MdePkg DevicePathLib: Validate before touch input buffer.
[mirror_edk2.git] / MdePkg / Library / UefiDevicePathLibDevicePathProtocol / UefiDevicePathLib.c
1 /** @file
2 Library instance that implement UEFI Device Path Library class based on protocol
3 gEfiDevicePathUtilitiesProtocolGuid.
4
5 Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
6 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.
10
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.
13
14 **/
15
16
17 #include <Uefi.h>
18
19 #include <Protocol/DevicePathUtilities.h>
20 #include <Protocol/DevicePathToText.h>
21 #include <Protocol/DevicePathFromText.h>
22
23 #include <Library/DevicePathLib.h>
24 #include <Library/DebugLib.h>
25 #include <Library/BaseLib.h>
26 #include <Library/MemoryAllocationLib.h>
27 #include <Library/BaseMemoryLib.h>
28 #include <Library/UefiBootServicesTableLib.h>
29 #include <Library/PcdLib.h>
30
31 GLOBAL_REMOVE_IF_UNREFERENCED EFI_DEVICE_PATH_UTILITIES_PROTOCOL *mDevicePathLibDevicePathUtilities = NULL;
32 GLOBAL_REMOVE_IF_UNREFERENCED EFI_DEVICE_PATH_TO_TEXT_PROTOCOL *mDevicePathLibDevicePathToText = NULL;
33 GLOBAL_REMOVE_IF_UNREFERENCED EFI_DEVICE_PATH_FROM_TEXT_PROTOCOL *mDevicePathLibDevicePathFromText = NULL;
34
35 //
36 // Template for an end-of-device path node.
37 //
38 GLOBAL_REMOVE_IF_UNREFERENCED CONST EFI_DEVICE_PATH_PROTOCOL mUefiDevicePathLibEndDevicePath = {
39 END_DEVICE_PATH_TYPE,
40 END_ENTIRE_DEVICE_PATH_SUBTYPE,
41 {
42 END_DEVICE_PATH_LENGTH,
43 0
44 }
45 };
46
47 /**
48 The constructor function caches the pointer to DevicePathUtilites protocol.
49
50 The constructor function locates DevicePathUtilities protocol from protocol database.
51 It will ASSERT() if that operation fails and it will always return EFI_SUCCESS.
52
53 @param ImageHandle The firmware allocated handle for the EFI image.
54 @param SystemTable A pointer to the EFI System Table.
55
56 @retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.
57
58 **/
59 EFI_STATUS
60 EFIAPI
61 DevicePathLibConstructor (
62 IN EFI_HANDLE ImageHandle,
63 IN EFI_SYSTEM_TABLE *SystemTable
64 )
65 {
66 EFI_STATUS Status;
67
68 Status = gBS->LocateProtocol (
69 &gEfiDevicePathUtilitiesProtocolGuid,
70 NULL,
71 (VOID**) &mDevicePathLibDevicePathUtilities
72 );
73 ASSERT_EFI_ERROR (Status);
74 ASSERT (mDevicePathLibDevicePathUtilities != NULL);
75 return Status;
76 }
77
78 /**
79 Determine whether a given device path is valid.
80 If DevicePath is NULL, then ASSERT().
81
82 @param DevicePath A pointer to a device path data structure.
83 @param MaxSize The maximum size of the device path data structure.
84
85 @retval TRUE DevicePath is valid.
86 @retval FALSE The length of any node node in the DevicePath is less
87 than sizeof (EFI_DEVICE_PATH_PROTOCOL).
88 @retval FALSE If MaxSize is not zero, the size of the DevicePath
89 exceeds MaxSize.
90 @retval FALSE If PcdMaximumDevicePathNodeCount is not zero, the node
91 count of the DevicePath exceeds PcdMaximumDevicePathNodeCount.
92 **/
93 BOOLEAN
94 EFIAPI
95 IsDevicePathValid (
96 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
97 IN UINTN MaxSize
98 )
99 {
100 UINTN Count;
101 UINTN Size;
102 UINTN NodeLength;
103
104 ASSERT (DevicePath != NULL);
105
106 if (MaxSize == 0) {
107 MaxSize = MAX_UINTN;
108 }
109
110 //
111 // Validate the input size big enough to touch the first node.
