diff options
| author | Ruiyu Ni <ruiyu.ni@intel.com> | 2013-07-26 03:00:21 +0000 |
|---|---|---|
| committer | niruiyu <niruiyu@6f19259b-4bc3-4df7-8a09-765794883524> | 2013-07-26 03:00:21 +0000 |
| commit | 4d0a30a494599226450bf69ad9d6fc689f61712e (patch) | |
| tree | a5b8f92e8ef899771952d4d0b9b215b7113906c4 /MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c | |
| parent | 1fd4578528e62646025f3eabb3d059c308516e71 (diff) | |
| download | edk2-4d0a30a494599226450bf69ad9d6fc689f61712e.tar.gz edk2-4d0a30a494599226450bf69ad9d6fc689f61712e.tar.bz2 edk2-4d0a30a494599226450bf69ad9d6fc689f61712e.zip | |
Add 4 APIs to DevicePathLib: ConvertDeviceNodeToText, ConvertDevicePathToText, ConvertTextToDeviceNode and ConvertTextToDevicePath.
Add a new instance of DevicePathLib which tries to locate the protocol and if it's not found, it uses the internal functions.
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14504 6f19259b-4bc3-4df7-8a09-765794883524
Diffstat (limited to 'MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c')
| -rw-r--r-- | MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c | 882 |
1 files changed, 882 insertions, 0 deletions
diff --git a/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c b/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c new file mode 100644 index 0000000000..b48bf02ae8 --- /dev/null +++ b/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c @@ -0,0 +1,882 @@ +/** @file
+ Device Path services. The thing to remember is device paths are built out of
+ nodes. The device path is terminated by an end node that is length
+ sizeof(EFI_DEVICE_PATH_PROTOCOL). That would be why there is sizeof(EFI_DEVICE_PATH_PROTOCOL)
+ all over this file.
+
+ The only place where multi-instance device paths are supported is in
+ environment varibles. Multi-instance device paths should never be placed
+ on a Handle.
+
+ Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
+ This program and the accompanying materials
+ are licensed and made available under the terms and conditions of the BSD License
+ which accompanies this distribution. The full text of the license may be found at
+ http://opensource.org/licenses/bsd-license.php.
+
+ THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include "UefiDevicePathLib.h"
+
+//
+// Template for an end-of-device path node.
+//
+GLOBAL_REMOVE_IF_UNREFERENCED CONST EFI_DEVICE_PATH_PROTOCOL mUefiDevicePathLibEndDevicePath = {
+ END_DEVICE_PATH_TYPE,
+ END_ENTIRE_DEVICE_PATH_SUBTYPE,
+ {
+ END_DEVICE_PATH_LENGTH,
+ 0
+ }
+};
+
+/**
+ Determine whether a given device path is valid.
+ If DevicePath is NULL, then ASSERT().
+
+ @param DevicePath A pointer to a device path data structure.
+ @param MaxSize The maximum size of the device path data structure.
+
+ @retval TRUE DevicePath is valid.
+ @retval FALSE The length of any node node in the DevicePath is less
+ than sizeof (EFI_DEVICE_PATH_PROTOCOL).
+ @retval FALSE If MaxSize is not zero, the size of the DevicePath
+ exceeds MaxSize.
+ @retval FALSE If PcdMaximumDevicePathNodeCount is not zero, the node
+ count of the DevicePath exceeds PcdMaximumDevicePathNodeCount.
