2 Provides library functions to construct and parse UEFI Device Paths.
4 This library provides defines, macros, and functions to help create and parse
5 EFI_DEVICE_PATH_PROTOCOL structures.
7 Copyright (c) 2006 - 2009, Intel Corporation<BR>
8 All rights reserved. This program and the accompanying materials
9 are licensed and made available under the terms and conditions of the BSD License
10 which accompanies this distribution. The full text of the license may be found at
11 http://opensource.org/licenses/bsd-license.php
13 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
14 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
18 #ifndef __DEVICE_PATH_LIB_H__
19 #define __DEVICE_PATH_LIB_H__
21 #define END_DEVICE_PATH_LENGTH (sizeof (EFI_DEVICE_PATH_PROTOCOL))
24 Returns the Type field of a device path node.
26 Returns the Type field of the device path node specified by Node.
28 If Node is NULL, then ASSERT().
30 @param Node A pointer to a device path node data structure.
32 @return The Type field of the device path node specified by Node.
42 Returns the SubType field of a device path node.
44 Returns the SubType field of the device path node specified by Node.
46 If Node is NULL, then ASSERT().
48 @param Node A pointer to a device path node data structure.
50 @return The SubType field of the device path node specified by Node.
60 Returns the 16-bit Length field of a device path node.
62 Returns the 16-bit Length field of the device path node specified by Node.
63 Node is not required to be aligned on a 16-bit boundary, so it is recommended
64 that a function such as ReadUnaligned16() be used to extract the contents of
67 If Node is NULL, then ASSERT().
69 @param Node A pointer to a device path node data structure.
71 @return The 16-bit Length field of the device path node specified by Node.
76 DevicePathNodeLength (
81 Returns a pointer to the next node in a device path.
83 Returns a pointer to the device path node that follows the device path node specified by Node.
85 If Node is NULL, then ASSERT().
87 @param Node A pointer to a device path node data structure.
89 @return a pointer to the device path node that follows the device path node specified by Node.
92 EFI_DEVICE_PATH_PROTOCOL
*
99 Determines if a device path node is an end node of a device path.
100 This includes nodes that are the end of a device path instance and nodes that are the end of an entire device path.
102 Determines if the device path node specified by Node is an end node of a device path.
103 This includes nodes that are the end of a device path instance and nodes that are the
104 end of an entire device path. If Node represents an end node of a device path,
105 then TRUE is returned. Otherwise, FALSE is returned.
107 If Node is NULL, then ASSERT().
109 @param Node A pointer to a device path node data structure.
111 @retval TRUE The device path node specified by Node is an end node of a device path.
112 @retval FALSE The device path node specified by Node is not an end node of a device path.
117 IsDevicePathEndType (
122 Determines if a device path node is an end node of an entire device path.
124 Determines if a device path node specified by Node is an end node of an entire device path.
125 If Node represents the end of an entire device path, then TRUE is returned. Otherwise, FALSE is returned.
127 If Node is NULL, then ASSERT().
129 @param Node A pointer to a device path node data structure.
131 @retval TRUE The device path node specified by Node is the end of an entire device path.
132 @retval FALSE The device path node specified by Node is not the end of an entire device path.
142 Determines if a device path node is an end node of a device path instance.
144 Determines if a device path node specified by Node is an end node of a device path instance.
145 If Node represents the end of a device path instance, then TRUE is returned. Otherwise, FALSE is returned.
147 If Node is NULL, then ASSERT().
149 @param Node A pointer to a device path node data structure.
151 @retval TRUE The device path node specified by Node is the end of a device path instance.
152 @retval FALSE The device path node specified by Node is not the end of a device path instance.
157 IsDevicePathEndInstance (
162 Sets the length, in bytes, of a device path node.
164 Sets the length of the device path node specified by Node to the value specified
165 by NodeLength. NodeLength is returned. Node is not required to be aligned on
166 a 16-bit boundary, so it is recommended that a function such as WriteUnaligned16()
167 be used to set the contents of the Length field.
169 If Node is NULL, then ASSERT().
170 If NodeLength >= 0x10000, then ASSERT().
172 @param Node A pointer to a device path node data structure.
173 @param Length The length, in bytes, of the device path node.
