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
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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>
36 #include <sys/endian.h>
38 #include "efi-osdep.h"
40 #include "uefi-dplib.h"
42 /* XXX maybe I should include the entire DevicePathUtiltiies.c and ifdef out what we don't use */
45 * Taken from MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
46 * hash a11928f3310518ab1c6fd34e8d0fdbb72de9602c 2017-Mar-01
50 Device Path services. The thing to remember is device paths are built out of
51 nodes. The device path is terminated by an end node that is length
52 sizeof(EFI_DEVICE_PATH_PROTOCOL). That would be why there is sizeof(EFI_DEVICE_PATH_PROTOCOL)
55 The only place where multi-instance device paths are supported is in
56 environment varibles. Multi-instance device paths should never be placed
59 Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
60 This program and the accompanying materials
61 are licensed and made available under the terms and conditions of the BSD License
62 which accompanies this distribution. The full text of the license may be found at
63 http://opensource.org/licenses/bsd-license.php.
65 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
66 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
71 // Template for an end-of-device path node.
73 static CONST EFI_DEVICE_PATH_PROTOCOL mUefiDevicePathLibEndDevicePath = {
75 END_ENTIRE_DEVICE_PATH_SUBTYPE,
77 END_DEVICE_PATH_LENGTH,
84 Returns the size of a device path in bytes.
86 This function returns the size, in bytes, of the device path data structure
87 specified by DevicePath including the end of device path node.
88 If DevicePath is NULL or invalid, then 0 is returned.
90 @param DevicePath A pointer to a device path data structure.
92 @retval 0 If DevicePath is NULL or invalid.
93 @retval Others The size of a device path in bytes.
99 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
102 CONST EFI_DEVICE_PATH_PROTOCOL *Start;
104 if (DevicePath == NULL) {
108 if (!IsDevicePathValid (DevicePath, 0)) {
113 // Search for the end of the device path structure
116 while (!IsDevicePathEnd (DevicePath)) {
117 DevicePath = NextDevicePathNode (DevicePath);
121 // Compute the size and add back in the size of the end device path structure
123 return ((UINTN) DevicePath - (UINTN) Start) + DevicePathNodeLength (DevicePath);
127 Determine whether a given device path is valid.
128 If DevicePath is NULL, then ASSERT().
130 @param DevicePath A pointer to a device path data structure.
131 @param MaxSize The maximum size of the device path data structure.
133 @retval TRUE DevicePath is valid.
134 @retval FALSE The length of any node in the DevicePath is less
135 than sizeof (EFI_DEVICE_PATH_PROTOCOL).
136 @retval FALSE If MaxSize is not zero, the size of the DevicePath
138 @retval FALSE If PcdMaximumDevicePathNodeCount is not zero, the node
139 count of the DevicePath exceeds PcdMaximumDevicePathNodeCount.
144 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
152 ASSERT (DevicePath != NULL);
159 // Validate the input size big enough to touch the first node.
161 if (MaxSize < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
165 for (Count = 0, Size = 0; !IsDevicePathEnd (DevicePath); DevicePath = NextDevicePathNode (DevicePath)) {
166 NodeLength = DevicePathNodeLength (DevicePath);
167 if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
171 if (NodeLength > MAX_UINTN - Size) {
177 // Validate next node before touch it.
179 if (Size > MaxSize - END_DEVICE_PATH_LENGTH ) {
183 if (PcdGet32 (PcdMaximumDevicePathNodeCount) > 0) {
185 if (Count >= PcdGet32 (PcdMaximumDevicePathNodeCount)) {
192 // Only return TRUE when the End Device Path node is valid.
194 return (BOOLEAN) (DevicePathNodeLength (DevicePath) == END_DEVICE_PATH_LENGTH);
198 Returns the Type field of a device path node.
200 Returns the Type field of the device path node specified by Node.
202 If Node is NULL, then ASSERT().
204 @param Node A pointer to a device path node data structure.
206 @return The Type field of the device path node specified by Node.
