locate.c

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/*++

Copyright (c) 2004, Intel Corporation                                                         
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:

  locate.c

Abstract:

  Locate handle functions    

Revision History

--*/

#include "hand.h"

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

//
// Internal prototypes
//

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

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

STATIC
IHANDLE *
CoreGetNextLocateAllHandles (
  IN OUT LOCATE_POSITION    *Position,
  OUT VOID                  **Interface
  );

STATIC
IHANDLE *
CoreGetNextLocateByRegisterNotify (
  IN OUT LOCATE_POSITION    *Position,
  OUT VOID                  **Interface
  );

STATIC
IHANDLE *
CoreGetNextLocateByProtocol (
  IN OUT LOCATE_POSITION    *Position,
  OUT VOID                  **Interface
  );

//
//
//



EFI_BOOTSERVICE 
EFI_STATUS
EFIAPI
CoreLocateHandle (
  IN EFI_LOCATE_SEARCH_TYPE   SearchType,
  IN EFI_GUID                 *Protocol   OPTIONAL,
  IN VOID                     *SearchKey  OPTIONAL,
  IN OUT UINTN                *BufferSize,
  OUT EFI_HANDLE              *Buffer
  )
/*++

Routine Description:

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

Arguments:

  SearchType  - The type of search to perform to locate the handles

  Protocol    - The protocol to search for
  
  SearchKey   - Dependant on SearchType

  BufferSize  - On input the size of Buffer.  On output the 
                size of data returned.  

  Buffer      - The buffer to return the results in


Returns:

  EFI_BUFFER_TOO_SMALL      - Buffer too small, required buffer size is returned in BufferSize.

  EFI_INVALID_PARAMETER     - Invalid parameter
  
  EFI_SUCCESS               - Successfully found the requested handle(s) and returns them in 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) {
    Status = 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;

  //
  // Lock the protocol database
  //
  
  CoreAcquireProtocolLock ();

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

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

  case ByProtocol:      
    GetNext = CoreGetNextLocateByProtocol;
    if (Protocol == NULL) {
      Status = EFI_INVALID_PARAMETER;
      break;
    }
    //
    // Look up the protocol entry and set the head pointer
    //
    Position.ProtEntry = CoreFindProtocolEntry (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)) {
    CoreReleaseProtocolLock ();
    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)) {
      //
      // 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;
    }
  }

  CoreReleaseProtocolLock ();
  return Status;
}


STATIC
IHANDLE *
CoreGetNextLocateAllHandles (
  IN OUT LOCATE_POSITION    *Position,
  OUT VOID                  **Interface
  )
/*++

Routine Description:

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

Arguments:

  Position  - Information about which Handle to seach for.

  Interface - Return the interface structure for the matching protocol.
  
Returns:
  IHANDLE - An IHANDLE is returned if the next Position is not the end of the
            list. A NULL_HANDLE is returned if it's the end of the list.
  
--*/
{
  IHANDLE     *Handle;

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

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

  return Handle;
}


STATIC
IHANDLE *
CoreGetNextLocateByRegisterNotify (
  IN OUT LOCATE_POSITION    *Position,
  OUT VOID                  **Interface
  )
/*++

Routine Description:

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

Arguments:

  Position  - Information about which Handle to seach for.

  Interface - Return the interface structure for the matching protocol.
  
Returns:
  IHANDLE - An IHANDLE is returned if the next Position is not the end of the
            list. A NULL_HANDLE is returned if it's the end of the list.
  
--*/
{
  IHANDLE             *Handle;
  PROTOCOL_NOTIFY     *ProtNotify;
  PROTOCOL_INTERFACE  *Prot;
  EFI_LIST_ENTRY      *Link;    

  Handle      = NULL_HANDLE;
  *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 = (IHANDLE *) Prot->Handle;
      *Interface = Prot->Interface;
    }  
  }

  return Handle;
}


STATIC
IHANDLE *
CoreGetNextLocateByProtocol (
  IN OUT LOCATE_POSITION    *Position,
  OUT VOID                  **Interface
  )
/*++

Routine Description:

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

Arguments:

  Position  - Information about which Handle to seach for.