3ds-to-cia.py 文件源码

def fix_cxi(filename, xorpad_file):
    f = open(filename, "r+b")
    # get exheader
    f.seek(0x200)
    exheader = bytearray(f.read(0x400))
    # decrypt exheader when needed
    if not xorpad_file is None:
        xorpad = bytearray(open(xorpad_file, "rb").read(0x400))
        exheader = xor(exheader, xorpad)
    # set sd flag in exheader
    exh_flags = exheader[0xD]
    exh_flags = exh_flags | 2
    exheader = exheader[:0xD] + struct.pack("B", exh_flags) + exheader[0xE:]
    # reset the hash
    f.seek(0x160)
    f.write(sha256(exheader))
    # write back modified exheader
    f.seek(0x200)
    # return save data size to be used on make_cia
    save_data_size = struct.unpack("<Q", exheader[0x1C0:0x1C8])[0] / 1024
    # reencrypt exheader when needed
    if not xorpad_file is None:
        exheader = xor(exheader, xorpad)
    f.write(exheader)
    return save_data_size