OvmfPkg/Library/NvVarsFileLib/NvVarsFileLib.c

   1 /** @file
   2   Save Non-Volatile Variables to a file system.
   3
   4   Copyright (c) 2009, Intel Corporation. All rights reserved.<BR>
   5   SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 #include "NvVarsFileLib.h"
  10 #include <Library/DebugLib.h>
  11 #include <Library/NvVarsFileLib.h>
  12
  13 EFI_HANDLE    mNvVarsFileLibFsHandle = NULL;
  14
  15
  16 /**
  17   Attempts to connect the NvVarsFileLib to the specified file system.
  18
  19   @param[in]  FsHandle - Handle for a gEfiSimpleFileSystemProtocolGuid instance
  20
  21   @return     The EFI_STATUS while attempting to connect the NvVarsFileLib
  22               to the file system instance.
  23   @retval     EFI_SUCCESS - The given file system was connected successfully
  24
  25 **/
  26 EFI_STATUS
  27 EFIAPI
  28 ConnectNvVarsToFileSystem (
  29   IN EFI_HANDLE    FsHandle
  30   )
  31 {
  32   EFI_STATUS Status;
  33
  34   //
  35   // We might fail to load the variable, since the file system initially
  36   // will not have the NvVars file.
  37   //
  38   LoadNvVarsFromFs (FsHandle);
  39
  40   //
  41   // We must be able to save the variables successfully to the file system
  42   // to have connected successfully.
  43   //
  44   Status = SaveNvVarsToFs (FsHandle);
  45   if (!EFI_ERROR (Status)) {
  46     mNvVarsFileLibFsHandle = FsHandle;
  47   }
  48
  49   return Status;
  50 }
  51
  52
  53 /**
  54   Update non-volatile variables stored on the file system.
  55
  56   @return     The EFI_STATUS while attempting to update the variable on
  57               the connected file system.
  58   @retval     EFI_SUCCESS - The non-volatile variables were saved to the disk
  59   @retval     EFI_NOT_STARTED - A file system has not been connected
  60
  61 **/
  62 EFI_STATUS
  63 EFIAPI
  64 UpdateNvVarsOnFileSystem (
  65   )
  66 {
  67   if (mNvVarsFileLibFsHandle == NULL) {
  68     //
  69     // A file system had not been connected to the library.
  70     //
  71     return EFI_NOT_STARTED;
  72   } else {
  73     return SaveNvVarsToFs (mNvVarsFileLibFsHandle);
  74   }
  75 }
  76
  77