openwrt/scripts/cfe-partition-tag.py

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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()