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
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
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.
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * Routines to format EFI_DEVICE_PATHs from the UEFI standard. Much of
28 * this file is taken from EDK2 and rototilled.
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
38 #include <sys/endian.h>
40 #include "efi-osdep.h"
42 #include "uefi-dplib.h"
44 /* XXX maybe I should include the entire DevicePathUtiltiies.c and ifdef out what we don't use */
47 * Taken from MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
48 * hash a11928f3310518ab1c6fd34e8d0fdbb72de9602c 2017-Mar-01
52 Device Path services. The thing to remember is device paths are built out of
53 nodes. The device path is terminated by an end node that is length
54 sizeof(EFI_DEVICE_PATH_PROTOCOL). That would be why there is sizeof(EFI_DEVICE_PATH_PROTOCOL)
57 The only place where multi-instance device paths are supported is in
58 environment varibles. Multi-instance device paths should never be placed
61 Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
62 This program and the accompanying materials
63 are licensed and made available under the terms and conditions of the BSD License
64 which accompanies this distribution. The full text of the license may be found at
65 http://opensource.org/licenses/bsd-license.php.
67 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
68 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
73 // Template for an end-of-device path node.
75 static CONST EFI_DEVICE_PATH_PROTOCOL mUefiDevicePathLibEndDevicePath = {
77 END_ENTIRE_DEVICE_PATH_SUBTYPE,
79 END_DEVICE_PATH_LENGTH,
86 Returns the size of a device path in bytes.
88 This function returns the size, in bytes, of the device path data structure
89 specified by DevicePath including the end of device path node.
90 If DevicePath is NULL or invalid, then 0 is returned.
92 @param DevicePath A pointer to a device path data structure.
94 @retval 0 If DevicePath is NULL or invalid.
95 @retval Others The size of a device path in bytes.
101 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
104 CONST EFI_DEVICE_PATH_PROTOCOL *Start;
106 if (DevicePath == NULL) {
110 if (!IsDevicePathValid (DevicePath, 0)) {
115 // Search for the end of the device path structure
118 while (!IsDevicePathEnd (DevicePath)) {
119 DevicePath = NextDevicePathNode (DevicePath);
123 // Compute the size and add back in the size of the end device path structure
125 return ((UINTN) DevicePath - (UINTN) Start) + DevicePathNodeLength (DevicePath);
129 Determine whether a given device path is valid.
130 If DevicePath is NULL, then ASSERT().
132 @param DevicePath A pointer to a device path data structure.
133 @param MaxSize The maximum size of the device path data structure.
135 @retval TRUE DevicePath is valid.
136 @retval FALSE The length of any node in the DevicePath is less
137 than sizeof (EFI_DEVICE_PATH_PROTOCOL).
138 @retval FALSE If MaxSize is not zero, the size of the DevicePath
140 @retval FALSE If PcdMaximumDevicePathNodeCount is not zero, the node
141 count of the DevicePath exceeds PcdMaximumDevicePathNodeCount.
146 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
154 ASSERT (DevicePath != NULL);
161 // Validate the input size big enough to touch the first node.
163 if (MaxSize < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
167 for (Count = 0, Size = 0; !IsDevicePathEnd (DevicePath); DevicePath = NextDevicePathNode (DevicePath)) {
168 NodeLength = DevicePathNodeLength (DevicePath);
169 if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
173 if (NodeLength > MAX_UINTN - Size) {
179 // Validate next node before touch it.
181 if (Size > MaxSize - END_DEVICE_PATH_LENGTH ) {
185 if (PcdGet32 (PcdMaximumDevicePathNodeCount) > 0) {
187 if (Count >= PcdGet32 (PcdMaximumDevicePathNodeCount)) {
194 // Only return TRUE when the End Device Path node is valid.
196 return (BOOLEAN) (DevicePathNodeLength (DevicePath) == END_DEVICE_PATH_LENGTH);
200 Returns the Type field of a device path node.
202 Returns the Type field of the device path node specified by Node.
204 If Node is NULL, then ASSERT().
206 @param Node A pointer to a device path node data structure.