+**/
+BOOLEAN
+EFIAPI
+IsDevicePathValid (
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
+ IN UINTN MaxSize
+ )
+{
+ UINTN Count;
+ UINTN Size;
+ UINTN NodeLength;
+
+ ASSERT (DevicePath != NULL);
+
+ for (Count = 0, Size = 0; !IsDevicePathEnd (DevicePath); DevicePath = NextDevicePathNode (DevicePath)) {
+ NodeLength = DevicePathNodeLength (DevicePath);
+ if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
+ return FALSE;
+ }
+
+ if (MaxSize > 0) {
+ Size += NodeLength;
+ if (Size + END_DEVICE_PATH_LENGTH > MaxSize) {
+ return FALSE;
+ }
+ }
+
+ if (PcdGet32 (PcdMaximumDevicePathNodeCount) > 0) {
+ Count++;
+ if (Count >= PcdGet32 (PcdMaximumDevicePathNodeCount)) {
+ return FALSE;
+ }
+ }
+ }
+
+ //
+ // Only return TRUE when the End Device Path node is valid.
+ //
+ return (BOOLEAN) (DevicePathNodeLength (DevicePath) == END_DEVICE_PATH_LENGTH);
+}
+
+/**
+ Returns the Type field of a device path node.
+
+ Returns the Type field of the device path node specified by Node.
+
+ If Node is NULL, then ASSERT().
+
+ @param Node A pointer to a device path node data structure.
+
+ @return The Type field of the device path node specified by Node.
+
+**/
+UINT8
+EFIAPI
+DevicePathType (
+ IN CONST VOID *Node
+ )
+{
+ ASSERT (Node != NULL);
+ return ((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Type;
+}
+
+/**
+ Returns the SubType field of a device path node.
+
+ Returns the SubType field of the device path node specified by Node.
+
+ If Node is NULL, then ASSERT().
+
+ @param Node A pointer to a device path node data structure.
+
+ @return The SubType field of the device path node specified by Node.
+
+**/
+UINT8
+EFIAPI
+DevicePathSubType (
+ IN CONST VOID *Node
+ )
+{
+ ASSERT (Node != NULL);
+ return ((EFI_DEVICE_PATH_PROTOCOL *)(Node))->SubType;
+}
+
+/**
+ Returns the 16-bit Length field of a device path node.
+
+ Returns the 16-bit Length field of the device path node specified by Node.
+ Node is not required to be aligned on a 16-bit boundary, so it is recommended
+ that a function such as ReadUnaligned16() be used to extract the contents of
+ the Length field.
+
+ If Node is NULL, then ASSERT().
+
+ @param Node A pointer to a device path node data structure.
+
+ @return The 16-bit Length field of the device path node specified by Node.
+
+**/
+UINTN
+EFIAPI
+DevicePathNodeLength (
+ IN CONST VOID *Node
+ )
+{
+ UINTN Length;
+
+ ASSERT (Node != NULL);
+ Length = ReadUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0]);
+ ASSERT (Length >= sizeof (EFI_DEVICE_PATH_PROTOCOL));
+ return Length;
+}
+
+/**
+ Returns a pointer to the next node in a device path.
+
+ Returns a pointer to the device path node that follows the device path node
+ specified by Node.
+
+ If Node is NULL, then ASSERT().
+
+ @param Node A pointer to a device path node data structure.
+
+ @return a pointer to the device path node that follows the device path node
+ specified by Node.
+
+**/
+EFI_DEVICE_PATH_PROTOCOL *
+EFIAPI
+NextDevicePathNode (
+ IN CONST VOID *Node
+ )
+{
+ ASSERT (Node != NULL);
+ return (EFI_DEVICE_PATH_PROTOCOL *)((UINT8 *)(Node) + DevicePathNodeLength(Node));
+}
+
+/**
+ Determines if a device path node is an end node of a device path.
+ This includes nodes that are the end of a device path instance and nodes that
+ are the end of an entire device path.
+
+ Determines if the device path node specified by Node is an end node of a device path.
+ This includes nodes that are the end of a device path instance and nodes that are the
+ end of an entire device path. If Node represents an end node of a device path,
+ then TRUE is returned. Otherwise, FALSE is returned.
+
+ If Node is NULL, then ASSERT().
+
+ @param Node A pointer to a device path node data structure.
+
+ @retval TRUE The device path node specified by Node is an end node of a
+ device path.
