path: root/IntelFrameworkModulePkg/Universal/VariablePei/Variable.c

/** @file
  Framework PEIM to provide the Variable functionality
  
Copyright (c) 2006 - 2008 Intel Corporation. <BR>
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution.  The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
Module Name:

**/


#include "Variable.h"

//
// Module globals
//
EFI_PEI_READ_ONLY_VARIABLE_PPI mVariablePpi = {
  PeiGetVariable,
  PeiGetNextVariableName
};

EFI_PEI_READ_ONLY_VARIABLE2_PPI mVariable2Ppi = {
  PeiGetVariable2,
  PeiGetNextVariableName2
};

EFI_PEI_PPI_DESCRIPTOR     mPpiListVariable[] = {
  {
    (EFI_PEI_PPI_DESCRIPTOR_PPI),
    &gEfiPeiReadOnlyVariable2PpiGuid,
    &mVariable2Ppi
  },
  {
    (EFI_PEI_PPI_DESCRIPTOR_PPI | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),
    &gEfiPeiReadOnlyVariablePpiGuid,
    &mVariablePpi
  }
};

EFI_GUID mEfiVariableIndexTableGuid = EFI_VARIABLE_INDEX_TABLE_GUID;

/**
  Provide the functionality of the variable services.

  @param  FileHandle      Handle of the file being invoked.
  @param  PeiServices     Describes the list of possible PEI Services.

  @return EFI_SUCCESS     If the interface could be successfully installed.
  @return EFI_UNSUPPORTED If current boot path is in recovery mode, then does not
                          install this interface.

**/
EFI_STATUS
EFIAPI
PeimInitializeVariableServices (
  IN       EFI_PEI_FILE_HANDLE  FileHandle,
  IN CONST EFI_PEI_SERVICES     **PeiServices
  )
{
  EFI_BOOT_MODE BootMode;
  EFI_STATUS    Status;

  //
  // Check if this is recovery boot path. If no, publish the variable access capability
  // to other modules. If yes, the content of variable area is not reliable. Therefore,
  // in this case we should not provide variable service to other pei modules. 
  // 
  Status = (*PeiServices)->GetBootMode (PeiServices, &BootMode);
  ASSERT_EFI_ERROR (Status);
  
  if (BootMode == BOOT_IN_RECOVERY_MODE) {
    return EFI_UNSUPPORTED;
  }
  
  return (**PeiServices).InstallPpi (PeiServices, &mPpiListVariable[0]);

}

/**
  This code gets the pointer to the first variable memory pointer byte

  @param VarStoreHeader        Pointer to the Variable Store Header.

  @return VARIABLE_HEADER*      Pointer to last unavailable Variable Header

**/
VARIABLE_HEADER *
GetStartPointer (
  IN VARIABLE_STORE_HEADER       *VarStoreHeader
  )
{
  //
  // The end of variable store
  //
  return (VARIABLE_HEADER *) HEADER_ALIGN (VarStoreHeader + 1);
}

/**
  This code gets the pointer to the last variable memory pointer byte

  @param VarStoreHeader        Pointer to the Variable Store Header.

  @return  VARIABLE_HEADER*      Pointer to last unavailable Variable Header

**/
VARIABLE_HEADER *
GetEndPointer (
  IN VARIABLE_STORE_HEADER       *VarStoreHeader
  )

{
  //
  // The end of variable store
  //
  return (VARIABLE_HEADER *) HEADER_ALIGN ((UINTN) VarStoreHeader + VarStoreHeader->Size);
}

/**

  This code checks if variable header is valid or not.

  @param Variable              Pointer to the Variable Header.

  @retval TRUE            Variable header is valid.
  @retval FALSE           Variable header is not valid.

**/
BOOLEAN
EFIAPI
IsValidVariableHeader (
  IN  VARIABLE_HEADER   *Variable
  )
{
  if (Variable == NULL || Variable->StartId != VARIABLE_DATA ) {
    return FALSE;
  }

  return TRUE;
}

/**
  This code gets the size of name of variable.

  @param Variable            Pointer to the Variable Header.

  @return UINTN               Size of variable in bytes

**/
UINTN
NameSizeOfVariable (
  IN  VARIABLE_HEADER   *Variable
  )
{
  if (Variable->State    == (UINT8) (-1) ||
      Variable->DataSize == (UINT32) -1 ||
      Variable->NameSize == (UINT32) -1 ||
      Variable->Attributes == (UINT32) -1) {
    return 0;
  }
  return (UINTN) Variable->NameSize;
}

/**
  This code gets the size of name of variable.

