, @_root)
@logical_block_size = U2bi.new(@_io, self, @_root)
@path_table_size = U4bi.new(@_io, self, @_root)
@lba_path_table_le = @_io.read_u4le
@lba_opt_path_table_le = @_io.read_u4le
@lba_path_table_be = @_io.read_u4be
@lba_opt_path_table_be = @_io.read_u4be
@_raw_root_dir = @_io.read_bytes(34)
_io__raw_root_dir = Kaitai::Struct::Stream.new(@_raw_root_dir)
@root_dir = DirEntry.new(_io__raw_root_dir, self, @_root)
@vol_set_id = (@_io.read_bytes(128)).force_encoding("UTF-8")
@publisher_id = (@_io.read_bytes(128)).force_encoding("UTF-8")
@data_preparer_id = (@_io.read_bytes(128)).force_encoding("UTF-8")
@application_id = (@_io.read_bytes(128)).force_encoding("UTF-8")
@copyright_file_id = (@_io.read_bytes(38)).force_encoding("UTF-8")
@abstract_file_id = (@_io.read_bytes(36)).force_encoding("UTF-8")
@bibliographic_file_id = (@_io.read_bytes(37)).force_encoding("UTF-8")
@vol_create_datetime = DecDatetime.new(@_io, self, @_root)
@vol_mod_datetime = DecDatetime.new(@_io, self, @_root)
@vol_expire_datetime = DecDatetime.new(@_io, self, @_root)
@vol_effective_datetime = DecDatetime.new(@_io, self, @_root)
@file_structure_version = @_io.read_u1
@unused4 = @_io.read_u1
@application_area = @_io.read_bytes(512)
self
end
def path_table
return @path_table unless @path_table.nil?
_pos = @_io.pos
@_io.seek((lba_path_table_le * _root.sector_size))
@_raw_path_table = @_io.read_bytes(path_table_size.le)
_io__raw_path_table = Kaitai::Struct::Stream.new(@_raw_path_table)
@path_table = PathTableLe.new(_io__raw_path_table, self, @_root)
@_io.seek(_pos)
@path_table
end
attr_reader :unused1
attr_reader :system_id
attr_reader :volume_id
attr_reader :unused2
attr_reader :vol_space_size
attr_reader :unused3
attr_reader :vol_set_size
attr_reader :vol_seq_num
attr_reader :logical_block_size
attr_reader :path_table_size
attr_reader :lba_path_table_le
attr_reader :lba_opt_path_table_le
attr_reader :lba_path_table_be
attr_reader :lba_opt_path_table_be
attr_reader :root_dir
attr_reader :vol_set_id
attr_reader :publisher_id
attr_reader :data_preparer_id
attr_reader :application_id
attr_reader :copyright_file_id
attr_reader :abstract_file_id
attr_reader :bibliographic_file_id
attr_reader :vol_create_datetime
attr_reader :vol_mod_datetime
attr_reader :vol_expire_datetime
attr_reader :vol_effective_datetime
attr_reader :file_structure_version
attr_reader :unused4
attr_reader :application_area
attr_reader :_raw_root_dir
attr_reader :_raw_path_table
end
class VolDescBootRecord < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@boot_system_id = (@_io.read_bytes(32)).force_encoding("UTF-8")
@boot_id = (@_io.read_bytes(32)).force_encoding("UTF-8")
self
end
attr_reader :boot_system_id
attr_reader :boot_id
end
class Datetime < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@year = @_io.read_u1
@month = @_io.read_u1
@day = @_io.read_u1
@hour = @_io.read_u1
@minute = @_io.read_u1
@sec = @_io.read_u1
@timezone = @_io.read_u1
self
end
attr_reader :year
attr_reader :month
attr_reader :day
attr_reader :hour
attr_reader :minute
attr_reader :sec
attr_reader :timezone
end
class DirEntry < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@len = @_io.read_u1
if len > 0
@_raw_body = @_io.read_bytes((len - 1))
_io__raw_body = Kaitai::Struct::Stream.new(@_raw_body)
@body = DirEntryBody.new(_io__raw_body, self, @_root)
end
self
end
attr_reader :len
attr_reader :body
attr_reader :_raw_body
end
class VolDesc < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@type = @_io.read_u1
@magic = @_io.read_bytes(5)
raise Kaitai::Struct::ValidationNotEqualError.new([67, 68, 48, 48, 49].pack('C*'), magic, _io, "/types/vol_desc/seq/1") if not magic == [67, 68, 48, 48, 49].pack('C*')
@version = @_io.read_u1
if type == 0
@vol_desc_boot_record = VolDescBootRecord.new(@_io, self, @_root)
end
if type == 1
@vol_desc_primary = VolDescPrimary.new(@_io, self, @_root)
end
self
end
attr_reader :type
attr_reader :magic
attr_reader :version
attr_reader :vol_desc_boot_record
attr_reader :vol_desc_primary
end
class PathTableEntryLe < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@len_dir_name = @_io.read_u1
@len_ext_attr_rec = @_io.read_u1
@lba_extent = @_io.read_u4le
@parent_dir_idx = @_io.read_u2le
@dir_name = (@_io.read_bytes(len_dir_name)).force_encoding("UTF-8")
if (len_dir_name % 2) == 1
@padding = @_io.read_u1
end
self
end
attr_reader :len_dir_name
attr_reader :len_ext_attr_rec
attr_reader :lba_extent
attr_reader :parent_dir_idx
attr_reader :dir_name
attr_reader :padding
end
class DirEntries < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@entries = []
i = 0
begin
_ = DirEntry.new(@_io, self, @_root)
@entries << _
i += 1
end until _.len == 0
self
end
attr_reader :entries
end
class U4bi < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@le = @_io.read_u4le
@be = @_io.read_u4be
self
end
attr_reader :le
attr_reader :be
end
class U2bi < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@le = @_io.read_u2le
@be = @_io.read_u2be
self
end
attr_reader :le
attr_reader :be
end
##
# @see https://wiki.osdev.org/ISO_9660#The_Path_Table Source
class PathTableLe < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@entries = []
i = 0
while not @_io.eof?
