MdePkg/Include/Ppi/ReadOnlyVariable2.h

   1 /** @file
   2   This file declares Read-only Variable Service2 PPI.
   3   This ppi permits read-only access to the UEFI variable store during the PEI phase.
   4
   5   Copyright (c) 2006 - 2008, Intel Corporation
   6   All rights reserved. This program and the accompanying materials
   7   are licensed and made available under the terms and conditions of the BSD License
   8   which accompanies this distribution.  The full text of the license may be found at
   9   http://opensource.org/licenses/bsd-license.php
  10
  11   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13
  14   @par Revision Reference:
  15   This PPI is defined in PI
  16   Version 1.00.
  17
  18 **/
  19
  20 #ifndef __PEI_READ_ONLY_VARIABLE2_PPI_H__
  21 #define __PEI_READ_ONLY_VARIABLE2_PPI_H__
  22
  23 #define EFI_PEI_READ_ONLY_VARIABLE2_PPI_GUID \
  24   { 0x2ab86ef5, 0xecb5, 0x4134, { 0xb5, 0x56, 0x38, 0x54, 0xca, 0x1f, 0xe1, 0xb4 } }
  25
  26
  27 typedef struct _EFI_PEI_READ_ONLY_VARIABLE2_PPI  EFI_PEI_READ_ONLY_VARIABLE2_PPI;
  28
  29 /**
  30   This service retrieves a variable's value using its name and GUID.
  31
  32   Read the specified variable from the UEFI variable store. If the Data
  33   buffer is too small to hold the contents of the variable,
  34   the error EFI_BUFFER_TOO_SMALL is returned and DataSize is set to the
  35   required buffer size to obtain the data.
  36
  37   @param  This            A pointer to this instance of the EFI_PEI_READ_ONLY_VARIABLE2_PPI.
  38
  39   @param  VariableName    A pointer to a null-terminated string that is the variable's name.
  40
  41   @param  VendorGuid      A pointer to an EFI_GUID that is the variable's GUID. The combination of
  42                           VariableGuid and VariableName must be unique.
  43
  44   @param  Attributes      If non-NULL, on return, points to the variable's attributes. See "Related Definitons"
  45                           below for possible attribute values.
  46
  47   @param  DataSize        On entry, points to the size in bytes of the Data buffer. On return, points to the size of
  48                           the data returned in Data.
  49
  50   @param  Data            Points to the buffer which will hold the returned variable value.
  51
  52
  53   @retval EFI_SUCCESS           The function completed successfully.
  54
  55   @retval EFI_NOT_FOUND         The variable was not found.
  56
  57   @retval EFI_BUFFER_TOO_SMALL  The DataSize is too small for the resulting data.
  58                                 DataSize is updated with the size required for
  59                                 the specified variable.
  60
  61   @retval EFI_INVALID_PARAMETER VariableName, VariableGuid, DataSize or Data is NULL.
  62
  63   @retval EFI_DEVICE_ERROR      The variable could not be retrieved because of a device error.
  64
  65 **/
  66 typedef
  67 EFI_STATUS
  68 (EFIAPI *EFI_PEI_GET_VARIABLE2)(
  69   IN CONST  EFI_PEI_READ_ONLY_VARIABLE2_PPI *This,
  70   IN CONST  CHAR16                          *VariableName,
  71   IN CONST  EFI_GUID                        *VariableGuid,
  72   OUT       UINT32                          *Attributes,
  73   IN OUT    UINTN                           *DataSize,
  74   OUT       VOID                            *Data
  75   );
  76
  77
  78 /**
  79   Return the next variable name and GUID.
  80
  81   This function is called multiple times to retrieve the VariableName
  82   and VariableGuid of all variables currently available in the system.
  83   On each call, the previous results are passed into the interface,
  84   and, on return, the interface returns the data for the next
  85   interface. When the entire variable list has been returned,
  86   EFI_NOT_FOUND is returned.
  87
  88   @param  This              A pointer to this instance of the EFI_PEI_READ_ONLY_VARIABLE2_PPI.
  89
  90   @param  VariableNameSize  On entry, points to the size of the buffer pointed to by VariableName.
  91
  92   @param  VariableName      On entry, a pointer to a null-terminated string that is the variable's name.
  93                             On return, points to the next variable's null-terminated name string.
  94
  95   @param  VendorGuid        On entry, a pointer to an UEFI _GUID that is the variable's GUID.
  96                             On return, a pointer to the next variable's GUID.
  97
  98
  99   @retval EFI_SUCCESS           The variable was read successfully.
 100
 101   @retval EFI_NOT_FOUND         The variable could not be found.
 102
 103   @retval EFI_BUFFER_TOO_SMALL  The VariableNameSize is too small for the resulting
 104                                 data. VariableNameSize is updated with the size
 105                                 required for the specified variable.
 106
 107   @retval EFI_INVALID_PARAMETER VariableName, VariableGuid or
 108                                 VariableNameSize is NULL.
 109
 110   @retval EFI_DEVICE_ERROR      The variable could not be retrieved because of a device error.
 111
 112 **/
 113 typedef
 114 EFI_STATUS
 115 (EFIAPI *EFI_PEI_NEXT_VARIABLE_NAME2)(
 116   IN CONST  EFI_PEI_READ_ONLY_VARIABLE2_PPI *This,
 117   IN OUT    UINTN                           *VariableNameSize,
 118   IN OUT    CHAR16                          *VariableName,
 119   IN OUT    EFI_GUID                        *VariableGuid
 120   );
 121
 122 /**
 123   This PPI provides a lightweight, read-only variant of the full EFI
 124   variable services.
 125
 126   @param GetVariable
 127   A service to ascertain a given variable name.
 128
 129   @param GetNextVariableName
 130   A service to ascertain a variable based upon a given, known variable
 131
 132 **/
 133 struct _EFI_PEI_READ_ONLY_VARIABLE2_PPI {
 134   EFI_PEI_GET_VARIABLE2       GetVariable;
 135   EFI_PEI_NEXT_VARIABLE_NAME2 NextVariableName;
 136 };
 137
 138 extern EFI_GUID gEfiPeiReadOnlyVariable2PpiGuid;
 139
 140 #endif