180 SetDevicePathNodeLength (
186 Fills in all the fields of a device path node that is the end of an entire device path.
188 Fills in all the fields of a device path node specified by Node so Node represents
189 the end of an entire device path. The Type field of Node is set to
190 END_DEVICE_PATH_TYPE, the SubType field of Node is set to
191 END_ENTIRE_DEVICE_PATH_SUBTYPE, and the Length field of Node is set to
192 END_DEVICE_PATH_LENGTH. Node is not required to be aligned on a 16-bit boundary,
193 so it is recommended that a function such as WriteUnaligned16() be used to set
194 the contents of the Length field.
196 If Node is NULL, then ASSERT().
198 @param Node A pointer to a device path node data structure.
203 SetDevicePathEndNode (
208 Returns the size of a device path in bytes.
210 This function returns the size, in bytes, of the device path data structure specified by
211 DevicePath including the end of device path node. If DevicePath is NULL, then 0 is returned.
213 @param DevicePath A pointer to a device path data structure.
215 @retval 0 If DevicePath is NULL.
216 @retval Others The size of a device path in bytes.
222 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
226 Creates a new copy of an existing device path.
228 This function allocates space for a new copy of the device path specified by DevicePath. If
229 DevicePath is NULL, then NULL is returned. If the memory is successfully allocated, then the
230 contents of DevicePath are copied to the newly allocated buffer, and a pointer to that buffer
231 is returned. Otherwise, NULL is returned.
232 The memory for the new device path is allocated from EFI boot services memory.
233 It is the responsibility of the caller to free the memory allocated.
235 @param DevicePath A pointer to a device path data structure.
237 @retval NULL If DevicePath is NULL.
238 @retval Others A pointer to the duplicated device path.
241 EFI_DEVICE_PATH_PROTOCOL
*
243 DuplicateDevicePath (
244 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
248 Creates a new device path by appending a second device path to a first device path.
250 This function creates a new device path by appending a copy of SecondDevicePath to a copy of
251 FirstDevicePath in a newly allocated buffer. Only the end-of-device-path device node from
252 SecondDevicePath is retained. The newly created device path is returned.
253 If FirstDevicePath is NULL, then it is ignored, and a duplicate of SecondDevicePath is returned.
254 If SecondDevicePath is NULL, then it is ignored, and a duplicate of FirstDevicePath is returned.
255 If both FirstDevicePath and SecondDevicePath are NULL, then a copy of an end-of-device-path is
257 If there is not enough memory for the newly allocated buffer, then NULL is returned.
258 The memory for the new device path is allocated from EFI boot services memory. It is the
259 responsibility of the caller to free the memory allocated.
261 @param FirstDevicePath A pointer to a device path data structure.
262 @param SecondDevicePath A pointer to a device path data structure.
264 @retval NULL If there is not enough memory for the newly allocated buffer.
265 @retval Others A pointer to the new device path if success.
266 Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.
269 EFI_DEVICE_PATH_PROTOCOL
*
272 IN CONST EFI_DEVICE_PATH_PROTOCOL
*FirstDevicePath
, OPTIONAL
273 IN CONST EFI_DEVICE_PATH_PROTOCOL
*SecondDevicePath OPTIONAL
277 Creates a new path by appending the device node to the device path.
279 This function creates a new device path by appending a copy of the device node specified by
280 DevicePathNode to a copy of the device path specified by DevicePath in an allocated buffer.
281 The end-of-device-path device node is moved after the end of the appended device node.
282 If DevicePathNode is NULL then a copy of DevicePath is returned.
283 If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device path device
285 If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path device node
287 If there is not enough memory to allocate space for the new device path, then NULL is returned.
288 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
289 free the memory allocated.
291 @param DevicePath A pointer to a device path data structure.
292 @param DevicePathNode A pointer to a single device path node.
294 @retval NULL If there is not enough memory for the new device path.
295 @retval Others A pointer to the new device path if success.
296 A copy of DevicePathNode followed by an end-of-device-path node
297 if both FirstDevicePath and SecondDevicePath are NULL.
298 A copy of an end-of-device-path node if both FirstDevicePath and SecondDevicePath are NULL.
301 EFI_DEVICE_PATH_PROTOCOL
*
303 AppendDevicePathNode (
304 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
, OPTIONAL
305 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePathNode OPTIONAL
309 Creates a new device path by appending the specified device path instance to the specified device
312 This function creates a new device path by appending a copy of the device path instance specified
313 by DevicePathInstance to a copy of the device path secified by DevicePath in a allocated buffer.