112 //
113 if (MaxSize < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
114 return FALSE;
115 }
116
117 for (Count = 0, Size = 0; !IsDevicePathEnd (DevicePath); DevicePath = NextDevicePathNode (DevicePath)) {
118 NodeLength = DevicePathNodeLength (DevicePath);
119 if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
120 return FALSE;
121 }
122
123 if (NodeLength > MAX_UINTN - Size) {
124 return FALSE;
125 }
126 Size += NodeLength;
127
128 //
129 // Validate next node before touch it.
130 //
131 if (Size > MaxSize - END_DEVICE_PATH_LENGTH ) {
132 return FALSE;
133 }
134
135 if (PcdGet32 (PcdMaximumDevicePathNodeCount) > 0) {
136 Count++;
137 if (Count >= PcdGet32 (PcdMaximumDevicePathNodeCount)) {
138 return FALSE;
139 }
140 }
141 }
142
143 //
144 // Only return TRUE when the End Device Path node is valid.
145 //
146 return (BOOLEAN) (DevicePathNodeLength (DevicePath) == END_DEVICE_PATH_LENGTH);
147 }
148
149 /**
150 Returns the Type field of a device path node.
151
152 Returns the Type field of the device path node specified by Node.
153
154 If Node is NULL, then ASSERT().
155
156 @param Node A pointer to a device path node data structure.
157
158 @return The Type field of the device path node specified by Node.
159
160 **/
161 UINT8
162 EFIAPI
163 DevicePathType (
164 IN CONST VOID *Node
165 )
166 {
167 ASSERT (Node != NULL);
168 return ((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Type;
169 }
170
171 /**
172 Returns the SubType field of a device path node.
173
174 Returns the SubType field of the device path node specified by Node.
175
176 If Node is NULL, then ASSERT().
177
178 @param Node A pointer to a device path node data structure.
179
180 @return The SubType field of the device path node specified by Node.
181
182 **/
183 UINT8
184 EFIAPI
185 DevicePathSubType (
186 IN CONST VOID *Node
187 )
188 {
189 ASSERT (Node != NULL);
190 return ((EFI_DEVICE_PATH_PROTOCOL *)(Node))->SubType;
191 }
192
193 /**
194 Returns the 16-bit Length field of a device path node.
195
196 Returns the 16-bit Length field of the device path node specified by Node.
197 Node is not required to be aligned on a 16-bit boundary, so it is recommended
198 that a function such as ReadUnaligned16() be used to extract the contents of
199 the Length field.
200
201 If Node is NULL, then ASSERT().
202
203 @param Node A pointer to a device path node data structure.
204
205 @return The 16-bit Length field of the device path node specified by Node.
206
207 **/
208 UINTN
209 EFIAPI
210 DevicePathNodeLength (
211 IN CONST VOID *Node
212 )
213 {
214 ASSERT (Node != NULL);
215 return ReadUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0]);
216 }
217
218 /**
219 Returns a pointer to the next node in a device path.
220
221 Returns a pointer to the device path node that follows the device path node
222 specified by Node.
223
224 If Node is NULL, then ASSERT().
225
226 @param Node A pointer to a device path node data structure.
227
228 @return a pointer to the device path node that follows the device path node
229 specified by Node.
230
231 **/
232 EFI_DEVICE_PATH_PROTOCOL *
233 EFIAPI
234 NextDevicePathNode (
235 IN CONST VOID *Node
236 )
237 {
238 ASSERT (Node != NULL);
239 return (EFI_DEVICE_PATH_PROTOCOL *)((UINT8 *)(Node) + DevicePathNodeLength(Node));
240 }
241
242 /**
243 Determines if a device path node is an end node of a device path.
244 This includes nodes that are the end of a device path instance and nodes that
245 are the end of an entire device path.
246
247 Determines if the device path node specified by Node is an end node of a device path.
248 This includes nodes that are the end of a device path instance and nodes that are the
249 end of an entire device path. If Node represents an end node of a device path,
250 then TRUE is returned. Otherwise, FALSE is returned.
251
252 If Node is NULL, then ASSERT().
253
254 @param Node A pointer to a device path node data structure.
255
256 @retval TRUE The device path node specified by Node is an end node of a device path.
257 @retval FALSE The device path node specified by Node is not an end node of
258 a device path.
259
260 **/
261 BOOLEAN
262 EFIAPI
263 IsDevicePathEndType (
264 IN CONST VOID *Node
265 )
266 {
267 ASSERT (Node != NULL);
268 return (BOOLEAN) (DevicePathType (Node) == END_DEVICE_PATH_TYPE);
269 }
270
271 /**
272 Determines if a device path node is an end node of an entire device path.
273
274 Determines if a device path node specified by Node is an end node of an entire
275 device path.
