--- /dev/null
+/** @file\r
+ Device Path services. The thing to remember is device paths are built out of\r
+ nodes. The device path is terminated by an end node that is length\r
+ sizeof(EFI_DEVICE_PATH_PROTOCOL). That would be why there is sizeof(EFI_DEVICE_PATH_PROTOCOL)\r
+ all over this file.\r
+\r
+ The only place where multi-instance device paths are supported is in\r
+ environment varibles. Multi-instance device paths should never be placed\r
+ on a Handle.\r
+\r
+ Copyright (c) 2006, Intel Corporation \r
+ All rights reserved. This program and the accompanying materials \r
+ are licensed and made available under the terms and conditions of the BSD License \r
+ which accompanies this distribution. The full text of the license may be found at \r
+ http://opensource.org/licenses/bsd-license.php \r
+\r
+ THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, \r
+ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. \r
+\r
+ Module Name: UefiDevicePathLib.c\r
+\r
+**/\r
+\r
+/**\r
+ Returns the size of a device path in bytes.\r
+\r
+ This function returns the size, in bytes, of the device path data structure specified by\r
+ DevicePath including the end of device path node. If DevicePath is NULL, then 0 is returned.\r
+\r
+ @param DevicePath A pointer to a device path data structure.\r
+\r
+ @return The size of a device path in bytes.\r
+\r
+**/\r
+UINTN\r
+EFIAPI\r
+GetDevicePathSize (\r
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath\r
+ )\r
+{\r
+ CONST EFI_DEVICE_PATH_PROTOCOL *Start;\r
+\r
+ if (DevicePath == NULL) {\r
+ return 0;\r
+ }\r
+\r
+ //\r
+ // Search for the end of the device path structure\r
+ //\r
+ Start = DevicePath;\r
+ while (!EfiIsDevicePathEnd (DevicePath)) {\r
+ DevicePath = EfiNextDevicePathNode (DevicePath);\r
+ }\r
+\r
+ //\r
+ // Compute the size and add back in the size of the end device path structure\r
+ //\r
+ return ((UINTN) DevicePath - (UINTN) Start) + sizeof (EFI_DEVICE_PATH_PROTOCOL);\r
+}\r
+\r
+/**\r
+ Creates a new device path by appending a second device path to a first device path.\r
+\r
+ This function allocates space for a new copy of the device path specified by DevicePath. If\r
+ DevicePath is NULL, then NULL is returned. If the memory is successfully allocated, then the\r
+ contents of DevicePath are copied to the newly allocated buffer, and a pointer to that buffer\r
+ is returned. Otherwise, NULL is returned. \r
+ \r
+ @param DevicePath A pointer to a device path data structure.\r
+\r
+ @return A pointer to the duplicated device path.\r
+\r
+**/\r
+EFI_DEVICE_PATH_PROTOCOL *\r
+EFIAPI\r
+DuplicateDevicePath (\r
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath\r
+ )\r
+{\r
+ EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;\r
+ UINTN Size;\r
+\r
+ //\r
+ // Compute the size\r
+ //\r
+ Size = GetDevicePathSize (DevicePath);\r
+ if (Size == 0) {\r
+ return NULL;\r
+ }\r
+\r
+ //\r
+ // Allocate space for duplicate device path\r
+ //\r
+ NewDevicePath = AllocateCopyPool (Size, DevicePath);\r
+\r
+ return NewDevicePath;\r
+}\r
+\r
+/**\r
+ Creates a new device path by appending a second device path to a first device path.\r
+\r
+ This function creates a new device path by appending a copy of SecondDevicePath to a copy of\r
+ FirstDevicePath in a newly allocated buffer. Only the end-of-device-path device node from\r
+ SecondDevicePath is retained. The newly created device path is returned. \r
+ If FirstDevicePath is NULL, then it is ignored, and a duplicate of SecondDevicePath is returned. \r
