2 Library instance that implement UEFI Device Path Library class based on protocol
3 gEfiDevicePathUtilitiesProtocolGuid.
5 Copyright (c) 2006 - 2008, Intel Corporation<BR>
6 All rights reserved. This program and the accompanying materials
7 are licensed and made available under the terms and conditions of the BSD License
8 which accompanies this distribution. The full text of the license may be found at
9 http://opensource.org/licenses/bsd-license.php
11 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
12 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
19 #include <Protocol/DevicePathUtilities.h>
20 #include <Protocol/DevicePath.h>
22 #include <Library/DevicePathLib.h>
23 #include <Library/DebugLib.h>
24 #include <Library/BaseLib.h>
25 #include <Library/MemoryAllocationLib.h>
26 #include <Library/BaseMemoryLib.h>
27 #include <Library/UefiBootServicesTableLib.h>
29 EFI_DEVICE_PATH_UTILITIES_PROTOCOL
*mDevicePathUtilities
= NULL
;
32 // Template for an end-of-device path node.
34 GLOBAL_REMOVE_IF_UNREFERENCED CONST EFI_DEVICE_PATH_PROTOCOL mUefiDevicePathLibEndDevicePath
= {
36 END_ENTIRE_DEVICE_PATH_SUBTYPE
,
38 END_DEVICE_PATH_LENGTH
,
44 The constructor function caches the pointer to DevicePathUtilites protocol.
46 The constructor function locates DevicePathUtilities protocol from protocol database.
47 It will ASSERT() if that operation fails and it will always return EFI_SUCCESS.
49 @param ImageHandle The firmware allocated handle for the EFI image.
50 @param SystemTable A pointer to the EFI System Table.
52 @retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.
57 DevicePathLibConstructor (
58 IN EFI_HANDLE ImageHandle
,
59 IN EFI_SYSTEM_TABLE
*SystemTable
64 Status
= gBS
->LocateProtocol (
65 &gEfiDevicePathUtilitiesProtocolGuid
,
67 (VOID
**) &mDevicePathUtilities
69 ASSERT_EFI_ERROR (Status
);
70 ASSERT (mDevicePathUtilities
!= NULL
);
76 Returns the Type field of a device path node.
78 Returns the Type field of the device path node specified by Node.
80 If Node is NULL, then ASSERT().
82 @param Node A pointer to a device path node data structure.
84 @return The Type field of the device path node specified by Node.
92 ASSERT (Node
!= NULL
);
93 return ((EFI_DEVICE_PATH_PROTOCOL
*)(Node
))->Type
;
97 Returns the SubType field of a device path node.
99 Returns the SubType field of the device path node specified by Node.
101 If Node is NULL, then ASSERT().
103 @param Node A pointer to a device path node data structure.
105 @return The SubType field of the device path node specified by Node.
113 ASSERT (Node
!= NULL
);
114 return ((EFI_DEVICE_PATH_PROTOCOL
*)(Node
))->SubType
;
118 Returns the 16-bit Length field of a device path node.
120 Returns the 16-bit Length field of the device path node specified by Node.
121 Node is not required to be aligned on a 16-bit boundary, so it is recommended
122 that a function such as ReadUnaligned16() be used to extract the contents of
125 If Node is NULL, then ASSERT().
127 @param Node A pointer to a device path node data structure.
129 @return The 16-bit Length field of the device path node specified by Node.
133 DevicePathNodeLength (
137 ASSERT (Node
!= NULL
);
138 return ReadUnaligned16 ((UINT16
*)&((EFI_DEVICE_PATH_PROTOCOL
*)(Node
))->Length
[0]);
142 Returns a pointer to the next node in a device path.
144 Returns a pointer to the device path node that follows the device path node specified by Node.
146 If Node is NULL, then ASSERT().
148 @param Node A pointer to a device path node data structure.
150 @return a pointer to the device path node that follows the device path node specified by Node.
153 EFI_DEVICE_PATH_PROTOCOL
*
158 ASSERT (Node
!= NULL
);
159 return (EFI_DEVICE_PATH_PROTOCOL
*)((UINT8
*)(Node
) + DevicePathNodeLength(Node
));
163 Determines if a device path node is an end node of a device path.
164 This includes nodes that are the end of a device path instance and nodes that are the end of an entire device path.
166 Determines if the device path node specified by Node is an end node of a device path.
167 This includes nodes that are the end of a device path instance and nodes that are the
168 end of an entire device path. If Node represents an end node of a device path,
169 then TRUE is returned. Otherwise, FALSE is returned.
171 If Node is NULL, then ASSERT().
173 @param Node A pointer to a device path node data structure.
