#include "UefiDevicePathLib.h"

Functions
BOOLEAN EFIAPI	IsDevicePathValid (IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, IN UINTN MaxSize)

UINT8 EFIAPI	DevicePathType (IN CONST VOID *Node)

UINT8 EFIAPI	DevicePathSubType (IN CONST VOID *Node)

UINTN EFIAPI	DevicePathNodeLength (IN CONST VOID *Node)

EFI_DEVICE_PATH_PROTOCOL *EFIAPI	NextDevicePathNode (IN CONST VOID *Node)

BOOLEAN EFIAPI	IsDevicePathEndType (IN CONST VOID *Node)

BOOLEAN EFIAPI	IsDevicePathEnd (IN CONST VOID *Node)

BOOLEAN EFIAPI	IsDevicePathEndInstance (IN CONST VOID *Node)

UINT16 EFIAPI	SetDevicePathNodeLength (IN OUT VOID *Node, IN UINTN Length)

VOID EFIAPI	SetDevicePathEndNode (OUT VOID *Node)

UINTN EFIAPI	UefiDevicePathLibGetDevicePathSize (IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath)

EFI_DEVICE_PATH_PROTOCOL *EFIAPI	UefiDevicePathLibDuplicateDevicePath (IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath)

EFI_DEVICE_PATH_PROTOCOL *EFIAPI	UefiDevicePathLibAppendDevicePath (IN CONST EFI_DEVICE_PATH_PROTOCOL FirstDevicePath OPTIONAL, IN CONST EFI_DEVICE_PATH_PROTOCOL SecondDevicePath OPTIONAL)

EFI_DEVICE_PATH_PROTOCOL *EFIAPI	UefiDevicePathLibAppendDevicePathNode (IN CONST EFI_DEVICE_PATH_PROTOCOL DevicePath OPTIONAL, IN CONST EFI_DEVICE_PATH_PROTOCOL DevicePathNode OPTIONAL)

EFI_DEVICE_PATH_PROTOCOL *EFIAPI	UefiDevicePathLibAppendDevicePathInstance (IN CONST EFI_DEVICE_PATH_PROTOCOL DevicePath OPTIONAL, IN CONST EFI_DEVICE_PATH_PROTOCOL DevicePathInstance OPTIONAL)

EFI_DEVICE_PATH_PROTOCOL *EFIAPI	UefiDevicePathLibGetNextDevicePathInstance (IN OUT EFI_DEVICE_PATH_PROTOCOL *DevicePath, OUT UINTN Size)

EFI_DEVICE_PATH_PROTOCOL *EFIAPI	UefiDevicePathLibCreateDeviceNode (IN UINT8 NodeType, IN UINT8 NodeSubType, IN UINT16 NodeLength)

BOOLEAN EFIAPI	UefiDevicePathLibIsDevicePathMultiInstance (IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath)

EFI_DEVICE_PATH_PROTOCOL *EFIAPI	FileDevicePath (IN EFI_HANDLE Device OPTIONAL, IN CONST CHAR16 *FileName)

Variables
GLOBAL_REMOVE_IF_UNREFERENCED CONST EFI_DEVICE_PATH_PROTOCOL	mUefiDevicePathLibEndDevicePath

Detailed Description

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.
SPDX-License-Identifier: BSD-2-Clause-Patent

Definition in file DevicePathUtilities.c.

Function Documentation

◆ DevicePathNodeLength()

UINTN EFIAPI DevicePathNodeLength ( IN CONST VOID * Node )

Returns the 16-bit Length field of a device path node.

Returns the 16-bit Length field of the device path node specified by Node. Node is not required to be aligned on a 16-bit boundary, so it is recommended that a function such as ReadUnaligned16() be used to extract the contents of the Length field.

If Node is NULL, then ASSERT().

Parameters

Node	A pointer to a device path node data structure.

Returns: The 16-bit Length field of the device path node specified by Node.

Definition at line 172 of file DevicePathUtilities.c.

◆ DevicePathSubType()

UINT8 EFIAPI DevicePathSubType ( IN CONST VOID * Node )

Returns the SubType field of a device path node.

