mirror of https://github.com/acidanthera/audk.git
396 lines
17 KiB
C
396 lines
17 KiB
C
/** @file
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Provides library functions to construct and parse UEFI Device Paths.
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This library provides defines, macros, and functions to help create and parse
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EFI_DEVICE_PATH_PROTOCOL structures. The macros that help create and parse device
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path nodes make use of the ReadUnaligned16() and WriteUnaligned16() functions from
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the Base Library, so this library class has an implied dependency on the Base Library.
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Copyright (c) 2006 - 2008, Intel Corporation<BR>
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All rights reserved. This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#ifndef __DEVICE_PATH_LIB_H__
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#define __DEVICE_PATH_LIB_H__
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#include <Library/BaseLib.h>
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#define END_DEVICE_PATH_LENGTH (sizeof (EFI_DEVICE_PATH_PROTOCOL))
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/**
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Macro that returns the Type field of a device path node.
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Returns the Type field of the device path node specified by Node.
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@param Node A pointer to a device path node data structure.
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@return The Type field of the device path node specified by Node.
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**/
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#define DevicePathType(Node) (((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Type)
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/**
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Macro that returns the SubType field of a device path node.
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Returns the SubType field of the device path node specified by Node.
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@param Node A pointer to a device path node data structure.
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@return The SubType field of the device path node specified by Node.
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**/
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#define DevicePathSubType(Node) (((EFI_DEVICE_PATH_PROTOCOL *)(Node))->SubType)
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/**
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Macro that returns the 16-bit Length field of a device path node.
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Returns the 16-bit Length field of the device path node specified by Node.
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@param Node A pointer to a device path node data structure.
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@return The 16-bit Length field of the device path node specified by Node.
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**/
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#define DevicePathNodeLength(Node) ReadUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0])
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/**
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Macro that returns a pointer to the next node in a device path.
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Returns a pointer to the device path node that follows the device path node specified by Node.
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@param Node A pointer to a device path node data structure.
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@return a pointer to the device path node that follows the device path node specified by Node.
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**/
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#define NextDevicePathNode(Node) ((EFI_DEVICE_PATH_PROTOCOL *)((UINT8 *)(Node) + DevicePathNodeLength(Node)))
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/**
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Macro that determines if a device path node is an end node of a device path.
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This includes nodes that are the end of a device path instance and nodes that are the end of an entire device path.
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Determines if the device path node specified by Node is an end node of a device path.
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This includes nodes that are the end of a device path instance and nodes that are the
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end of an entire device path. If Node represents an end node of a device path,
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then TRUE is returned. Otherwise, FALSE is returned.
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@param Node A pointer to a device path node data structure.
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@retval TRUE The device path node specified by Node is an end node of a device path.
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@retval FALSE The device path node specified by Node is not an end node of a device path.
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**/
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#define IsDevicePathEndType(Node) ((DevicePathType (Node) & 0x7f) == END_DEVICE_PATH_TYPE)
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/**
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Macro that determines if a device path node is an end node of an entire device path.
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Determines if a device path node specified by Node is an end node of an entire device path.
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If Node represents the end of an entire device path, then TRUE is returned. Otherwise, FALSE is returned.
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@param Node A pointer to a device path node data structure.
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@retval TRUE The device path node specified by Node is the end of an entire device path.
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@retval FALSE The device path node specified by Node is not the end of an entire device path.
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**/
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#define IsDevicePathEnd(Node) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_ENTIRE_DEVICE_PATH_SUBTYPE)
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/**
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Macro that determines if a device path node is an end node of a device path instance.
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Determines if a device path node specified by Node is an end node of a device path instance.
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If Node represents the end of a device path instance, then TRUE is returned. Otherwise, FALSE is returned.
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@param Node A pointer to a device path node data structure.
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@retval TRUE The device path node specified by Node is the end of a device path instance.
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@retval FALSE The device path node specified by Node is not the end of a device path instance.
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**/
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#define IsDevicePathEndInstance(Node) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_INSTANCE_DEVICE_PATH_SUBTYPE)
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/**
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Macro that sets the length, in bytes, of a device path node.
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Sets the length of the device path node specified by Node to the value specified by Length. Length is returned.
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@param Node A pointer to a device path node data structure.