276 If Node represents the end of an entire device path, then TRUE is returned.
277 Otherwise, FALSE is returned.
278
279 If Node is NULL, then ASSERT().
280
281 @param Node A pointer to a device path node data structure.
282
283 @retval TRUE The device path node specified by Node is the end of an entire device path.
284 @retval FALSE The device path node specified by Node is not the end of an entire device path.
285
286 **/
287 BOOLEAN
288 EFIAPI
289 IsDevicePathEnd (
290 IN CONST VOID *Node
291 )
292 {
293 ASSERT (Node != NULL);
294 return (BOOLEAN) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_ENTIRE_DEVICE_PATH_SUBTYPE);
295 }
296
297 /**
298 Determines if a device path node is an end node of a device path instance.
299
300 Determines if a device path node specified by Node is an end node of a device
301 path instance.
302 If Node represents the end of a device path instance, then TRUE is returned.
303 Otherwise, FALSE is returned.
304
305 If Node is NULL, then ASSERT().
306
307 @param Node A pointer to a device path node data structure.
308
309 @retval TRUE The device path node specified by Node is the end of a device
310 path instance.
311 @retval FALSE The device path node specified by Node is not the end of a
312 device path instance.
313
314 **/
315 BOOLEAN
316 EFIAPI
317 IsDevicePathEndInstance (
318 IN CONST VOID *Node
319 )
320 {
321 ASSERT (Node != NULL);
322 return (BOOLEAN) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_INSTANCE_DEVICE_PATH_SUBTYPE);
323 }
324
325 /**
326 Sets the length, in bytes, of a device path node.
327
328 Sets the length of the device path node specified by Node to the value specified
329 by NodeLength. NodeLength is returned. Node is not required to be aligned on
330 a 16-bit boundary, so it is recommended that a function such as WriteUnaligned16()
331 be used to set the contents of the Length field.
332
333 If Node is NULL, then ASSERT().
334 If NodeLength >= SIZE_64KB, then ASSERT().
335 If NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL), then ASSERT().
336
337 @param Node A pointer to a device path node data structure.
338 @param Length The length, in bytes, of the device path node.
339
340 @return Length
341
342 **/
343 UINT16
344 EFIAPI
345 SetDevicePathNodeLength (
346 IN OUT VOID *Node,
347 IN UINTN Length
348 )
349 {
350 ASSERT (Node != NULL);
351 ASSERT ((Length >= sizeof (EFI_DEVICE_PATH_PROTOCOL)) && (Length < SIZE_64KB));
352 return WriteUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(Length));
353 }
354
355 /**
356 Fills in all the fields of a device path node that is the end of an entire device path.
357
358 Fills in all the fields of a device path node specified by Node so Node represents
359 the end of an entire device path. The Type field of Node is set to
360 END_DEVICE_PATH_TYPE, the SubType field of Node is set to
361 END_ENTIRE_DEVICE_PATH_SUBTYPE, and the Length field of Node is set to
362 END_DEVICE_PATH_LENGTH. Node is not required to be aligned on a 16-bit boundary,
363 so it is recommended that a function such as WriteUnaligned16() be used to set
364 the contents of the Length field.
365
366 If Node is NULL, then ASSERT().
367
368 @param Node A pointer to a device path node data structure.
369
370 **/
371 VOID
372 EFIAPI
373 SetDevicePathEndNode (
374 OUT VOID *Node
375 )
376 {
377 ASSERT (Node != NULL);
378 CopyMem (Node, &mUefiDevicePathLibEndDevicePath, sizeof (mUefiDevicePathLibEndDevicePath));
379 }
380
381 /**
382 Returns the size of a device path in bytes.
383
384 This function returns the size, in bytes, of the device path data structure
385 specified by DevicePath including the end of device path node.
386 If DevicePath is NULL or invalid, then 0 is returned.
387
388 @param DevicePath A pointer to a device path data structure.
389
390 @retval 0 If DevicePath is NULL or invalid.
391 @retval Others The size of a device path in bytes.
