scripts/cfe-partition-tag.py

   1 #!/usr/bin/env python3
   2
   3 """
   4 CFE Partition Tag
   5
   6 {
   7         u32 part_id;
   8         u32 part_size;
   9         u16 flags;
  10         char part_name[33];
  11         char part_version[21];
  12         u32 part_crc32;
  13 }
  14
  15 """
  16
  17 import argparse
  18 import os
  19 import struct
  20 import binascii
  21
  22
  23 PART_NAME_SIZE = 33
  24 PART_VERSION_SIZE = 21
  25
  26
  27 def auto_int(x):
  28     return int(x, 0)
  29
  30
  31 def str_to_bytes_pad(string, size):
  32     str_bytes = string.encode()
  33     num_bytes = len(str_bytes)
  34     if num_bytes >= size:
  35         str_bytes = str_bytes[: size - 1] + "\0".encode()
  36     else:
  37         str_bytes += "\0".encode() * (size - num_bytes)
  38     return str_bytes
  39
  40
  41 def create_tag(args, in_bytes, size):
  42     # JAM CRC32 is bitwise not and unsigned
  43     crc = ~binascii.crc32(in_bytes) & 0xFFFFFFFF
  44
  45     tag = bytearray()
  46     tag += struct.pack(">I", args.part_id)
  47     tag += struct.pack(">I", size)
  48     tag += struct.pack(">H", args.part_flags)
  49     tag += str_to_bytes_pad(args.part_name, PART_NAME_SIZE)
  50     tag += str_to_bytes_pad(args.part_version, PART_VERSION_SIZE)
  51     tag += struct.pack(">I", crc)
  52
  53     return tag
  54
  55
  56 def create_output(args):
  57     in_st = os.stat(args.input_file)
  58     in_size = in_st.st_size
  59
  60     in_f = open(args.input_file, "r+b")
  61     in_bytes = in_f.read(in_size)
  62     in_f.close()
  63
  64     tag = create_tag(args, in_bytes, in_size)
  65
  66     out_f = open(args.output_file, "w+b")
  67     out_f.write(tag)
  68     out_f.close()
  69
  70
  71 def main():
  72     global args
  73
  74     parser = argparse.ArgumentParser(description="")
  75
  76     parser.add_argument(
  77         "--flags",
  78         dest="part_flags",
  79         action="store",
  80         type=auto_int,
  81         help="Partition Flags",
  82     )
  83
  84     parser.add_argument(
  85         "--id",
  86         dest="part_id",
  87         action="store",
  88         type=auto_int,
  89         help="Partition ID",
  90     )
  91
  92     parser.add_argument(
  93         "--input-file",
  94         dest="input_file",
  95         action="store",
  96         type=str,
  97         help="Input file",
  98     )
  99
 100     parser.add_argument(
 101         "--output-file",
 102         dest="output_file",
 103         action="store",
 104         type=str,
 105         help="Output file",
 106     )
 107
 108     parser.add_argument(
 109         "--name",
 110         dest="part_name",
 111         action="store",
 112         type=str,
 113         help="Partition Name",
 114     )
 115
 116     parser.add_argument(
 117         "--version",
 118         dest="part_version",
 119         action="store",
 120         type=str,
 121         help="Partition Version",
 122     )
 123
 124     args = parser.parse_args()
 125
 126     if (
 127         (not args.part_flags)
 128         or (not args.part_id)
 129         or (not args.input_file)
 130         or (not args.output_file)
 131         or (not args.part_name)
 132         or (not args.part_version)
 133     ):
 134         parser.print_help()
 135     else:
 136         create_output(args)
 137
 138
 139 main()