Function SetNvramVariable

rEFIt_UEFI/Platform/Nvram.cpp:177–220

Sets NVRAM variable. Does nothing if variable with the same data and attributes already exists. */

/** Sets NVRAM variable. Does nothing if variable with the same data and attributes already exists. */
EFI_STATUS
SetNvramVariable (
    IN  CONST CHAR16     *VariableName,
    IN  EFI_GUID   *VendorGuid,
    IN  UINT32      Attributes,
    IN  UINTN       DataSize,
    IN  CONST VOID *Data
  )
{
  //EFI_STATUS Status;
  VOID   *OldData;
  UINTN  OldDataSize = 0;
  UINT32 OldAttributes = 0;
  
  //DBG("SetNvramVariable (%ls, guid, 0x%X, %d):", VariableName, Attributes, DataSize);
  OldData = (__typeof__(OldData))GetNvramVariable(VariableName, VendorGuid, &OldAttributes, &OldDataSize);
  if (OldData != NULL) {
    // var already exists - check if it equal to new value
    //DBG(" exists(0x%X, %d)", OldAttributes, OldDataSize);
    if ((OldAttributes == Attributes) &&
        (OldDataSize == DataSize) &&
        (CompareMem (OldData, Data, DataSize) == 0)) {
      // it's the same - do nothing
      //DBG(", equal -> not writing again.\n");
      FreePool(OldData);
      return EFI_SUCCESS;
    }
    //DBG(", not equal\n");
    
    FreePool(OldData);
    
    // not the same - delete previous one if attributes are different
    if (OldAttributes != Attributes) {
      DeleteNvramVariable (VariableName, VendorGuid);
      //DBG(", diff. attr: deleting old (%s)", efiStrError(Status));
    }
  }
  //DBG("\n"); // for debug without Status
  //DBG(" -> writing new (%s)\n", efiStrError(Status));
  //return Status;
 
  return gRT->SetVariable(VariableName, VendorGuid, Attributes, DataSize, (VOID*)Data); // CONST missing in EFI_SET_VARIABLE->SetVariable
  
}
EFI_STATUS
SetNvramXString8 (
    IN  CONST CHAR16     *VariableName,