392
393 **/
394 UINTN
395 EFIAPI
396 GetDevicePathSize (
397 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
398 )
399 {
400 return mDevicePathLibDevicePathUtilities->GetDevicePathSize (DevicePath);
401 }
402
403 /**
404 Creates a new copy of an existing device path.
405
406 This function allocates space for a new copy of the device path specified by
407 DevicePath. If DevicePath is NULL, then NULL is returned.
408 If the memory is successfully allocated, then the
409 contents of DevicePath are copied to the newly allocated buffer, and a pointer to that buffer
410 is returned. Otherwise, NULL is returned.
411 The memory for the new device path is allocated from EFI boot services memory.
412 It is the responsibility of the caller to free the memory allocated.
413
414 @param DevicePath A pointer to a device path data structure.
415
416 @retval NULL If DevicePath is NULL or invalid.
417 @retval Others A pointer to the duplicated device path.
418
419 **/
420 EFI_DEVICE_PATH_PROTOCOL *
421 EFIAPI
422 DuplicateDevicePath (
423 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
424 )
425 {
426 return mDevicePathLibDevicePathUtilities->DuplicateDevicePath (DevicePath);
427 }
428
429 /**
430 Creates a new device path by appending a second device path to a first device path.
431
432 This function creates a new device path by appending a copy of SecondDevicePath to a copy of
433 FirstDevicePath in a newly allocated buffer. Only the end-of-device-path device node from
434 SecondDevicePath is retained. The newly created device path is returned.
435 If FirstDevicePath is NULL, then it is ignored, and a duplicate of SecondDevicePath is returned.
436 If SecondDevicePath is NULL, then it is ignored, and a duplicate of FirstDevicePath is returned.
437 If both FirstDevicePath and SecondDevicePath are NULL, then a copy of an end-of-device-path is
438 returned.
439 If there is not enough memory for the newly allocated buffer, then NULL is returned.
440 The memory for the new device path is allocated from EFI boot services memory. It is the
441 responsibility of the caller to free the memory allocated.
442
443 @param FirstDevicePath A pointer to a device path data structure.
444 @param SecondDevicePath A pointer to a device path data structure.
445
446 @retval NULL If there is not enough memory for the newly allocated buffer.
447 @retval NULL If FirstDevicePath or SecondDevicePath is invalid.
448 @retval Others A pointer to the new device path if success.
449 Or a copy an end-of-device-path if both FirstDevicePath and
450 SecondDevicePath are NULL.
451
452 **/
453 EFI_DEVICE_PATH_PROTOCOL *
454 EFIAPI
455 AppendDevicePath (
456 IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath, OPTIONAL
457 IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath OPTIONAL
458 )
459 {
460 return mDevicePathLibDevicePathUtilities->AppendDevicePath (FirstDevicePath, SecondDevicePath);
461 }
462
463 /**
464 Creates a new path by appending the device node to the device path.
465
466 This function creates a new device path by appending a copy of the device node
467 specified by DevicePathNode to a copy of the device path specified by DevicePath
468 in an allocated buffer.
469 The end-of-device-path device node is moved after the end of the appended device node.
470 If DevicePathNode is NULL then a copy of DevicePath is returned.
471 If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device
472 path device node is returned.
473 If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path
474 device node is returned.
475 If there is not enough memory to allocate space for the new device path, then
476 NULL is returned.
477 The memory is allocated from EFI boot services memory. It is the responsibility
478 of the caller to free the memory allocated.
479
480 @param DevicePath A pointer to a device path data structure.
481 @param DevicePathNode A pointer to a single device path node.
482
483 @retval NULL If there is not enough memory for the new device path.
484 @retval Others A pointer to the new device path if success.
485 A copy of DevicePathNode followed by an end-of-device-path node
486 if both FirstDevicePath and SecondDevicePath are NULL.
487 A copy of an end-of-device-path node if both FirstDevicePath
488 and SecondDevicePath are NULL.
489
490 **/
491 EFI_DEVICE_PATH_PROTOCOL *
492 EFIAPI
493 AppendDevicePathNode (
494 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
495 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode OPTIONAL
496 )
497 {
498 return mDevicePathLibDevicePathUtilities->AppendDeviceNode (DevicePath, DevicePathNode);
499 }
500
501 /**
502 Creates a new device path by appending the specified device path instance to
503 the specified device path.
504
505 This function creates a new device path by appending a copy of the device path
506 instance specified by DevicePathInstance to a copy of the device path specified
507 by DevicePath in a allocated buffer.
