MdeModulePkg/Core/Dxe/FwVol/Ffs.c

   1 /** @file
   2
   3   FFS file access utilities.
   4
   5 Copyright (c) 2006 - 2008, Intel Corporation
   6 All rights reserved. This program and the accompanying materials
   7 are licensed and made available under the terms and conditions of the BSD License
   8 which accompanies this distribution.  The full text of the license may be found at
   9 http://opensource.org/licenses/bsd-license.php
  10
  11 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13
  14 **/
  15
  16
  17 #include <DxeMain.h>
  18
  19 #define PHYSICAL_ADDRESS_TO_POINTER(Address) ((VOID *)((UINTN)(Address)))
  20
  21
  22 EFI_FFS_FILE_STATE
  23 GetFileState (
  24   IN UINT8                ErasePolarity,
  25   IN EFI_FFS_FILE_HEADER  *FfsHeader
  26   )
  27 /*++
  28
  29 Routine Description:
  30   Get the FFS file state by checking the highest bit set in the header's state field
  31
  32 Arguments:
  33   ErasePolarity -  Erase polarity attribute of the firmware volume
  34   FfsHeader     -  Points to the FFS file header
  35
  36 Returns:
  37   FFS File state
  38
  39 --*/
  40 {
  41   EFI_FFS_FILE_STATE      FileState;
  42   UINT8                   HighestBit;
  43
  44   FileState = FfsHeader->State;
  45
  46   if (ErasePolarity != 0) {
  47     FileState = (EFI_FFS_FILE_STATE)~FileState;
  48   }
  49
  50   HighestBit = 0x80;
  51   while (HighestBit != 0 && ((HighestBit & FileState) == 0)) {
  52     HighestBit >>= 1;
  53   }
  54
  55   return (EFI_FFS_FILE_STATE)HighestBit;
  56 }
  57
  58
  59 BOOLEAN
  60 IsBufferErased (
  61   IN UINT8    ErasePolarity,
  62   IN VOID     *InBuffer,
  63   IN UINTN    BufferSize
  64   )
  65 /*++
  66
  67 Routine Description:
  68   Check if a block of buffer is erased
  69
  70 Arguments:
  71   ErasePolarity -  Erase polarity attribute of the firmware volume
  72   InBuffer      -  The buffer to be checked
  73   BufferSize    -  Size of the buffer in bytes
  74
  75 Returns:
  76   TRUE  -  The block of buffer is erased
  77   FALSE -  The block of buffer is not erased
  78
  79 --*/
  80 {
  81   UINTN   Count;
  82   UINT8   EraseByte;
  83   UINT8   *Buffer;
  84
  85   if(ErasePolarity == 1) {
  86     EraseByte = 0xFF;
  87   } else {
  88     EraseByte = 0;
  89   }
  90
  91   Buffer = InBuffer;
  92   for (Count = 0; Count < BufferSize; Count++) {
  93     if (Buffer[Count] != EraseByte) {
  94       return FALSE;
  95     }
  96   }
  97
  98   return TRUE;
  99 }
 100
 101
 102 BOOLEAN
 103 VerifyFvHeaderChecksum (
 104   IN EFI_FIRMWARE_VOLUME_HEADER *FvHeader
 105   )
 106 /*++
 107
 108 Routine Description:
 109   Verify checksum of the firmware volume header
 110
 111 Arguments:
 112   FvHeader  -  Points to the firmware volume header to be checked
 113
 114 Returns:
 115   TRUE  -  Checksum verification passed
 116   FALSE -  Checksum verification failed
 117
 118 --*/
 119 {
 120   UINT32  Index;
 121   UINT32  HeaderLength;
 122   UINT16  Checksum;
 123   UINT16  *ptr;
 124
 125   HeaderLength = FvHeader->HeaderLength;
 126   ptr = (UINT16 *)FvHeader;
 127   Checksum = 0;
 128
 129   for (Index = 0; Index < HeaderLength / sizeof (UINT16); Index++) {
 130     Checksum = (UINT16)(Checksum + ptr[Index]);
 131   }
 132
