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   Attempts to connect the NvVarsFileLib to the specified file system.
  17
  18   @param[in]  FsHandle - Handle for a gEfiSimpleFileSystemProtocolGuid instance
  19
  20   @return     The EFI_STATUS while attempting to connect the NvVarsFileLib
  21               to the file system instance.
  22   @retval     EFI_SUCCESS - The given file system was connected successfully
  23
  24 **/
  25 EFI_STATUS
  26 EFIAPI
  27 ConnectNvVarsToFileSystem (
  28   IN EFI_HANDLE  FsHandle
  29   )
  30 {
  31   EFI_STATUS  Status;
  32
  33   //
  34   // We might fail to load the variable, since the file system initially
  35   // will not have the NvVars file.
  36   //
  37   LoadNvVarsFromFs (FsHandle);
  38
  39   //
  40   // We must be able to save the variables successfully to the file system
  41   // to have connected successfully.
  42   //
  43   Status = SaveNvVarsToFs (FsHandle);
  44   if (!EFI_ERROR (Status)) {
  45     mNvVarsFileLibFsHandle = FsHandle;
  46   }
  47
  48   return Status;
  49 }
  50
  51 /**
  52   Update non-volatile variables stored on the file system.
  53
  54   @return     The EFI_STATUS while attempting to update the variable on
  55               the connected file system.
  56   @retval     EFI_SUCCESS - The non-volatile variables were saved to the disk
  57   @retval     EFI_NOT_STARTED - A file system has not been connected
  58
  59 **/
  60 EFI_STATUS
  61 EFIAPI
  62 UpdateNvVarsOnFileSystem (
  63   )
  64 {
  65   if (mNvVarsFileLibFsHandle == NULL) {
  66     //
  67     // A file system had not been connected to the library.
  68     //
  69     return EFI_NOT_STARTED;
  70   } else {
  71     return SaveNvVarsToFs (mNvVarsFileLibFsHandle);
  72   }
  73 }