2 * Copyright (c) 2017 Netflix, Inc.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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9 * 2. Redistributions in binary form must reproduce the above copyright
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11 * documentation and/or other materials provided with the distribution.
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25 * $FreeBSD: head/lib/libefivar/uefi-dputil.c 343755 2019-02-04 21:28:25Z imp $
29 * Routines to format EFI_DEVICE_PATHs from the UEFI standard. Much of
30 * this file is taken from EDK2 and rototilled.
37 #include <sys/endian.h>
39 #include "efi-osdep.h"
41 #include "uefi-dplib.h"
43 /* XXX maybe I should include the entire DevicePathUtilities.c and ifdef out what we don't use */
46 * Taken from MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
47 * hash a11928f3310518ab1c6fd34e8d0fdbb72de9602c 2017-Mar-01
51 Device Path services. The thing to remember is device paths are built out of
52 nodes. The device path is terminated by an end node that is length
53 sizeof(EFI_DEVICE_PATH_PROTOCOL). That would be why there is sizeof(EFI_DEVICE_PATH_PROTOCOL)
56 The only place where multi-instance device paths are supported is in
57 environment varibles. Multi-instance device paths should never be placed
60 Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
61 This program and the accompanying materials
62 are licensed and made available under the terms and conditions of the BSD License
63 which accompanies this distribution. The full text of the license may be found at
64 http://opensource.org/licenses/bsd-license.php.
66 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
67 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
72 // Template for an end-of-device path node.
74 static CONST EFI_DEVICE_PATH_PROTOCOL mUefiDevicePathLibEndDevicePath = {
76 END_ENTIRE_DEVICE_PATH_SUBTYPE,
78 END_DEVICE_PATH_LENGTH,
85 Returns the size of a device path in bytes.
87 This function returns the size, in bytes, of the device path data structure
88 specified by DevicePath including the end of device path node.
89 If DevicePath is NULL or invalid, then 0 is returned.
91 @param DevicePath A pointer to a device path data structure.
93 @retval 0 If DevicePath is NULL or invalid.
94 @retval Others The size of a device path in bytes.
100 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
103 CONST EFI_DEVICE_PATH_PROTOCOL *Start;
105 if (DevicePath == NULL) {
109 if (!IsDevicePathValid (DevicePath, 0)) {
114 // Search for the end of the device path structure
117 while (!IsDevicePathEnd (DevicePath)) {
118 DevicePath = NextDevicePathNode (DevicePath);
122 // Compute the size and add back in the size of the end device path structure
124 return ((UINTN) DevicePath - (UINTN) Start) + DevicePathNodeLength (DevicePath);
128 Determine whether a given device path is valid.
129 If DevicePath is NULL, then ASSERT().
131 @param DevicePath A pointer to a device path data structure.
132 @param MaxSize The maximum size of the device path data structure.
134 @retval TRUE DevicePath is valid.
135 @retval FALSE The length of any node in the DevicePath is less
136 than sizeof (EFI_DEVICE_PATH_PROTOCOL).
137 @retval FALSE If MaxSize is not zero, the size of the DevicePath
139 @retval FALSE If PcdMaximumDevicePathNodeCount is not zero, the node
140 count of the DevicePath exceeds PcdMaximumDevicePathNodeCount.
145 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
153 ASSERT (DevicePath != NULL);
160 // Validate the input size big enough to touch the first node.
162 if (MaxSize < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
166 for (Count = 0, Size = 0; !IsDevicePathEnd (DevicePath); DevicePath = NextDevicePathNode (DevicePath)) {
167 NodeLength = DevicePathNodeLength (DevicePath);
168 if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
172 if (NodeLength > MAX_UINTN - Size) {
178 // Validate next node before touch it.
180 if (Size > MaxSize - END_DEVICE_PATH_LENGTH ) {
184 if (PcdGet32 (PcdMaximumDevicePathNodeCount) > 0) {
186 if (Count >= PcdGet32 (PcdMaximumDevicePathNodeCount)) {
193 // Only return TRUE when the End Device Path node is valid.