+ @retval FALSE The device path node specified by Node is not an end node of
+ a device path.
+
+**/
+BOOLEAN
+EFIAPI
+IsDevicePathEndType (
+ IN CONST VOID *Node
+ )
+{
+ ASSERT (Node != NULL);
+ return (BOOLEAN) (DevicePathType (Node) == END_DEVICE_PATH_TYPE);
+}
+
+/**
+ Determines if a device path node is an end node of an entire device path.
+
+ Determines if a device path node specified by Node is an end node of an entire
+ device path. If Node represents the end of an entire device path, then TRUE is
+ returned. Otherwise, FALSE is returned.
+
+ If Node is NULL, then ASSERT().
+
+ @param Node A pointer to a device path node data structure.
+
+ @retval TRUE The device path node specified by Node is the end of an entire
+ device path.
+ @retval FALSE The device path node specified by Node is not the end of an
+ entire device path.
+
+**/
+BOOLEAN
+EFIAPI
+IsDevicePathEnd (
+ IN CONST VOID *Node
+ )
+{
+ ASSERT (Node != NULL);
+ return (BOOLEAN) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_ENTIRE_DEVICE_PATH_SUBTYPE);
+}
+
+/**
+ Determines if a device path node is an end node of a device path instance.
+
+ Determines if a device path node specified by Node is an end node of a device
+ path instance. If Node represents the end of a device path instance, then TRUE
+ is returned. Otherwise, FALSE is returned.
+
+ If Node is NULL, then ASSERT().
+
+ @param Node A pointer to a device path node data structure.
+
+ @retval TRUE The device path node specified by Node is the end of a device
+ path instance.
+ @retval FALSE The device path node specified by Node is not the end of a
+ device path instance.
+
+**/
+BOOLEAN
+EFIAPI
+IsDevicePathEndInstance (
+ IN CONST VOID *Node
+ )
+{
+ ASSERT (Node != NULL);
+ return (BOOLEAN) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_INSTANCE_DEVICE_PATH_SUBTYPE);
+}
+
+/**
+ Sets the length, in bytes, of a device path node.
+
+ Sets the length of the device path node specified by Node to the value specified
+ by NodeLength. NodeLength is returned. Node is not required to be aligned on
+ a 16-bit boundary, so it is recommended that a function such as WriteUnaligned16()
+ be used to set the contents of the Length field.
+
+ If Node is NULL, then ASSERT().
+ If NodeLength >= SIZE_64KB, then ASSERT().
+ If NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL), then ASSERT().
+
+ @param Node A pointer to a device path node data structure.
+ @param Length The length, in bytes, of the device path node.
+
+ @return Length
+
+**/
+UINT16
+EFIAPI
+SetDevicePathNodeLength (
+ IN OUT VOID *Node,
+ IN UINTN Length
+ )
+{
+ ASSERT (Node != NULL);
+ ASSERT ((Length >= sizeof (EFI_DEVICE_PATH_PROTOCOL)) && (Length < SIZE_64KB));
+ return WriteUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(Length));
+}
+
+/**
+ Fills in all the fields of a device path node that is the end of an entire device path.
+
+ Fills in all the fields of a device path node specified by Node so Node represents
+ the end of an entire device path. The Type field of Node is set to
+ END_DEVICE_PATH_TYPE, the SubType field of Node is set to
+ END_ENTIRE_DEVICE_PATH_SUBTYPE, and the Length field of Node is set to
+ END_DEVICE_PATH_LENGTH. Node is not required to be aligned on a 16-bit boundary,
+ so it is recommended that a function such as WriteUnaligned16() be used to set
+ the contents of the Length field.
+
+ If Node is NULL, then ASSERT().
+
+ @param Node A pointer to a device path node data structure.
+
+**/
+VOID
+EFIAPI
+SetDevicePathEndNode (
+ OUT VOID *Node
+ )
+{
+ ASSERT (Node != NULL);
+ CopyMem (Node, &mUefiDevicePathLibEndDevicePath, sizeof (mUefiDevicePathLibEndDevicePath));
+}
+
+/**
+ Returns the size of a device path in bytes.
