openwrt/scripts/cfe-partition-tag.py

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Python
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#!/usr/bin/env python3
"""
CFE Partition Tag
{
u32 part_id;
u32 part_size;
u16 flags;
char part_name[33];
char part_version[21];
u32 part_crc32;
}
"""
import argparse
import os
import struct
import binascii
PART_NAME_SIZE = 33
PART_VERSION_SIZE = 21
def auto_int(x):
return int(x, 0)
def str_to_bytes_pad(string, size):
str_bytes = string.encode()
num_bytes = len(str_bytes)
if (num_bytes >= size):
str_bytes = str_bytes[:size - 1] + '\0'.encode()
else:
str_bytes += '\0'.encode() * (size - num_bytes)
return str_bytes
def create_tag(args, in_bytes, size):
# JAM CRC32 is bitwise not and unsigned
crc = (~binascii.crc32(in_bytes) & 0xFFFFFFFF)
tag = bytearray()
tag += struct.pack('>I', args.part_id)
tag += struct.pack('>I', size)
tag += struct.pack('>H', args.part_flags)
tag += str_to_bytes_pad(args.part_name, PART_NAME_SIZE)
tag += str_to_bytes_pad(args.part_version, PART_VERSION_SIZE)
tag += struct.pack('>I', crc)
return tag
def create_output(args):
in_st = os.stat(args.input_file)
in_size = in_st.st_size
in_f = open(args.input_file, 'r+b')
in_bytes = in_f.read(in_size)
in_f.close()
tag = create_tag(args, in_bytes, in_size)
out_f = open(args.output_file, 'w+b')
out_f.write(tag)
out_f.close()
def main():
global args
parser = argparse.ArgumentParser(description='')
parser.add_argument('--flags',
dest='part_flags',
action='store',
type=auto_int,
help='Partition Flags')
parser.add_argument('--id',
dest='part_id',
action='store',
type=auto_int,
help='Partition ID')
parser.add_argument('--input-file',
dest='input_file',
action='store',
type=str,
help='Input file')
parser.add_argument('--output-file',
dest='output_file',
action='store',
type=str,
help='Output file')
parser.add_argument('--name',
dest='part_name',
action='store',
type=str,
help='Partition Name')
parser.add_argument('--version',
dest='part_version',
action='store',
type=str,
help='Partition Version')
args = parser.parse_args()
if ((not args.part_flags) or
(not args.part_id) or
(not args.input_file) or
(not args.output_file) or
(not args.part_name) or
(not args.part_version)):
parser.print_help()
else:
create_output(args)
main()