MdeModulePkg/Core/Dxe/FwVol/Ffs.c

   1 /*++
   2
   3 Copyright (c) 2006, Intel Corporation
   4 All rights reserved. This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12 Module Name:
  13
  14   Ffs.c
  15
  16 Abstract:
  17
  18   FFS file access utilities.
  19
  20 --*/
  21
  22
  23 #include <DxeMain.h>
  24
  25 #define PHYSICAL_ADDRESS_TO_POINTER(Address) ((VOID *)((UINTN)(Address)))
  26
  27
  28 EFI_FFS_FILE_STATE
  29 GetFileState (
  30   IN UINT8                ErasePolarity,
  31   IN EFI_FFS_FILE_HEADER  *FfsHeader
  32   )
  33 /*++
  34
  35 Routine Description:
  36   Get the FFS file state by checking the highest bit set in the header's state field
  37
  38 Arguments:
  39   ErasePolarity -  Erase polarity attribute of the firmware volume
  40   FfsHeader     -  Points to the FFS file header
  41
  42 Returns:
  43   FFS File state
  44
  45 --*/
  46 {
  47   EFI_FFS_FILE_STATE      FileState;
  48   UINT8                   HighestBit;
  49
  50   FileState = FfsHeader->State;
  51
  52   if (ErasePolarity != 0) {
  53     FileState = (EFI_FFS_FILE_STATE)~FileState;
  54   }
  55
  56   HighestBit = 0x80;
  57   while (HighestBit != 0 && ((HighestBit & FileState) == 0)) {
  58     HighestBit >>= 1;
  59   }
  60
  61   return (EFI_FFS_FILE_STATE)HighestBit;
  62 }
  63
  64
  65 BOOLEAN
  66 IsBufferErased (
  67   IN UINT8    ErasePolarity,
  68   IN VOID     *InBuffer,
  69   IN UINTN    BufferSize
  70   )
  71 /*++
  72
  73 Routine Description:
  74   Check if a block of buffer is erased
  75
  76 Arguments:
  77   ErasePolarity -  Erase polarity attribute of the firmware volume
  78   InBuffer      -  The buffer to be checked
  79   BufferSize    -  Size of the buffer in bytes
  80
  81 Returns:
  82   TRUE  -  The block of buffer is erased
  83   FALSE -  The block of buffer is not erased
  84
  85 --*/
  86 {
  87   UINTN   Count;
  88   UINT8   EraseByte;
  89   UINT8   *Buffer;
  90
  91   if(ErasePolarity == 1) {
  92     EraseByte = 0xFF;
  93   } else {
  94     EraseByte = 0;
  95   }
  96
  97   Buffer = InBuffer;
  98   for (Count = 0; Count < BufferSize; Count++) {
  99     if (Buffer[Count] != EraseByte) {
 100       return FALSE;
 101     }
 102   }
 103
 104   return TRUE;
 105 }
 106
 107
 108 BOOLEAN
 109 VerifyFvHeaderChecksum (
 110   IN EFI_FIRMWARE_VOLUME_HEADER *FvHeader
 111   )
 112 /*++
 113
 114 Routine Description:
 115   Verify checksum of the firmware volume header
 116
 117 Arguments:
 118   FvHeader  -  Points to the firmware volume header to be checked
 119
 120 Returns:
 121   TRUE  -  Checksum verification passed
 122   FALSE -  Checksum verification failed
 123
 124 --*/
 125 {
 126   UINT32  Index;
 127   UINT32  HeaderLength;
 128   UINT16  Checksum;
 129   UINT16  *ptr;
 130
 131   HeaderLength = FvHeader->HeaderLength;
 132   ptr = (UINT16 *)FvHeader;
 133   Checksum = 0;
 134
 135   for (Index = 0; Index < HeaderLength / sizeof (UINT16); Index++) {
 136     Checksum = (UINT16)(Checksum + ptr[Index]);
 137   }
 138
 139   if (Checksum == 0) {
 140     return TRUE;
 141   } else {
 142     return FALSE;
 143   }
 144 }
 145
 146 STATIC