Returns the SubType field of the device path node specified by Node.

If Node is NULL, then ASSERT().

Parameters

Node	A pointer to a device path node data structure.

Returns: The SubType field of the device path node specified by Node.

Definition at line 147 of file DevicePathUtilities.c.

◆ DevicePathType()

UINT8 EFIAPI DevicePathType ( IN CONST VOID * Node )

Returns the Type field of a device path node.

Returns the Type field of the device path node specified by Node.

If Node is NULL, then ASSERT().

Parameters

Node	A pointer to a device path node data structure.

Returns: The Type field of the device path node specified by Node.

Definition at line 125 of file DevicePathUtilities.c.

◆ FileDevicePath()

EFI_DEVICE_PATH_PROTOCOL *EFIAPI FileDevicePath	(	IN EFI_HANDLE Device	OPTIONAL,
		IN CONST CHAR16 *	FileName
	)

Allocates a device path for a file and appends it to an existing device path.

If Device is a valid device handle that contains a device path protocol, then a device path for the file specified by FileName is allocated and appended to the device path associated with the handle Device. The allocated device path is returned. If Device is NULL or Device is a handle that does not support the device path protocol, then a device path containing a single device path node for the file specified by FileName is allocated and returned. The memory for the new device path is allocated from EFI boot services memory. It is the responsibility of the caller to free the memory allocated.

If FileName is NULL, then ASSERT(). If FileName is not aligned on a 16-bit boundary, then ASSERT().

Parameters

Device	A pointer to a device handle. This parameter is optional and may be NULL.
FileName	A pointer to a Null-terminated Unicode string.

Returns: The allocated device path.

Definition at line 833 of file DevicePathUtilities.c.

◆ IsDevicePathEnd()

BOOLEAN EFIAPI IsDevicePathEnd ( IN CONST VOID * Node )

Determines if a device path node is an end node of an entire device path.

Determines if a device path node specified by Node is an end node of an entire device path. If Node represents the end of an entire device path, then TRUE is returned. Otherwise, FALSE is returned.

If Node is NULL, then ASSERT().

Parameters

Node	A pointer to a device path node data structure.

Return values

TRUE	The device path node specified by Node is the end of an entire device path.
FALSE	The device path node specified by Node is not the end of an entire device path.

Definition at line 253 of file DevicePathUtilities.c.

◆ IsDevicePathEndInstance()

BOOLEAN EFIAPI IsDevicePathEndInstance ( IN CONST VOID * Node )

Determines if a device path node is an end node of a device path instance.

Determines if a device path node specified by Node is an end node of a device path instance. If Node represents the end of a device path instance, then TRUE is returned. Otherwise, FALSE is returned.

If Node is NULL, then ASSERT().

Parameters

Node	A pointer to a device path node data structure.

Return values

TRUE	The device path node specified by Node is the end of a device path instance.
FALSE	The device path node specified by Node is not the end of a device path instance.

Definition at line 280 of file DevicePathUtilities.c.

◆ IsDevicePathEndType()

BOOLEAN EFIAPI IsDevicePathEndType ( IN CONST VOID * Node )

Determines if a device path node is an end node of a device path. This includes nodes that are the end of a device path instance and nodes that are the end of an entire device path.

Determines if the device path node specified by Node is an end node of a device path. This includes nodes that are the end of a device path instance and nodes that are the end of an entire device path. If Node represents an end node of a device path, then TRUE is returned. Otherwise, FALSE is returned.

If Node is NULL, then ASSERT().

Parameters

Node	A pointer to a device path node data structure.

Return values

TRUE	The device path node specified by Node is an end node of a device path.
FALSE	The device path node specified by Node is not an end node of a device path.

Definition at line 226 of file DevicePathUtilities.c.

◆ IsDevicePathValid()

BOOLEAN EFIAPI IsDevicePathValid	(	IN CONST EFI_DEVICE_PATH_PROTOCOL *	DevicePath,
		IN UINTN	MaxSize
	)

Determine whether a given device path is valid.

Parameters

DevicePath	A pointer to a device path data structure.
MaxSize	The maximum size of the device path data structure.

