2 Provides library functions to construct and parse UEFI Device Paths.
4 Copyright (c) 2006 - 2008, Intel Corporation
5 All rights reserved. This program and the accompanying materials
6 are licensed and made available under the terms and conditions of the BSD License
7 which accompanies this distribution. The full text of the license may be found at
8 http://opensource.org/licenses/bsd-license.php
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
15 #ifndef __DEVICE_PATH_LIB_H__
16 #define __DEVICE_PATH_LIB_H__
18 #include <Library/BaseLib.h>
20 #define END_DEVICE_PATH_LENGTH (sizeof (EFI_DEVICE_PATH_PROTOCOL))
21 #define DevicePathNodeLength(Node) ReadUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0])
22 #define NextDevicePathNode(Node) ((EFI_DEVICE_PATH_PROTOCOL *)((UINT8 *)(Node) + DevicePathNodeLength(Node)))
23 #define DevicePathType(Node) (((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Type)
24 #define DevicePathSubType(Node) (((EFI_DEVICE_PATH_PROTOCOL *)(Node))->SubType)
25 #define IsDevicePathEndType(Node) ((DevicePathType (Node) & 0x7f) == END_DEVICE_PATH_TYPE)
26 #define IsDevicePathEnd(Node) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_ENTIRE_DEVICE_PATH_SUBTYPE)
27 #define IsDevicePathEndInstance(Node) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_INSTANCE_DEVICE_PATH_SUBTYPE)
29 #define SetDevicePathNodeLength(Node,NodeLength) WriteUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(NodeLength))
30 #define SetDevicePathEndNode(Node) { \
31 DevicePathType (Node) = END_DEVICE_PATH_TYPE; \
32 DevicePathSubType (Node) = END_ENTIRE_DEVICE_PATH_SUBTYPE; \
33 SetDevicePathNodeLength ((Node), END_DEVICE_PATH_LENGTH); \
37 Returns the size of a device path in bytes.
39 This function returns the size, in bytes, of the device path data structure specified by
40 DevicePath including the end of device path node. If DevicePath is NULL, then 0 is returned.
42 @param DevicePath A pointer to a device path data structure.
44 @return The size of a device path in bytes.
50 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
54 Creates a new device path by appending a second device path to a first device path.
56 This function allocates space for a new copy of the device path specified by DevicePath. If
57 DevicePath is NULL, then NULL is returned. If the memory is successfully allocated, then the
58 contents of DevicePath are copied to the newly allocated buffer, and a pointer to that buffer
59 is returned. Otherwise, NULL is returned.
61 @param DevicePath A pointer to a device path data structure.
63 @return A pointer to the duplicated device path.
66 EFI_DEVICE_PATH_PROTOCOL
*
69 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
73 Creates a new device path by appending a second device path to a first device path.
75 This function creates a new device path by appending a copy of SecondDevicePath to a copy of
76 FirstDevicePath in a newly allocated buffer. Only the end-of-device-path device node from
77 SecondDevicePath is retained. The newly created device path is returned.
78 If FirstDevicePath is NULL, then it is ignored, and a duplicate of SecondDevicePath is returned.
79 If SecondDevicePath is NULL, then it is ignored, and a duplicate of FirstDevicePath is returned.
80 If both FirstDevicePath and SecondDevicePath are NULL, then a copy of an end-of-device-path is
82 If there is not enough memory for the newly allocated buffer, then NULL is returned.
83 The memory for the new device path is allocated from EFI boot services memory. It is the
84 responsibility of the caller to free the memory allocated.
86 @param FirstDevicePath A pointer to a device path data structure.
87 @param SecondDevicePath A pointer to a device path data structure.
89 @return A pointer to the new device path.
92 EFI_DEVICE_PATH_PROTOCOL
*
95 IN CONST EFI_DEVICE_PATH_PROTOCOL
*FirstDevicePath
, OPTIONAL
96 IN CONST EFI_DEVICE_PATH_PROTOCOL
*SecondDevicePath OPTIONAL
100 Creates a new path by appending the device node to the device path.
102 This function creates a new device path by appending a copy of the device node specified by
103 DevicePathNode to a copy of the device path specified by DevicePath in an allocated buffer.
104 The end-of-device-path device node is moved after the end of the appended device node.
105 If DevicePathNode is NULL then a copy of DevicePath is returned.
106 If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device path device
108 If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path device node
110 If there is not enough memory to allocate space for the new device path, then NULL is returned.
111 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
112 free the memory allocated.
114 @param DevicePath A pointer to a device path data structure.
