OvmfPkg/Library/NvVarsFileLib/NvVarsFileLib.c

   1 /** @file
   2   Save Non-Volatile Variables to a file system.
   3
   4   Copyright (c) 2009, Intel Corporation. <BR>
   5   All rights reserved. This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "NvVarsFileLib.h"
  16 #include <Library/DebugLib.h>
  17 #include <Library/NvVarsFileLib.h>
  18
  19 EFI_HANDLE    mNvVarsFileLibFsHandle = NULL;
  20
  21
  22 /**
  23   Attempts to connect the NvVarsFileLib to the specified file system.
  24
  25   @param[in]  FsHandle - Handle for a gEfiSimpleFileSystemProtocolGuid instance
  26
  27   @return     The EFI_STATUS while attempting to connect the NvVarsFileLib
  28               to the file system instance.
  29   @retval     EFI_SUCCESS - The given file system was connected successfully
  30
  31 **/
  32 EFI_STATUS
  33 EFIAPI
  34 ConnectNvVarsToFileSystem (
  35   IN EFI_HANDLE    FsHandle
  36   )
  37 {
  38   EFI_STATUS Status;
  39
  40   //
  41   // We might fail to load the variable, since the file system initially
  42   // will not have the NvVars file.
  43   //
  44   LoadNvVarsFromFs (FsHandle);
  45
  46   //
  47   // We must be able to save the variables successfully to the file system
  48   // to have connected successfully.
  49   //
  50   Status = SaveNvVarsToFs (FsHandle);
  51   if (!EFI_ERROR (Status)) {
  52     mNvVarsFileLibFsHandle = FsHandle;
  53   }
  54
  55   return Status;
  56 }
  57
  58
  59 /**
  60   Update non-volatile variables stored on the file system.
  61
  62   @return     The EFI_STATUS while attempting to update the variable on
  63               the connected file system.
  64   @retval     EFI_SUCCESS - The non-volatile variables were saved to the disk
  65   @retval     EFI_NOT_STARTED - A file system has not been connected
  66
  67 **/
  68 EFI_STATUS
  69 EFIAPI
  70 UpdateNvVarsOnFileSystem (
  71   )
  72 {
  73   if (mNvVarsFileLibFsHandle == NULL) {
  74     //
  75     // A file system had not been connected to the library.
  76     //
  77     return EFI_NOT_STARTED;
  78   } else {
  79     return SaveNvVarsToFs (mNvVarsFileLibFsHandle);
  80   }
  81 }
  82
  83