system76-edk2/MdeModulePkg/Core/PiSmmCore/Locate.c

/** @file
  Locate handle functions

  Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.<BR>
  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.

**/

#include "PiSmmCore.h"

//
// ProtocolRequest - Last LocateHandle request ID
//
UINTN mEfiLocateHandleRequest = 0;

//
// Internal prototypes
//

typedef struct {
  EFI_GUID        *Protocol;
  VOID            *SearchKey;
  LIST_ENTRY      *Position;
  PROTOCOL_ENTRY  *ProtEntry;
} LOCATE_POSITION;

typedef
IHANDLE *
(* CORE_GET_NEXT) (
  IN OUT LOCATE_POSITION    *Position,
  OUT VOID                  **Interface
  );

/**
  Routine to get the next Handle, when you are searching for all handles.

  @param  Position               Information about which Handle to seach for.
  @param  Interface              Return the interface structure for the matching
                                 protocol.

  @return An pointer to IHANDLE if the next Position is not the end of the list.
          Otherwise,NULL is returned.

**/
IHANDLE *
SmmGetNextLocateAllHandles (
  IN OUT LOCATE_POSITION  *Position,
  OUT    VOID             **Interface
  )
{
  IHANDLE     *Handle;

  //
  // Next handle
  //
  Position->Position = Position->Position->ForwardLink;

  //
  // If not at the end of the list, get the handle
  //
  Handle      = NULL;
  *Interface  = NULL;
  if (Position->Position != &gHandleList) {
    Handle = CR (Position->Position, IHANDLE, AllHandles, EFI_HANDLE_SIGNATURE);
  }
  return Handle;
}

/**
  Routine to get the next Handle, when you are searching for register protocol
  notifies.

  @param  Position               Information about which Handle to seach for.
  @param  Interface              Return the interface structure for the matching
                                 protocol.

  @return An pointer to IHANDLE if the next Position is not the end of the list.
          Otherwise,NULL is returned.

**/
IHANDLE *
SmmGetNextLocateByRegisterNotify (
  IN OUT LOCATE_POSITION  *Position,
  OUT    VOID             **Interface
  )
{
  IHANDLE             *Handle;
  PROTOCOL_NOTIFY     *ProtNotify;
  PROTOCOL_INTERFACE  *Prot;
  LIST_ENTRY          *Link;

  Handle      = NULL;
  *Interface  = NULL;
  ProtNotify = Position->SearchKey;

  //
  // If this is the first request, get the next handle
  //
  if (ProtNotify != NULL) {
    ASSERT(ProtNotify->Signature == PROTOCOL_NOTIFY_SIGNATURE);
    Position->SearchKey = NULL;

    //
    // If not at the end of the list, get the next handle
    //
    Link = ProtNotify->Position->ForwardLink;
    if (Link != &ProtNotify->Protocol->Protocols) {
      Prot = CR (Link, PROTOCOL_INTERFACE, ByProtocol, PROTOCOL_INTERFACE_SIGNATURE);
      Handle = Prot->Handle;
      *Interface = Prot->Interface;
    }
  }
  return Handle;
}

/**
  Routine to get the next Handle, when you are searching for a given protocol.

  @param  Position               Information about which Handle to seach for.
  @param  Interface              Return the interface structure for the matching
                                 protocol.

  @return An pointer to IHANDLE if the next Position is not the end of the list.
          Otherwise,NULL is returned.

**/
IHANDLE *
SmmGetNextLocateByProtocol (
  IN OUT LOCATE_POSITION  *Position,
  OUT    VOID             **Interface
  )
{
  IHANDLE             *Handle;
  LIST_ENTRY          *Link;
  PROTOCOL_INTERFACE  *Prot;

  Handle      = NULL;
  *Interface  = NULL;
  for (; ;) {
    //
    // Next entry
    //
    Link = Position->Position->ForwardLink;
    Position->Position = Link;

    //
    // If not at the end, return the handle
    //
    if (Link == &Position->ProtEntry->Protocols) {
      Handle = NULL;
      break;
    }

    //
    // Get the handle
    //
    Prot = CR(Link, PROTOCOL_INTERFACE, ByProtocol, PROTOCOL_INTERFACE_SIGNATURE);
    Handle = Prot->Handle;
    *Interface = Prot->Interface;

    //
    // If this handle has not been returned this request, then
    // return it now
    //
    if (Handle->LocateRequest != mEfiLocateHandleRequest) {
      Handle->LocateRequest = mEfiLocateHandleRequest;
      break;
    }
  }
  return Handle;
}

/**
  Return the first Protocol Interface that matches the Protocol GUID. If
  Registration is pasased in return a Protocol Instance that was just add
  to the system. If Retistration is NULL return the first Protocol Interface
  you find.