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@param Length The length, in bytes, of the device path node.
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@return Length
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**/
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#define SetDevicePathNodeLength(Node,NodeLength) WriteUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(NodeLength))
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/**
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Macro that fills in all the fields of a device path node that is the end of an entire device path.
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Fills in all the fields of a device path node specified by Node so Node represents the end of an entire device path.
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@param Node A pointer to a device path node data structure.
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**/
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#define SetDevicePathEndNode(Node) { \
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DevicePathType (Node) = END_DEVICE_PATH_TYPE; \
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DevicePathSubType (Node) = END_ENTIRE_DEVICE_PATH_SUBTYPE; \
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SetDevicePathNodeLength ((Node), END_DEVICE_PATH_LENGTH); \
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}
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/**
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Returns the size of a device path in bytes.
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This function returns the size, in bytes, of the device path data structure specified by
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DevicePath including the end of device path node. If DevicePath is NULL, then 0 is returned.
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@param DevicePath A pointer to a device path data structure.
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@retval 0 If DevicePath is NULL.
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@retval Others The size of a device path in bytes.
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**/
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UINTN
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EFIAPI
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GetDevicePathSize (
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
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);
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/**
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Creates a new device path by appending a second device path to a first device path.
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This function allocates space for a new copy of the device path specified by DevicePath. If
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DevicePath is NULL, then NULL is returned. If the memory is successfully allocated, then the
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contents of DevicePath are copied to the newly allocated buffer, and a pointer to that buffer
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is returned. Otherwise, NULL is returned.
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The memory for the new device path is allocated from EFI boot services memory.
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It is the responsibility of the caller to free the memory allocated.
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@param DevicePath A pointer to a device path data structure.
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@retval NULL If DevicePath is NULL.
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@retval Others A pointer to the duplicated device path.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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DuplicateDevicePath (
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
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);
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/**
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Creates a new device path by appending a second device path to a first device path.
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This function creates a new device path by appending a copy of SecondDevicePath to a copy of
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FirstDevicePath in a newly allocated buffer. Only the end-of-device-path device node from
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SecondDevicePath is retained. The newly created device path is returned.
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If FirstDevicePath is NULL, then it is ignored, and a duplicate of SecondDevicePath is returned.
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If SecondDevicePath is NULL, then it is ignored, and a duplicate of FirstDevicePath is returned.
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If both FirstDevicePath and SecondDevicePath are NULL, then a copy of an end-of-device-path is
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returned.
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If there is not enough memory for the newly allocated buffer, then NULL is returned.
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The memory for the new device path is allocated from EFI boot services memory. It is the
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responsibility of the caller to free the memory allocated.
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@param FirstDevicePath A pointer to a device path data structure.
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@param SecondDevicePath A pointer to a device path data structure.
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@retval NULL If there is not enough memory for the newly allocated buffer.
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@retval Others A pointer to the new device path if success.
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Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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AppendDevicePath (
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IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath, OPTIONAL
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IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath OPTIONAL
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);
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/**
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Creates a new path by appending the device node to the device path.
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This function creates a new device path by appending a copy of the device node specified by
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DevicePathNode to a copy of the device path specified by DevicePath in an allocated buffer.
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The end-of-device-path device node is moved after the end of the appended device node.
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If DevicePathNode is NULL then a copy of DevicePath is returned.
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If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device path device
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node is returned.
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If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path device node
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is returned.
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If there is not enough memory to allocate space for the new device path, then NULL is returned.
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The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
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free the memory allocated.
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@param DevicePath A pointer to a device path data structure.
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@param DevicePathNode A pointer to a single device path node.
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@retval NULL If there is not enough memory for the new device path.
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@retval Others A pointer to the new device path if success.
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A copy of DevicePathNode followed by an end-of-device-path node
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if both FirstDevicePath and SecondDevicePath are NULL.
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A copy of an end-of-device-path node if both FirstDevicePath and SecondDevicePath are NULL.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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AppendDevicePathNode (
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode OPTIONAL
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);
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/**
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Creates a new device path by appending the specified device path instance to the specified device
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path.
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This function creates a new device path by appending a copy of the device path instance specified
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by DevicePathInstance to a copy of the device path secified by DevicePath in a allocated buffer.
