#!/usr/bin/env python3 import array import struct def read_struct(fmt,buf,offset): out, = struct.unpack_from(fmt,buf,offset) return out, offset + struct.calcsize(fmt) class ISO(object): def __init__(self, path): with open(path, 'rb') as f: tmp = f.read() self.data = array.array('b', tmp) self.sector_size = 2048 o = 0x10 * self.sector_size self.type, o = read_struct('B',self.data,o) self.id, o = read_struct('5s',self.data,o) self.version, o = read_struct('B',self.data,o) _unused0, o = read_struct('B',self.data,o) self.system_id, o = read_struct('32s',self.data,o) self.volume_id, o = read_struct('32s',self.data,o) _unused1, o = read_struct('8s',self.data,o) self.volume_space_lsb, o = read_struct('I',self.data,o) _unused2, o = read_struct('32s',self.data,o) self.volume_set_lsb, o = read_struct('H',self.data,o) self.volume_seq_lsb, o = read_struct('H',self.data,o) self.logical_block_size_lsb, o = read_struct('H',self.data,o) self.path_table_size_lsb, o = read_struct('I',self.data,o) self.path_table_lsb, o = read_struct('I',self.data,o) self.optional_path_table_msb, o = read_struct('>I',self.data,o) _offset = o self.root_dir_entry, o = read_struct('34s',self.data,o) self.root = ISOFile(self,_offset) self._cache = {} def get_file(self, path): if path == '/': return self.root else: if path in self._cache: return self._cache[path] units = path.split('/') units = units[1:] # remove root me = self.root for i in units: next_file = me.find(i) if not next_file: me = None break else: me = next_file self._cache[path] = me return me class ISOFile(object): def __init__(self, iso, offset): self.iso = iso self.offset = offset o = offset self.length, o = read_struct('B', self.iso.data, o) if not self.length: return self.ext_length, o = read_struct('B', self.iso.data, o) self.extent_start_lsb, o = read_struct('I',self.iso.data, o) self.extent_length_lsb, o = read_struct('I',self.iso.data, o) self.date_data, o = read_struct('7s', self.iso.data, o) self.flags, o = read_struct('b', self.iso.data, o) self.interleave_units, o = read_struct('b', self.iso.data, o) self.interleave_gap, o = read_struct('b', self.iso.data, o) self.volume_seq_lsb, o = read_struct('H',self.iso.data, o) self.name_len, o = read_struct('b', self.iso.data, o) self.name, o = read_struct('{}s'.format(self.name_len), self.iso.data, o) self.name = self.name.decode('ascii') def write_extents(self): struct.pack_into('I', self.iso.data, self.offset + 6, self.extent_start_lsb) struct.pack_into('I', self.iso.data, self.offset + 14, self.extent_length_lsb) def readable_name(self): if not ';' in self.name: return self.name.lower() else: tmp, _ = self.name.split(';') return tmp.lower() def list(self): sectors = self.iso.data[self.extent_start_lsb * self.iso.sector_size: self.extent_start_lsb * self.iso.sector_size+ 3 * self.iso.sector_size] offset = 0 while 1: f = ISOFile(self.iso, self.extent_start_lsb * self.iso.sector_size + offset) yield f offset += f.length if not f.length: break def find(self, name): sectors = self.iso.data[self.extent_start_lsb * self.iso.sector_size: self.extent_start_lsb * self.iso.sector_size+ 3 * self.iso.sector_size] offset = 0 if '.' in name and len(name.split('.')[0]) > 8: a, b = name.split('.') name = a[:8] + '.' + b if '-' in name: name = name.replace('-','_') while 1: f = ISOFile(self.iso, self.extent_start_lsb * self.iso.sector_size + offset) if not f.length: if offset < self.extent_length_lsb: offset += 1 continue else: break if ';' in f.name: tmp, _ = f.name.split(';') if tmp.endswith('.'): tmp = tmp[:-1] if tmp.lower() == name.lower(): return f elif f.name.lower() == name.lower(): return f offset += f.length return None class FAT(object): def __init__(self, iso, offset): self.iso = iso self.offset = offset self.bytespersector, _ = read_struct('H', self.iso.data, offset + 11) self.sectorspercluster, _ = read_struct('B', self.iso.data, offset + 13) self.reservedsectors, _ = read_struct('H', self.iso.data, offset + 14) self.numberoffats, _ = read_struct('B', self.iso.data, offset + 16) self.numberofdirs, _ = read_struct('H', self.iso.data, offset + 17) self.fatsize, _ = read_struct('H', self.iso.data, offset + 22) self.root_dir_sectors = (self.numberofdirs * 32 + (self.bytespersector - 1)) // self.bytespersector self.first_data_sector = self.reservedsectors + (self.numberoffats * self.fatsize) + self.root_dir_sectors self.root_sector= self.first_data_sector - self.root_dir_sectors self.root = FATDirectory(self, self.offset + self.root_sector * self.bytespersector) def get_offset(self, cluster): return self.offset + ((cluster - 2) * self.sectorspercluster + self.first_data_sector) * self.bytespersector def get_file(self, path): units = path.split('/') units = units[1:] me = self.root out = None for i in units: for fatfile in me.list(): if fatfile.readable_name() == i: me = fatfile.to_dir() out = fatfile break else: return None return out class FATDirectory(object): def __init__(self, fat, offset): self.fat = fat self.offset = offset def list(self): o = self.offset while 1: out = FATFile(self.fat, o) if out.name != '\0\0\0\0\0\0\0\0': yield out else: break o += out.size class FATFile(object): def __init__(self, fat, offset): self.fat = fat self.offset = offset self.magic_long = None self.size = 0 self.long_name = '' o = self.offset self.actual_offset = o self.attrib, _ = read_struct('B',self.fat.iso.data,o+11) while (self.attrib & 0x0F) == 0x0F: # Long file name entry tmp = read_struct('10s',self.fat.iso.data,o+1)[0] tmp += read_struct('12s',self.fat.iso.data,o+14)[0] tmp += read_struct('4s',self.fat.iso.data,o+28)[0] tmp = "".join([x for x in tmp[::2] if x != '\xFF']).strip('\x00') self.long_name = tmp + self.long_name self.size += 32 o = self.offset + self.size self.actual_offset = o self.attrib, _ = read_struct('B',self.fat.iso.data,o+11) o = self.offset + self.size self.name, o = read_struct('8s',self.fat.iso.data,o) self.ext, o = read_struct('3s',self.fat.iso.data,o) self.attrib, o = read_struct('B',self.fat.iso.data,o) self.userattrib, o = read_struct('B',self.fat.iso.data,o) self.undelete, o = read_struct('b',self.fat.iso.data,o) self.createtime, o = read_struct('H',self.fat.iso.data,o) self.createdate, o = read_struct('H',self.fat.iso.data,o) self.accessdate, o = read_struct('H',self.fat.iso.data,o) self.clusterhi, o = read_struct('H',self.fat.iso.data,o) self.modifiedti, o = read_struct('H',self.fat.iso.data,o) self.modifiedda, o = read_struct('H',self.fat.iso.data,o) self.clusterlow, o = read_struct('H',self.fat.iso.data,o) self.filesize, o = read_struct('I',self.fat.iso.data,o) self.name = self.name.decode('ascii') self.ext = self.ext.decode('ascii') self.size += 32 self.cluster = (self.clusterhi << 16) + self.clusterlow def is_dir(self): return bool(self.attrib & 0x10) def is_long(self): return bool((self.attrib & 0x0F) == 0x0F) def to_dir(self): return FATDirectory(self.fat, self.fat.get_offset(self.cluster)) def get_offset(self): return self.fat.get_offset(self.cluster) def readable_name(self): if self.long_name: return self.long_name if self.ext.strip(): return (self.name.strip() + '.' + self.ext.strip()).lower() else: return self.name.strip().lower() image = ISO('image.iso') fat = image.root.find('FAT.IMG') fatfs = FAT(image, fat.extent_start_lsb * image.sector_size) def process(fatfile, path): if fatfile.is_long(): return if fatfile.readable_name() == '.': return if fatfile.readable_name() == '..': return if fatfile.is_dir(): for i in fatfile.to_dir().list(): process(i, path + fatfile.readable_name() + '/') else: cdfile = image.get_file(path + fatfile.readable_name()) if not cdfile: if fatfile.readable_name() != 'bootia32.efi' and fatfile.readable_name() != 'bootx64.efi': print("Warning:", fatfile.readable_name(), "not found in ISO") else: cdfile.extent_start_lsb = fatfile.get_offset() // 2048 cdfile.extent_length_lsb = fatfile.filesize cdfile.write_extents() for i in fatfs.root.list(): process(i,'/') with open('image.iso','wb') as f: f.write(image.data)