314 The end-of-device-path device node is moved after the end of the appended device path instance
315 and a new end-of-device-path-instance node is inserted between.
316 If DevicePath is NULL, then a copy if DevicePathInstance is returned.
317 If DevicePathInstance is NULL, then NULL is returned.
318 If there is not enough memory to allocate space for the new device path, then NULL is returned.
319 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
320 free the memory allocated.
322 @param DevicePath A pointer to a device path data structure.
323 @param DevicePathInstance A pointer to a device path instance.
325 @return A pointer to the new device path.
328 EFI_DEVICE_PATH_PROTOCOL
*
330 AppendDevicePathInstance (
331 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
, OPTIONAL
332 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePathInstance OPTIONAL
336 Creates a copy of the current device path instance and returns a pointer to the next device path
339 This function creates a copy of the current device path instance. It also updates DevicePath to
340 point to the next device path instance in the device path (or NULL if no more) and updates Size
341 to hold the size of the device path instance copy.
342 If DevicePath is NULL, then NULL is returned.
343 If there is not enough memory to allocate space for the new device path, then NULL is returned.
344 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
345 free the memory allocated.
346 If Size is NULL, then ASSERT().
348 @param DevicePath On input, this holds the pointer to the current device path
349 instance. On output, this holds the pointer to the next device
350 path instance or NULL if there are no more device path
351 instances in the device path pointer to a device path data
353 @param Size On output, this holds the size of the device path instance, in
354 bytes or zero, if DevicePath is NULL.
356 @return A pointer to the current device path instance.
359 EFI_DEVICE_PATH_PROTOCOL
*
361 GetNextDevicePathInstance (
362 IN OUT EFI_DEVICE_PATH_PROTOCOL
**DevicePath
,
367 Creates a device node.
369 This function creates a new device node in a newly allocated buffer of size NodeLength and
370 initializes the device path node header with NodeType and NodeSubType. The new device path node
372 If NodeLength is smaller than a device path header, then NULL is returned.
373 If there is not enough memory to allocate space for the new device path, then NULL is returned.
374 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
375 free the memory allocated.
377 @param NodeType The device node type for the new device node.
378 @param NodeSubType The device node sub-type for the new device node.
379 @param NodeLength The length of the new device node.
381 @return The new device path.
384 EFI_DEVICE_PATH_PROTOCOL
*
388 IN UINT8 NodeSubType
,
393 Determines if a device path is single or multi-instance.
395 This function returns TRUE if the device path specified by DevicePath is multi-instance.
396 Otherwise, FALSE is returned. If DevicePath is NULL, then FALSE is returned.
398 @param DevicePath A pointer to a device path data structure.
400 @retval TRUE DevicePath is multi-instance.
401 @retval FALSE DevicePath is not multi-instance or DevicePath is NULL.
406 IsDevicePathMultiInstance (
407 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
411 Retrieves the device path protocol from a handle.
413 This function returns the device path protocol from the handle specified by Handle. If Handle is
414 NULL or Handle does not contain a device path protocol, then NULL is returned.
416 @param Handle The handle from which to retrieve the device path protocol.
418 @return The device path protocol from the handle specified by Handle.
421 EFI_DEVICE_PATH_PROTOCOL
*
423 DevicePathFromHandle (
428 Allocates a device path for a file and appends it to an existing device path.
430 If Device is a valid device handle that contains a device path protocol, then a device path for
431 the file specified by FileName is allocated and appended to the device path associated with the
432 handle Device. The allocated device path is returned. If Device is NULL or Device is a handle
433 that does not support the device path protocol, then a device path containing a single device
434 path node for the file specified by FileName is allocated and returned.
435 The memory for the new device path is allocated from EFI boot services memory. It is the responsibility
436 of the caller to free the memory allocated.
438 If FileName is NULL, then ASSERT().
439 If FileName is not aligned on a 16-bit boundary, then ASSERT().
441 @param Device A pointer to a device handle. This parameter is optional and
443 @param FileName A pointer to a Null-terminated Unicode string.
445 @return The allocated device path.
448 EFI_DEVICE_PATH_PROTOCOL
*
451 IN EFI_HANDLE Device
, OPTIONAL
452 IN CONST CHAR16
*FileName