+ If SecondDevicePath is NULL, then it is ignored, and a duplicate of FirstDevicePath is returned. \r
+ If both FirstDevicePath and SecondDevicePath are NULL, then NULL is returned. \r
+ If there is not enough memory for the newly allocated buffer, then NULL is returned.\r
+ The memory for the new device path is allocated from EFI boot services memory. It is the\r
+ responsibility of the caller to free the memory allocated.\r
+\r
+ @param FirstDevicePath A pointer to a device path data structure.\r
+ @param SecondDevicePath A pointer to a device path data structure.\r
+\r
+ @return A pointer to the new device path.\r
+\r
+**/\r
+EFI_DEVICE_PATH_PROTOCOL *\r
+EFIAPI\r
+AppendDevicePath (\r
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath, OPTIONAL\r
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath OPTIONAL\r
+ )\r
+{\r
+ UINTN Size;\r
+ UINTN Size1;\r
+ UINTN Size2;\r
+ EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;\r
+ EFI_DEVICE_PATH_PROTOCOL *DevicePath2;\r
+\r
+ //\r
+ // If there's only 1 path, just duplicate it.\r
+ //\r
+ if (FirstDevicePath == NULL) {\r
+ return DuplicateDevicePath (SecondDevicePath);\r
+ }\r
+\r
+ if (SecondDevicePath == NULL) {\r
+ return DuplicateDevicePath (FirstDevicePath);\r
+ }\r
+\r
+ //\r
+ // Allocate space for the combined device path. It only has one end node of\r
+ // length EFI_DEVICE_PATH_PROTOCOL.\r
+ //\r
+ Size1 = GetDevicePathSize (FirstDevicePath);\r
+ Size2 = GetDevicePathSize (SecondDevicePath);\r
+ Size = Size1 + Size2 - sizeof (EFI_DEVICE_PATH_PROTOCOL);\r
+\r
+ NewDevicePath = AllocatePool (Size);\r
+\r
+ if (NewDevicePath != NULL) {\r
+ NewDevicePath = CopyMem (NewDevicePath, FirstDevicePath, Size1);\r
+ //\r
+ // Over write FirstDevicePath EndNode and do the copy\r
+ //\r
+ DevicePath2 = (EFI_DEVICE_PATH_PROTOCOL *) ((CHAR8 *) NewDevicePath +\r
+ (Size1 - sizeof (EFI_DEVICE_PATH_PROTOCOL)));\r
+ CopyMem (DevicePath2, SecondDevicePath, Size2);\r
+ }\r
+\r
+ return NewDevicePath;\r
+}\r
+\r
+/**\r
+ Creates a new path by appending the device node to the device path.\r
+\r
+ This function creates a new device path by appending a copy of the device node specified by\r
+ DevicePathNode to a copy of the device path specified by DevicePath in an allocated buffer.\r
+ The end-of-device-path device node is moved after the end of the appended device node.\r
+ If DevicePath is NULL, then NULL is returned.\r
+ If DevicePathNode is NULL, then NULL is returned.\r
+ If there is not enough memory to allocate space for the new device path, then NULL is returned. \r
+ The memory is allocated from EFI boot services memory. It is the responsibility of the caller to\r
+ free the memory allocated.\r
+\r
+ @param DevicePath A pointer to a device path data structure.\r
+ @param DevicePathNode A pointer to a single device path node.\r
+\r
+ @return A pointer to the new device path.\r
+\r
+**/\r
+EFI_DEVICE_PATH_PROTOCOL *\r
+EFIAPI\r
+AppendDevicePathNode (\r
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL\r
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode OPTIONAL\r
+ )\r
+{\r
+ EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;\r
+ EFI_DEVICE_PATH_PROTOCOL *NextNode;\r
+ EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;\r
+ UINTN NodeLength;\r
+\r
+ if (DevicePath == NULL || DevicePathNode == NULL) {\r
+ return NULL;\r
+ }\r
+ //\r
+ // Build a Node that has a terminator on it\r
+ //\r