195 return (BOOLEAN) (DevicePathNodeLength (DevicePath) == END_DEVICE_PATH_LENGTH);
199 Returns the Type field of a device path node.
201 Returns the Type field of the device path node specified by Node.
203 If Node is NULL, then ASSERT().
205 @param Node A pointer to a device path node data structure.
207 @return The Type field of the device path node specified by Node.
216 ASSERT (Node != NULL);
217 return ((const EFI_DEVICE_PATH_PROTOCOL *)(Node))->Type;
222 Returns the SubType field of a device path node.
224 Returns the SubType field of the device path node specified by Node.
226 If Node is NULL, then ASSERT().
228 @param Node A pointer to a device path node data structure.
230 @return The SubType field of the device path node specified by Node.
239 ASSERT (Node != NULL);
240 return ((const EFI_DEVICE_PATH_PROTOCOL *)(Node))->SubType;
244 Returns the 16-bit Length field of a device path node.
246 Returns the 16-bit Length field of the device path node specified by Node.
247 Node is not required to be aligned on a 16-bit boundary, so it is recommended
248 that a function such as ReadUnaligned16() be used to extract the contents of
251 If Node is NULL, then ASSERT().
253 @param Node A pointer to a device path node data structure.
255 @return The 16-bit Length field of the device path node specified by Node.
260 DevicePathNodeLength (
264 ASSERT (Node != NULL);
265 return ((const EFI_DEVICE_PATH_PROTOCOL *)Node)->Length[0] |
266 (((const EFI_DEVICE_PATH_PROTOCOL *)Node)->Length[1] << 8);
270 Returns a pointer to the next node in a device path.
272 Returns a pointer to the device path node that follows the device path node
275 If Node is NULL, then ASSERT().
277 @param Node A pointer to a device path node data structure.
279 @return a pointer to the device path node that follows the device path node
283 EFI_DEVICE_PATH_PROTOCOL *
289 ASSERT (Node != NULL);
290 return ((EFI_DEVICE_PATH_PROTOCOL *)(__DECONST(UINT8 *, Node) + DevicePathNodeLength(Node)));
294 Determines if a device path node is an end node of a device path.
295 This includes nodes that are the end of a device path instance and nodes that
296 are the end of an entire device path.
298 Determines if the device path node specified by Node is an end node of a device path.
299 This includes nodes that are the end of a device path instance and nodes that are the
300 end of an entire device path. If Node represents an end node of a device path,
301 then TRUE is returned. Otherwise, FALSE is returned.
303 If Node is NULL, then ASSERT().
305 @param Node A pointer to a device path node data structure.
307 @retval TRUE The device path node specified by Node is an end node of a
309 @retval FALSE The device path node specified by Node is not an end node of
315 IsDevicePathEndType (
319 ASSERT (Node != NULL);
320 return (BOOLEAN) (DevicePathType (Node) == END_DEVICE_PATH_TYPE);
324 Determines if a device path node is an end node of an entire device path.
326 Determines if a device path node specified by Node is an end node of an entire
327 device path. If Node represents the end of an entire device path, then TRUE is
328 returned. Otherwise, FALSE is returned.
330 If Node is NULL, then ASSERT().
332 @param Node A pointer to a device path node data structure.
334 @retval TRUE The device path node specified by Node is the end of an entire
336 @retval FALSE The device path node specified by Node is not the end of an
346 ASSERT (Node != NULL);
347 return (BOOLEAN) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_ENTIRE_DEVICE_PATH_SUBTYPE);
351 Fills in all the fields of a device path node that is the end of an entire device path.
353 Fills in all the fields of a device path node specified by Node so Node represents
354 the end of an entire device path. The Type field of Node is set to
355 END_DEVICE_PATH_TYPE, the SubType field of Node is set to
356 END_ENTIRE_DEVICE_PATH_SUBTYPE, and the Length field of Node is set to
357 END_DEVICE_PATH_LENGTH. Node is not required to be aligned on a 16-bit boundary,
358 so it is recommended that a function such as WriteUnaligned16() be used to set
359 the contents of the Length field.