208 @return The Type field of the device path node specified by Node.
217 ASSERT (Node != NULL);
218 return ((const EFI_DEVICE_PATH_PROTOCOL *)(Node))->Type;
223 Returns the SubType field of a device path node.
225 Returns the SubType field of the device path node specified by Node.
227 If Node is NULL, then ASSERT().
229 @param Node A pointer to a device path node data structure.
231 @return The SubType field of the device path node specified by Node.
240 ASSERT (Node != NULL);
241 return ((const EFI_DEVICE_PATH_PROTOCOL *)(Node))->SubType;
245 Returns the 16-bit Length field of a device path node.
247 Returns the 16-bit Length field of the device path node specified by Node.
248 Node is not required to be aligned on a 16-bit boundary, so it is recommended
249 that a function such as ReadUnaligned16() be used to extract the contents of
252 If Node is NULL, then ASSERT().
254 @param Node A pointer to a device path node data structure.
256 @return The 16-bit Length field of the device path node specified by Node.
261 DevicePathNodeLength (
265 ASSERT (Node != NULL);
266 return ((const EFI_DEVICE_PATH_PROTOCOL *)Node)->Length[0] |
267 (((const EFI_DEVICE_PATH_PROTOCOL *)Node)->Length[1] << 8);
271 Returns a pointer to the next node in a device path.
273 Returns a pointer to the device path node that follows the device path node
276 If Node is NULL, then ASSERT().
278 @param Node A pointer to a device path node data structure.
280 @return a pointer to the device path node that follows the device path node
284 EFI_DEVICE_PATH_PROTOCOL *
290 ASSERT (Node != NULL);
291 return ((EFI_DEVICE_PATH_PROTOCOL *)(__DECONST(UINT8 *, Node) + DevicePathNodeLength(Node)));
295 Determines if a device path node is an end node of a device path.
296 This includes nodes that are the end of a device path instance and nodes that
297 are the end of an entire device path.
299 Determines if the device path node specified by Node is an end node of a device path.
300 This includes nodes that are the end of a device path instance and nodes that are the
301 end of an entire device path. If Node represents an end node of a device path,
302 then TRUE is returned. Otherwise, FALSE is returned.
304 If Node is NULL, then ASSERT().
306 @param Node A pointer to a device path node data structure.
308 @retval TRUE The device path node specified by Node is an end node of a
310 @retval FALSE The device path node specified by Node is not an end node of
316 IsDevicePathEndType (
320 ASSERT (Node != NULL);
321 return (BOOLEAN) (DevicePathType (Node) == END_DEVICE_PATH_TYPE);
325 Determines if a device path node is an end node of an entire device path.
327 Determines if a device path node specified by Node is an end node of an entire
328 device path. If Node represents the end of an entire device path, then TRUE is
329 returned. Otherwise, FALSE is returned.
331 If Node is NULL, then ASSERT().
333 @param Node A pointer to a device path node data structure.
335 @retval TRUE The device path node specified by Node is the end of an entire
337 @retval FALSE The device path node specified by Node is not the end of an
347 ASSERT (Node != NULL);
348 return (BOOLEAN) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_ENTIRE_DEVICE_PATH_SUBTYPE);
352 Fills in all the fields of a device path node that is the end of an entire device path.
354 Fills in all the fields of a device path node specified by Node so Node represents
355 the end of an entire device path. The Type field of Node is set to
356 END_DEVICE_PATH_TYPE, the SubType field of Node is set to
357 END_ENTIRE_DEVICE_PATH_SUBTYPE, and the Length field of Node is set to
358 END_DEVICE_PATH_LENGTH. Node is not required to be aligned on a 16-bit boundary,
359 so it is recommended that a function such as WriteUnaligned16() be used to set
360 the contents of the Length field.
362 If Node is NULL, then ASSERT().
364 @param Node A pointer to a device path node data structure.