  @param Variable            Pointer to the Variable Header.

  @return  UINTN               Size of variable in bytes

**/
UINTN
DataSizeOfVariable (
  IN  VARIABLE_HEADER   *Variable
  )
{
  if (Variable->State    == (UINT8)  -1 ||
      Variable->DataSize == (UINT32) -1 ||
      Variable->NameSize == (UINT32) -1 ||
      Variable->Attributes == (UINT32) -1) {
    return 0;
  }
  return (UINTN) Variable->DataSize;
}

/**
  This code gets the pointer to the variable name.

  @param Variable            Pointer to the Variable Header.

  @return CHAR16*              Pointer to Variable Name

**/
CHAR16 *
GetVariableNamePtr (
  IN  VARIABLE_HEADER   *Variable
  )

{

  return (CHAR16 *) (Variable + 1);
}

/**
  This code gets the pointer to the variable data.

  @param Variable            Pointer to the Variable Header.

  @return  UINT8*              Pointer to Variable Data

**/
UINT8 *
GetVariableDataPtr (
  IN  VARIABLE_HEADER   *Variable
  )
{
  UINTN Value;
  
  //
  // Be careful about pad size for alignment
  //
  Value =  (UINTN) GetVariableNamePtr (Variable);
  Value += NameSizeOfVariable (Variable);
  Value += GET_PAD_SIZE (NameSizeOfVariable (Variable));

  return (UINT8 *) Value;
}

/**
  This code gets the pointer to the next variable header.

  @param Variable              Pointer to the Variable Header.

  @return VARIABLE_HEADER*      Pointer to next variable header.

**/
VARIABLE_HEADER *
GetNextVariablePtr (
  IN  VARIABLE_HEADER   *Variable
  )

{
  UINTN Value;

  if (!IsValidVariableHeader (Variable)) {
    return NULL;
  }

  Value =  (UINTN) GetVariableDataPtr (Variable);
  Value += DataSizeOfVariable (Variable);
  Value += GET_PAD_SIZE (DataSizeOfVariable (Variable));

  //
  // Be careful about pad size for alignment
  //
  return (VARIABLE_HEADER *) HEADER_ALIGN (Value);
}

/**
  This code gets the pointer to the variable name.

  @param VarStoreHeader  Pointer to the Variable Store Header.

  @retval EfiRaw        Variable store is raw
  @retval EfiValid      Variable store is valid
  @retval EfiInvalid    Variable store is invalid

**/
VARIABLE_STORE_STATUS
EFIAPI
GetVariableStoreStatus (
  IN VARIABLE_STORE_HEADER *VarStoreHeader
  )

{
	
  if (CompareGuid (&VarStoreHeader->Signature, &gEfiVariableGuid) &&
      VarStoreHeader->Format == VARIABLE_STORE_FORMATTED &&
      VarStoreHeader->State == VARIABLE_STORE_HEALTHY
      ) {

    return EfiValid;
  }

  if (((UINT32 *)(&VarStoreHeader->Signature))[0] == 0xffffffff &&
      ((UINT32 *)(&VarStoreHeader->Signature))[1] == 0xffffffff &&
      ((UINT32 *)(&VarStoreHeader->Signature))[2] == 0xffffffff &&
      ((UINT32 *)(&VarStoreHeader->Signature))[3] == 0xffffffff &&
      VarStoreHeader->Size == 0xffffffff &&
      VarStoreHeader->Format == 0xff &&
      VarStoreHeader->State == 0xff
      ) {

    return EfiRaw;
  } else {
    return EfiInvalid;
  }
}

/**
  This function compares a variable with variable entries in database

  @param Variable       - Pointer to the variable in our database
  @param VariableName   - Name of the variable to compare to 'Variable'
  @param VendorGuid     - GUID of the variable to compare to 'Variable'
  @param PtrTrack       - Variable Track Pointer structure that contains
                   Variable Information.