+
+ This function returns the size, in bytes, of the device path data structure
+ specified by DevicePath including the end of device path node.
+ If DevicePath is NULL or invalid, then 0 is returned.
+
+ @param DevicePath A pointer to a device path data structure.
+
+ @retval 0 If DevicePath is NULL or invalid.
+ @retval Others The size of a device path in bytes.
+
+**/
+UINTN
+EFIAPI
+UefiDevicePathLibGetDevicePathSize (
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
+ )
+{
+ CONST EFI_DEVICE_PATH_PROTOCOL *Start;
+
+ if (DevicePath == NULL) {
+ return 0;
+ }
+
+ if (!IsDevicePathValid (DevicePath, 0)) {
+ return 0;
+ }
+
+ //
+ // Search for the end of the device path structure
+ //
+ Start = DevicePath;
+ while (!IsDevicePathEnd (DevicePath)) {
+ DevicePath = NextDevicePathNode (DevicePath);
+ }
+
+ //
+ // Compute the size and add back in the size of the end device path structure
+ //
+ return ((UINTN) DevicePath - (UINTN) Start) + DevicePathNodeLength (DevicePath);
+}
+
+/**
+ Creates a new copy of an existing device path.
+
+ This function allocates space for a new copy of the device path specified by DevicePath.
+ If DevicePath is NULL, then NULL is returned. If the memory is successfully
+ allocated, then the contents of DevicePath are copied to the newly allocated
+ buffer, and a pointer to that buffer is returned. Otherwise, NULL is returned.
+ The memory for the new device path is allocated from EFI boot services memory.
+ It is the responsibility of the caller to free the memory allocated.
+
+ @param DevicePath A pointer to a device path data structure.
+
+ @retval NULL DevicePath is NULL or invalid.
+ @retval Others A pointer to the duplicated device path.
+
+**/
+EFI_DEVICE_PATH_PROTOCOL *
+EFIAPI
+UefiDevicePathLibDuplicateDevicePath (
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
+ )
+{
+ UINTN Size;
+
+ //
+ // Compute the size
+ //
+ Size = GetDevicePathSize (DevicePath);
+ if (Size == 0) {
+ return NULL;
+ }
+
+ //
+ // Allocate space for duplicate device path
+ //
+
+ return AllocateCopyPool (Size, DevicePath);
+}
+
+/**
+ Creates a new device path by appending a second device path to a first device path.
+
+ This function creates a new device path by appending a copy of SecondDevicePath
+ to a copy of FirstDevicePath in a newly allocated buffer. Only the end-of-device-path
+ device node from SecondDevicePath is retained. The newly created device path is
+ returned. If FirstDevicePath is NULL, then it is ignored, and a duplicate of
+ SecondDevicePath is returned. If SecondDevicePath is NULL, then it is ignored,
+ and a duplicate of FirstDevicePath is returned. If both FirstDevicePath and
+ SecondDevicePath are NULL, then a copy of an end-of-device-path is returned.
+
+ If there is not enough memory for the newly allocated buffer, then NULL is returned.
+ The memory for the new device path is allocated from EFI boot services memory.
+ It is the responsibility of the caller to free the memory allocated.
+
+ @param FirstDevicePath A pointer to a device path data structure.
+ @param SecondDevicePath A pointer to a device path data structure.
+
+ @retval NULL If there is not enough memory for the newly allocated buffer.
+ @retval NULL If FirstDevicePath or SecondDevicePath is invalid.
+ @retval Others A pointer to the new device path if success.
+ Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.
