MdeModulePkg/Include/Protocol/VariableLock.h

/** @file
  Variable Lock Protocol is related to EDK II-specific implementation of variables
  and intended for use as a means to mark a variable read-only after the event
  EFI_END_OF_DXE_EVENT_GUID is signaled.

  Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#ifndef __VARIABLE_LOCK_H__
#define __VARIABLE_LOCK_H__

#define EDKII_VARIABLE_LOCK_PROTOCOL_GUID \
  { \
    0xcd3d0a05, 0x9e24, 0x437c, { 0xa8, 0x91, 0x1e, 0xe0, 0x53, 0xdb, 0x76, 0x38 } \
  }

typedef struct _EDKII_VARIABLE_LOCK_PROTOCOL EDKII_VARIABLE_LOCK_PROTOCOL;

/**
  Mark a variable that will become read-only after leaving the DXE phase of execution.
  Write request coming from SMM environment through EFI_SMM_VARIABLE_PROTOCOL is allowed.

  @param[in] This          The EDKII_VARIABLE_LOCK_PROTOCOL instance.
  @param[in] VariableName  A pointer to the variable name that will be made read-only subsequently.
  @param[in] VendorGuid    A pointer to the vendor GUID that will be made read-only subsequently.

  @retval EFI_SUCCESS           The variable specified by the VariableName and the VendorGuid was marked
                                as pending to be read-only.
  @retval EFI_INVALID_PARAMETER VariableName or VendorGuid is NULL.
                                Or VariableName is an empty string.
  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or EFI_EVENT_GROUP_READY_TO_BOOT has
                                already been signaled.
  @retval EFI_OUT_OF_RESOURCES  There is not enough resource to hold the lock request.
**/
typedef
EFI_STATUS
(EFIAPI *EDKII_VARIABLE_LOCK_PROTOCOL_REQUEST_TO_LOCK)(
  IN CONST EDKII_VARIABLE_LOCK_PROTOCOL *This,
  IN       CHAR16                       *VariableName,
  IN       EFI_GUID                     *VendorGuid
  );

///
/// Variable Lock Protocol is related to EDK II-specific implementation of variables
/// and intended for use as a means to mark a variable read-only after the event
/// EFI_END_OF_DXE_EVENT_GUID is signaled.
///
struct _EDKII_VARIABLE_LOCK_PROTOCOL {
  EDKII_VARIABLE_LOCK_PROTOCOL_REQUEST_TO_LOCK    RequestToLock;
};

extern EFI_GUID  gEdkiiVariableLockProtocolGuid;

#endif