/** @file
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NULL implementation of Variable Read Lib
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This library provides phase agnostic access to the UEFI Variable Services.
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This is done by implementing a wrapper on top of the phase specific mechanism
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for reading from UEFI variables. For example, the PEI implementation of this
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library uses EFI_PEI_READ_ONLY_VARIABLE2_PPI. The DXE implementation accesses
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the UEFI Runtime Services Table, and the SMM implementation uses
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EFI_SMM_VARIABLE_PROTOCOL.
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Using this library allows code to be written in a generic manner that can be
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used in PEI, DXE, or SMM without modification.
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@copyright
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Copyright 2021 Intel Corporation. <BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include <Uefi/UefiBaseType.h>
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/**
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Returns the value of a variable.
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@param[in] VariableName A Null-terminated string that is the name of the vendor's
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variable.
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@param[in] VendorGuid A unique identifier for the vendor.
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@param[out] Attributes If not NULL, a pointer to the memory location to return the
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attributes bitmask for the variable.
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@param[in, out] DataSize On input, the size in bytes of the return Data buffer.
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On output the size of data returned in Data.
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@param[out] Data The buffer to return the contents of the variable. May be NULL
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with a zero DataSize in order to determine the size buffer needed.
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@retval EFI_UNSUPPORTED This function is not implemented by this instance of the LibraryClass
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**/
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EFI_STATUS
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EFIAPI
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VarLibGetVariable (
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IN CHAR16 *VariableName,
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IN EFI_GUID *VendorGuid,
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OUT UINT32 *Attributes, OPTIONAL
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IN OUT UINTN *DataSize,
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OUT VOID *Data OPTIONAL
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)
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{
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return EFI_UNSUPPORTED;
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}
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/**
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Enumerates the current variable names.
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@param[in, out] VariableNameSize The size of the VariableName buffer. The size must be large
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enough to fit input string supplied in VariableName buffer.
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@param[in, out] VariableName On input, supplies the last VariableName that was returned
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by GetNextVariableName(). On output, returns the Nullterminated
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string of the current variable.
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@param[in, out] VendorGuid On input, supplies the last VendorGuid that was returned by
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GetNextVariableName(). On output, returns the
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VendorGuid of the current variable.
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@retval EFI_UNSUPPORTED This function is not implemented by this instance of the LibraryClass
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**/
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EFI_STATUS
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EFIAPI
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VarLibGetNextVariableName (
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IN OUT UINTN *VariableNameSize,
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IN OUT CHAR16 *VariableName,
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IN OUT EFI_GUID *VendorGuid
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)
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{
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return EFI_UNSUPPORTED;
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}
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