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 # This program and the accompanying materials
   8 # are licensed and made available under the terms and conditions of the BSD License
   9 # which accompanies this distribution.  The full text of the license may be found at
  10 # http://opensource.org/licenses/bsd-license.php
  11 #
  12 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14 #
  15
  16 '''
  17 FmpPayloadHeader
  18 '''
  19
  20 import struct
  21
  22 def _SIGNATURE_32 (A, B, C, D):
  23     return struct.unpack ('=I',bytearray (A + B + C + D, 'ascii'))[0]
  24
  25 def _SIGNATURE_32_TO_STRING (Signature):
  26     return struct.pack ("<I", Signature).decode ()
  27
  28 class FmpPayloadHeaderClass (object):
  29     #
  30     # typedef struct {
  31     #   UINT32  Signature;
  32     #   UINT32  HeaderSize;
  33     #   UINT32  FwVersion;
  34     #   UINT32  LowestSupportedVersion;
  35     # } FMP_PAYLOAD_HEADER;
  36     #
  37     # #define FMP_PAYLOAD_HEADER_SIGNATURE SIGNATURE_32 ('M', 'S', 'S', '1')
  38     #
  39     _StructFormat = '<IIII'
  40     _StructSize   = struct.calcsize (_StructFormat)
  41
  42     _FMP_PAYLOAD_HEADER_SIGNATURE = _SIGNATURE_32 ('M', 'S', 'S', '1')
  43
  44     def __init__ (self):
  45         self._Valid                 = False
  46         self.Signature              = self._FMP_PAYLOAD_HEADER_SIGNATURE
  47         self.HeaderSize             = self._StructSize
  48         self.FwVersion              = 0x00000000
  49         self.LowestSupportedVersion = 0x00000000
  50         self.Payload                = b''
  51
  52     def Encode (self):
  53         FmpPayloadHeader = struct.pack (
  54                                      self._StructFormat,
  55                                      self.Signature,
  56                                      self.HeaderSize,
  57                                      self.FwVersion,
  58                                      self.LowestSupportedVersion
  59                                      )
  60         self._Valid = True
  61         return FmpPayloadHeader + self.Payload
  62
  63     def Decode (self, Buffer):
  64         if len (Buffer) < self._StructSize:
  65             raise ValueError
  66         (Signature, HeaderSize, FwVersion, LowestSupportedVersion) = \
  67             struct.unpack (
  68                      self._StructFormat,
  69                      Buffer[0:self._StructSize]
  70                      )
  71         if Signature != self._FMP_PAYLOAD_HEADER_SIGNATURE:
  72             raise ValueError
  73         if HeaderSize < self._StructSize:
  74             raise ValueError
  75         self.Signature              = Signature
  76         self.HeaderSize             = HeaderSize
  77         self.FwVersion              = FwVersion
  78         self.LowestSupportedVersion = LowestSupportedVersion
  79         self.Payload                = Buffer[self.HeaderSize:]
  80
  81         self._Valid                 = True
  82         return self.Payload
  83
  84     def DumpInfo (self):
  85         if not self._Valid:
  86             raise ValueError
  87         print ('FMP_PAYLOAD_HEADER.Signature              = {Signature:08X} ({SignatureString})'.format (Signature = self.Signature, SignatureString = _SIGNATURE_32_TO_STRING (self.Signature)))
  88         print ('FMP_PAYLOAD_HEADER.HeaderSize             = {HeaderSize:08X}'.format (HeaderSize = self.HeaderSize))
  89         print ('FMP_PAYLOAD_HEADER.FwVersion              = {FwVersion:08X}'.format (FwVersion = self.FwVersion))
  90         print ('FMP_PAYLOAD_HEADER.LowestSupportedVersion = {LowestSupportedVersion:08X}'.format (LowestSupportedVersion = self.LowestSupportedVersion))
  91         print ('sizeof (Payload)                          = {Size:08X}'.format (Size = len (self.Payload)))