+ NodeLength = DevicePathNodeLength (DevicePathNode);\r
+\r
+ TempDevicePath = AllocatePool (NodeLength + sizeof (EFI_DEVICE_PATH_PROTOCOL));\r
+ if (TempDevicePath == NULL) {\r
+ return NULL;\r
+ }\r
+ TempDevicePath = CopyMem (TempDevicePath, DevicePathNode, NodeLength);\r
+ //\r
+ // Add and end device path node to convert Node to device path\r
+ //\r
+ NextNode = NextDevicePathNode (TempDevicePath);\r
+ SetDevicePathEndNode (NextNode);\r
+ //\r
+ // Append device paths\r
+ //\r
+ NewDevicePath = AppendDevicePath (DevicePath, TempDevicePath);\r
+\r
+ FreePool (TempDevicePath);\r
+\r
+ return NewDevicePath;\r
+}\r
+\r
+/**\r
+ Creates a new device path by appending the specified device path instance to the specified device\r
+ path.\r
+ \r
+ This function creates a new device path by appending a copy of the device path instance specified\r
+ by DevicePathInstance to a copy of the device path secified by DevicePath in a allocated buffer.\r
+ The end-of-device-path device node is moved after the end of the appended device path instance\r
+ and a new end-of-device-path-instance node is inserted between. \r
+ If DevicePath is NULL, then a copy if DevicePathInstance is returned.\r
+ If DevicePathInstance is NULL, then NULL is returned.\r
+ If there is not enough memory to allocate space for the new device path, then NULL is returned. \r
+ The memory is allocated from EFI boot services memory. It is the responsibility of the caller to\r
+ free the memory allocated.\r
+ \r
+ @param DevicePath A pointer to a device path data structure.\r
+ @param DevicePathInstance A pointer to a device path instance.\r
+\r
+ @return A pointer to the new device path.\r
+\r
+**/\r
+EFI_DEVICE_PATH_PROTOCOL *\r
+EFIAPI\r
+AppendDevicePathInstance (\r
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL\r
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathInstance OPTIONAL\r
+ )\r
+{\r
+ EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;\r
+ EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;\r
+ UINTN SrcSize;\r
+ UINTN InstanceSize;\r
+\r
+ if (DevicePath == NULL) {\r
+ return DuplicateDevicePath (DevicePathInstance);\r
+ }\r
+\r
+ if (DevicePathInstance == NULL) {\r
+ return NULL;\r
+ }\r
+\r
+ SrcSize = GetDevicePathSize (DevicePath);\r
+ InstanceSize = GetDevicePathSize (DevicePathInstance);\r
+\r
+ NewDevicePath = AllocatePool (SrcSize + InstanceSize);\r
+ if (NewDevicePath != NULL) {\r
+ \r
+ TempDevicePath = CopyMem (NewDevicePath, DevicePath, SrcSize);;\r
+ \r
+ while (!IsDevicePathEnd (TempDevicePath)) {\r
+ TempDevicePath = NextDevicePathNode (TempDevicePath);\r
+ }\r
+ \r
+ TempDevicePath->SubType = END_INSTANCE_DEVICE_PATH_SUBTYPE;\r
+ TempDevicePath = NextDevicePathNode (TempDevicePath);\r
+ CopyMem (TempDevicePath, DevicePathInstance, InstanceSize);\r
+ }\r
+\r
+ return NewDevicePath;\r
+}\r
+\r
+/**\r
+ Creates a copy of the current device path instance and returns a pointer to the next device path\r
+ instance.\r
+\r
+ This function creates a copy of the current device path instance. It also updates DevicePath to\r
+ point to the next device path instance in the device path (or NULL if no more) and updates Size\r
+ to hold the size of the device path instance copy.\r
+ If DevicePath is NULL, then NULL is returned.\r
+ If there is not enough memory to allocate space for the new device path, then NULL is returned. \r
+ The memory is allocated from EFI boot services memory. It is the responsibility of the caller to\r
+ free the memory allocated.\r