361 If Node is NULL, then ASSERT().
363 @param Node A pointer to a device path node data structure.
368 SetDevicePathEndNode (
372 ASSERT (Node != NULL);
373 memcpy (Node, &mUefiDevicePathLibEndDevicePath, sizeof (mUefiDevicePathLibEndDevicePath));
377 Sets the length, in bytes, of a device path node.
379 Sets the length of the device path node specified by Node to the value specified
380 by NodeLength. NodeLength is returned. Node is not required to be aligned on
381 a 16-bit boundary, so it is recommended that a function such as WriteUnaligned16()
382 be used to set the contents of the Length field.
384 If Node is NULL, then ASSERT().
385 If NodeLength >= SIZE_64KB, then ASSERT().
386 If NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL), then ASSERT().
388 @param Node A pointer to a device path node data structure.
389 @param Length The length, in bytes, of the device path node.
396 SetDevicePathNodeLength (
401 ASSERT (Node != NULL);
402 ASSERT ((Length >= sizeof (EFI_DEVICE_PATH_PROTOCOL)) && (Length < SIZE_64KB));
403 // return WriteUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(Length));
404 le16enc(&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(Length));
409 Creates a device node.
411 This function creates a new device node in a newly allocated buffer of size
412 NodeLength and initializes the device path node header with NodeType and NodeSubType.
413 The new device path node is returned.
414 If NodeLength is smaller than a device path header, then NULL is returned.
415 If there is not enough memory to allocate space for the new device path, then
417 The memory is allocated from EFI boot services memory. It is the responsibility
418 of the caller to free the memory allocated.
420 @param NodeType The device node type for the new device node.
421 @param NodeSubType The device node sub-type for the new device node.
422 @param NodeLength The length of the new device node.
424 @return The new device path.
427 EFI_DEVICE_PATH_PROTOCOL *
431 IN UINT8 NodeSubType,
435 EFI_DEVICE_PATH_PROTOCOL *DevicePath;
437 if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
439 // NodeLength is less than the size of the header.
444 DevicePath = AllocateZeroPool (NodeLength);
445 if (DevicePath != NULL) {
446 DevicePath->Type = NodeType;
447 DevicePath->SubType = NodeSubType;
448 SetDevicePathNodeLength (DevicePath, NodeLength);
455 Creates a new copy of an existing device path.
457 This function allocates space for a new copy of the device path specified by DevicePath.
458 If DevicePath is NULL, then NULL is returned. If the memory is successfully
459 allocated, then the contents of DevicePath are copied to the newly allocated
460 buffer, and a pointer to that buffer is returned. Otherwise, NULL is returned.
461 The memory for the new device path is allocated from EFI boot services memory.
462 It is the responsibility of the caller to free the memory allocated.
464 @param DevicePath A pointer to a device path data structure.
466 @retval NULL DevicePath is NULL or invalid.
467 @retval Others A pointer to the duplicated device path.
470 EFI_DEVICE_PATH_PROTOCOL *
472 DuplicateDevicePath (
473 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
481 Size = GetDevicePathSize (DevicePath);
487 // Allocate space for duplicate device path
490 return AllocateCopyPool (Size, DevicePath);
494 Creates a new device path by appending a second device path to a first device path.
496 This function creates a new device path by appending a copy of SecondDevicePath
497 to a copy of FirstDevicePath in a newly allocated buffer. Only the end-of-device-path
498 device node from SecondDevicePath is retained. The newly created device path is
499 returned. If FirstDevicePath is NULL, then it is ignored, and a duplicate of
500 SecondDevicePath is returned. If SecondDevicePath is NULL, then it is ignored,
501 and a duplicate of FirstDevicePath is returned. If both FirstDevicePath and
502 SecondDevicePath are NULL, then a copy of an end-of-device-path is returned.
504 If there is not enough memory for the newly allocated buffer, then NULL is returned.
505 The memory for the new device path is allocated from EFI boot services memory.
506 It is the responsibility of the caller to free the memory allocated.
508 @param FirstDevicePath A pointer to a device path data structure.
