mirror of
https://github.com/xemu-project/xemu.git
synced 2024-11-24 20:19:44 +00:00
fd28938b7a
Because of the risk that compilers might not emit the asm() block at the beginning of the option ROM, check that the ROM contains the required magic signature. Signed-off-by: Richard W.M. Jones <rjones@redhat.com> Message-Id: <1463000807-18015-3-git-send-email-rjones@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
63 lines
1.6 KiB
Python
63 lines
1.6 KiB
Python
#
|
|
# Option ROM signing utility
|
|
#
|
|
# Authors:
|
|
# Jan Kiszka <jan.kiszka@siemens.com>
|
|
#
|
|
# This work is licensed under the terms of the GNU GPL, version 2 or later.
|
|
# See the COPYING file in the top-level directory.
|
|
|
|
import sys
|
|
import struct
|
|
|
|
if len(sys.argv) < 3:
|
|
print('usage: signrom.py input output')
|
|
sys.exit(1)
|
|
|
|
fin = open(sys.argv[1], 'rb')
|
|
fout = open(sys.argv[2], 'wb')
|
|
|
|
magic = fin.read(2)
|
|
if magic != '\x55\xaa':
|
|
sys.exit("%s: option ROM does not begin with magic 55 aa" % sys.argv[1])
|
|
|
|
size_byte = ord(fin.read(1))
|
|
fin.seek(0)
|
|
|
|
if size_byte == 0:
|
|
# If the caller left the size field blank then we will fill it in,
|
|
# also rounding the whole input to a multiple of 512 bytes.
|
|
data = fin.read()
|
|
# +1 because we need a byte to store the checksum.
|
|
size = len(data) + 1
|
|
# Round up to next multiple of 512.
|
|
size += 511
|
|
size -= size % 512
|
|
if size >= 65536:
|
|
sys.exit("%s: option ROM size too large" % sys.argv[1])
|
|
# size-1 because a final byte is added below to store the checksum.
|
|
data = data.ljust(size-1, '\0')
|
|
data = data[:2] + chr(size/512) + data[3:]
|
|
else:
|
|
# Otherwise the input file specifies the size so use it.
|
|
# -1 because we overwrite the last byte of the file with the checksum.
|
|
size = size_byte * 512 - 1
|
|
data = fin.read(size)
|
|
|
|
fout.write(data)
|
|
|
|
checksum = 0
|
|
for b in data:
|
|
# catch Python 2 vs. 3 differences
|
|
if isinstance(b, int):
|
|
checksum += b
|
|
else:
|
|
checksum += ord(b)
|
|
checksum = (256 - checksum) % 256
|
|
|
|
# Python 3 no longer allows chr(checksum)
|
|
fout.write(struct.pack('B', checksum))
|
|
|
|
fin.close()
|
|
fout.close()
|