+ If Size is NULL, then ASSERT().\r
+ \r
+ @param DevicePath On input, this holds the pointer to the current device path\r
+ instance. On output, this holds the pointer to the next device\r
+ path instance or NULL if there are no more device path\r
+ instances in the device path pointer to a device path data\r
+ structure.\r
+ @param Size On output, this holds the size of the device path instance, in\r
+ bytes or zero, if DevicePath is NULL.\r
+\r
+ @return A pointer to the current device path instance.\r
+\r
+**/\r
+EFI_DEVICE_PATH_PROTOCOL *\r
+EFIAPI\r
+GetNextDevicePathInstance (\r
+ IN OUT EFI_DEVICE_PATH_PROTOCOL **DevicePath,\r
+ OUT UINTN *Size\r
+ )\r
+{\r
+ EFI_DEVICE_PATH_PROTOCOL *DevPath;\r
+ EFI_DEVICE_PATH_PROTOCOL *ReturnValue;\r
+ UINT8 Temp;\r
+\r
+ ASSERT (Size != NULL);\r
+\r
+ if (DevicePath == NULL || *DevicePath == NULL) {\r
+ *Size = 0;\r
+ return NULL;\r
+ }\r
+\r
+ //\r
+ // Find the end of the device path instance\r
+ //\r
+ DevPath = *DevicePath;\r
+ while (!IsDevicePathEndType (DevPath)) {\r
+ DevPath = NextDevicePathNode (DevPath);\r
+ }\r
+\r
+ //\r
+ // Compute the size of the device path instance\r
+ //\r
+ *Size = ((UINTN) DevPath - (UINTN) (*DevicePath)) + sizeof (EFI_DEVICE_PATH_PROTOCOL);\r
+ \r
+ //\r
+ // Make a copy and return the device path instance\r
+ //\r
+ Temp = DevPath->SubType;\r
+ DevPath->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;\r
+ ReturnValue = DuplicateDevicePath (*DevicePath);\r
+ DevPath->SubType = Temp;\r
+\r
+ //\r
+ // If DevPath is the end of an entire device path, then another instance\r
+ // does not follow, so *DevicePath is set to NULL.\r
+ //\r
+ if (DevicePathSubType (DevPath) == END_ENTIRE_DEVICE_PATH_SUBTYPE) {\r
+ *DevicePath = NULL;\r
+ } else {\r
+ *DevicePath = NextDevicePathNode (DevPath);\r
+ }\r
+\r
+ return ReturnValue;\r
+}\r
+\r
+/**\r
+ Creates a copy of the current device path instance and returns a pointer to the next device path\r
+ instance.\r
+\r
+ This function creates a new device node in a newly allocated buffer of size NodeLength and\r
+ initializes the device path node header with NodeType and NodeSubType. The new device path node\r
+ is returned.\r
+ If NodeLength is smaller than a device path header, then NULL is returned. \r
+ If there is not enough memory to allocate space for the new device path, then NULL is returned. \r
+ The memory is allocated from EFI boot services memory. It is the responsibility of the caller to\r
+ free the memory allocated.\r
+\r
+ @param NodeType The device node type for the new device node.\r
+ @param NodeSubType The device node sub-type for the new device node.\r
+ @param NodeLength The length of the new device node.\r
+\r
+ @return The new device path.\r
+\r
+**/\r
+EFI_DEVICE_PATH_PROTOCOL *\r
+EFIAPI\r
+CreateDeviceNode (\r
+ IN UINT8 NodeType,\r
+ IN UINT8 NodeSubType,\r
+ IN UINT16 NodeLength\r
+ )\r
+{\r
+ EFI_DEVICE_PATH_PROTOCOL *DevicePath;\r
+\r
+ if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {\r
+ //\r
+ // NodeLength is less than the size of the header.\r
+ //\r
+ return NULL;\r
+ }\r
+ \r
+ DevicePath = AllocatePool (NodeLength);\r
+ if (DevicePath != NULL) {\r
+ DevicePath->Type = NodeType;\r
+ DevicePath->SubType = NodeSubType;\r
+ SetDevicePathNodeLength (DevicePath, NodeLength);\r
+ }\r
+\r
+ return DevicePath;\r
+}\r
+\r
+/**\r
+ Determines if a device path is single or multi-instance.\r
+\r
+ This function returns TRUE if the device path specified by DevicePath is multi-instance.\r