@entries << PathTableEntryLe.new(@_io, self, @_root)
i += 1
end
self
end
attr_reader :entries
end
##
# @see https://wiki.osdev.org/ISO_9660#Date.2Ftime_format Source
class DecDatetime < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@year = (@_io.read_bytes(4)).force_encoding("ASCII")
@month = (@_io.read_bytes(2)).force_encoding("ASCII")
@day = (@_io.read_bytes(2)).force_encoding("ASCII")
@hour = (@_io.read_bytes(2)).force_encoding("ASCII")
@minute = (@_io.read_bytes(2)).force_encoding("ASCII")
@sec = (@_io.read_bytes(2)).force_encoding("ASCII")
@sec_hundreds = (@_io.read_bytes(2)).force_encoding("ASCII")
@timezone = @_io.read_u1
self
end
attr_reader :year
attr_reader :month
attr_reader :day
attr_reader :hour
attr_reader :minute
attr_reader :sec
attr_reader :sec_hundreds
attr_reader :timezone
end
class DirEntryBody < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@len_ext_attr_rec = @_io.read_u1
@lba_extent = U4bi.new(@_io, self, @_root)
@size_extent = U4bi.new(@_io, self, @_root)
@datetime = Datetime.new(@_io, self, @_root)
@file_flags = @_io.read_u1
@file_unit_size = @_io.read_u1
@interleave_gap_size = @_io.read_u1
@vol_seq_num = U2bi.new(@_io, self, @_root)
@len_file_name = @_io.read_u1
@file_name = (@_io.read_bytes(len_file_name)).force_encoding("UTF-8")
if (len_file_name % 2) == 0
@padding = @_io.read_u1
end
@rest = @_io.read_bytes_full
self
end
def extent_as_dir
return @extent_as_dir unless @extent_as_dir.nil?
if (file_flags & 2) != 0
io = _root._io
_pos = io.pos
io.seek((lba_extent.le * _root.sector_size))
@_raw_extent_as_dir = io.read_bytes(size_extent.le)
_io__raw_extent_as_dir = Kaitai::Struct::Stream.new(@_raw_extent_as_dir)
@extent_as_dir = DirEntries.new(_io__raw_extent_as_dir, self, @_root)
io.seek(_pos)
end
@extent_as_dir
end
def extent_as_file
return @extent_as_file unless @extent_as_file.nil?
if (file_flags & 2) == 0
io = _root._io
_pos = io.pos
io.seek((lba_extent.le * _root.sector_size))
@extent_as_file = io.read_bytes(size_extent.le)
io.seek(_pos)
end
@extent_as_file
end
attr_reader :len_ext_attr_rec
attr_reader :lba_extent
attr_reader :size_extent
attr_reader :datetime
attr_reader :file_flags
attr_reader :file_unit_size
attr_reader :interleave_gap_size
attr_reader :vol_seq_num
attr_reader :len_file_name
attr_reader :file_name
attr_reader :padding
attr_reader :rest
attr_reader :_raw_extent_as_dir
end
def sector_size
return @sector_size unless @sector_size.nil?
@sector_size = 2048
@sector_size
end
def primary_vol_desc
return @primary_vol_desc unless @primary_vol_desc.nil?
_pos = @_io.pos
@_io.seek((16 * sector_size))
@primary_vol_desc = VolDesc.new(@_io, self, @_root)
@_io.seek(_pos)
@primary_vol_desc
end
end