175 @retval TRUE The device path node specified by Node is an end node of a device path.
176 @retval FALSE The device path node specified by Node is not an end node of a device path.
180 IsDevicePathEndType (
184 ASSERT (Node
!= NULL
);
185 return ((DevicePathType (Node
) & 0x7f) == END_DEVICE_PATH_TYPE
);
189 Determines if a device path node is an end node of an entire device path.
191 Determines if a device path node specified by Node is an end node of an entire device path.
192 If Node represents the end of an entire device path, then TRUE is returned. Otherwise, FALSE is returned.
194 If Node is NULL, then ASSERT().
196 @param Node A pointer to a device path node data structure.
198 @retval TRUE The device path node specified by Node is the end of an entire device path.
199 @retval FALSE The device path node specified by Node is not the end of an entire device path.
207 ASSERT (Node
!= NULL
);
208 return (IsDevicePathEndType (Node
) && DevicePathSubType(Node
) == END_ENTIRE_DEVICE_PATH_SUBTYPE
);
212 Determines if a device path node is an end node of a device path instance.
214 Determines if a device path node specified by Node is an end node of a device path instance.
215 If Node represents the end of a device path instance, then TRUE is returned. Otherwise, FALSE is returned.
217 If Node is NULL, then ASSERT().
219 @param Node A pointer to a device path node data structure.
221 @retval TRUE The device path node specified by Node is the end of a device path instance.
222 @retval FALSE The device path node specified by Node is not the end of a device path instance.
226 IsDevicePathEndInstance (
230 ASSERT (Node
!= NULL
);
231 return (IsDevicePathEndType (Node
) && DevicePathSubType(Node
) == END_INSTANCE_DEVICE_PATH_SUBTYPE
);
235 Sets the length, in bytes, of a device path node.
237 Sets the length of the device path node specified by Node to the value specified
238 by NodeLength. NodeLength is returned. Node is not required to be aligned on
239 a 16-bit boundary, so it is recommended that a function such as WriteUnaligned16()
240 be used to set the contents of the Length field.
242 If Node is NULL, then ASSERT().
243 If NodeLength >= 0x10000, then ASSERT().
245 @param Node A pointer to a device path node data structure.
246 @param Length The length, in bytes, of the device path node.
252 SetDevicePathNodeLength (
257 ASSERT (Node
!= NULL
);
258 ASSERT (NodeLength
< 0x10000);
259 return WriteUnaligned16 ((UINT16
*)&((EFI_DEVICE_PATH_PROTOCOL
*)(Node
))->Length
[0], (UINT16
)(NodeLength
));
263 Fills in all the fields of a device path node that is the end of an entire device path.
265 Fills in all the fields of a device path node specified by Node so Node represents
266 the end of an entire device path. The Type field of Node is set to
267 END_DEVICE_PATH_TYPE, the SubType field of Node is set to
268 END_ENTIRE_DEVICE_PATH_SUBTYPE, and the Length field of Node is set to
269 END_DEVICE_PATH_LENGTH. Node is not required to be aligned on a 16-bit boundary,
270 so it is recommended that a function such as WriteUnaligned16() be used to set
271 the contents of the Length field.
273 If Node is NULL, then ASSERT().
275 @param Node A pointer to a device path node data structure.
279 SetDevicePathEndNode (
283 ASSERT (Node
!= NULL
);
284 CopyMem (Node
, &mUefiDevicePathLibEndDevicePath
, sizeof (mUefiDevicePathLibEndDevicePath
));
288 Returns the size of a device path in bytes.
290 This function returns the size, in bytes, of the device path data structure specified by
291 DevicePath including the end of device path node. If DevicePath is NULL, then 0 is returned.
293 @param DevicePath A pointer to a device path data structure.
295 @retval 0 If DevicePath is NULL.
296 @retval Others The size of a device path in bytes.
302 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
305 return mDevicePathUtilities
->GetDevicePathSize (DevicePath
);
309 Creates a new copy of an existing device path.
311 This function allocates space for a new copy of the device path specified by DevicePath. If
312 DevicePath is NULL, then NULL is returned. If the memory is successfully allocated, then the
313 contents of DevicePath are copied to the newly allocated buffer, and a pointer to that buffer
314 is returned. Otherwise, NULL is returned.
315 The memory for the new device path is allocated from EFI boot services memory.
316 It is the responsibility of the caller to free the memory allocated.
318 @param DevicePath A pointer to a device path data structure.
320 @retval NULL If DevicePath is NULL.
321 @retval Others A pointer to the duplicated device path.
