https://github.com/gabtremblay/pysrec
Enhancements:
Python 3 mods
Writes output to file
Empty lines removed
Fixed crash in def offset_data when data length is not even
#!/usr/bin/python
# srecparser.py
#
# Copyright (C) 2011 Gabriel Tremblay - initnull hat gmail.com
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
"""
Motorola S-Record parser
- Kudos to Montreal CISSP Groupies
"""
import sys
import srecutils
from optparse import OptionParser
def __generate_option_parser():
usage_str = "usage: %prog [options] filename"
parser = OptionParser(usage=usage_str)
parser.add_option("-r", action="store_true",
dest="readable", help="Human-readable output [default: %default]", default=False)
parser.add_option("-w", action="store_true",
dest="wraparound", help="Wrap around characters [default: %default]", default=True)
parser.add_option("-c", action="store_true",
dest="validate_checksum", help="Disable checksum validation [default: %default]", default=False)
parser.add_option("-l", action="store_true",
dest="print_lines_number", help="Print line number [default: %default]", default=False)
parser.add_option("-d", action="store_true",
dest="data_only", help="Data only [default: %default]", default=False)
parser.add_option("-o", metavar="OFFSET", dest="offset", help="Add OFFSET to bytes [default: %default]", default=0)
return parser
if __name__ == "__main__":
parser = __generate_option_parser()
(options, args) = parser.parse_args(sys.argv)
if len(args) <= 1 or len(args) > 2:
parser.print_help()
sys.exit()
# open input file
scn_file = open(args[1])
output_file = open("srec-output.txt", "w")
linecount = 0
for srec in scn_file:
# Strip some file content
srec = srec.strip("\n")
srec = srec.strip("\r")
# Validate checksum and parse record
if options.validate_checksum and not srecutils.validate_srec_checksum(srec):
print("Invalid checksum found!")
else:
# Extract data from the srec
record_type, data_len, addr, data, checksum = srecutils.parse_srec(srec)
if record_type == 'S1' or record_type == 'S2' or record_type == 'S3':
# Make a copy of the original data record for checksum calculation
raw_data = data
# Apply offset (default is 0)
data = srecutils.offset_data(data, int(options.offset), options.readable, options.wraparound)
# Get checksum of the new offset srec
raw_offset_srec = ''.join([record_type, data_len, addr, raw_data])
int_checksum = srecutils.compute_srec_checksum(raw_offset_srec)
checksum = srecutils.int_to_padded_hex_byte(int_checksum)
if not options.data_only:
data = ''.join([record_type, data_len, addr, data, checksum])
if options.print_lines_number:
data = ''.join([str(linecount), ': ', data])
# output to file
output_file.write(''.join([data, '\n']),)
#print(''.join([data, '\n']),)
# All the other record types
else:
output_str = ''.join([srec, '\n'])
if options.print_lines_number:
output_str = ''.join([str(linecount), ': ', output_str])
output_file.write(output_str)
#print(output_str,)
# increment our fancy linecounter
linecount += 1
scn_file.close()
output_file.close()
# srecutils.py
#
# Copyright (C) 2011 Gabriel Tremblay - initnull hat gmail.com
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
"""
Motorola S-Record utis
- Kudos to Montreal CISSP Groupies
"""
# Address len in bytes for S* types
# http://www.amelek.gda.pl/avr/uisp/srecord.htm
__ADDR_LEN = {'S0' : 2,
'S1' : 2,
'S2' : 3,
'S3' : 4,
'S5' : 2,
'S7' : 4,
'S8' : 3,
'S9' : 2}
def int_to_padded_hex_byte(integer):
"""
Convert an int to a 0-padded hex byte string
example: 65 == 41, 10 == 0A
Returns: The hex byte as string (ex: "0C")
"""
to_hex = hex(integer)
xpos = to_hex.find('x')
hex_byte = to_hex[xpos+1 : len(to_hex)].upper()
if len(hex_byte) == 1:
hex_byte = ''.join(['0', hex_byte])
return hex_byte
def compute_srec_checksum(srec):
"""
Compute the checksum byte of a given S-Record
Returns: The checksum as a string hex byte (ex: "0C")
"""
# Get the summable data from srec
# start at 2 to remove the S* record entry
data = srec[2:len(srec)]