+ Otherwise, FALSE is returned. If DevicePath is NULL, then FALSE is returned.\r
+\r
+ @param DevicePath A pointer to a device path data structure.\r
+\r
+ @retval TRUE DevicePath is multi-instance.\r
+ @retval FALSE DevicePath is not multi-instance or DevicePath is NULL.\r
+\r
+**/\r
+BOOLEAN\r
+EFIAPI\r
+IsDevicePathMultiInstance (\r
+ IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath\r
+ )\r
+{\r
+ CONST EFI_DEVICE_PATH_PROTOCOL *Node;\r
+\r
+ if (DevicePath == NULL) {\r
+ return FALSE;\r
+ }\r
+\r
+ Node = DevicePath;\r
+ while (!EfiIsDevicePathEnd (Node)) {\r
+ if (EfiIsDevicePathEndInstance (Node)) {\r
+ return TRUE;\r
+ }\r
+\r
+ Node = EfiNextDevicePathNode (Node);\r
+ }\r
+\r
+ return FALSE;\r
+}\r
+\r
+\r
+/**\r
+ Retrieves the device path protocol from a handle.\r
+\r
+ This function returns the device path protocol from the handle specified by Handle. If Handle is\r
+ NULL or Handle does not contain a device path protocol, then NULL is returned.\r
+ \r
+ @param Handle The handle from which to retrieve the device path protocol.\r
+\r
+ @return The device path protocol from the handle specified by Handle.\r
+\r
+**/\r
+EFI_DEVICE_PATH_PROTOCOL *\r
+EFIAPI\r
+DevicePathFromHandle (\r
+ IN EFI_HANDLE Handle\r
+ )\r
+{\r
+ EFI_DEVICE_PATH_PROTOCOL *DevicePath;\r
+ EFI_STATUS Status;\r
+\r
+ Status = gBS->HandleProtocol (\r
+ Handle,\r
+ &gEfiDevicePathProtocolGuid,\r
+ (VOID *) &DevicePath\r
+ );\r
+ if (EFI_ERROR (Status)) {\r
+ DevicePath = NULL;\r
+ }\r
+ return DevicePath;\r
+}\r
+\r
+/**\r
+ Allocates a device path for a file and appends it to an existing device path.\r
+\r
+ If Device is a valid device handle that contains a device path protocol, then a device path for\r
+ the file specified by FileName is allocated and appended to the device path associated with the\r
+ handle Device. The allocated device path is returned. If Device is NULL or Device is a handle\r
+ that does not support the device path protocol, then a device path containing a single device\r
+ path node for the file specified by FileName is allocated and returned.\r
+ If FileName is NULL, then ASSERT().\r
+\r
+ @param Device A pointer to a device handle. This parameter is optional and\r
+ may be NULL.\r
+ @param FileName A pointer to a Null-terminated Unicode string.\r
+\r
+ @return The allocated device path.\r
+\r
+**/\r
+EFI_DEVICE_PATH_PROTOCOL *\r
+EFIAPI\r
+FileDevicePath (\r
+ IN EFI_HANDLE Device, OPTIONAL\r
+ IN CONST CHAR16 *FileName\r
+ )\r
+{\r
+ UINTN Size;\r
+ FILEPATH_DEVICE_PATH *FilePath;\r
+ EFI_DEVICE_PATH_PROTOCOL *DevicePath;\r
+ EFI_DEVICE_PATH_PROTOCOL *FileDevicePath;\r
+\r
+ DevicePath = NULL;\r
+\r
+ Size = StrSize (FileName);\r
+ FileDevicePath = AllocatePool (Size + SIZE_OF_FILEPATH_DEVICE_PATH + EFI_END_DEVICE_PATH_LENGTH);\r
+ if (FileDevicePath != NULL) {\r
+ FilePath = (FILEPATH_DEVICE_PATH *) FileDevicePath;\r
+ FilePath->Header.Type = MEDIA_DEVICE_PATH;\r
+ FilePath->Header.SubType = MEDIA_FILEPATH_DP;\r
+ CopyMem (&FilePath->PathName, FileName, Size);\r
+ SetDevicePathNodeLength (&FilePath->Header, Size + SIZE_OF_FILEPATH_DEVICE_PATH);\r
+ SetDevicePathEndNode (NextDevicePathNode (&FilePath->Header));\r
+\r
+ if (Device != NULL) {\r
+ DevicePath = DevicePathFromHandle (Device);\r
+ }\r
+\r
+ DevicePath = AppendDevicePath (DevicePath, FileDevicePath);\r
+ FreePool (FileDevicePath);\r
+ }\r
+\r
+ return DevicePath;\r
+}\r
+\r
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