215 ASSERT (Node != NULL);
216 return ((const EFI_DEVICE_PATH_PROTOCOL *)(Node))->Type;
221 Returns the SubType field of a device path node.
223 Returns the SubType field of the device path node specified by Node.
225 If Node is NULL, then ASSERT().
227 @param Node A pointer to a device path node data structure.
229 @return The SubType field of the device path node specified by Node.
238 ASSERT (Node != NULL);
239 return ((const EFI_DEVICE_PATH_PROTOCOL *)(Node))->SubType;
243 Returns the 16-bit Length field of a device path node.
245 Returns the 16-bit Length field of the device path node specified by Node.
246 Node is not required to be aligned on a 16-bit boundary, so it is recommended
247 that a function such as ReadUnaligned16() be used to extract the contents of
250 If Node is NULL, then ASSERT().
252 @param Node A pointer to a device path node data structure.
254 @return The 16-bit Length field of the device path node specified by Node.
259 DevicePathNodeLength (
263 ASSERT (Node != NULL);
264 return ((const EFI_DEVICE_PATH_PROTOCOL *)Node)->Length[0] |
265 (((const EFI_DEVICE_PATH_PROTOCOL *)Node)->Length[1] << 8);
269 Returns a pointer to the next node in a device path.
271 Returns a pointer to the device path node that follows the device path node
274 If Node is NULL, then ASSERT().
276 @param Node A pointer to a device path node data structure.
278 @return a pointer to the device path node that follows the device path node
282 EFI_DEVICE_PATH_PROTOCOL *
288 ASSERT (Node != NULL);
289 return ((EFI_DEVICE_PATH_PROTOCOL *)(__DECONST(UINT8 *, Node) + DevicePathNodeLength(Node)));
293 Determines if a device path node is an end node of a device path.
294 This includes nodes that are the end of a device path instance and nodes that
295 are the end of an entire device path.
297 Determines if the device path node specified by Node is an end node of a device path.
298 This includes nodes that are the end of a device path instance and nodes that are the
299 end of an entire device path. If Node represents an end node of a device path,
300 then TRUE is returned. Otherwise, FALSE is returned.
302 If Node is NULL, then ASSERT().
304 @param Node A pointer to a device path node data structure.
306 @retval TRUE The device path node specified by Node is an end node of a
308 @retval FALSE The device path node specified by Node is not an end node of
314 IsDevicePathEndType (
318 ASSERT (Node != NULL);
319 return (BOOLEAN) (DevicePathType (Node) == END_DEVICE_PATH_TYPE);
323 Determines if a device path node is an end node of an entire device path.
325 Determines if a device path node specified by Node is an end node of an entire
326 device path. If Node represents the end of an entire device path, then TRUE is
327 returned. Otherwise, FALSE is returned.
329 If Node is NULL, then ASSERT().
331 @param Node A pointer to a device path node data structure.
333 @retval TRUE The device path node specified by Node is the end of an entire
335 @retval FALSE The device path node specified by Node is not the end of an
345 ASSERT (Node != NULL);
346 return (BOOLEAN) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_ENTIRE_DEVICE_PATH_SUBTYPE);
350 Fills in all the fields of a device path node that is the end of an entire device path.
352 Fills in all the fields of a device path node specified by Node so Node represents
353 the end of an entire device path. The Type field of Node is set to
354 END_DEVICE_PATH_TYPE, the SubType field of Node is set to
355 END_ENTIRE_DEVICE_PATH_SUBTYPE, and the Length field of Node is set to
356 END_DEVICE_PATH_LENGTH. Node is not required to be aligned on a 16-bit boundary,
357 so it is recommended that a function such as WriteUnaligned16() be used to set
358 the contents of the Length field.
360 If Node is NULL, then ASSERT().
362 @param Node A pointer to a device path node data structure.