sum = 0
# For each byte, convert to int and add.
# (step each two character to form a byte)
for position in range(0, len(data), 2):
current_byte = data[position : position+2]
int_value = int(current_byte, 16)
sum += int_value
# Extract the Least significant byte from the hex form
hex_sum = hex(sum)
least_significant_byte = hex_sum[len(hex_sum)-2:]
least_significant_byte = least_significant_byte.replace('x', '0')
# turn back to int and find the 8-bit one's complement
int_lsb = int(least_significant_byte, 16)
computed_checksum = (~int_lsb) & 0xff
return computed_checksum
def validate_srec_checksum(srec):
"""
Validate if the checksum of the supplied s-record is valid
Returns: True if valid, False if not
"""
checksum = srec[len(srec)-2:]
# Strip the original checksum and compare with the computed one
if compute_srec_checksum(srec[:len(srec) - 2]) == int(checksum, 16):
return True
else:
return False
def get_readable_string(integer):
r"""
Convert an integer to a readable 2-character representation. This is useful for reversing
examples: 41 == ".A", 13 == "\n", 20 (space) == "__"
Returns a readable 2-char representation of an int.
"""
if integer == 9: #\t
readable_string = "\\t"
elif integer == 10: #\r
readable_string = "\\r"
elif integer == 13: #\n
readable_string = "\\n"
elif integer == 32: # space
readable_string = '__'
elif integer >= 33 and integer <= 126: # Readable ascii
readable_string = ''.join([chr(integer), '.'])
else: # rest
readable_string = int_to_padded_hex_byte(integer)
return readable_string
def offset_byte_in_data(target_data, offset, target_byte_pos, readable = False, wraparound = False):
"""
Offset a given byte in the provided data payload (kind of rot(x))
readable will return a human-readable representation of the byte+offset
wraparound will wrap around 255 to 0 (ex: 257 = 2)
Returns: the offseted byte
"""
byte_pos = target_byte_pos * 2
prefix = target_data[:byte_pos]
suffix = target_data[byte_pos+2:]
target_byte = target_data[byte_pos:byte_pos+2]
int_value = int(target_byte, 16)
int_value += offset
# Wraparound
if int_value > 255 and wraparound:
int_value -= 256
# Extract readable char for analysis
if readable:
if int_value < 256 and int_value > 0:
offset_byte = get_readable_string(int_value)
else:
offset_byte = int_to_padded_hex_byte(int_value)
else:
offset_byte = int_to_padded_hex_byte(int_value)
return ''.join([prefix, offset_byte, suffix])
# offset can be from -255 to 255
def offset_data(data_section, offset, readable = False, wraparound = False):
"""
Offset the whole data section.
see offset_byte_in_data for more information
Returns: the entire data section + offset on each byte
"""
dataLen = int(len(data_section)/2)
for pos in range(0, dataLen):
data_section = offset_byte_in_data(data_section, offset, pos, readable, wraparound)
return data_section
def parse_srec(srec):
"""
Extract the data portion of a given S-Record (without checksum)
Returns: the record type, the lenght of the data section, the write address, the data itself and the checksum
"""
record_type = srec[0:2]
data_len = srec[2:4]
addr_len = __ADDR_LEN.get(record_type) * 2
addr = srec[4:4 + addr_len]
data = srec[4 + addr_len:len(srec)-2]
checksum = srec[len(srec) - 2:]
return record_type, data_len, addr, data, checksum
Kommentit
Tämän blogin kommentit tarkistetaan ennen julkaisua.