audk/MdePkg/Library/UefiDevicePathLib/DevicePathUtilitiesDxeSmm.c

52 lines
1.5 KiB
C

/** @file
Device Path services. The thing to remember is device paths are built out of
nodes. The device path is terminated by an end node that is length
sizeof(EFI_DEVICE_PATH_PROTOCOL). That would be why there is sizeof(EFI_DEVICE_PATH_PROTOCOL)
all over this file.
The only place where multi-instance device paths are supported is in
environment varibles. Multi-instance device paths should never be placed
on a Handle.
Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
Copyright (c) Microsoft Corporation.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "UefiDevicePathLib.h"
/**
Retrieves the device path protocol from a handle.
This function returns the device path protocol from the handle specified by Handle.
If Handle is NULL or Handle does not contain a device path protocol, then NULL
is returned.
@param Handle The handle from which to retrieve the device
path protocol.
@return The device path protocol from the handle specified by Handle.
**/
EFI_DEVICE_PATH_PROTOCOL *
EFIAPI
DevicePathFromHandle (
IN EFI_HANDLE Handle
)
{
EFI_DEVICE_PATH_PROTOCOL *DevicePath;
EFI_STATUS Status;
Status = gBS->HandleProtocol (
Handle,
&gEfiDevicePathProtocolGuid,
(VOID *)&DevicePath
);
if (EFI_ERROR (Status)) {
DevicePath = NULL;
}
return DevicePath;
}