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  #ifdef SECURE_BOOT_FEATURE_ENABLED
  32
  33   return EFI_UNSUPPORTED;
  34
  35  #else
  36
  37   EFI_STATUS  Status;
  38
  39   //
  40   // We might fail to load the variable, since the file system initially
  41   // will not have the NvVars file.
  42   //
  43   LoadNvVarsFromFs (FsHandle);
  44
  45   //
  46   // We must be able to save the variables successfully to the file system
  47   // to have connected successfully.
  48   //
  49   Status = SaveNvVarsToFs (FsHandle);
  50   if (!EFI_ERROR (Status)) {
  51     mNvVarsFileLibFsHandle = FsHandle;
  52   }
  53
  54   return Status;
  55  #endif
  56 }
  57
  58 /**
  59   Update non-volatile variables stored on the file system.
  60
  61   @return     The EFI_STATUS while attempting to update the variable on
  62               the connected file system.
  63   @retval     EFI_SUCCESS - The non-volatile variables were saved to the disk
  64   @retval     EFI_NOT_STARTED - A file system has not been connected
  65
  66 **/
  67 EFI_STATUS
  68 EFIAPI
  69 UpdateNvVarsOnFileSystem (
  70   )
  71 {
  72   if (mNvVarsFileLibFsHandle == NULL) {
  73     //
  74     // A file system had not been connected to the library.
  75     //
  76     return EFI_NOT_STARTED;
  77   } else {
  78     return SaveNvVarsToFs (mNvVarsFileLibFsHandle);
  79   }
  80 }