1*b38c2458SPaolo Bonzini#!/usr/bin/env python3 2*b38c2458SPaolo Bonzini 30d6b9cc7SJan Kiszka# 40d6b9cc7SJan Kiszka# Option ROM signing utility 50d6b9cc7SJan Kiszka# 60d6b9cc7SJan Kiszka# Authors: 70d6b9cc7SJan Kiszka# Jan Kiszka <jan.kiszka@siemens.com> 80d6b9cc7SJan Kiszka# 90d6b9cc7SJan Kiszka# This work is licensed under the terms of the GNU GPL, version 2 or later. 100d6b9cc7SJan Kiszka# See the COPYING file in the top-level directory. 110d6b9cc7SJan Kiszka 120d6b9cc7SJan Kiszkaimport sys 130d6b9cc7SJan Kiszkaimport struct 140d6b9cc7SJan Kiszka 150d6b9cc7SJan Kiszkaif len(sys.argv) < 3: 160d6b9cc7SJan Kiszka print('usage: signrom.py input output') 170d6b9cc7SJan Kiszka sys.exit(1) 180d6b9cc7SJan Kiszka 190d6b9cc7SJan Kiszkafin = open(sys.argv[1], 'rb') 200d6b9cc7SJan Kiszkafout = open(sys.argv[2], 'wb') 210d6b9cc7SJan Kiszka 22fd28938bSRichard W.M. Jonesmagic = fin.read(2) 2331d8f92eSDaniel P. Berrangeif magic != b'\x55\xaa': 24fd28938bSRichard W.M. Jones sys.exit("%s: option ROM does not begin with magic 55 aa" % sys.argv[1]) 25fd28938bSRichard W.M. Jones 266f71b779SRichard W.M. Jonessize_byte = ord(fin.read(1)) 270d6b9cc7SJan Kiszkafin.seek(0) 286f71b779SRichard W.M. Jonesdata = fin.read() 297f256924SPaolo Bonzini 307f256924SPaolo Bonzinisize = size_byte * 512 317f256924SPaolo Bonziniif len(data) > size: 327f256924SPaolo Bonzini sys.stderr.write('error: ROM is too large (%d > %d)\n' % (len(data), size)) 337f256924SPaolo Bonzini sys.exit(1) 347f256924SPaolo Bonzinielif len(data) < size: 357f256924SPaolo Bonzini # Add padding if necessary, rounding the whole input to a multiple of 367f256924SPaolo Bonzini # 512 bytes according to the third byte of the input. 376f71b779SRichard W.M. Jones # size-1 because a final byte is added below to store the checksum. 3831d8f92eSDaniel P. Berrange data = data.ljust(size-1, b'\0') 396f71b779SRichard W.M. Joneselse: 407f256924SPaolo Bonzini if ord(data[-1:]) != 0: 417f256924SPaolo Bonzini sys.stderr.write('WARNING: ROM includes nonzero checksum\n') 427f256924SPaolo Bonzini data = data[:size-1] 436f71b779SRichard W.M. Jones 440d6b9cc7SJan Kiszkafout.write(data) 450d6b9cc7SJan Kiszka 460d6b9cc7SJan Kiszkachecksum = 0 470d6b9cc7SJan Kiszkafor b in data: 48*b38c2458SPaolo Bonzini checksum = (checksum - b) & 255 490d6b9cc7SJan Kiszka 500d6b9cc7SJan Kiszkafout.write(struct.pack('B', checksum)) 510d6b9cc7SJan Kiszka 520d6b9cc7SJan Kiszkafin.close() 530d6b9cc7SJan Kiszkafout.close() 54