508 The end-of-device-path device node is moved after the end of the appended device
509 path instance and a new end-of-device-path-instance node is inserted between.
510 If DevicePath is NULL, then a copy if DevicePathInstance is returned.
511 If DevicePathInstance is NULL, then NULL is returned.
512 If DevicePath or DevicePathInstance is invalid, then NULL is returned.
513 If there is not enough memory to allocate space for the new device path, then
514 NULL is returned.
515 The memory is allocated from EFI boot services memory. It is the responsibility
516 of the caller to free the memory allocated.
517
518 @param DevicePath A pointer to a device path data structure.
519 @param DevicePathInstance A pointer to a device path instance.
520
521 @return A pointer to the new device path.
522
523 **/
524 EFI_DEVICE_PATH_PROTOCOL *
525 EFIAPI
526 AppendDevicePathInstance (
527 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
528 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathInstance OPTIONAL
529 )
530 {
531 return mDevicePathLibDevicePathUtilities->AppendDevicePathInstance (DevicePath, DevicePathInstance);
532 }
533
534 /**
535 Creates a copy of the current device path instance and returns a pointer to the
536 next device path instance.
537
538 This function creates a copy of the current device path instance. It also updates
539 DevicePath to point to the next device path instance in the device path (or NULL
540 if no more) and updates Size to hold the size of the device path instance copy.
541 If DevicePath is NULL, then NULL is returned.
542 If there is not enough memory to allocate space for the new device path, then
543 NULL is returned.
544 The memory is allocated from EFI boot services memory. It is the responsibility
545 of the caller to free the memory allocated.
546 If Size is NULL, then ASSERT().
547
548 @param DevicePath On input, this holds the pointer to the current
549 device path instance. On output, this holds
550 the pointer to the next device path instance
551 or NULL if there are no more device path
552 instances in the device path pointer to a
553 device path data structure.
554 @param Size On output, this holds the size of the device
555 path instance, in bytes or zero, if DevicePath
556 is NULL.
557
558 @return A pointer to the current device path instance.
559
560 **/
561 EFI_DEVICE_PATH_PROTOCOL *
562 EFIAPI
563 GetNextDevicePathInstance (
564 IN OUT EFI_DEVICE_PATH_PROTOCOL **DevicePath,
565 OUT UINTN *Size
566 )
567 {
568 ASSERT (Size != NULL);
569 return mDevicePathLibDevicePathUtilities->GetNextDevicePathInstance (DevicePath, Size);
570 }
571
572 /**
573 Creates a device node.
574
575 This function creates a new device node in a newly allocated buffer of size
576 NodeLength and initializes the device path node header with NodeType and NodeSubType.
577 The new device path node is returned.
578 If NodeLength is smaller than a device path header, then NULL is returned.
579 If there is not enough memory to allocate space for the new device path, then
580 NULL is returned.
581 The memory is allocated from EFI boot services memory. It is the responsibility
582 of the caller to free the memory allocated.
583
584 @param NodeType The device node type for the new device node.
585 @param NodeSubType The device node sub-type for the new device node.
586 @param NodeLength The length of the new device node.
587
588 @return The new device path.
589
590 **/
591 EFI_DEVICE_PATH_PROTOCOL *
592 EFIAPI
593 CreateDeviceNode (
594 IN UINT8 NodeType,
595 IN UINT8 NodeSubType,
596 IN UINT16 NodeLength
597 )
598 {
599 return mDevicePathLibDevicePathUtilities->CreateDeviceNode (NodeType, NodeSubType, NodeLength);
600 }
601
602 /**
603 Determines if a device path is single or multi-instance.
604
605 This function returns TRUE if the device path specified by DevicePath is
606 multi-instance.
607 Otherwise, FALSE is returned.
608 If DevicePath is NULL or invalid, then FALSE is returned.
609
610 @param DevicePath A pointer to a device path data structure.
611
612 @retval TRUE DevicePath is multi-instance.
613 @retval FALSE DevicePath is not multi-instance, or DevicePath
614 is NULL or invalid.
615
616 **/
617 BOOLEAN
618 EFIAPI
619 IsDevicePathMultiInstance (
620 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
621 )
622 {
623 return mDevicePathLibDevicePathUtilities->IsDevicePathMultiInstance (DevicePath);
624 }
625
626 /**
627 Retrieves the device path protocol from a handle.
628
629 This function returns the device path protocol from the handle specified by Handle.
630 If Handle is NULL or Handle does not contain a device path protocol, then NULL
631 is returned.