+
+**/
+EFI_DEVICE_PATH_PROTOCOL *
+EFIAPI
+UefiDevicePathLibAppendDevicePath (
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath, OPTIONAL
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath OPTIONAL
+ )
+{
+ UINTN Size;
+ UINTN Size1;
+ UINTN Size2;
+ EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
+ EFI_DEVICE_PATH_PROTOCOL *DevicePath2;
+
+ //
+ // If there's only 1 path, just duplicate it.
+ //
+ if (FirstDevicePath == NULL) {
+ return DuplicateDevicePath ((SecondDevicePath != NULL) ? SecondDevicePath : &mUefiDevicePathLibEndDevicePath);
+ }
+
+ if (SecondDevicePath == NULL) {
+ return DuplicateDevicePath (FirstDevicePath);
+ }
+
+ if (!IsDevicePathValid (FirstDevicePath, 0) || !IsDevicePathValid (SecondDevicePath, 0)) {
+ return NULL;
+ }
+
+ //
+ // Allocate space for the combined device path. It only has one end node of
+ // length EFI_DEVICE_PATH_PROTOCOL.
+ //
+ Size1 = GetDevicePathSize (FirstDevicePath);
+ Size2 = GetDevicePathSize (SecondDevicePath);
+ Size = Size1 + Size2 - END_DEVICE_PATH_LENGTH;
+
+ NewDevicePath = AllocatePool (Size);
+
+ if (NewDevicePath != NULL) {
+ NewDevicePath = CopyMem (NewDevicePath, FirstDevicePath, Size1);
+ //
+ // Over write FirstDevicePath EndNode and do the copy
+ //
+ DevicePath2 = (EFI_DEVICE_PATH_PROTOCOL *) ((CHAR8 *) NewDevicePath +
+ (Size1 - END_DEVICE_PATH_LENGTH));
+ CopyMem (DevicePath2, SecondDevicePath, Size2);
+ }
+
+ return NewDevicePath;
+}
+
+/**
+ Creates a new path by appending the device node to the device path.
+
+ This function creates a new device path by appending a copy of the device node
+ specified by DevicePathNode to a copy of the device path specified by DevicePath
+ in an allocated buffer. The end-of-device-path device node is moved after the
+ end of the appended device node.
+ If DevicePathNode is NULL then a copy of DevicePath is returned.
+ If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device
+ path device node is returned.
+ If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path
+ device node is returned.
+ If there is not enough memory to allocate space for the new device path, then
+ NULL is returned.
+ The memory is allocated from EFI boot services memory. It is the responsibility
+ of the caller to free the memory allocated.
+
+ @param DevicePath A pointer to a device path data structure.
+ @param DevicePathNode A pointer to a single device path node.
+
+ @retval NULL If there is not enough memory for the new device path.
+ @retval Others A pointer to the new device path if success.
+ A copy of DevicePathNode followed by an end-of-device-path node
+ if both FirstDevicePath and SecondDevicePath are NULL.
+ A copy of an end-of-device-path node if both FirstDevicePath
+ and SecondDevicePath are NULL.
+
+**/
+EFI_DEVICE_PATH_PROTOCOL *
+EFIAPI
+UefiDevicePathLibAppendDevicePathNode (
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode OPTIONAL
+ )
+{
+ EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
+ EFI_DEVICE_PATH_PROTOCOL *NextNode;
+ EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
+ UINTN NodeLength;
+
+ if (DevicePathNode == NULL) {
+ return DuplicateDevicePath ((DevicePath != NULL) ? DevicePath : &mUefiDevicePathLibEndDevicePath);
+ }
+ //
+ // Build a Node that has a terminator on it
+ //
+ NodeLength = DevicePathNodeLength (DevicePathNode);
+
+ TempDevicePath = AllocatePool (NodeLength + END_DEVICE_PATH_LENGTH);
+ if (TempDevicePath == NULL) {
+ return NULL;
+ }
+ TempDevicePath = CopyMem (TempDevicePath, DevicePathNode, NodeLength);
+ //
+ // Add and end device path node to convert Node to device path
+ //
+ NextNode = NextDevicePathNode (TempDevicePath);
+ SetDevicePathEndNode (NextNode);
+ //
+ // Append device paths
+ //
+ NewDevicePath = AppendDevicePath (DevicePath, TempDevicePath);
+
+ FreePool (TempDevicePath);
+
+ return NewDevicePath;
+}
+
+/**
+ Creates a new device path by appending the specified device path instance to the specified device
+ path.
