bmlib.c

来自「EFI BIOS是Intel提出的下一代的BIOS标准。这里上传的Edk源代码是」· C语言 代码 · 共 661 行 · 第 1/2 页

/*++

Copyright (c) 2004 - 2006, 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:

  bmlib.c
    
AgBStract:

  Boot Maintainence Helper functions

--*/

#include "bootmaint.h"

#include EFI_GUID_DEFINITION (DataHubRecords)

VOID *
EfiAllocateZeroPool (
  IN UINTN            Size
  )
/*++

Routine Description:
  Wrap original AllocatePool gBS call
  and ZeroMem gBS call into a single 
  function in order to decrease code length
  
Arguments:

Returns:
  Valid pointer to the allocated buffer
  Null for failure

--*/
{
  EFI_STATUS  Status;
  VOID        *Ptr;
  Status = gBS->AllocatePool (EfiBootServicesData, Size, &Ptr);
  if (EFI_ERROR (Status)) {
    Ptr = NULL;
    return Ptr;
  }

  EfiZeroMem (Ptr, Size);
  return Ptr;
}

EFI_STATUS
EfiLibLocateProtocol (
  IN  EFI_GUID    *ProtocolGuid,
  OUT VOID        **Interface
  )
/*++

Routine Description:

  Find the first instance of this Protocol 
  in the system and return it's interface

Arguments:

  ProtocolGuid    - Provides the protocol to search for
  Interface       - On return, a pointer to the first interface 
                    that matches ProtocolGuid

Returns:

  EFI_SUCCESS     - A protocol instance matching ProtocolGuid was found

  EFI_NOT_FOUND   - No protocol instances were found that match ProtocolGuid

--*/
{
  EFI_STATUS  Status;

  Status = gBS->LocateProtocol (
                  ProtocolGuid,
                  NULL,
                  Interface
                  );
  return Status;
}

EFI_FILE_HANDLE
EfiLibOpenRoot (
  IN EFI_HANDLE                   DeviceHandle
  )
/*++

Routine Description:

  Function opens and returns a file handle to the root directory of a volume.

Arguments:

  DeviceHandle         - A handle for a device

Returns:
  
  A valid file handle or NULL is returned

--*/
{
  EFI_STATUS                      Status;
  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *Volume;
  EFI_FILE_HANDLE                 File;

  File = NULL;

  //
  // File the file system interface to the device
  //
  Status = gBS->HandleProtocol (
                  DeviceHandle,
                  &gEfiSimpleFileSystemProtocolGuid,
                  (VOID *) &Volume
                  );

  //
  // Open the root directory of the volume
  //
  if (!EFI_ERROR (Status)) {
    Status = Volume->OpenVolume (
                      Volume,
                      &File
                      );
  }
  //
  // Done
  //
  return EFI_ERROR (Status) ? NULL : File;
}

BOOLEAN
EfiGrowBuffer (
  IN OUT EFI_STATUS   *Status,
  IN OUT VOID         **Buffer,
  IN UINTN            BufferSize
  )
/*++

Routine Description:

    Helper function called as part of the code needed
    to allocate the proper sized buffer for various 
    EFI interfaces.

Arguments:

    Status      - Current status

    Buffer      - Current allocated buffer, or NULL

    BufferSize  - Current buffer size needed
    
Returns:
    
    TRUE - if the buffer was reallocated and the caller 
    should try the API again.

--*/
{
  BOOLEAN TryAgain;

  //
  // If this is an initial request, buffer will be null with a new buffer size
  //
  if (!*Buffer && BufferSize) {
    *Status = EFI_BUFFER_TOO_SMALL;
  }
  //
  // If the status code is "buffer too small", resize the buffer
  //
  TryAgain = FALSE;
  if (*Status == EFI_BUFFER_TOO_SMALL) {

    SafeFreePool (*Buffer);

    *Buffer = EfiAllocateZeroPool (BufferSize);

    if (*Buffer) {
      TryAgain = TRUE;
    } else {
      *Status = EFI_OUT_OF_RESOURCES;
    }
  }
  //
  // If there's an error, free the buffer
  //
  if (!TryAgain && EFI_ERROR (*Status) && *Buffer) {
    SafeFreePool (*Buffer);
    *Buffer = NULL;
  }

  return TryAgain;
}

VOID *
EfiLibGetVariable (
  IN CHAR16               *Name,
  IN EFI_GUID             *VendorGuid
  )
/*++

Routine Description:
  Function returns the value of the specified variable.

Arguments:
  Name                - A Null-terminated Unicode string that is 
                        the name of the vendor's variable.

  VendorGuid          - A unique identifier for the vendor.

Returns:

  None

--*/
{
  UINTN VarSize;

  return BdsLibGetVariableAndSize (Name, VendorGuid, &VarSize);
}

EFI_STATUS
EfiLibDeleteVariable (
  IN CHAR16   *VarName,
  IN EFI_GUID *VarGuid
  )
/*++

Routine Description:
  Function deletes the variable specified by VarName and VarGuid.

Arguments:
  VarName              - A Null-terminated Unicode string that is 
                         the name of the vendor's variable.

  VendorGuid           - A unique identifier for the vendor.

Returns:

  EFI_SUCCESS          - The variable was found and removed

  EFI_UNSUPPORTED      - The variable store was inaccessible

  EFI_OUT_OF_RESOURCES - The temporary buffer was not available

  EFI_NOT_FOUND        - The variable was not found

--*/
{
  VOID        *VarBuf;
  EFI_STATUS  Status;

  VarBuf  = EfiLibGetVariable (VarName, VarGuid);
  Status  = EFI_NOT_FOUND;

  if (VarBuf) {
    //
    // Delete variable from Storage
    //
    Status = gRT->SetVariable (VarName, VarGuid, VAR_FLAG, 0, NULL);
    ASSERT (!EFI_ERROR (Status));
    SafeFreePool (VarBuf);
  }

  return Status;
}

EFI_FILE_SYSTEM_VOLUME_LABEL_INFO *
EfiLibFileSystemVolumeLabelInfo (
  IN EFI_FILE_HANDLE      FHand
  )
/*++

Routine Description:

  Function gets the file system information from an open file descriptor, 
  and stores it in a buffer allocated from pool.

Arguments:

  Fhand         - A file handle

Returns:
  
  A pointer to a buffer with file information or NULL is returned

--*/
{
  EFI_STATUS                        Status;
  EFI_FILE_SYSTEM_VOLUME_LABEL_INFO *Buffer;
  UINTN                             BufferSize;
  //
  // Initialize for GrowBuffer loop
  //
  Buffer      = NULL;
  BufferSize  = SIZE_OF_EFI_FILE_SYSTEM_VOLUME_LABEL_INFO + 200;

  //
  // Call the real function
  //
  while (EfiGrowBuffer (&Status, (VOID **) &Buffer, BufferSize)) {
    Status = FHand->GetInfo (
                      FHand,
                      &gEfiFileSystemVolumeLabelInfoIdGuid,
                      &BufferSize,
                      Buffer
                      );
  }

  return Buffer;
}

CHAR16 *
EfiStrDuplicate (
  IN CHAR16   *Src
  )
{
  CHAR16  *Dest;
  UINTN   Size;