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The end-of-device-path device node is moved after the end of the appended device path instance
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and a new end-of-device-path-instance node is inserted between.
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If DevicePath is NULL, then a copy if DevicePathInstance is returned.
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If DevicePathInstance is NULL, then NULL is returned.
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If there is not enough memory to allocate space for the new device path, then NULL is returned.
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The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
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free the memory allocated.
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@param DevicePath A pointer to a device path data structure.
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@param DevicePathInstance A pointer to a device path instance.
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@return A pointer to the new device path.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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AppendDevicePathInstance (
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathInstance OPTIONAL
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);
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/**
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Creates a copy of the current device path instance and returns a pointer to the next device path
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instance.
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This function creates a copy of the current device path instance. It also updates DevicePath to
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point to the next device path instance in the device path (or NULL if no more) and updates Size
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to hold the size of the device path instance copy.
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If DevicePath is NULL, then NULL is returned.
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If there is not enough memory to allocate space for the new device path, then NULL is returned.
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The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
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free the memory allocated.
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If Size is NULL, then ASSERT().
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@param DevicePath On input, this holds the pointer to the current device path
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instance. On output, this holds the pointer to the next device
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path instance or NULL if there are no more device path
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instances in the device path pointer to a device path data
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structure.
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@param Size On output, this holds the size of the device path instance, in
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bytes or zero, if DevicePath is NULL.
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@return A pointer to the current device path instance.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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GetNextDevicePathInstance (
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IN OUT EFI_DEVICE_PATH_PROTOCOL **DevicePath,
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OUT UINTN *Size
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);
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/**
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Creates a device node.
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This function creates a new device node in a newly allocated buffer of size NodeLength and
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initializes the device path node header with NodeType and NodeSubType. The new device path node
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is returned.
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If NodeLength is smaller than a device path header, then NULL is returned.
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If there is not enough memory to allocate space for the new device path, then NULL is returned.
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The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
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free the memory allocated.
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@param NodeType The device node type for the new device node.
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@param NodeSubType The device node sub-type for the new device node.
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@param NodeLength The length of the new device node.
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@return The new device path.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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CreateDeviceNode (
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IN UINT8 NodeType,
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IN UINT8 NodeSubType,
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IN UINT16 NodeLength
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);
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/**
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Determines if a device path is single or multi-instance.
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This function returns TRUE if the device path specified by DevicePath is multi-instance.
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Otherwise, FALSE is returned. If DevicePath is NULL, then FALSE is returned.
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@param DevicePath A pointer to a device path data structure.
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@retval TRUE DevicePath is multi-instance.
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@retval FALSE DevicePath is not multi-instance or DevicePath is NULL.
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**/
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BOOLEAN
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EFIAPI
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IsDevicePathMultiInstance (
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IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
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);
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/**
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Retrieves the device path protocol from a handle.
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This function returns the device path protocol from the handle specified by Handle. If Handle is
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NULL or Handle does not contain a device path protocol, then NULL is returned.
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@param Handle The handle from which to retrieve the device path protocol.
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@return The device path protocol from the handle specified by Handle.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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DevicePathFromHandle (
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IN EFI_HANDLE Handle
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);
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/**
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Allocates a device path for a file and appends it to an existing device path.
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If Device is a valid device handle that contains a device path protocol, then a device path for
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the file specified by FileName is allocated and appended to the device path associated with the
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handle Device. The allocated device path is returned. If Device is NULL or Device is a handle
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that does not support the device path protocol, then a device path containing a single device
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path node for the file specified by FileName is allocated and returned.
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The memory for the new device path is allocated from EFI boot services memory. It is the responsibility
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of the caller to free the memory allocated.
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If FileName is NULL, then ASSERT().
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If FileName is not aligned on a 16-bit boundary, then ASSERT().
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@param Device A pointer to a device handle. This parameter is optional and
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may be NULL.
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@param FileName A pointer to a Null-terminated Unicode string.
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@return The allocated device path.
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**/
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EFI_DEVICE_PATH_PROTOCOL *
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EFIAPI
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FileDevicePath (
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IN EFI_HANDLE Device, OPTIONAL
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IN CONST CHAR16 *FileName
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);
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#endif
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