+
+ This function creates a new device path by appending a copy of the device path
+ instance specified by DevicePathInstance to a copy of the device path specified
+ by DevicePath in a allocated buffer.
+ The end-of-device-path device node is moved after the end of the appended device
+ path instance and a new end-of-device-path-instance node is inserted between.
+ If DevicePath is NULL, then a copy if DevicePathInstance is returned.
+ If DevicePathInstance is NULL, then NULL is returned.
+ If DevicePath or DevicePathInstance is invalid, then NULL is returned.
+ If there is not enough memory to allocate space for the new device path, then
+ NULL is returned.
+ The memory is allocated from EFI boot services memory. It is the responsibility
+ of the caller to free the memory allocated.
+
+ @param DevicePath A pointer to a device path data structure.
+ @param DevicePathInstance A pointer to a device path instance.
+
+ @return A pointer to the new device path.
+
+**/
+EFI_DEVICE_PATH_PROTOCOL *
+EFIAPI
+UefiDevicePathLibAppendDevicePathInstance (
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathInstance OPTIONAL
+ )
+{
+ EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
+ EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
+ UINTN SrcSize;
+ UINTN InstanceSize;
+
+ if (DevicePath == NULL) {
+ return DuplicateDevicePath (DevicePathInstance);
+ }
+
+ if (DevicePathInstance == NULL) {
+ return NULL;
+ }
+
+ if (!IsDevicePathValid (DevicePath, 0) || !IsDevicePathValid (DevicePathInstance, 0)) {
+ return NULL;
+ }
+
+ SrcSize = GetDevicePathSize (DevicePath);
+ InstanceSize = GetDevicePathSize (DevicePathInstance);
+
+ NewDevicePath = AllocatePool (SrcSize + InstanceSize);
+ if (NewDevicePath != NULL) {
+
+ TempDevicePath = CopyMem (NewDevicePath, DevicePath, SrcSize);;
+
+ while (!IsDevicePathEnd (TempDevicePath)) {
+ TempDevicePath = NextDevicePathNode (TempDevicePath);
+ }
+
+ TempDevicePath->SubType = END_INSTANCE_DEVICE_PATH_SUBTYPE;
+ TempDevicePath = NextDevicePathNode (TempDevicePath);
+ CopyMem (TempDevicePath, DevicePathInstance, InstanceSize);
+ }
+
+ return NewDevicePath;
+}
+
+/**
+ Creates a copy of the current device path instance and returns a pointer to the next device path
+ instance.
+
+ This function creates a copy of the current device path instance. It also updates
+ DevicePath to point to the next device path instance in the device path (or NULL
+ if no more) and updates Size to hold the size of the device path instance copy.
+ If DevicePath is NULL, then NULL is returned.
+ If DevicePath points to a invalid device path, then NULL is returned.
+ If there is not enough memory to allocate space for the new device path, then
+ NULL is returned.
+ The memory is allocated from EFI boot services memory. It is the responsibility
+ of the caller to free the memory allocated.
+ If Size is NULL, then ASSERT().
+
+ @param DevicePath On input, this holds the pointer to the current
+ device path instance. On output, this holds
+ the pointer to the next device path instance
+ or NULL if there are no more device path
+ instances in the device path pointer to a
+ device path data structure.
+ @param Size On output, this holds the size of the device
+ path instance, in bytes or zero, if DevicePath
+ is NULL.
+
+ @return A pointer to the current device path instance.