369 SetDevicePathEndNode (
373 ASSERT (Node != NULL);
374 memcpy (Node, &mUefiDevicePathLibEndDevicePath, sizeof (mUefiDevicePathLibEndDevicePath));
378 Sets the length, in bytes, of a device path node.
380 Sets the length of the device path node specified by Node to the value specified
381 by NodeLength. NodeLength is returned. Node is not required to be aligned on
382 a 16-bit boundary, so it is recommended that a function such as WriteUnaligned16()
383 be used to set the contents of the Length field.
385 If Node is NULL, then ASSERT().
386 If NodeLength >= SIZE_64KB, then ASSERT().
387 If NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL), then ASSERT().
389 @param Node A pointer to a device path node data structure.
390 @param Length The length, in bytes, of the device path node.
397 SetDevicePathNodeLength (
402 ASSERT (Node != NULL);
403 ASSERT ((Length >= sizeof (EFI_DEVICE_PATH_PROTOCOL)) && (Length < SIZE_64KB));
404 // return WriteUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(Length));
405 le16enc(&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(Length));
410 Creates a device node.
412 This function creates a new device node in a newly allocated buffer of size
413 NodeLength and initializes the device path node header with NodeType and NodeSubType.
414 The new device path node is returned.
415 If NodeLength is smaller than a device path header, then NULL is returned.
416 If there is not enough memory to allocate space for the new device path, then
418 The memory is allocated from EFI boot services memory. It is the responsibility
419 of the caller to free the memory allocated.
421 @param NodeType The device node type for the new device node.
422 @param NodeSubType The device node sub-type for the new device node.
423 @param NodeLength The length of the new device node.
425 @return The new device path.
428 EFI_DEVICE_PATH_PROTOCOL *
432 IN UINT8 NodeSubType,
436 EFI_DEVICE_PATH_PROTOCOL *DevicePath;
438 if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
440 // NodeLength is less than the size of the header.
445 DevicePath = AllocateZeroPool (NodeLength);
446 if (DevicePath != NULL) {
447 DevicePath->Type = NodeType;
448 DevicePath->SubType = NodeSubType;
449 SetDevicePathNodeLength (DevicePath, NodeLength);
456 Creates a new copy of an existing device path.
458 This function allocates space for a new copy of the device path specified by DevicePath.
459 If DevicePath is NULL, then NULL is returned. If the memory is successfully
460 allocated, then the contents of DevicePath are copied to the newly allocated
461 buffer, and a pointer to that buffer is returned. Otherwise, NULL is returned.
462 The memory for the new device path is allocated from EFI boot services memory.
463 It is the responsibility of the caller to free the memory allocated.
465 @param DevicePath A pointer to a device path data structure.
467 @retval NULL DevicePath is NULL or invalid.
468 @retval Others A pointer to the duplicated device path.
471 EFI_DEVICE_PATH_PROTOCOL *
473 DuplicateDevicePath (
474 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
482 Size = GetDevicePathSize (DevicePath);
488 // Allocate space for duplicate device path
491 return AllocateCopyPool (Size, DevicePath);
495 Creates a new device path by appending a second device path to a first device path.
497 This function creates a new device path by appending a copy of SecondDevicePath
498 to a copy of FirstDevicePath in a newly allocated buffer. Only the end-of-device-path
499 device node from SecondDevicePath is retained. The newly created device path is
500 returned. If FirstDevicePath is NULL, then it is ignored, and a duplicate of
501 SecondDevicePath is returned. If SecondDevicePath is NULL, then it is ignored,
502 and a duplicate of FirstDevicePath is returned. If both FirstDevicePath and
503 SecondDevicePath are NULL, then a copy of an end-of-device-path is returned.
505 If there is not enough memory for the newly allocated buffer, then NULL is returned.
506 The memory for the new device path is allocated from EFI boot services memory.
507 It is the responsibility of the caller to free the memory allocated.
509 @param FirstDevicePath A pointer to a device path data structure.
510 @param SecondDevicePath A pointer to a device path data structure.