324 EFI_DEVICE_PATH_PROTOCOL
*
326 DuplicateDevicePath (
327 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
330 return mDevicePathUtilities
->DuplicateDevicePath (DevicePath
);
334 Creates a new device path by appending a second device path to a first device path.
336 This function creates a new device path by appending a copy of SecondDevicePath to a copy of
337 FirstDevicePath in a newly allocated buffer. Only the end-of-device-path device node from
338 SecondDevicePath is retained. The newly created device path is returned.
339 If FirstDevicePath is NULL, then it is ignored, and a duplicate of SecondDevicePath is returned.
340 If SecondDevicePath is NULL, then it is ignored, and a duplicate of FirstDevicePath is returned.
341 If both FirstDevicePath and SecondDevicePath are NULL, then a copy of an end-of-device-path is
343 If there is not enough memory for the newly allocated buffer, then NULL is returned.
344 The memory for the new device path is allocated from EFI boot services memory. It is the
345 responsibility of the caller to free the memory allocated.
347 @param FirstDevicePath A pointer to a device path data structure.
348 @param SecondDevicePath A pointer to a device path data structure.
350 @retval NULL If there is not enough memory for the newly allocated buffer.
351 @retval Others A pointer to the new device path if success.
352 Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.
355 EFI_DEVICE_PATH_PROTOCOL
*
358 IN CONST EFI_DEVICE_PATH_PROTOCOL
*FirstDevicePath
, OPTIONAL
359 IN CONST EFI_DEVICE_PATH_PROTOCOL
*SecondDevicePath OPTIONAL
362 return mDevicePathUtilities
->AppendDevicePath (FirstDevicePath
, SecondDevicePath
);
366 Creates a new path by appending the device node to the device path.
368 This function creates a new device path by appending a copy of the device node specified by
369 DevicePathNode to a copy of the device path specified by DevicePath in an allocated buffer.
370 The end-of-device-path device node is moved after the end of the appended device node.
371 If DevicePathNode is NULL then a copy of DevicePath is returned.
372 If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device path device
374 If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path device node
376 If there is not enough memory to allocate space for the new device path, then NULL is returned.
377 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
378 free the memory allocated.
380 @param DevicePath A pointer to a device path data structure.
381 @param DevicePathNode A pointer to a single device path node.
383 @retval NULL If there is not enough memory for the new device path.
384 @retval Others A pointer to the new device path if success.
385 A copy of DevicePathNode followed by an end-of-device-path node
386 if both FirstDevicePath and SecondDevicePath are NULL.
387 A copy of an end-of-device-path node if both FirstDevicePath and SecondDevicePath are NULL.
390 EFI_DEVICE_PATH_PROTOCOL
*
392 AppendDevicePathNode (
393 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
, OPTIONAL
394 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePathNode OPTIONAL
397 return mDevicePathUtilities
->AppendDeviceNode (DevicePath
, DevicePathNode
);
401 Creates a new device path by appending the specified device path instance to the specified device
404 This function creates a new device path by appending a copy of the device path instance specified
405 by DevicePathInstance to a copy of the device path secified by DevicePath in a allocated buffer.
406 The end-of-device-path device node is moved after the end of the appended device path instance
407 and a new end-of-device-path-instance node is inserted between.
408 If DevicePath is NULL, then a copy if DevicePathInstance is returned.
409 If DevicePathInstance is NULL, then NULL is returned.
410 If there is not enough memory to allocate space for the new device path, then NULL is returned.
411 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
412 free the memory allocated.
414 @param DevicePath A pointer to a device path data structure.
415 @param DevicePathInstance A pointer to a device path instance.
417 @return A pointer to the new device path.
420 EFI_DEVICE_PATH_PROTOCOL
*
422 AppendDevicePathInstance (
423 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
, OPTIONAL
424 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePathInstance OPTIONAL
427 return mDevicePathUtilities
->AppendDevicePathInstance (DevicePath
, DevicePathInstance
);
431 Creates a copy of the current device path instance and returns a pointer to the next device path
434 This function creates a copy of the current device path instance. It also updates DevicePath to
435 point to the next device path instance in the device path (or NULL if no more) and updates Size
436 to hold the size of the device path instance copy.
437 If DevicePath is NULL, then NULL is returned.
438 If there is not enough memory to allocate space for the new device path, then NULL is returned.
439 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
440 free the memory allocated.
441 If Size is NULL, then ASSERT().
443 @param DevicePath On input, this holds the pointer to the current device path
444 instance. On output, this holds the pointer to the next device
445 path instance or NULL if there are no more device path
446 instances in the device path pointer to a device path data
448 @param Size On output, this holds the size of the device path instance, in
449 bytes or zero, if DevicePath is NULL.