+
+**/
+EFI_DEVICE_PATH_PROTOCOL *
+EFIAPI
+UefiDevicePathLibGetNextDevicePathInstance (
+ IN OUT EFI_DEVICE_PATH_PROTOCOL **DevicePath,
+ OUT UINTN *Size
+ )
+{
+ EFI_DEVICE_PATH_PROTOCOL *DevPath;
+ EFI_DEVICE_PATH_PROTOCOL *ReturnValue;
+ UINT8 Temp;
+
+ ASSERT (Size != NULL);
+
+ if (DevicePath == NULL || *DevicePath == NULL) {
+ *Size = 0;
+ return NULL;
+ }
+
+ if (!IsDevicePathValid (*DevicePath, 0)) {
+ return NULL;
+ }
+
+ //
+ // Find the end of the device path instance
+ //
+ DevPath = *DevicePath;
+ while (!IsDevicePathEndType (DevPath)) {
+ DevPath = NextDevicePathNode (DevPath);
+ }
+
+ //
+ // Compute the size of the device path instance
+ //
+ *Size = ((UINTN) DevPath - (UINTN) (*DevicePath)) + sizeof (EFI_DEVICE_PATH_PROTOCOL);
+
+ //
+ // Make a copy and return the device path instance
+ //
+ Temp = DevPath->SubType;
+ DevPath->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
+ ReturnValue = DuplicateDevicePath (*DevicePath);
+ DevPath->SubType = Temp;
+
+ //
+ // If DevPath is the end of an entire device path, then another instance
+ // does not follow, so *DevicePath is set to NULL.
+ //
+ if (DevicePathSubType (DevPath) == END_ENTIRE_DEVICE_PATH_SUBTYPE) {
+ *DevicePath = NULL;
+ } else {
+ *DevicePath = NextDevicePathNode (DevPath);
+ }
+
+ return ReturnValue;
+}
+
+/**
+ Creates a device node.
+
+ This function creates a new device node in a newly allocated buffer of size
+ NodeLength and initializes the device path node header with NodeType and NodeSubType.
+ The new device path node is returned.
+ If NodeLength is smaller than a device path header, then NULL is returned.
+ If there is not enough memory to allocate space for the new device path, then
+ NULL is returned.
+ The memory is allocated from EFI boot services memory. It is the responsibility
+ of the caller to free the memory allocated.
+
+ @param NodeType The device node type for the new device node.
+ @param NodeSubType The device node sub-type for the new device node.
+ @param NodeLength The length of the new device node.
+
+ @return The new device path.
+
+**/
+EFI_DEVICE_PATH_PROTOCOL *
+EFIAPI
+UefiDevicePathLibCreateDeviceNode (
+ IN UINT8 NodeType,
+ IN UINT8 NodeSubType,
+ IN UINT16 NodeLength
+ )
+{
+ EFI_DEVICE_PATH_PROTOCOL *DevicePath;
+
+ if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
+ //
+ // NodeLength is less than the size of the header.
+ //
+ return NULL;
+ }
+
+ DevicePath = AllocateZeroPool (NodeLength);
+ if (DevicePath != NULL) {
+ DevicePath->Type = NodeType;
+ DevicePath->SubType = NodeSubType;
+ SetDevicePathNodeLength (DevicePath, NodeLength);
+ }
+
+ return DevicePath;
+}
+
+/**
+ Determines if a device path is single or multi-instance.
+
+ This function returns TRUE if the device path specified by DevicePath is
+ multi-instance.
+ Otherwise, FALSE is returned.
+ If DevicePath is NULL or invalid, then FALSE is returned.
+
+ @param DevicePath A pointer to a device path data structure.
+
+ @retval TRUE DevicePath is multi-instance.
+ @retval FALSE DevicePath is not multi-instance, or DevicePath
+ is NULL or invalid.