 147 BOOLEAN
 148 VerifyHeaderChecksum (
 149   IN EFI_FFS_FILE_HEADER  *FfsHeader
 150   )
 151 /*++
 152
 153 Routine Description:
 154   Verify checksum of the FFS file header
 155
 156 Arguments:
 157   FfsHeader  -  Points to the FFS file header to be checked
 158
 159 Returns:
 160   TRUE  -  Checksum verification passed
 161   FALSE -  Checksum verification failed
 162
 163 --*/
 164 {
 165   UINT32            Index;
 166   UINT8             *ptr;
 167   UINT8             HeaderChecksum;
 168
 169   ptr = (UINT8 *)FfsHeader;
 170   HeaderChecksum = 0;
 171   for (Index = 0; Index < sizeof(EFI_FFS_FILE_HEADER); Index++) {
 172     HeaderChecksum = (UINT8)(HeaderChecksum + ptr[Index]);
 173   }
 174
 175   HeaderChecksum = (UINT8) (HeaderChecksum - FfsHeader->State - FfsHeader->IntegrityCheck.Checksum.File);
 176
 177   if (HeaderChecksum == 0) {
 178     return TRUE;
 179   } else {
 180     return FALSE;
 181   }
 182 }
 183
 184
 185 BOOLEAN
 186 IsValidFfsHeader (
 187   IN UINT8                ErasePolarity,
 188   IN EFI_FFS_FILE_HEADER  *FfsHeader,
 189   OUT EFI_FFS_FILE_STATE  *FileState
 190   )
 191 /*++
 192
 193 Routine Description:
 194   Check if it's a valid FFS file header
 195
 196 Arguments:
 197   ErasePolarity -  Erase polarity attribute of the firmware volume
 198   FfsHeader     -  Points to the FFS file header to be checked
 199   FileState     -  FFS file state to be returned
 200
 201 Returns:
 202   TRUE  -  Valid FFS file header
 203   FALSE -  Invalid FFS file header
 204
 205 --*/
 206 {
 207   *FileState = GetFileState (ErasePolarity, FfsHeader);
 208
 209   switch (*FileState) {
 210     case EFI_FILE_HEADER_VALID:
 211     case EFI_FILE_DATA_VALID:
 212     case EFI_FILE_MARKED_FOR_UPDATE:
 213     case EFI_FILE_DELETED:
 214       //
 215       // Here we need to verify header checksum
 216       //
 217       return VerifyHeaderChecksum (FfsHeader);
 218
 219     case EFI_FILE_HEADER_CONSTRUCTION:
 220     case EFI_FILE_HEADER_INVALID:
 221     default:
 222       return FALSE;
 223   }
 224 }
 225
 226
 227 BOOLEAN
 228 IsValidFfsFile (
 229   IN UINT8                ErasePolarity,
 230   IN EFI_FFS_FILE_HEADER  *FfsHeader
 231   )
 232 /*++
 233
 234 Routine Description:
 235   Check if it's a valid FFS file.
 236   Here we are sure that it has a valid FFS file header since we must call IsValidFfsHeader() first.
 237
 238 Arguments:
 239   ErasePolarity -  Erase polarity attribute of the firmware volume
 240   FfsHeader     -  Points to the FFS file to be checked
 241
 242 Returns:
 243   TRUE  -  Valid FFS file
 244   FALSE -  Invalid FFS file
 245
 246 --*/
 247 {
 248   EFI_FFS_FILE_STATE  FileState;
 249
 250   FileState = GetFileState (ErasePolarity, FfsHeader);
 251   switch (FileState) {
 252
 253     case EFI_FILE_DELETED:
 254     case EFI_FILE_DATA_VALID:
 255     case EFI_FILE_MARKED_FOR_UPDATE:
 256       //
 257       // Some other vliadation like file content checksum might be done here.
 258       // For performance issue, Tiano only do FileState check.
 259       //
 260       return TRUE;
 261
 262     default:
 263       return FALSE;
 264   }
 265 }
 266