  @retval  EFI_SUCCESS    - Found match variable
  @retval EFI_NOT_FOUND  - Variable not found

**/
EFI_STATUS
CompareWithValidVariable (
  IN  VARIABLE_HEADER               *Variable,
  IN  CONST CHAR16                  *VariableName,
  IN  CONST EFI_GUID                *VendorGuid,
  OUT VARIABLE_POINTER_TRACK        *PtrTrack
  )

{
  VOID  *Point;

  if (VariableName[0] == 0) {
    PtrTrack->CurrPtr = Variable;
    return EFI_SUCCESS;
  } else {
    //
    // Don't use CompareGuid function here for performance reasons.
    // Instead we compare the GUID a UINT32 at a time and branch
    // on the first failed comparison.
    //
    if ((((INT32 *) VendorGuid)[0] == ((INT32 *) &Variable->VendorGuid)[0]) &&
        (((INT32 *) VendorGuid)[1] == ((INT32 *) &Variable->VendorGuid)[1]) &&
        (((INT32 *) VendorGuid)[2] == ((INT32 *) &Variable->VendorGuid)[2]) &&
        (((INT32 *) VendorGuid)[3] == ((INT32 *) &Variable->VendorGuid)[3])
        ) {
      ASSERT (NameSizeOfVariable (Variable) != 0);
      Point = (VOID *) GetVariableNamePtr (Variable);
      if (!CompareMem (VariableName, Point, NameSizeOfVariable (Variable))) {
        PtrTrack->CurrPtr = Variable;
        return EFI_SUCCESS;
      }
    }
  }

  return EFI_NOT_FOUND;
}

/**
  This code finds variable in storage blocks (Non-Volatile)

  @param PeiServices    - General purpose services available to every PEIM.
  @param VariableName   - Name of the variable to be found
  @param VendorGuid     - Vendor GUID to be found.
  @param PtrTrack       - Variable Track Pointer structure that contains
                   Variable Information.

  @retval EFI_SUCCESS      - Variable found successfully
  @retval EFI_NOT_FOUND    - Variable not found
  @retval EFI_INVALID_PARAMETER  - Invalid variable name

**/
EFI_STATUS
EFIAPI
FindVariable (
  IN        EFI_PEI_SERVICES   **PeiServices,
  IN CONST  CHAR16            *VariableName,
  IN CONST  EFI_GUID          *VendorGuid,
  OUT VARIABLE_POINTER_TRACK  *PtrTrack
  )

{
  EFI_HOB_GUID_TYPE       *GuidHob;
  VARIABLE_STORE_HEADER   *VariableStoreHeader;
  VARIABLE_HEADER         *Variable;
  VARIABLE_HEADER         *MaxIndex;
  VARIABLE_INDEX_TABLE    *IndexTable;
  UINT32                  Count;
  UINT8                   *VariableBase;

  if (VariableName[0] != 0 && VendorGuid == NULL) {
    return EFI_INVALID_PARAMETER;
  }
  //
  // No Variable Address equals zero, so 0 as initial value is safe.
  //
  MaxIndex = 0;

  GuidHob = GetFirstGuidHob (&mEfiVariableIndexTableGuid);
  if (GuidHob == NULL) {
    IndexTable = BuildGuidHob (&mEfiVariableIndexTableGuid, sizeof (VARIABLE_INDEX_TABLE));
    IndexTable->Length      = 0;
    IndexTable->StartPtr    = NULL;
    IndexTable->EndPtr      = NULL;
    IndexTable->GoneThrough = 0;
  } else {
    IndexTable = GET_GUID_HOB_DATA (GuidHob);
    for (Count = 0; Count < IndexTable->Length; Count++)
    {
      MaxIndex = GetVariableByIndex (IndexTable, Count);

      if (CompareWithValidVariable (MaxIndex, VariableName, VendorGuid, PtrTrack) == EFI_SUCCESS) {
        PtrTrack->StartPtr  = IndexTable->StartPtr;
        PtrTrack->EndPtr    = IndexTable->EndPtr;

        return EFI_SUCCESS;
      }
    }

    if (IndexTable->GoneThrough) {
      return EFI_NOT_FOUND;
    }
  }
  //
  // If not found in HOB, then let's start from the MaxIndex we've found.
  //
  if (MaxIndex != NULL) {
    Variable = GetNextVariablePtr (MaxIndex);
  } else {
    if (IndexTable->StartPtr || IndexTable->EndPtr) {
      Variable = IndexTable->StartPtr;
    } else {
      VariableBase = (UINT8 *) (UINTN) PcdGet32 (PcdFlashNvStorageVariableBase);
      VariableStoreHeader = (VARIABLE_STORE_HEADER *) (VariableBase + \
                            ((EFI_FIRMWARE_VOLUME_HEADER *) (VariableBase)) -> HeaderLength);

      if (GetVariableStoreStatus (VariableStoreHeader) != EfiValid) {
        return EFI_UNSUPPORTED;
      }

      if (~VariableStoreHeader->Size == 0) {
        return EFI_NOT_FOUND;
      }
      //
      // Find the variable by walk through non-volatile variable store
      //
      IndexTable->StartPtr  = GetStartPointer (VariableStoreHeader);
      IndexTable->EndPtr    = GetEndPointer (VariableStoreHeader);