632
633 @param Handle The handle from which to retrieve the device
634 path protocol.
635
636 @return The device path protocol from the handle specified by Handle.
637
638 **/
639 EFI_DEVICE_PATH_PROTOCOL *
640 EFIAPI
641 DevicePathFromHandle (
642 IN EFI_HANDLE Handle
643 )
644 {
645 EFI_DEVICE_PATH_PROTOCOL *DevicePath;
646 EFI_STATUS Status;
647
648 Status = gBS->HandleProtocol (
649 Handle,
650 &gEfiDevicePathProtocolGuid,
651 (VOID *) &DevicePath
652 );
653 if (EFI_ERROR (Status)) {
654 DevicePath = NULL;
655 }
656 return DevicePath;
657 }
658
659 /**
660 Allocates a device path for a file and appends it to an existing device path.
661
662 If Device is a valid device handle that contains a device path protocol, then
663 a device path for the file specified by FileName is allocated and appended to
664 the device path associated with the handle Device. The allocated device path
665 is returned. If Device is NULL or Device is a handle that does not support the
666 device path protocol, then a device path containing a single device path node
667 for the file specified by FileName is allocated and returned.
668 The memory for the new device path is allocated from EFI boot services memory.
669 It is the responsibility of the caller to free the memory allocated.
670
671 If FileName is NULL, then ASSERT().
672 If FileName is not aligned on a 16-bit boundary, then ASSERT().
673
674 @param Device A pointer to a device handle. This parameter
675 is optional and may be NULL.
676 @param FileName A pointer to a Null-terminated Unicode string.
677
678 @return The allocated device path.
679
680 **/
681 EFI_DEVICE_PATH_PROTOCOL *
682 EFIAPI
683 FileDevicePath (
684 IN EFI_HANDLE Device, OPTIONAL
685 IN CONST CHAR16 *FileName
686 )
687 {
688 UINTN Size;
689 FILEPATH_DEVICE_PATH *FilePath;
690 EFI_DEVICE_PATH_PROTOCOL *DevicePath;
691 EFI_DEVICE_PATH_PROTOCOL *FileDevicePath;
692
693 DevicePath = NULL;
694
695 Size = StrSize (FileName);
696 FileDevicePath = AllocatePool (Size + SIZE_OF_FILEPATH_DEVICE_PATH + END_DEVICE_PATH_LENGTH);
697 if (FileDevicePath != NULL) {
698 FilePath = (FILEPATH_DEVICE_PATH *) FileDevicePath;
699 FilePath->Header.Type = MEDIA_DEVICE_PATH;
700 FilePath->Header.SubType = MEDIA_FILEPATH_DP;
701 CopyMem (&FilePath->PathName, FileName, Size);
702 SetDevicePathNodeLength (&FilePath->Header, Size + SIZE_OF_FILEPATH_DEVICE_PATH);
703 SetDevicePathEndNode (NextDevicePathNode (&FilePath->Header));
704
705 if (Device != NULL) {
706 DevicePath = DevicePathFromHandle (Device);
707 }
708
709 DevicePath = AppendDevicePath (DevicePath, FileDevicePath);
710 FreePool (FileDevicePath);
711 }
712
713 return DevicePath;
714 }
715
716 /**
717 Locate and return the protocol instance identified by the ProtocolGuid.
718
719 @param ProtocolGuid The GUID of the protocol.
720
721 @return A pointer to the protocol instance or NULL when absent.
722 **/
723 VOID *
724 UefiDevicePathLibLocateProtocol (
725 EFI_GUID *ProtocolGuid
726 )
727 {
728 EFI_STATUS Status;
729 VOID *Protocol;
730 Status = gBS->LocateProtocol (
731 ProtocolGuid,
732 NULL,
733 (VOID**) &Protocol
734 );
735 if (EFI_ERROR (Status)) {
736 return NULL;
737 } else {
738 return Protocol;
739 }
740 }
741
742 /**
743 Converts a device node to its string representation.
744
745 @param DeviceNode A Pointer to the device node to be converted.
746 @param DisplayOnly If DisplayOnly is TRUE, then the shorter text representation
747 of the display node is used, where applicable. If DisplayOnly
748 is FALSE, then the longer text representation of the display node
749 is used.