451 @return A pointer to the current device path instance.
454 EFI_DEVICE_PATH_PROTOCOL
*
456 GetNextDevicePathInstance (
457 IN OUT EFI_DEVICE_PATH_PROTOCOL
**DevicePath
,
461 ASSERT (Size
!= NULL
);
462 return mDevicePathUtilities
->GetNextDevicePathInstance (DevicePath
, Size
);
466 Creates a device node.
468 This function creates a new device node in a newly allocated buffer of size NodeLength and
469 initializes the device path node header with NodeType and NodeSubType. The new device path node
471 If NodeLength is smaller than a device path header, then NULL is returned.
472 If there is not enough memory to allocate space for the new device path, then NULL is returned.
473 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
474 free the memory allocated.
476 @param NodeType The device node type for the new device node.
477 @param NodeSubType The device node sub-type for the new device node.
478 @param NodeLength The length of the new device node.
480 @return The new device path.
483 EFI_DEVICE_PATH_PROTOCOL
*
487 IN UINT8 NodeSubType
,
491 return mDevicePathUtilities
->CreateDeviceNode (NodeType
, NodeSubType
, NodeLength
);
495 Determines if a device path is single or multi-instance.
497 This function returns TRUE if the device path specified by DevicePath is multi-instance.
498 Otherwise, FALSE is returned. If DevicePath is NULL, then FALSE is returned.
500 @param DevicePath A pointer to a device path data structure.
502 @retval TRUE DevicePath is multi-instance.
503 @retval FALSE DevicePath is not multi-instance or DevicePath is NULL.
508 IsDevicePathMultiInstance (
509 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
512 return mDevicePathUtilities
->IsDevicePathMultiInstance (DevicePath
);
516 Retrieves the device path protocol from a handle.
518 This function returns the device path protocol from the handle specified by Handle. If Handle is
519 NULL or Handle does not contain a device path protocol, then NULL is returned.
521 @param Handle The handle from which to retrieve the device path protocol.
523 @return The device path protocol from the handle specified by Handle.
526 EFI_DEVICE_PATH_PROTOCOL
*
528 DevicePathFromHandle (
532 EFI_DEVICE_PATH_PROTOCOL
*DevicePath
;
535 Status
= gBS
->HandleProtocol (
537 &gEfiDevicePathProtocolGuid
,
540 if (EFI_ERROR (Status
)) {
547 Allocates a device path for a file and appends it to an existing device path.
549 If Device is a valid device handle that contains a device path protocol, then a device path for
550 the file specified by FileName is allocated and appended to the device path associated with the
551 handle Device. The allocated device path is returned. If Device is NULL or Device is a handle
552 that does not support the device path protocol, then a device path containing a single device
553 path node for the file specified by FileName is allocated and returned.
554 The memory for the new device path is allocated from EFI boot services memory. It is the responsibility
555 of the caller to free the memory allocated.
557 If FileName is NULL, then ASSERT().
558 If FileName is not aligned on a 16-bit boundary, then ASSERT().
560 @param Device A pointer to a device handle. This parameter is optional and
562 @param FileName A pointer to a Null-terminated Unicode string.
564 @return The allocated device path.
567 EFI_DEVICE_PATH_PROTOCOL
*
570 IN EFI_HANDLE Device
, OPTIONAL
571 IN CONST CHAR16
*FileName
575 FILEPATH_DEVICE_PATH
*FilePath
;
576 EFI_DEVICE_PATH_PROTOCOL
*DevicePath
;
577 EFI_DEVICE_PATH_PROTOCOL
*FileDevicePath
;
581 Size
= StrSize (FileName
);
582 FileDevicePath
= AllocatePool (Size
+ SIZE_OF_FILEPATH_DEVICE_PATH
+ END_DEVICE_PATH_LENGTH
);
583 if (FileDevicePath
!= NULL
) {
584 FilePath
= (FILEPATH_DEVICE_PATH
*) FileDevicePath
;
585 FilePath
->Header
.Type
= MEDIA_DEVICE_PATH
;
586 FilePath
->Header
.SubType
= MEDIA_FILEPATH_DP
;
587 CopyMem (&FilePath
->PathName
, FileName
, Size
);
588 SetDevicePathNodeLength (&FilePath
->Header
, Size
+ SIZE_OF_FILEPATH_DEVICE_PATH
);
589 SetDevicePathEndNode (NextDevicePathNode (&FilePath
->Header
));
591 if (Device
!= NULL
) {
592 DevicePath
= DevicePathFromHandle (Device
);
595 DevicePath
= AppendDevicePath (DevicePath
, FileDevicePath
);
596 FreePool (FileDevicePath
);