      //
      // Start Pointers for the variable.
      // Actual Data Pointer where data can be written.
      //
      Variable = IndexTable->StartPtr;
    }
  }
  //
  // Find the variable by walk through non-volatile variable store
  //
  PtrTrack->StartPtr  = IndexTable->StartPtr;
  PtrTrack->EndPtr    = IndexTable->EndPtr;

  while (IsValidVariableHeader (Variable) && (Variable <= IndexTable->EndPtr)) {
    if (Variable->State == VAR_ADDED) {
      //
      // Record Variable in VariableIndex HOB
      //
      if (IndexTable->Length < VARIABLE_INDEX_TABLE_VOLUME)
      {
        VariableIndexTableUpdate (IndexTable, Variable);
      }

      if (CompareWithValidVariable (Variable, VariableName, VendorGuid, PtrTrack) == EFI_SUCCESS) {
        return EFI_SUCCESS;
      }
    }

    Variable = GetNextVariablePtr (Variable);
  }
  //
  // If gone through the VariableStore, that means we never find in Firmware any more.
  //
  if (IndexTable->Length < VARIABLE_INDEX_TABLE_VOLUME) {
    IndexTable->GoneThrough = 1;
  }

  PtrTrack->CurrPtr = NULL;

  return EFI_NOT_FOUND;
}

/**
  Provide the read variable functionality of the variable services.

  @param PeiServices - General purpose services available to every PEIM.

  @param VariableName     - The variable name

  @param VendorGuid       - The vendor's GUID

  @param Attributes       - Pointer to the attribute

  @param DataSize         - Size of data

  @param Data             - Pointer to data

  @retval EFI_SUCCESS           - The interface could be successfully installed

  @retval EFI_NOT_FOUND         - The variable could not be discovered

  @retval EFI_BUFFER_TOO_SMALL  - The caller buffer is not large enough

**/
EFI_STATUS
EFIAPI
PeiGetVariable (
  IN EFI_PEI_SERVICES             **PeiServices,
  IN CHAR16                       *VariableName,
  IN EFI_GUID                     * VendorGuid,
  OUT UINT32                             *Attributes OPTIONAL,
  IN OUT UINTN                           *DataSize,
  OUT VOID                               *Data
  )

{
  VARIABLE_POINTER_TRACK  Variable;
  UINTN                   VarDataSize;
  EFI_STATUS              Status;

  if (VariableName == NULL || VendorGuid == NULL || DataSize == NULL) {
    return EFI_INVALID_PARAMETER;
  }
  //
  // Find existing variable
  //
  Status = FindVariable (PeiServices, VariableName, VendorGuid, &Variable);

  if (Variable.CurrPtr == NULL || Status != EFI_SUCCESS) {
    return Status;
  }
  //
  // Get data size
  //
  VarDataSize = DataSizeOfVariable (Variable.CurrPtr);
  if (*DataSize >= VarDataSize) {
    //
    // PO-TKW: Address one checking in this place
    //
    if (Data == NULL) {
      return EFI_INVALID_PARAMETER;
    }

    (*PeiServices)->CopyMem (Data, GetVariableDataPtr (Variable.CurrPtr), VarDataSize);

    if (Attributes != NULL) {
      *Attributes = Variable.CurrPtr->Attributes;
    }

    *DataSize = VarDataSize;
    return EFI_SUCCESS;
  } else {
    *DataSize = VarDataSize;
    return EFI_BUFFER_TOO_SMALL;
  }
}

/**
  Provide the read variable functionality of the variable services.

  @param PeiServices - General purpose services available to every PEIM.

