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 def str_to_bytes_pad(string, size):
  31         str_bytes = string.encode()
  32         num_bytes = len(str_bytes)
  33         if (num_bytes >= size):
  34                 str_bytes = str_bytes[:size - 1] + '\0'.encode()
  35         else:
  36                 str_bytes += '\0'.encode() * (size - num_bytes)
  37         return str_bytes
  38
  39 def create_tag(args, in_bytes, size):
  40     # JAM CRC32 is bitwise not and unsigned
  41     crc = (~binascii.crc32(in_bytes) & 0xFFFFFFFF)
  42
  43         tag = bytearray()
  44         tag += struct.pack('>I', args.part_id)
  45         tag += struct.pack('>I', size)
  46         tag += struct.pack('>H', args.part_flags)
  47         tag += str_to_bytes_pad(args.part_name, PART_NAME_SIZE)
  48         tag += str_to_bytes_pad(args.part_version, PART_VERSION_SIZE)
  49         tag += struct.pack('>I', crc)
  50
  51         return tag
  52
  53 def create_output(args):
  54         in_st = os.stat(args.input_file)
  55         in_size = in_st.st_size
  56
  57         in_f = open(args.input_file, 'r+b')
  58         in_bytes = in_f.read(in_size)
  59         in_f.close()
  60
  61         tag = create_tag(args, in_bytes, in_size)
  62
  63         out_f = open(args.output_file, 'w+b')
  64         out_f.write(tag)
  65         out_f.close()
  66
  67 def main():
  68         global args
  69
  70         parser = argparse.ArgumentParser(description='')
  71
  72         parser.add_argument('--flags',
  73                 dest='part_flags',
  74                 action='store',
  75                 type=auto_int,
  76                 help='Partition Flags')
  77
  78         parser.add_argument('--id',
  79                 dest='part_id',
  80                 action='store',
  81                 type=auto_int,
  82                 help='Partition ID')
  83
  84         parser.add_argument('--input-file',
  85                 dest='input_file',
  86                 action='store',
  87                 type=str,
  88                 help='Input file')
  89
  90         parser.add_argument('--output-file',
  91                 dest='output_file',
  92                 action='store',
  93                 type=str,
  94                 help='Output file')
  95
  96         parser.add_argument('--name',
  97                 dest='part_name',
  98                 action='store',
  99                 type=str,
 100                 help='Partition Name')
 101
 102         parser.add_argument('--version',
 103                 dest='part_version',
 104                 action='store',
 105                 type=str,
 106                 help='Partition Version')
 107
 108         args = parser.parse_args()
 109
 110         if ((not args.part_flags) or
 111             (not args.part_id) or
 112             (not args.input_file) or
 113             (not args.output_file) or
 114             (not args.part_name) or
 115             (not args.part_version)):
 116                 parser.print_help()
 117         else:
 118                 create_output(args)
 119
 120 main()