Return values

TRUE	DevicePath is valid.
FALSE	DevicePath is NULL.
FALSE	Maxsize is less than sizeof(EFI_DEVICE_PATH_PROTOCOL).
FALSE	The length of any node node in the DevicePath is less than sizeof (EFI_DEVICE_PATH_PROTOCOL).
FALSE	If MaxSize is not zero, the size of the DevicePath exceeds MaxSize.
FALSE	If PcdMaximumDevicePathNodeCount is not zero, the node count of the DevicePath exceeds PcdMaximumDevicePathNodeCount.

Definition at line 48 of file DevicePathUtilities.c.

◆ NextDevicePathNode()

EFI_DEVICE_PATH_PROTOCOL *EFIAPI NextDevicePathNode ( IN CONST VOID * Node )

Returns a pointer to the next node in a device path.

Returns a pointer to the device path node that follows the device path node specified by Node.

If Node is NULL, then ASSERT().

Parameters

Node	A pointer to a device path node data structure.

Returns: a pointer to the device path node that follows the device path node specified by Node.

Definition at line 196 of file DevicePathUtilities.c.

◆ SetDevicePathEndNode()

VOID EFIAPI SetDevicePathEndNode ( OUT VOID * Node )

Fills in all the fields of a device path node that is the end of an entire device path.

Fills in all the fields of a device path node specified by Node so Node represents the end of an entire device path. The Type field of Node is set to END_DEVICE_PATH_TYPE, the SubType field of Node is set to END_ENTIRE_DEVICE_PATH_SUBTYPE, and the Length field of Node is set to END_DEVICE_PATH_LENGTH. Node is not required to be aligned on a 16-bit boundary, so it is recommended that a function such as WriteUnaligned16() be used to set the contents of the Length field.

If Node is NULL, then ASSERT().

Parameters

Node	A pointer to a device path node data structure.

Definition at line 336 of file DevicePathUtilities.c.

◆ SetDevicePathNodeLength()

UINT16 EFIAPI SetDevicePathNodeLength	(	IN OUT VOID *	Node,
		IN UINTN	Length
	)

Sets the length, in bytes, of a device path node.

Sets the length of the device path node specified by Node to the value specified by NodeLength. NodeLength is returned. Node is not required to be aligned on a 16-bit boundary, so it is recommended that a function such as WriteUnaligned16() be used to set the contents of the Length field.

If Node is NULL, then ASSERT(). If NodeLength >= SIZE_64KB, then ASSERT(). If NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL), then ASSERT().

Parameters

Node	A pointer to a device path node data structure.
Length	The length, in bytes, of the device path node.

Returns: Length

Definition at line 308 of file DevicePathUtilities.c.

◆ UefiDevicePathLibAppendDevicePath()

EFI_DEVICE_PATH_PROTOCOL *EFIAPI UefiDevicePathLibAppendDevicePath	(	IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath	OPTIONAL,
		IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath	OPTIONAL
	)

Creates a new device path by appending a second device path to a first device path.

This function creates a new device path by appending a copy of SecondDevicePath to a copy of FirstDevicePath in a newly allocated buffer. Only the end-of-device-path device node from SecondDevicePath is retained. The newly created device path is returned. If FirstDevicePath is NULL, then it is ignored, and a duplicate of SecondDevicePath is returned. If SecondDevicePath is NULL, then it is ignored, and a duplicate of FirstDevicePath is returned. If both FirstDevicePath and SecondDevicePath are NULL, then a copy of an end-of-device-path is returned.

If there is not enough memory for the newly allocated buffer, then NULL is returned. The memory for the new device path is allocated from EFI boot services memory. It is the responsibility of the caller to free the memory allocated.

Parameters

FirstDevicePath	A pointer to a device path data structure.
SecondDevicePath	A pointer to a device path data structure.

Return values

NULL	If there is not enough memory for the newly allocated buffer.
NULL	If FirstDevicePath or SecondDevicePath is invalid.
Others	A pointer to the new device path if success. Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.

Definition at line 452 of file DevicePathUtilities.c.