 133   if (Checksum == 0) {
 134     return TRUE;
 135   } else {
 136     return FALSE;
 137   }
 138 }
 139
 140 STATIC
 141 BOOLEAN
 142 VerifyHeaderChecksum (
 143   IN EFI_FFS_FILE_HEADER  *FfsHeader
 144   )
 145 /*++
 146
 147 Routine Description:
 148   Verify checksum of the FFS file header
 149
 150 Arguments:
 151   FfsHeader  -  Points to the FFS file header to be checked
 152
 153 Returns:
 154   TRUE  -  Checksum verification passed
 155   FALSE -  Checksum verification failed
 156
 157 --*/
 158 {
 159   UINT32            Index;
 160   UINT8             *ptr;
 161   UINT8             HeaderChecksum;
 162
 163   ptr = (UINT8 *)FfsHeader;
 164   HeaderChecksum = 0;
 165   for (Index = 0; Index < sizeof(EFI_FFS_FILE_HEADER); Index++) {
 166     HeaderChecksum = (UINT8)(HeaderChecksum + ptr[Index]);
 167   }
 168
 169   HeaderChecksum = (UINT8) (HeaderChecksum - FfsHeader->State - FfsHeader->IntegrityCheck.Checksum.File);
 170
 171   if (HeaderChecksum == 0) {
 172     return TRUE;
 173   } else {
 174     return FALSE;
 175   }
 176 }
 177
 178
 179 BOOLEAN
 180 IsValidFfsHeader (
 181   IN UINT8                ErasePolarity,
 182   IN EFI_FFS_FILE_HEADER  *FfsHeader,
 183   OUT EFI_FFS_FILE_STATE  *FileState
 184   )
 185 /*++
 186
 187 Routine Description:
 188   Check if it's a valid FFS file header
 189
 190 Arguments:
 191   ErasePolarity -  Erase polarity attribute of the firmware volume
 192   FfsHeader     -  Points to the FFS file header to be checked
 193   FileState     -  FFS file state to be returned
 194
 195 Returns:
 196   TRUE  -  Valid FFS file header
 197   FALSE -  Invalid FFS file header
 198
 199 --*/
 200 {
 201   *FileState = GetFileState (ErasePolarity, FfsHeader);
 202
 203   switch (*FileState) {
 204     case EFI_FILE_HEADER_VALID:
 205     case EFI_FILE_DATA_VALID:
 206     case EFI_FILE_MARKED_FOR_UPDATE:
 207     case EFI_FILE_DELETED:
 208       //
 209       // Here we need to verify header checksum
 210       //
 211       return VerifyHeaderChecksum (FfsHeader);
 212
 213     case EFI_FILE_HEADER_CONSTRUCTION:
 214     case EFI_FILE_HEADER_INVALID:
 215     default:
 216       return FALSE;
 217   }
 218 }
 219
 220
 221 BOOLEAN
 222 IsValidFfsFile (
 223   IN UINT8                ErasePolarity,
 224   IN EFI_FFS_FILE_HEADER  *FfsHeader
 225   )
 226 /*++
 227
 228 Routine Description:
 229   Check if it's a valid FFS file.
 230   Here we are sure that it has a valid FFS file header since we must call IsValidFfsHeader() first.
 231
 232 Arguments:
 233   ErasePolarity -  Erase polarity attribute of the firmware volume
 234   FfsHeader     -  Points to the FFS file to be checked
 235
 236 Returns:
 237   TRUE  -  Valid FFS file
 238   FALSE -  Invalid FFS file
 239
 240 --*/
 241 {
 242   EFI_FFS_FILE_STATE  FileState;
 243
 244   FileState = GetFileState (ErasePolarity, FfsHeader);
 245   switch (FileState) {
 246
 247     case EFI_FILE_DELETED:
 248     case EFI_FILE_DATA_VALID:
 249     case EFI_FILE_MARKED_FOR_UPDATE:
 250       //
 251       // Some other vliadation like file content checksum might be done here.
 252       // For performance issue, Tiano only do FileState check.
 253       //
 254       return TRUE;
 255
 256     default:
 257       return FALSE;
 258   }
 259 }
 260