  @param VariableName     - The variable name

  @param VendorGuid       - The vendor's GUID

  @param Attributes       - Pointer to the attribute

  @param DataSize         - Size of data

  @param Data             - Pointer to data

  @retval EFI_SUCCESS           - The interface could be successfully installed

  @retval EFI_NOT_FOUND         - The variable could not be discovered

  @retval EFI_BUFFER_TOO_SMALL  - The caller buffer is not large enough

**/
EFI_STATUS
EFIAPI
PeiGetVariable2 (
  IN CONST  EFI_PEI_READ_ONLY_VARIABLE2_PPI *This,
  IN CONST  CHAR16                          *VariableName,
  IN CONST  EFI_GUID                        *VariableGuid,
  OUT       UINT32                          *Attributes,
  IN OUT    UINTN                           *DataSize,
  OUT       VOID                            *Data
  )

{
  return PeiGetVariable (
           (EFI_PEI_SERVICES **) GetPeiServicesTablePointer (),
           (CHAR16*)VariableName,
           (EFI_GUID*)VariableGuid,
           Attributes,
           DataSize,
           Data
           );
}

/**
  Provide the get next variable functionality of the variable services.

  @param PeiServices        - General purpose services available to every PEIM.
  @param VariabvleNameSize  - The variable name's size.
  @param VariableName       - A pointer to the variable's name.
  @param VendorGuid         - A pointer to the EFI_GUID structure.

  @param VariableNameSize - Size of the variable name

  @param VariableName     - The variable name

  @param VendorGuid       - The vendor's GUID

  @retval EFI_SUCCESS - The interface could be successfully installed

  @retval EFI_NOT_FOUND - The variable could not be discovered

**/
EFI_STATUS
EFIAPI
PeiGetNextVariableName (
  IN EFI_PEI_SERVICES             **PeiServices,
  IN OUT UINTN                    *VariableNameSize,
  IN OUT CHAR16                   *VariableName,
  IN OUT EFI_GUID                 *VendorGuid
  )

{
  VARIABLE_POINTER_TRACK  Variable;
  UINTN                   VarNameSize;
  EFI_STATUS              Status;

  if (VariableNameSize == NULL || VariableName == NULL || VendorGuid == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Status = FindVariable (PeiServices, VariableName, VendorGuid, &Variable);

  if (Variable.CurrPtr == NULL || Status != EFI_SUCCESS) {
    return Status;
  }

  if (VariableName[0] != 0) {
    //
    // If variable name is not NULL, get next variable
    //
    Variable.CurrPtr = GetNextVariablePtr (Variable.CurrPtr);
  }

  while (!(Variable.CurrPtr >= Variable.EndPtr || Variable.CurrPtr == NULL)) {
    if (IsValidVariableHeader (Variable.CurrPtr)) {
      if (Variable.CurrPtr->State == VAR_ADDED) {
        ASSERT (NameSizeOfVariable (Variable.CurrPtr) != 0);

        VarNameSize = (UINTN) NameSizeOfVariable (Variable.CurrPtr);
        if (VarNameSize <= *VariableNameSize) {
          (*PeiServices)->CopyMem (VariableName, GetVariableNamePtr (Variable.CurrPtr), VarNameSize);

          (*PeiServices)->CopyMem (VendorGuid, &Variable.CurrPtr->VendorGuid, sizeof (EFI_GUID));

          Status = EFI_SUCCESS;
        } else {
          Status = EFI_BUFFER_TOO_SMALL;
        }

        *VariableNameSize = VarNameSize;
        return Status;
        //
        // Variable is found
        //
      } else {
        Variable.CurrPtr = GetNextVariablePtr (Variable.CurrPtr);
      }
    } else {
      break;
    }
  }

  return EFI_NOT_FOUND;
}

/**
  Provide the get next variable functionality of the variable services.

  @param PeiServices        - General purpose services available to every PEIM.
  @param VariabvleNameSize  - The variable name's size.
  @param VariableName       - A pointer to the variable's name.
  @param VariableGuid       - A pointer to the EFI_GUID structure.

  @param VariableNameSize - Size of the variable name

  @param VariableName     - The variable name

  @param VendorGuid       - The vendor's GUID


  @retval EFI_SUCCESS - The interface could be successfully installed

  @retval EFI_NOT_FOUND - The variable could not be discovered

**/
EFI_STATUS
EFIAPI
PeiGetNextVariableName2 (
  IN CONST  EFI_PEI_READ_ONLY_VARIABLE2_PPI *This,
  IN OUT UINTN                              *VariableNameSize,
  IN OUT CHAR16                             *VariableName,
  IN OUT EFI_GUID                           *VariableGuid
  )

{
  return PeiGetNextVariableName (
           (EFI_PEI_SERVICES **) GetPeiServicesTablePointer (),
           VariableNameSize,
           VariableName,
           VariableGuid
           );
}