BaseTools/Source/Python/Common/Edk2/Capsule/FmpPayloadHeader.py

   1 ## @file
   2 # Module that encodes and decodes a FMP_PAYLOAD_HEADER with a payload.
   3 # The FMP_PAYLOAD_HEADER is processed by the FmpPayloadHeaderLib in the
   4 # FmpDevicePkg.
   5 #
   6 # Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>
   7 # SPDX-License-Identifier: BSD-2-Clause-Patent
   8 #
   9
  10 '''
  11 FmpPayloadHeader
  12 '''
  13
  14 import struct
  15
  16 def _SIGNATURE_32 (A, B, C, D):
  17     return struct.unpack ('=I',bytearray (A + B + C + D, 'ascii'))[0]
  18
  19 def _SIGNATURE_32_TO_STRING (Signature):
  20     return struct.pack ("<I", Signature).decode ()
  21
  22 class FmpPayloadHeaderClass (object):
  23     #
  24     # typedef struct {
  25     #   UINT32  Signature;
  26     #   UINT32  HeaderSize;
  27     #   UINT32  FwVersion;
  28     #   UINT32  LowestSupportedVersion;
  29     # } FMP_PAYLOAD_HEADER;
  30     #
  31     # #define FMP_PAYLOAD_HEADER_SIGNATURE SIGNATURE_32 ('M', 'S', 'S', '1')
  32     #
  33     _StructFormat = '<IIII'
  34     _StructSize   = struct.calcsize (_StructFormat)
  35
  36     _FMP_PAYLOAD_HEADER_SIGNATURE = _SIGNATURE_32 ('M', 'S', 'S', '1')
  37
  38     def __init__ (self):
  39         self._Valid                 = False
  40         self.Signature              = self._FMP_PAYLOAD_HEADER_SIGNATURE
  41         self.HeaderSize             = self._StructSize
  42         self.FwVersion              = 0x00000000
  43         self.LowestSupportedVersion = 0x00000000
  44         self.Payload                = b''
  45
  46     def Encode (self):
  47         FmpPayloadHeader = struct.pack (
  48                                      self._StructFormat,
  49                                      self.Signature,
  50                                      self.HeaderSize,
  51                                      self.FwVersion,
  52                                      self.LowestSupportedVersion
  53                                      )
  54         self._Valid = True
  55         return FmpPayloadHeader + self.Payload
  56
  57     def Decode (self, Buffer):
  58         if len (Buffer) < self._StructSize:
  59             raise ValueError
  60         (Signature, HeaderSize, FwVersion, LowestSupportedVersion) = \
  61             struct.unpack (
  62                      self._StructFormat,
  63                      Buffer[0:self._StructSize]
  64                      )
  65         if Signature != self._FMP_PAYLOAD_HEADER_SIGNATURE:
  66             raise ValueError
  67         if HeaderSize < self._StructSize:
  68             raise ValueError
  69         self.Signature              = Signature
  70         self.HeaderSize             = HeaderSize
  71         self.FwVersion              = FwVersion
  72         self.LowestSupportedVersion = LowestSupportedVersion
  73         self.Payload                = Buffer[self.HeaderSize:]
  74
  75         self._Valid                 = True
  76         return self.Payload
  77
  78     def DumpInfo (self):
  79         if not self._Valid:
  80             raise ValueError
  81         print ('FMP_PAYLOAD_HEADER.Signature              = {Signature:08X} ({SignatureString})'.format (Signature = self.Signature, SignatureString = _SIGNATURE_32_TO_STRING (self.Signature)))
  82         print ('FMP_PAYLOAD_HEADER.HeaderSize             = {HeaderSize:08X}'.format (HeaderSize = self.HeaderSize))
  83         print ('FMP_PAYLOAD_HEADER.FwVersion              = {FwVersion:08X}'.format (FwVersion = self.FwVersion))
  84         print ('FMP_PAYLOAD_HEADER.LowestSupportedVersion = {LowestSupportedVersion:08X}'.format (LowestSupportedVersion = self.LowestSupportedVersion))
  85         print ('sizeof (Payload)                          = {Size:08X}'.format (Size = len (self.Payload)))