◆ UefiDevicePathLibAppendDevicePathInstance()

EFI_DEVICE_PATH_PROTOCOL *EFIAPI UefiDevicePathLibAppendDevicePathInstance	(	IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath	OPTIONAL,
		IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathInstance	OPTIONAL
	)

Creates a new device path by appending the specified device path instance to the specified device path.

This function creates a new device path by appending a copy of the device path instance specified by DevicePathInstance to a copy of the device path specified by DevicePath in a allocated buffer. The end-of-device-path device node is moved after the end of the appended device path instance and a new end-of-device-path-instance node is inserted between. If DevicePath is NULL, then a copy if DevicePathInstance is returned. If DevicePathInstance is NULL, then NULL is returned. If DevicePath or DevicePathInstance is invalid, then NULL is returned. If there is not enough memory to allocate space for the new device path, then NULL is returned. The memory is allocated from EFI boot services memory. It is the responsibility of the caller to free the memory allocated.

Parameters

DevicePath	A pointer to a device path data structure.
DevicePathInstance	A pointer to a device path instance.

Returns: A pointer to the new device path.

Definition at line 596 of file DevicePathUtilities.c.

◆ UefiDevicePathLibAppendDevicePathNode()

EFI_DEVICE_PATH_PROTOCOL *EFIAPI UefiDevicePathLibAppendDevicePathNode	(	IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath	OPTIONAL,
		IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode	OPTIONAL
	)

Creates a new path by appending the device node to the device path.

This function creates a new device path by appending a copy of the device node specified by DevicePathNode to a copy of the device path specified by DevicePath in an allocated buffer. The end-of-device-path device node is moved after the end of the appended device node. If DevicePathNode is NULL then a copy of DevicePath is returned. If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device path device node is returned. If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path device node is returned. If there is not enough memory to allocate space for the new device path, then NULL is returned. The memory is allocated from EFI boot services memory. It is the responsibility of the caller to free the memory allocated.

Parameters

DevicePath	A pointer to a device path data structure.
DevicePathNode	A pointer to a single device path node.

Return values

NULL	If there is not enough memory for the new device path.
Others	A pointer to the new device path if success. A copy of DevicePathNode followed by an end-of-device-path node if both FirstDevicePath and SecondDevicePath are NULL. A copy of an end-of-device-path node if both FirstDevicePath and SecondDevicePath are NULL.

Definition at line 531 of file DevicePathUtilities.c.

◆ UefiDevicePathLibCreateDeviceNode()

EFI_DEVICE_PATH_PROTOCOL *EFIAPI UefiDevicePathLibCreateDeviceNode	(	IN UINT8	NodeType,
		IN UINT8	NodeSubType,
		IN UINT16	NodeLength
	)

Creates a device node.

This function creates a new device node in a newly allocated buffer of size NodeLength and initializes the device path node header with NodeType and NodeSubType. The new device path node is returned. If NodeLength is smaller than a device path header, then NULL is returned. If there is not enough memory to allocate space for the new device path, then NULL is returned. The memory is allocated from EFI boot services memory. It is the responsibility of the caller to free the memory allocated.

Parameters

NodeType	The device node type for the new device node.
NodeSubType	The device node sub-type for the new device node.
NodeLength	The length of the new device node.

Returns: The new device path.

Definition at line 742 of file DevicePathUtilities.c.

◆ UefiDevicePathLibDuplicateDevicePath()

EFI_DEVICE_PATH_PROTOCOL *EFIAPI UefiDevicePathLibDuplicateDevicePath ( IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePath )

Creates a new copy of an existing device path.

This function allocates space for a new copy of the device path specified by DevicePath. If DevicePath is NULL, then NULL is returned. If the memory is successfully allocated, then the contents of DevicePath are copied to the newly allocated buffer, and a pointer to that buffer is returned. Otherwise, NULL is returned. The memory for the new device path is allocated from EFI boot services memory. It is the responsibility of the caller to free the memory allocated.

Parameters

DevicePath A pointer to a device path data structure.

Return values

NULL	DevicePath is NULL or invalid.
Others	A pointer to the duplicated device path.