367 SetDevicePathEndNode (
371 ASSERT (Node != NULL);
372 memcpy (Node, &mUefiDevicePathLibEndDevicePath, sizeof (mUefiDevicePathLibEndDevicePath));
376 Sets the length, in bytes, of a device path node.
378 Sets the length of the device path node specified by Node to the value specified
379 by NodeLength. NodeLength is returned. Node is not required to be aligned on
380 a 16-bit boundary, so it is recommended that a function such as WriteUnaligned16()
381 be used to set the contents of the Length field.
383 If Node is NULL, then ASSERT().
384 If NodeLength >= SIZE_64KB, then ASSERT().
385 If NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL), then ASSERT().
387 @param Node A pointer to a device path node data structure.
388 @param Length The length, in bytes, of the device path node.
395 SetDevicePathNodeLength (
400 ASSERT (Node != NULL);
401 ASSERT ((Length >= sizeof (EFI_DEVICE_PATH_PROTOCOL)) && (Length < SIZE_64KB));
402 // return WriteUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(Length));
403 le16enc(&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(Length));
408 Creates a device node.
410 This function creates a new device node in a newly allocated buffer of size
411 NodeLength and initializes the device path node header with NodeType and NodeSubType.
412 The new device path node is returned.
413 If NodeLength is smaller than a device path header, then NULL is returned.
414 If there is not enough memory to allocate space for the new device path, then
416 The memory is allocated from EFI boot services memory. It is the responsibility
417 of the caller to free the memory allocated.
419 @param NodeType The device node type for the new device node.
420 @param NodeSubType The device node sub-type for the new device node.
421 @param NodeLength The length of the new device node.
423 @return The new device path.
426 EFI_DEVICE_PATH_PROTOCOL *
430 IN UINT8 NodeSubType,
434 EFI_DEVICE_PATH_PROTOCOL *DevicePath;
436 if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
438 // NodeLength is less than the size of the header.
443 DevicePath = AllocateZeroPool (NodeLength);
444 if (DevicePath != NULL) {
445 DevicePath->Type = NodeType;
446 DevicePath->SubType = NodeSubType;
447 SetDevicePathNodeLength (DevicePath, NodeLength);
454 Creates a new copy of an existing device path.
456 This function allocates space for a new copy of the device path specified by DevicePath.
457 If DevicePath is NULL, then NULL is returned. If the memory is successfully
458 allocated, then the contents of DevicePath are copied to the newly allocated
459 buffer, and a pointer to that buffer is returned. Otherwise, NULL is returned.
460 The memory for the new device path is allocated from EFI boot services memory.
461 It is the responsibility of the caller to free the memory allocated.
463 @param DevicePath A pointer to a device path data structure.
465 @retval NULL DevicePath is NULL or invalid.
466 @retval Others A pointer to the duplicated device path.
469 EFI_DEVICE_PATH_PROTOCOL *
471 DuplicateDevicePath (
472 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
480 Size = GetDevicePathSize (DevicePath);
486 // Allocate space for duplicate device path
489 return AllocateCopyPool (Size, DevicePath);
493 Creates a new device path by appending a second device path to a first device path.
495 This function creates a new device path by appending a copy of SecondDevicePath
496 to a copy of FirstDevicePath in a newly allocated buffer. Only the end-of-device-path
497 device node from SecondDevicePath is retained. The newly created device path is
498 returned. If FirstDevicePath is NULL, then it is ignored, and a duplicate of
499 SecondDevicePath is returned. If SecondDevicePath is NULL, then it is ignored,
500 and a duplicate of FirstDevicePath is returned. If both FirstDevicePath and
501 SecondDevicePath are NULL, then a copy of an end-of-device-path is returned.
503 If there is not enough memory for the newly allocated buffer, then NULL is returned.
504 The memory for the new device path is allocated from EFI boot services memory.
505 It is the responsibility of the caller to free the memory allocated.
507 @param FirstDevicePath A pointer to a device path data structure.
508 @param SecondDevicePath A pointer to a device path data structure.
510 @retval NULL If there is not enough memory for the newly allocated buffer.