+
+**/
+BOOLEAN
+EFIAPI
+UefiDevicePathLibIsDevicePathMultiInstance (
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
+ )
+{
+ CONST EFI_DEVICE_PATH_PROTOCOL *Node;
+
+ if (DevicePath == NULL) {
+ return FALSE;
+ }
+
+ if (!IsDevicePathValid (DevicePath, 0)) {
+ return FALSE;
+ }
+
+ Node = DevicePath;
+ while (!IsDevicePathEnd (Node)) {
+ if (IsDevicePathEndInstance (Node)) {
+ return TRUE;
+ }
+
+ Node = NextDevicePathNode (Node);
+ }
+
+ return FALSE;
+}
+
+
+/**
+ Retrieves the device path protocol from a handle.
+
+ This function returns the device path protocol from the handle specified by Handle.
+ If Handle is NULL or Handle does not contain a device path protocol, then NULL
+ is returned.
+
+ @param Handle The handle from which to retrieve the device
+ path protocol.
+
+ @return The device path protocol from the handle specified by Handle.
+
+**/
+EFI_DEVICE_PATH_PROTOCOL *
+EFIAPI
+DevicePathFromHandle (
+ IN EFI_HANDLE Handle
+ )
+{
+ EFI_DEVICE_PATH_PROTOCOL *DevicePath;
+ EFI_STATUS Status;
+
+ Status = gBS->HandleProtocol (
+ Handle,
+ &gEfiDevicePathProtocolGuid,
+ (VOID *) &DevicePath
+ );
+ if (EFI_ERROR (Status)) {
+ DevicePath = NULL;
+ }
+ return DevicePath;
+}
+
+/**
+ Allocates a device path for a file and appends it to an existing device path.
+
+ If Device is a valid device handle that contains a device path protocol, then a device path for
+ the file specified by FileName is allocated and appended to the device path associated with the
+ handle Device. The allocated device path is returned. If Device is NULL or Device is a handle
+ that does not support the device path protocol, then a device path containing a single device
+ path node for the file specified by FileName is allocated and returned.
+ The memory for the new device path is allocated from EFI boot services memory. It is the responsibility
+ of the caller to free the memory allocated.
+
+ If FileName is NULL, then ASSERT().
+ If FileName is not aligned on a 16-bit boundary, then ASSERT().
+
+ @param Device A pointer to a device handle. This parameter
+ is optional and may be NULL.
+ @param FileName A pointer to a Null-terminated Unicode string.
+
+ @return The allocated device path.
+
+**/
+EFI_DEVICE_PATH_PROTOCOL *
+EFIAPI
+FileDevicePath (
+ IN EFI_HANDLE Device, OPTIONAL
+ IN CONST CHAR16 *FileName
+ )
+{
+ UINTN Size;
+ FILEPATH_DEVICE_PATH *FilePath;
+ EFI_DEVICE_PATH_PROTOCOL *DevicePath;
+ EFI_DEVICE_PATH_PROTOCOL *FileDevicePath;
+
+ DevicePath = NULL;
+
+ Size = StrSize (FileName);
+ FileDevicePath = AllocatePool (Size + SIZE_OF_FILEPATH_DEVICE_PATH + END_DEVICE_PATH_LENGTH);
+ if (FileDevicePath != NULL) {
+ FilePath = (FILEPATH_DEVICE_PATH *) FileDevicePath;
+ FilePath->Header.Type = MEDIA_DEVICE_PATH;
+ FilePath->Header.SubType = MEDIA_FILEPATH_DP;
+ CopyMem (&FilePath->PathName, FileName, Size);
+ SetDevicePathNodeLength (&FilePath->Header, Size + SIZE_OF_FILEPATH_DEVICE_PATH);
+ SetDevicePathEndNode (NextDevicePathNode (&FilePath->Header));
+
+ if (Device != NULL) {
+ DevicePath = DevicePathFromHandle (Device);
+ }
+
+ DevicePath = AppendDevicePath (DevicePath, FileDevicePath);
+ FreePool (FileDevicePath);
+ }
+
+ return DevicePath;
+}
+
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