509 @param SecondDevicePath A pointer to a device path data structure.
511 @retval NULL If there is not enough memory for the newly allocated buffer.
512 @retval NULL If FirstDevicePath or SecondDevicePath is invalid.
513 @retval Others A pointer to the new device path if success.
514 Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.
517 EFI_DEVICE_PATH_PROTOCOL *
520 IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath, OPTIONAL
521 IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath OPTIONAL
527 EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
528 EFI_DEVICE_PATH_PROTOCOL *DevicePath2;
531 // If there's only 1 path, just duplicate it.
533 if (FirstDevicePath == NULL) {
534 return DuplicateDevicePath ((SecondDevicePath != NULL) ? SecondDevicePath : &mUefiDevicePathLibEndDevicePath);
537 if (SecondDevicePath == NULL) {
538 return DuplicateDevicePath (FirstDevicePath);
541 if (!IsDevicePathValid (FirstDevicePath, 0) || !IsDevicePathValid (SecondDevicePath, 0)) {
546 // Allocate space for the combined device path. It only has one end node of
547 // length EFI_DEVICE_PATH_PROTOCOL.
549 Size1 = GetDevicePathSize (FirstDevicePath);
550 Size2 = GetDevicePathSize (SecondDevicePath);
551 Size = Size1 + Size2 - END_DEVICE_PATH_LENGTH;
553 NewDevicePath = AllocatePool (Size);
555 if (NewDevicePath != NULL) {
556 NewDevicePath = CopyMem (NewDevicePath, FirstDevicePath, Size1);
558 // Over write FirstDevicePath EndNode and do the copy
560 DevicePath2 = (EFI_DEVICE_PATH_PROTOCOL *) ((CHAR8 *) NewDevicePath +
561 (Size1 - END_DEVICE_PATH_LENGTH));
562 CopyMem (DevicePath2, SecondDevicePath, Size2);
565 return NewDevicePath;
569 Creates a new path by appending the device node to the device path.
571 This function creates a new device path by appending a copy of the device node
572 specified by DevicePathNode to a copy of the device path specified by DevicePath
573 in an allocated buffer. The end-of-device-path device node is moved after the
574 end of the appended device node.
575 If DevicePathNode is NULL then a copy of DevicePath is returned.
576 If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device
577 path device node is returned.
578 If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path
579 device node is returned.
580 If there is not enough memory to allocate space for the new device path, then
582 The memory is allocated from EFI boot services memory. It is the responsibility
583 of the caller to free the memory allocated.
585 @param DevicePath A pointer to a device path data structure.
586 @param DevicePathNode A pointer to a single device path node.
588 @retval NULL If there is not enough memory for the new device path.
589 @retval Others A pointer to the new device path if success.
590 A copy of DevicePathNode followed by an end-of-device-path node
591 if both FirstDevicePath and SecondDevicePath are NULL.
592 A copy of an end-of-device-path node if both FirstDevicePath
593 and SecondDevicePath are NULL.
596 EFI_DEVICE_PATH_PROTOCOL *
598 AppendDevicePathNode (
599 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
600 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode OPTIONAL
603 EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
604 EFI_DEVICE_PATH_PROTOCOL *NextNode;
605 EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
608 if (DevicePathNode == NULL) {
609 return DuplicateDevicePath ((DevicePath != NULL) ? DevicePath : &mUefiDevicePathLibEndDevicePath);
612 // Build a Node that has a terminator on it
614 NodeLength = DevicePathNodeLength (DevicePathNode);
616 TempDevicePath = AllocatePool (NodeLength + END_DEVICE_PATH_LENGTH);
617 if (TempDevicePath == NULL) {
620 TempDevicePath = CopyMem (TempDevicePath, DevicePathNode, NodeLength);
622 // Add and end device path node to convert Node to device path
624 NextNode = NextDevicePathNode (TempDevicePath);
625 SetDevicePathEndNode (NextNode);
627 // Append device paths
629 NewDevicePath = AppendDevicePath (DevicePath, TempDevicePath);
631 FreePool (TempDevicePath);
633 return NewDevicePath;