511 @retval NULL If FirstDevicePath or SecondDevicePath is invalid.
512 @retval Others A pointer to the new device path if success.
513 Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.
516 EFI_DEVICE_PATH_PROTOCOL *
519 IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath, OPTIONAL
520 IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath OPTIONAL
526 EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
527 EFI_DEVICE_PATH_PROTOCOL *DevicePath2;
530 // If there's only 1 path, just duplicate it.
532 if (FirstDevicePath == NULL) {
533 return DuplicateDevicePath ((SecondDevicePath != NULL) ? SecondDevicePath : &mUefiDevicePathLibEndDevicePath);
536 if (SecondDevicePath == NULL) {
537 return DuplicateDevicePath (FirstDevicePath);
540 if (!IsDevicePathValid (FirstDevicePath, 0) || !IsDevicePathValid (SecondDevicePath, 0)) {
545 // Allocate space for the combined device path. It only has one end node of
546 // length EFI_DEVICE_PATH_PROTOCOL.
548 Size1 = GetDevicePathSize (FirstDevicePath);
549 Size2 = GetDevicePathSize (SecondDevicePath);
550 Size = Size1 + Size2 - END_DEVICE_PATH_LENGTH;
552 NewDevicePath = AllocatePool (Size);
554 if (NewDevicePath != NULL) {
555 NewDevicePath = CopyMem (NewDevicePath, FirstDevicePath, Size1);
557 // Over write FirstDevicePath EndNode and do the copy
559 DevicePath2 = (EFI_DEVICE_PATH_PROTOCOL *) ((CHAR8 *) NewDevicePath +
560 (Size1 - END_DEVICE_PATH_LENGTH));
561 CopyMem (DevicePath2, SecondDevicePath, Size2);
564 return NewDevicePath;
568 Creates a new path by appending the device node to the device path.
570 This function creates a new device path by appending a copy of the device node
571 specified by DevicePathNode to a copy of the device path specified by DevicePath
572 in an allocated buffer. The end-of-device-path device node is moved after the
573 end of the appended device node.
574 If DevicePathNode is NULL then a copy of DevicePath is returned.
575 If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device
576 path device node is returned.
577 If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path
578 device node is returned.
579 If there is not enough memory to allocate space for the new device path, then
581 The memory is allocated from EFI boot services memory. It is the responsibility
582 of the caller to free the memory allocated.
584 @param DevicePath A pointer to a device path data structure.
585 @param DevicePathNode A pointer to a single device path node.
587 @retval NULL If there is not enough memory for the new device path.
588 @retval Others A pointer to the new device path if success.
589 A copy of DevicePathNode followed by an end-of-device-path node
590 if both FirstDevicePath and SecondDevicePath are NULL.
591 A copy of an end-of-device-path node if both FirstDevicePath
592 and SecondDevicePath are NULL.
595 EFI_DEVICE_PATH_PROTOCOL *
597 AppendDevicePathNode (
598 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
599 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode OPTIONAL
602 EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
603 EFI_DEVICE_PATH_PROTOCOL *NextNode;
604 EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
607 if (DevicePathNode == NULL) {
608 return DuplicateDevicePath ((DevicePath != NULL) ? DevicePath : &mUefiDevicePathLibEndDevicePath);
611 // Build a Node that has a terminator on it
613 NodeLength = DevicePathNodeLength (DevicePathNode);
615 TempDevicePath = AllocatePool (NodeLength + END_DEVICE_PATH_LENGTH);
616 if (TempDevicePath == NULL) {
619 TempDevicePath = CopyMem (TempDevicePath, DevicePathNode, NodeLength);
621 // Add and end device path node to convert Node to device path
623 NextNode = NextDevicePathNode (TempDevicePath);
624 SetDevicePathEndNode (NextNode);
626 // Append device paths
628 NewDevicePath = AppendDevicePath (DevicePath, TempDevicePath);
630 FreePool (TempDevicePath);
632 return NewDevicePath;