512 @retval NULL If there is not enough memory for the newly allocated buffer.
513 @retval NULL If FirstDevicePath or SecondDevicePath is invalid.
514 @retval Others A pointer to the new device path if success.
515 Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.
518 EFI_DEVICE_PATH_PROTOCOL *
521 IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath, OPTIONAL
522 IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath OPTIONAL
528 EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
529 EFI_DEVICE_PATH_PROTOCOL *DevicePath2;
532 // If there's only 1 path, just duplicate it.
534 if (FirstDevicePath == NULL) {
535 return DuplicateDevicePath ((SecondDevicePath != NULL) ? SecondDevicePath : &mUefiDevicePathLibEndDevicePath);
538 if (SecondDevicePath == NULL) {
539 return DuplicateDevicePath (FirstDevicePath);
542 if (!IsDevicePathValid (FirstDevicePath, 0) || !IsDevicePathValid (SecondDevicePath, 0)) {
547 // Allocate space for the combined device path. It only has one end node of
548 // length EFI_DEVICE_PATH_PROTOCOL.
550 Size1 = GetDevicePathSize (FirstDevicePath);
551 Size2 = GetDevicePathSize (SecondDevicePath);
552 Size = Size1 + Size2 - END_DEVICE_PATH_LENGTH;
554 NewDevicePath = AllocatePool (Size);
556 if (NewDevicePath != NULL) {
557 NewDevicePath = CopyMem (NewDevicePath, FirstDevicePath, Size1);
559 // Over write FirstDevicePath EndNode and do the copy
561 DevicePath2 = (EFI_DEVICE_PATH_PROTOCOL *) ((CHAR8 *) NewDevicePath +
562 (Size1 - END_DEVICE_PATH_LENGTH));
563 CopyMem (DevicePath2, SecondDevicePath, Size2);
566 return NewDevicePath;
570 Creates a new path by appending the device node to the device path.
572 This function creates a new device path by appending a copy of the device node
573 specified by DevicePathNode to a copy of the device path specified by DevicePath
574 in an allocated buffer. The end-of-device-path device node is moved after the
575 end of the appended device node.
576 If DevicePathNode is NULL then a copy of DevicePath is returned.
577 If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device
578 path device node is returned.
579 If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path
580 device node is returned.
581 If there is not enough memory to allocate space for the new device path, then
583 The memory is allocated from EFI boot services memory. It is the responsibility
584 of the caller to free the memory allocated.
586 @param DevicePath A pointer to a device path data structure.
587 @param DevicePathNode A pointer to a single device path node.
589 @retval NULL If there is not enough memory for the new device path.
590 @retval Others A pointer to the new device path if success.
591 A copy of DevicePathNode followed by an end-of-device-path node
592 if both FirstDevicePath and SecondDevicePath are NULL.
593 A copy of an end-of-device-path node if both FirstDevicePath
594 and SecondDevicePath are NULL.
597 EFI_DEVICE_PATH_PROTOCOL *
599 AppendDevicePathNode (
600 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
601 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode OPTIONAL
604 EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
605 EFI_DEVICE_PATH_PROTOCOL *NextNode;
606 EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
609 if (DevicePathNode == NULL) {
610 return DuplicateDevicePath ((DevicePath != NULL) ? DevicePath : &mUefiDevicePathLibEndDevicePath);
613 // Build a Node that has a terminator on it
615 NodeLength = DevicePathNodeLength (DevicePathNode);
617 TempDevicePath = AllocatePool (NodeLength + END_DEVICE_PATH_LENGTH);
618 if (TempDevicePath == NULL) {
621 TempDevicePath = CopyMem (TempDevicePath, DevicePathNode, NodeLength);
623 // Add and end device path node to convert Node to device path
625 NextNode = NextDevicePathNode (TempDevicePath);
626 SetDevicePathEndNode (NextNode);
628 // Append device paths
630 NewDevicePath = AppendDevicePath (DevicePath, TempDevicePath);
632 FreePool (TempDevicePath);
634 return NewDevicePath;