750 @param AllowShortcuts If AllowShortcuts is TRUE, then the shortcut forms of text
751 representation for a device node can be used, where applicable.
752
753 @return A pointer to the allocated text representation of the device node or NULL if DeviceNode
754 is NULL or there was insufficient memory.
755
756 **/
757 CHAR16 *
758 EFIAPI
759 ConvertDeviceNodeToText (
760 IN CONST EFI_DEVICE_PATH_PROTOCOL *DeviceNode,
761 IN BOOLEAN DisplayOnly,
762 IN BOOLEAN AllowShortcuts
763 )
764 {
765 if (mDevicePathLibDevicePathToText == NULL) {
766 mDevicePathLibDevicePathToText = UefiDevicePathLibLocateProtocol (&gEfiDevicePathToTextProtocolGuid);
767 }
768 if (mDevicePathLibDevicePathToText != NULL) {
769 return mDevicePathLibDevicePathToText->ConvertDeviceNodeToText (DeviceNode, DisplayOnly, AllowShortcuts);
770 } else {
771 return NULL;
772 }
773 }
774
775 /**
776 Converts a device path to its text representation.
777
778 @param DevicePath A Pointer to the device to be converted.
779 @param DisplayOnly If DisplayOnly is TRUE, then the shorter text representation
780 of the display node is used, where applicable. If DisplayOnly
781 is FALSE, then the longer text representation of the display node
782 is used.
783 @param AllowShortcuts If AllowShortcuts is TRUE, then the shortcut forms of text
784 representation for a device node can be used, where applicable.
785
786 @return A pointer to the allocated text representation of the device path or
787 NULL if DeviceNode is NULL or there was insufficient memory.
788
789 **/
790 CHAR16 *
791 EFIAPI
792 ConvertDevicePathToText (
793 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
794 IN BOOLEAN DisplayOnly,
795 IN BOOLEAN AllowShortcuts
796 )
797 {
798 if (mDevicePathLibDevicePathToText == NULL) {
799 mDevicePathLibDevicePathToText = UefiDevicePathLibLocateProtocol (&gEfiDevicePathToTextProtocolGuid);
800 }
801 if (mDevicePathLibDevicePathToText != NULL) {
802 return mDevicePathLibDevicePathToText->ConvertDevicePathToText (DevicePath, DisplayOnly, AllowShortcuts);
803 } else {
804 return NULL;
805 }
806 }
807
808 /**
809 Convert text to the binary representation of a device node.
810
811 @param TextDeviceNode TextDeviceNode points to the text representation of a device
812 node. Conversion starts with the first character and continues
813 until the first non-device node character.
814
815 @return A pointer to the EFI device node or NULL if TextDeviceNode is NULL or there was
816 insufficient memory or text unsupported.
817
818 **/
819 EFI_DEVICE_PATH_PROTOCOL *
820 EFIAPI
821 ConvertTextToDeviceNode (
822 IN CONST CHAR16 *TextDeviceNode
823 )
824 {
825 if (mDevicePathLibDevicePathFromText == NULL) {
826 mDevicePathLibDevicePathFromText = UefiDevicePathLibLocateProtocol (&gEfiDevicePathFromTextProtocolGuid);
827 }
828 if (mDevicePathLibDevicePathFromText != NULL) {
829 return mDevicePathLibDevicePathFromText->ConvertTextToDeviceNode (TextDeviceNode);
830 } else {
831 return NULL;
832 }
833 }
834
835 /**
836 Convert text to the binary representation of a device path.
837
838
839 @param TextDevicePath TextDevicePath points to the text representation of a device
840 path. Conversion starts with the first character and continues
841 until the first non-device node character.
842
843 @return A pointer to the allocated device path or NULL if TextDeviceNode is NULL or
844 there was insufficient memory.
845
846 **/
847 EFI_DEVICE_PATH_PROTOCOL *
848 EFIAPI
849 ConvertTextToDevicePath (
850 IN CONST CHAR16 *TextDevicePath
851 )
852 {
853 if (mDevicePathLibDevicePathFromText == NULL) {
854 mDevicePathLibDevicePathFromText = UefiDevicePathLibLocateProtocol (&gEfiDevicePathFromTextProtocolGuid);
855 }
856 if (mDevicePathLibDevicePathFromText != NULL) {
857 return mDevicePathLibDevicePathFromText->ConvertTextToDevicePath (TextDevicePath);
858 } else {
859 return NULL;
860 }
861 }
862