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/** @file
FFS file access utilities.
Copyright (c) 2006 - 2008, Intel Corporation. <BR>
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "DxeMain.h"
/**
Get the FFS file state by checking the highest bit set in the header's state field.
@param ErasePolarity Erase polarity attribute of the firmware volume
@param FfsHeader Points to the FFS file header
@return FFS File state
**/
EFI_FFS_FILE_STATE
GetFileState (
IN UINT8 ErasePolarity,
IN EFI_FFS_FILE_HEADER *FfsHeader
)
{
EFI_FFS_FILE_STATE FileState;
UINT8 HighestBit;
FileState = FfsHeader->State;
if (ErasePolarity != 0) {
FileState = (EFI_FFS_FILE_STATE)~FileState;
}
HighestBit = 0x80;
while (HighestBit != 0 && ((HighestBit & FileState) == 0)) {
HighestBit >>= 1;
}
return (EFI_FFS_FILE_STATE) HighestBit;
}
/**
Check if a block of buffer is erased.
@param ErasePolarity Erase polarity attribute of the firmware volume
@param InBuffer The buffer to be checked
@param BufferSize Size of the buffer in bytes
@retval TRUE The block of buffer is erased
@retval FALSE The block of buffer is not erased
**/
BOOLEAN
IsBufferErased (
IN UINT8 ErasePolarity,
IN VOID *InBuffer,
IN UINTN BufferSize
)
{
UINTN Count;
UINT8 EraseByte;
UINT8 *Buffer;
if(ErasePolarity == 1) {
EraseByte = 0xFF;
} else {
EraseByte = 0;
}
Buffer = InBuffer;
for (Count = 0; Count < BufferSize; Count++) {
if (Buffer[Count] != EraseByte) {
return FALSE;
}
}
return TRUE;
}
/**
Verify checksum of the firmware volume header.
@param FvHeader Points to the firmware volume header to be checked
@retval TRUE Checksum verification passed
@retval FALSE Checksum verification failed
**/
BOOLEAN
VerifyFvHeaderChecksum (
IN EFI_FIRMWARE_VOLUME_HEADER *FvHeader
)
{
UINT32 Index;
UINT32 HeaderLength;
UINT16 Checksum;
UINT16 *Ptr;
HeaderLength = FvHeader->HeaderLength;
Ptr = (UINT16 *)FvHeader;
Checksum = 0;
for (Index = 0; Index < HeaderLength / sizeof (UINT16); Index++) {
Checksum = (UINT16)(Checksum + Ptr[Index]);
}
if (Checksum == 0) {
return TRUE;
} else {
return FALSE;
}
}
/**
Verify checksum of the FFS file header.
@param FfsHeader Points to the FFS file header to be checked
@retval TRUE Checksum verification passed
@retval FALSE Checksum verification failed
**/
BOOLEAN
VerifyHeaderChecksum (
IN EFI_FFS_FILE_HEADER *FfsHeader
)
{
UINT32 Index;
UINT8 *Ptr;
UINT8 HeaderChecksum;
Ptr = (UINT8 *)FfsHeader;
HeaderChecksum = 0;
for (Index = 0; Index < sizeof(EFI_FFS_FILE_HEADER); Index++) {
HeaderChecksum = (UINT8)(HeaderChecksum + Ptr[Index]);
}
HeaderChecksum = (UINT8) (HeaderChecksum - FfsHeader->State - FfsHeader->IntegrityCheck.Checksum.File);
if (HeaderChecksum == 0) {
return TRUE;
} else {
return FALSE;
}
}
/**
Check if it's a valid FFS file header.
@param ErasePolarity Erase polarity attribute of the firmware volume
@param FfsHeader Points to the FFS file header to be checked
@param FileState FFS file state to be returned
@retval TRUE Valid FFS file header
@retval FALSE Invalid FFS file header
**/
BOOLEAN
IsValidFfsHeader (
IN UINT8 ErasePolarity,
IN EFI_FFS_FILE_HEADER *FfsHeader,
OUT EFI_FFS_FILE_STATE *FileState
)
{
*FileState = GetFileState (ErasePolarity, FfsHeader);
switch (*FileState) {
case EFI_FILE_HEADER_VALID:
case EFI_FILE_DATA_VALID:
case EFI_FILE_MARKED_FOR_UPDATE:
case EFI_FILE_DELETED:
//
// Here we need to verify header checksum
//
return VerifyHeaderChecksum (FfsHeader);
case EFI_FILE_HEADER_CONSTRUCTION:
case EFI_FILE_HEADER_INVALID:
default:
return FALSE;
}
}
/**
Check if it's a valid FFS file.
Here we are sure that it has a valid FFS file header since we must call IsValidFfsHeader() first.
@param ErasePolarity Erase polarity attribute of the firmware volume
@param FfsHeader Points to the FFS file to be checked
@retval TRUE Valid FFS file
@retval FALSE Invalid FFS file
**/
BOOLEAN
IsValidFfsFile (
IN UINT8 ErasePolarity,
IN EFI_FFS_FILE_HEADER *FfsHeader
)
{
EFI_FFS_FILE_STATE FileState;
FileState = GetFileState (ErasePolarity, FfsHeader);
switch (FileState) {
case EFI_FILE_DELETED:
case EFI_FILE_DATA_VALID:
case EFI_FILE_MARKED_FOR_UPDATE:
//
// Some other vliadation like file content checksum might be done here.
// For performance issue, Tiano only do FileState check.
//
return TRUE;
default:
return FALSE;
}
}
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