KWP extract

main.py

import sys
import struct


def extract_firmware(input_file, output_file):
    DEFAULT_OUTPUT_SIZE = 300 * 1024 * 1024  # 1MB
    total_bytes_extracted = 0

    try:
        with open(input_file, "rb") as infile:
            with open(output_file, "wb") as outfile:
                # Initialize output buffer with 0xFF
                output_buffer = bytearray([0xFF] * DEFAULT_OUTPUT_SIZE)

                # Read the first 8 bytes and display ASCII values for bytes 3-7
                header_bytes = infile.read(8)
                if len(header_bytes) == 8:
                    firmware_version = "".join(chr(b) if 32 <= b <= 126 else '.' for b in header_bytes[3:8])
                    print(f"Firmware Version: {firmware_version}")

                # Reset the file pointer to the beginning
                infile.seek(0)

                prev_bytes = [0] * 6
                output_size = 0

                while True:
                    byte = infile.read(1)
                    if not byte:
                        break
                    byte = byte[0]

                    prev_bytes = [byte] + prev_bytes[:-1]

                    if byte == 0x34:
                        next_byte = infile.read(1)
                        if not next_byte or next_byte[0] != 0x82:
                            continue

                        # Read next 3 bytes as address
                        address_bytes = infile.read(3)
                        if len(address_bytes) != 3:
                            print("Error: Unexpected end of file")
                            break
                        address = struct.unpack(">I", b"\x00" + address_bytes)[0]

                        if address >= DEFAULT_OUTPUT_SIZE:
                            print(f"Error: Address 0x{address:06X} exceeds the 1MB limit.")
                            break

                        # Read length byte
                        length_byte = infile.read(1)
                        if not length_byte:
                            print("Error: Unexpected end of file")
                            break
                        length = length_byte[0]

                        # Read data bytes
                        data_bytes = infile.read(length)
                        if len(data_bytes) != length:
                            print("Error: Unexpected end of file")
                            break
                        output_buffer[address:address + length] = data_bytes
                        total_bytes_extracted += length

                        # Skip next 3 bytes
                        skip_bytes = infile.read(3)
                        if len(skip_bytes) != 3:
                            print("Error: Unexpected end of file")
                            break

                        output_size = max(output_size, address + length)

                # Write the extracted data to the output file
                outfile.write(output_buffer[:output_size])

                print(f"Total bytes extracted: {total_bytes_extracted}")
                print(f"Total file size: {output_size}")

    except IOError as e:
        print(f"File error: {e}")
        return 1
    return 0


if __name__ == "__main__":
    if len(sys.argv) != 3:
        print("KWP Extractor\n")
        print(f"Usage: {sys.argv[0]} <input_file> <output_file>")
        sys.exit(1)
    sys.exit(extract_firmware(sys.argv[1], sys.argv[2]))