115 @param DevicePathNode A pointer to a single device path node.
117 @return A pointer to the new device path.
120 EFI_DEVICE_PATH_PROTOCOL
*
122 AppendDevicePathNode (
123 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
, OPTIONAL
124 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePathNode OPTIONAL
128 Creates a new device path by appending the specified device path instance to the specified device
131 This function creates a new device path by appending a copy of the device path instance specified
132 by DevicePathInstance to a copy of the device path secified by DevicePath in a allocated buffer.
133 The end-of-device-path device node is moved after the end of the appended device path instance
134 and a new end-of-device-path-instance node is inserted between.
135 If DevicePath is NULL, then a copy if DevicePathInstance is returned.
136 If DevicePathInstance is NULL, then NULL is returned.
137 If there is not enough memory to allocate space for the new device path, then NULL is returned.
138 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
139 free the memory allocated.
141 @param DevicePath A pointer to a device path data structure.
142 @param DevicePathInstance A pointer to a device path instance.
144 @return A pointer to the new device path.
147 EFI_DEVICE_PATH_PROTOCOL
*
149 AppendDevicePathInstance (
150 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
, OPTIONAL
151 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePathInstance OPTIONAL
155 Creates a copy of the current device path instance and returns a pointer to the next device path
158 This function creates a copy of the current device path instance. It also updates DevicePath to
159 point to the next device path instance in the device path (or NULL if no more) and updates Size
160 to hold the size of the device path instance copy.
161 If DevicePath is NULL, then NULL is returned.
162 If there is not enough memory to allocate space for the new device path, then NULL is returned.
163 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
164 free the memory allocated.
165 If Size is NULL, then ASSERT().
167 @param DevicePath On input, this holds the pointer to the current device path
168 instance. On output, this holds the pointer to the next device
169 path instance or NULL if there are no more device path
170 instances in the device path pointer to a device path data
172 @param Size On output, this holds the size of the device path instance, in
173 bytes or zero, if DevicePath is NULL.
175 @return A pointer to the current device path instance.
178 EFI_DEVICE_PATH_PROTOCOL
*
180 GetNextDevicePathInstance (
181 IN OUT EFI_DEVICE_PATH_PROTOCOL
**DevicePath
,
186 Creates a copy of the current device path instance and returns a pointer to the next device path
189 This function creates a new device node in a newly allocated buffer of size NodeLength and
190 initializes the device path node header with NodeType and NodeSubType. The new device path node
192 If NodeLength is smaller than a device path header, then NULL is returned.
193 If there is not enough memory to allocate space for the new device path, then NULL is returned.
194 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
195 free the memory allocated.
197 @param NodeType The device node type for the new device node.
198 @param NodeSubType The device node sub-type for the new device node.
199 @param NodeLength The length of the new device node.
201 @return The new device path.
204 EFI_DEVICE_PATH_PROTOCOL
*
208 IN UINT8 NodeSubType
,
213 Determines if a device path is single or multi-instance.
215 This function returns TRUE if the device path specified by DevicePath is multi-instance.
216 Otherwise, FALSE is returned. If DevicePath is NULL, then FALSE is returned.
218 @param DevicePath A pointer to a device path data structure.
220 @retval TRUE DevicePath is multi-instance.
221 @retval FALSE DevicePath is not multi-instance or DevicePath is NULL.
226 IsDevicePathMultiInstance (
227 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
231 Retrieves the device path protocol from a handle.
233 This function returns the device path protocol from the handle specified by Handle. If Handle is
234 NULL or Handle does not contain a device path protocol, then NULL is returned.
236 @param Handle The handle from which to retrieve the device path protocol.
238 @return The device path protocol from the handle specified by Handle.
241 EFI_DEVICE_PATH_PROTOCOL
*
243 DevicePathFromHandle (
248 Allocates a device path for a file and appends it to an existing device path.
250 If Device is a valid device handle that contains a device path protocol, then a device path for
251 the file specified by FileName is allocated and appended to the device path associated with the
252 handle Device. The allocated device path is returned. If Device is NULL or Device is a handle
253 that does not support the device path protocol, then a device path containing a single device
254 path node for the file specified by FileName is allocated and returned.
255 If FileName is NULL, then ASSERT().
257 @param Device A pointer to a device handle. This parameter is optional and
259 @param FileName A pointer to a Null-terminated Unicode string.
261 @return The allocated device path.
264 EFI_DEVICE_PATH_PROTOCOL
*
267 IN EFI_HANDLE Device
, OPTIONAL
268 IN CONST CHAR16
*FileName