MdePkg/Library/UefiDevicePathLib/UefiDevicePathLib.c File Reference


Functions

UINTN EFIAPI GetDevicePathSize (IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath)
EFI_DEVICE_PATH_PROTOCOL *EFIAPI DuplicateDevicePath (IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath)
EFI_DEVICE_PATH_PROTOCOL *EFIAPI AppendDevicePath (IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath, IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath)
EFI_DEVICE_PATH_PROTOCOL *EFIAPI AppendDevicePathNode (IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode)
EFI_DEVICE_PATH_PROTOCOL *EFIAPI AppendDevicePathInstance (IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathInstance)
EFI_DEVICE_PATH_PROTOCOL *EFIAPI GetNextDevicePathInstance (IN OUT EFI_DEVICE_PATH_PROTOCOL **DevicePath, OUT UINTN *Size)
EFI_DEVICE_PATH_PROTOCOL *EFIAPI CreateDeviceNode (IN UINT8 NodeType, IN UINT8 NodeSubType, IN UINT16 NodeLength)
BOOLEAN EFIAPI IsDevicePathMultiInstance (IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath)
CHAR16 *EFIAPI ConvertDeviceNodeToText (IN CONST EFI_DEVICE_PATH_PROTOCOL *DeviceNode, IN BOOLEAN DisplayOnly, IN BOOLEAN AllowShortcuts)
CHAR16 *EFIAPI ConvertDevicePathToText (IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, IN BOOLEAN DisplayOnly, IN BOOLEAN AllowShortcuts)
EFI_DEVICE_PATH_PROTOCOL *EFIAPI ConvertTextToDeviceNode (IN CONST CHAR16 *TextDeviceNode)
EFI_DEVICE_PATH_PROTOCOL *EFIAPI ConvertTextToDevicePath (IN CONST CHAR16 *TextDevicePath)

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 - 2013, 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.


Function Documentation

EFI_DEVICE_PATH_PROTOCOL* EFIAPI AppendDevicePath ( IN CONST EFI_DEVICE_PATH_PROTOCOL FirstDevicePath,
IN CONST EFI_DEVICE_PATH_PROTOCOL SecondDevicePath 
)

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.

References UefiDevicePathLibAppendDevicePath().

EFI_DEVICE_PATH_PROTOCOL* EFIAPI AppendDevicePathInstance ( IN CONST EFI_DEVICE_PATH_PROTOCOL DevicePath,
IN CONST EFI_DEVICE_PATH_PROTOCOL DevicePathInstance 
)

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.

References UefiDevicePathLibAppendDevicePathInstance().

EFI_DEVICE_PATH_PROTOCOL* EFIAPI AppendDevicePathNode ( IN CONST EFI_DEVICE_PATH_PROTOCOL DevicePath,
IN CONST EFI_DEVICE_PATH_PROTOCOL DevicePathNode 
)

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.

References UefiDevicePathLibAppendDevicePathNode().

CHAR16* EFIAPI ConvertDeviceNodeToText ( IN CONST EFI_DEVICE_PATH_PROTOCOL DeviceNode,
IN BOOLEAN  DisplayOnly,
IN BOOLEAN  AllowShortcuts 
)

Converts a device node to its string representation.

Parameters:
DeviceNode A Pointer to the device node to be converted.
DisplayOnly If DisplayOnly is TRUE, then the shorter text representation of the display node is used, where applicable. If DisplayOnly is FALSE, then the longer text representation of the display node is used.
AllowShortcuts If AllowShortcuts is TRUE, then the shortcut forms of text representation for a device node can be used, where applicable.
Returns:
A pointer to the allocated text representation of the device node or NULL if DeviceNode is NULL or there was insufficient memory.

References UefiDevicePathLibConvertDeviceNodeToText().

CHAR16* EFIAPI ConvertDevicePathToText ( IN CONST EFI_DEVICE_PATH_PROTOCOL DevicePath,
IN BOOLEAN  DisplayOnly,
IN BOOLEAN  AllowShortcuts 
)

Converts a device path to its text representation.

Parameters:
DevicePath A Pointer to the device to be converted.
DisplayOnly If DisplayOnly is TRUE, then the shorter text representation of the display node is used, where applicable. If DisplayOnly is FALSE, then the longer text representation of the display node is used.
AllowShortcuts If AllowShortcuts is TRUE, then the shortcut forms of text representation for a device node can be used, where applicable.
Returns:
A pointer to the allocated text representation of the device path or NULL if DeviceNode is NULL or there was insufficient memory.

References UefiDevicePathLibConvertDevicePathToText().

EFI_DEVICE_PATH_PROTOCOL* EFIAPI ConvertTextToDeviceNode ( IN CONST CHAR16 TextDeviceNode  ) 

Convert text to the binary representation of a device node.

Parameters:
TextDeviceNode TextDeviceNode points to the text representation of a device node. Conversion starts with the first character and continues until the first non-device node character.
Returns:
A pointer to the EFI device node or NULL if TextDeviceNode is NULL or there was insufficient memory or text unsupported.

References UefiDevicePathLibConvertTextToDeviceNode().

EFI_DEVICE_PATH_PROTOCOL* EFIAPI ConvertTextToDevicePath ( IN CONST CHAR16 TextDevicePath  ) 

Convert text to the binary representation of a device path.

Parameters:
TextDevicePath TextDevicePath points to the text representation of a device path. Conversion starts with the first character and continues until the first non-device node character.
Returns:
A pointer to the allocated device path or NULL if TextDeviceNode is NULL or there was insufficient memory.

References UefiDevicePathLibConvertTextToDevicePath().

EFI_DEVICE_PATH_PROTOCOL* EFIAPI CreateDeviceNode ( 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.

References UefiDevicePathLibCreateDeviceNode().

EFI_DEVICE_PATH_PROTOCOL* EFIAPI DuplicateDevicePath ( 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.

References UefiDevicePathLibDuplicateDevicePath().

UINTN EFIAPI GetDevicePathSize ( 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.

References UefiDevicePathLibGetDevicePathSize().

EFI_DEVICE_PATH_PROTOCOL* EFIAPI GetNextDevicePathInstance ( 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.

References UefiDevicePathLibGetNextDevicePathInstance().

BOOLEAN EFIAPI IsDevicePathMultiInstance ( 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.

References UefiDevicePathLibIsDevicePathMultiInstance().


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