Definition at line 405 of file DevicePathUtilities.c.

◆ UefiDevicePathLibGetDevicePathSize()

UINTN EFIAPI UefiDevicePathLibGetDevicePathSize ( IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePath )

Returns the size of a device path in bytes.

This function returns the size, in bytes, of the device path data structure specified by DevicePath including the end of device path node. If DevicePath is NULL or invalid, then 0 is returned.

Parameters

DevicePath A pointer to a device path data structure.

Return values

0	If DevicePath is NULL or invalid.
Others	The size of a device path in bytes.

Definition at line 359 of file DevicePathUtilities.c.

◆ UefiDevicePathLibGetNextDevicePathInstance()

EFI_DEVICE_PATH_PROTOCOL *EFIAPI UefiDevicePathLibGetNextDevicePathInstance	(	IN OUT EFI_DEVICE_PATH_PROTOCOL **	DevicePath,
		OUT UINTN *	Size
	)

Creates a copy of the current device path instance and returns a pointer to the next device path instance.

This function creates a copy of the current device path instance. It also updates DevicePath to point to the next device path instance in the device path (or NULL if no more) and updates Size to hold the size of the device path instance copy. If DevicePath is NULL, then NULL is returned. If DevicePath points to a invalid device path, then NULL is returned. If there is not enough memory to allocate space for the new device path, then NULL is returned. The memory is allocated from EFI boot services memory. It is the responsibility of the caller to free the memory allocated. If Size is NULL, then ASSERT().

Parameters

DevicePath	On input, this holds the pointer to the current device path instance. On output, this holds the pointer to the next device path instance or NULL if there are no more device path instances in the device path pointer to a device path data structure.
Size	On output, this holds the size of the device path instance, in bytes or zero, if DevicePath is NULL.

Returns: A pointer to the current device path instance.

Definition at line 667 of file DevicePathUtilities.c.

◆ UefiDevicePathLibIsDevicePathMultiInstance()

BOOLEAN EFIAPI UefiDevicePathLibIsDevicePathMultiInstance ( IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePath )

Determines if a device path is single or multi-instance.

This function returns TRUE if the device path specified by DevicePath is multi-instance. Otherwise, FALSE is returned. If DevicePath is NULL or invalid, then FALSE is returned.

Parameters

DevicePath A pointer to a device path data structure.

Return values

TRUE	DevicePath is multi-instance.
FALSE	DevicePath is not multi-instance, or DevicePath is NULL or invalid.

Definition at line 784 of file DevicePathUtilities.c.

Variable Documentation

◆ mUefiDevicePathLibEndDevicePath

GLOBAL_REMOVE_IF_UNREFERENCED CONST EFI_DEVICE_PATH_PROTOCOL mUefiDevicePathLibEndDevicePath

Initial value:

= {
  END_DEVICE_PATH_TYPE,
  END_ENTIRE_DEVICE_PATH_SUBTYPE,
  {
    END_DEVICE_PATH_LENGTH,
    0
  }
}

Definition at line 21 of file DevicePathUtilities.c.

Functions

Variables

Detailed Description

Function Documentation

◆ DevicePathNodeLength()

◆ DevicePathSubType()

◆ DevicePathType()

◆ FileDevicePath()

◆ IsDevicePathEnd()

◆ IsDevicePathEndInstance()

◆ IsDevicePathEndType()

◆ IsDevicePathValid()

◆ NextDevicePathNode()

◆ SetDevicePathEndNode()

◆ SetDevicePathNodeLength()

◆ UefiDevicePathLibAppendDevicePath()

◆ UefiDevicePathLibAppendDevicePathInstance()

◆ UefiDevicePathLibAppendDevicePathNode()

◆ UefiDevicePathLibCreateDeviceNode()

◆ UefiDevicePathLibDuplicateDevicePath()

◆ UefiDevicePathLibGetDevicePathSize()

◆ UefiDevicePathLibGetNextDevicePathInstance()

◆ UefiDevicePathLibIsDevicePathMultiInstance()

Variable Documentation

◆ mUefiDevicePathLibEndDevicePath