  @param  Protocol               The protocol to search for
  @param  Registration           Optional Registration Key returned from
                                 RegisterProtocolNotify()
  @param  Interface              Return the Protocol interface (instance).

  @retval EFI_SUCCESS            If a valid Interface is returned
  @retval EFI_INVALID_PARAMETER  Invalid parameter
  @retval EFI_NOT_FOUND          Protocol interface not found

**/
EFI_STATUS
EFIAPI
SmmLocateProtocol (
  IN  EFI_GUID  *Protocol,
  IN  VOID      *Registration OPTIONAL,
  OUT VOID      **Interface
  )
{
  EFI_STATUS              Status;
  LOCATE_POSITION         Position;
  PROTOCOL_NOTIFY         *ProtNotify;
  IHANDLE                 *Handle;

  if ((Interface == NULL) || (Protocol == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  *Interface = NULL;
  Status = EFI_SUCCESS;

  //
  // Set initial position
  //
  Position.Protocol  = Protocol;
  Position.SearchKey = Registration;
  Position.Position  = &gHandleList;

  mEfiLocateHandleRequest += 1;

  if (Registration == NULL) {
    //
    // Look up the protocol entry and set the head pointer
    //
    Position.ProtEntry = SmmFindProtocolEntry (Protocol, FALSE);
    if (Position.ProtEntry == NULL) {
      return EFI_NOT_FOUND;
    }
    Position.Position = &Position.ProtEntry->Protocols;

    Handle = SmmGetNextLocateByProtocol (&Position, Interface);
  } else {
    Handle = SmmGetNextLocateByRegisterNotify (&Position, Interface);
  }

  if (Handle == NULL) {
    Status = EFI_NOT_FOUND;
  } else if (Registration != NULL) {
    //
    // If this is a search by register notify and a handle was
    // returned, update the register notification position
    //
    ProtNotify = Registration;
    ProtNotify->Position = ProtNotify->Position->ForwardLink;
  }

  return Status;
}

/**
  Locates the requested handle(s) and returns them in Buffer.

  @param  SearchType             The type of search to perform to locate the
                                 handles
  @param  Protocol               The protocol to search for
  @param  SearchKey              Dependant on SearchType
  @param  BufferSize             On input the size of Buffer.  On output the
                                 size of data returned.
  @param  Buffer                 The buffer to return the results in

  @retval EFI_BUFFER_TOO_SMALL   Buffer too small, required buffer size is
                                 returned in BufferSize.
  @retval EFI_INVALID_PARAMETER  Invalid parameter
  @retval EFI_SUCCESS            Successfully found the requested handle(s) and
                                 returns them in Buffer.

**/
EFI_STATUS
EFIAPI
SmmLocateHandle (
  IN     EFI_LOCATE_SEARCH_TYPE  SearchType,
  IN     EFI_GUID                *Protocol   OPTIONAL,
  IN     VOID                    *SearchKey  OPTIONAL,
  IN OUT UINTN                   *BufferSize,
  OUT    EFI_HANDLE              *Buffer
  )
{
  EFI_STATUS       Status;
  LOCATE_POSITION  Position;
  PROTOCOL_NOTIFY  *ProtNotify;
  CORE_GET_NEXT    GetNext;
  UINTN            ResultSize;
  IHANDLE          *Handle;
  IHANDLE          **ResultBuffer;
  VOID             *Interface;

  if (BufferSize == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  if ((*BufferSize > 0) && (Buffer == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  GetNext = NULL;

  //
  // Set initial position
  //
  Position.Protocol  = Protocol;
  Position.SearchKey = SearchKey;
  Position.Position  = &gHandleList;

  ResultSize = 0;
  ResultBuffer = (IHANDLE **) Buffer;
  Status = EFI_SUCCESS;

