slimbootloader/BootloaderCommonPkg/Include/Service/VariableService.h

/** @file

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

**/

#ifndef __VARIABLE_SERVICE_H__
#define __VARIABLE_SERVICE_H__

#include <Guid/BootLoaderServiceGuid.h>

#define VARIABLE_SERVICE_SIGNATURE  SIGNATURE_32 ('V', 'A', 'R', ' ')
#define VARIABLE_SERVICE_VERSION    1

/**

  This code finds variable in storage blocks (Volatile or Non-Volatile).

  Caution: This function may receive untrusted input.
  This function may be invoked in SMM mode, and datasize is external input.
  This function will do basic validation, before parse the data.

  @param VariableName               Name of Variable to be found.
  @param Attributes                 Attribute value of the variable found.
  @param DataSize                   Size of Data found. If size is less than the
                                    data, this value contains the required size.
  @param Data                       The buffer to return the contents of the variable. May be NULL
                                    with a zero DataSize in order to determine the size buffer needed.

  @return EFI_INVALID_PARAMETER     Invalid parameter.
  @return EFI_SUCCESS               Find the specified variable.
  @return EFI_NOT_FOUND             Not found.
  @return EFI_BUFFER_TO_SMALL       DataSize is too small for the result.

**/
typedef
EFI_STATUS
(EFIAPI *GET_VARIABLE) (
  IN      CHAR8             *VariableName,
  OUT     UINT8             *Attributes OPTIONAL,
  IN OUT  UINTN             *DataSize,
  OUT     VOID              *Data OPTIONAL
  );


/**

  This code Finds the Next available variable.

  Caution: This function may receive untrusted input.
  This function may be invoked in SMM mode. This function will do basic validation, before parse the data.

  @param VariableNameSize           The size of the VariableName buffer. The size must be large
                                    enough to fit input string supplied in VariableName buffer.
  @param VariableName               Pointer to variable name.
  @param VariableKey                Pointer to variable key.

  @retval EFI_SUCCESS               The function completed successfully.
  @retval EFI_NOT_FOUND             The next variable was not found.
  @retval EFI_BUFFER_TOO_SMALL      The VariableNameSize is too small for the result.
                                    VariableNameSize has been updated with the size needed to complete the request.
  @retval EFI_INVALID_PARAMETER     VariableNameSize is NULL.
  @retval EFI_INVALID_PARAMETER     VariableName is NULL.
  @retval EFI_INVALID_PARAMETER     VendorGuid is NULL.
  @retval EFI_INVALID_PARAMETER     The input values of VariableName and VendorGuid are not a name and
                                    GUID of an existing variable.
  @retval EFI_INVALID_PARAMETER     Null-terminator is not found in the first VariableNameSize bytes of
                                    the input VariableName buffer.

**/
typedef
EFI_STATUS
(EFIAPI *GET_NEXT_VARIABLE_NAME) (
  IN OUT  UINTN             *VariableNameSize,
  IN OUT  CHAR8             *VariableName,
  IN OUT  UINTN             *VariableKey
  );


/**

  This code sets variable in storage blocks (Volatile or Non-Volatile).

  Caution: This function may receive untrusted input.
  This function may be invoked in SMM mode, and datasize and data are external input.
  This function will do basic validation, before parse the data.
  This function will parse the authentication carefully to avoid security issues, like
  buffer overflow, integer overflow.
  This function will check attribute carefully to avoid authentication bypass.

  @param VariableName                     Name of Variable to be found.
  @param Attributes                       Attribute value of the variable found
  @param DataSize                         Size of Data found. If size is less than the
                                          data, this value contains the required size.
  @param Data                             Data pointer.

  @return EFI_INVALID_PARAMETER           Invalid parameter.
  @return EFI_SUCCESS                     Set successfully.
  @return EFI_OUT_OF_RESOURCES            Resource not enough to set variable.
  @return EFI_NOT_FOUND                   Not found.
  @return EFI_WRITE_PROTECTED             Variable is read-only.

**/
typedef
EFI_STATUS
(EFIAPI *SET_VARIABLE) (
  IN CHAR8                  *VariableName,
  IN UINT8                  Attributes,
  IN UINTN                  DataSize,
  IN VOID                   *Data
  );


typedef struct {
  SERVICE_COMMON_HEADER              Header;
  GET_VARIABLE                       GetVariable;
  GET_NEXT_VARIABLE_NAME             GetNextVariableName;
  SET_VARIABLE                       SetVariable;
} VARIABLE_SERVICE;

#endif