  //
  // Get the search function based on type
  //
  switch (SearchType) {
  case AllHandles:
    GetNext = SmmGetNextLocateAllHandles;
    break;

  case ByRegisterNotify:
    GetNext = SmmGetNextLocateByRegisterNotify;
    //
    // Must have SearchKey for locate ByRegisterNotify
    //
    if (SearchKey == NULL) {
      Status = EFI_INVALID_PARAMETER;
    }
    break;

  case ByProtocol:
    GetNext = SmmGetNextLocateByProtocol;
    if (Protocol == NULL) {
      Status = EFI_INVALID_PARAMETER;
      break;
    }
    //
    // Look up the protocol entry and set the head pointer
    //
    Position.ProtEntry = SmmFindProtocolEntry (Protocol, FALSE);
    if (Position.ProtEntry == NULL) {
      Status = EFI_NOT_FOUND;
      break;
    }
    Position.Position = &Position.ProtEntry->Protocols;
    break;

  default:
    Status = EFI_INVALID_PARAMETER;
    break;
  }

  if (EFI_ERROR(Status)) {
    return Status;
  }

  //
  // Enumerate out the matching handles
  //
  mEfiLocateHandleRequest += 1;
  for (; ;) {
    //
    // Get the next handle.  If no more handles, stop
    //
    Handle = GetNext (&Position, &Interface);
    if (NULL == Handle) {
      break;
    }

    //
    // Increase the resulting buffer size, and if this handle
    // fits return it
    //
    ResultSize += sizeof(Handle);
    if (ResultSize <= *BufferSize) {
        *ResultBuffer = Handle;
        ResultBuffer += 1;
    }
  }

  //
  // If the result is a zero length buffer, then there were no
  // matching handles
  //
  if (ResultSize == 0) {
    Status = EFI_NOT_FOUND;
  } else {
    //
    // Return the resulting buffer size.  If it's larger than what
    // was passed, then set the error code
    //
    if (ResultSize > *BufferSize) {
      Status = EFI_BUFFER_TOO_SMALL;
    }

    *BufferSize = ResultSize;

    if (SearchType == ByRegisterNotify && !EFI_ERROR(Status)) {
      ASSERT (SearchKey != NULL);
      //
      // If this is a search by register notify and a handle was
      // returned, update the register notification position
      //
      ProtNotify = SearchKey;
      ProtNotify->Position = ProtNotify->Position->ForwardLink;
    }
  }

  return Status;
}

/**
  Function returns an array of handles that support the requested protocol
  in a buffer allocated from pool. This is a version of SmmLocateHandle()
  that allocates a buffer for the caller.

  @param  SearchType             Specifies which handle(s) are to be returned.
  @param  Protocol               Provides the protocol to search by.    This
                                 parameter is only valid for SearchType
                                 ByProtocol.
  @param  SearchKey              Supplies the search key depending on the
                                 SearchType.
  @param  NumberHandles          The number of handles returned in Buffer.
  @param  Buffer                 A pointer to the buffer to return the requested
                                 array of  handles that support Protocol.

  @retval EFI_SUCCESS            The result array of handles was returned.
  @retval EFI_NOT_FOUND          No handles match the search.
  @retval EFI_OUT_OF_RESOURCES   There is not enough pool memory to store the
                                 matching results.
  @retval EFI_INVALID_PARAMETER  One or more parameters are not valid.

**/
EFI_STATUS
EFIAPI
SmmLocateHandleBuffer (
  IN     EFI_LOCATE_SEARCH_TYPE  SearchType,
  IN     EFI_GUID                *Protocol OPTIONAL,
  IN     VOID                    *SearchKey OPTIONAL,
  IN OUT UINTN                   *NumberHandles,
  OUT    EFI_HANDLE              **Buffer
  )
{
  EFI_STATUS  Status;
  UINTN       BufferSize;

  if (NumberHandles == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  if (Buffer == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  BufferSize = 0;
  *NumberHandles = 0;
  *Buffer = NULL;
  Status = SmmLocateHandle (
             SearchType,
             Protocol,
             SearchKey,
             &BufferSize,
             *Buffer
             );
  //
  // LocateHandleBuffer() returns incorrect status code if SearchType is
  // invalid.
  //
  // Add code to correctly handle expected errors from SmmLocateHandle().
  //
  if (EFI_ERROR(Status) && Status != EFI_BUFFER_TOO_SMALL) {
    if (Status != EFI_INVALID_PARAMETER) {
      Status = EFI_NOT_FOUND;
    }
    return Status;
  }

  *Buffer = AllocatePool (BufferSize);
  if (*Buffer == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  Status = SmmLocateHandle (
             SearchType,
             Protocol,
             SearchKey,
             &BufferSize,
             *Buffer
             );

  *NumberHandles = BufferSize / sizeof(EFI_HANDLE);
  if (EFI_ERROR(Status)) {
    *NumberHandles = 0;
  }

  return Status;
}