2 Entry point to a DXE Boot Services Driver
4 Copyright (c) 2006, 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.
13 Module Name: DevicePathLib.h
17 #ifndef __DEVICE_PATH_LIB_H__
18 #define __DEVICE_PATH_LIB_H__
21 Returns the size of a device path in bytes.
23 This function returns the size, in bytes, of the device path data structure specified by
24 DevicePath including the end of device path node. If DevicePath is NULL, then 0 is returned.
26 @param DevicePath A pointer to a device path data structure.
28 @return The size of a device path in bytes.
34 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
38 Creates a new device path by appending a second device path to a first device path.
40 This function allocates space for a new copy of the device path specified by DevicePath. If
41 DevicePath is NULL, then NULL is returned. If the memory is successfully allocated, then the
42 contents of DevicePath are copied to the newly allocated buffer, and a pointer to that buffer
43 is returned. Otherwise, NULL is returned.
45 @param DevicePath A pointer to a device path data structure.
47 @return A pointer to the duplicated device path.
50 EFI_DEVICE_PATH_PROTOCOL
*
53 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
57 Creates a new device path by appending a second device path to a first device path.
59 This function creates a new device path by appending a copy of SecondDevicePath to a copy of
60 FirstDevicePath in a newly allocated buffer. Only the end-of-device-path device node from
61 SecondDevicePath is retained. The newly created device path is returned.
62 If FirstDevicePath is NULL, then it is ignored, and a duplicate of SecondDevicePath is returned.
63 If SecondDevicePath is NULL, then it is ignored, and a duplicate of FirstDevicePath is returned.
64 If both FirstDevicePath and SecondDevicePath are NULL, then NULL is returned.
65 If there is not enough memory for the newly allocated buffer, then NULL is returned.
66 The memory for the new device path is allocated from EFI boot services memory. It is the
67 responsibility of the caller to free the memory allocated.
69 @param FirstDevicePath A pointer to a device path data structure.
70 @param SecondDevicePath A pointer to a device path data structure.
72 @return A pointer to the new device path.
75 EFI_DEVICE_PATH_PROTOCOL
*
78 IN CONST EFI_DEVICE_PATH_PROTOCOL
*FirstDevicePath
, OPTIONAL
79 IN CONST EFI_DEVICE_PATH_PROTOCOL
*SecondDevicePath OPTIONAL
83 Creates a new path by appending the device node to the device path.
85 This function creates a new device path by appending a copy of the device node specified by
86 DevicePathNode to a copy of the device path specified by DevicePath in an allocated buffer.
87 The end-of-device-path device node is moved after the end of the appended device node.
88 If DevicePath is NULL, then NULL is returned.
89 If DevicePathNode is NULL, then NULL is returned.
90 If there is not enough memory to allocate space for the new device path, then NULL is returned.
91 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
92 free the memory allocated.
94 @param DevicePath A pointer to a device path data structure.
95 @param DevicePathNode A pointer to a single device path node.
97 @return A pointer to the new device path.
100 EFI_DEVICE_PATH_PROTOCOL
*
102 AppendDevicePathNode (
103 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
, OPTIONAL
104 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePathNode OPTIONAL
108 Creates a new device path by appending the specified device path instance to the specified device
111 This function creates a new device path by appending a copy of the device path instance specified
112 by DevicePathInstance to a copy of the device path secified by DevicePath in a allocated buffer.
113 The end-of-device-path device node is moved after the end of the appended device path instance
114 and a new end-of-device-path-instance node is inserted between.
115 If DevicePath is NULL, then a copy if DevicePathInstance is returned.
116 If DevicePathInstance is NULL, then NULL is returned.
117 If there is not enough memory to allocate space for the new device path, then NULL is returned.
118 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
119 free the memory allocated.
121 @param DevicePath A pointer to a device path data structure.
122 @param DevicePathInstance A pointer to a device path instance.
124 @return A pointer to the new device path.
127 EFI_DEVICE_PATH_PROTOCOL
*
129 AppendDevicePathInstance (
130 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
, OPTIONAL
131 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePathInstance OPTIONAL
135 Creates a copy of the current device path instance and returns a pointer to the next device path
138 This function creates a copy of the current device path instance. It also updates DevicePath to
139 point to the next device path instance in the device path (or NULL if no more) and updates Size
140 to hold the size of the device path instance copy.
141 If DevicePath is NULL, then NULL is returned.
142 If there is not enough memory to allocate space for the new device path, then NULL is returned.
143 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
144 free the memory allocated.
145 If Size is NULL, then ASSERT().
147 @param DevicePath On input, this holds the pointer to the current device path
148 instance. On output, this holds the pointer to the next device
149 path instance or NULL if there are no more device path
150 instances in the device path pointer to a device path data
152 @param Size On output, this holds the size of the device path instance, in
153 bytes or zero, if DevicePath is NULL.
155 @return A pointer to the current device path instance.
158 EFI_DEVICE_PATH_PROTOCOL
*
160 GetNextDevicePathInstance (
161 IN OUT EFI_DEVICE_PATH_PROTOCOL
**DevicePath
,
166 Creates a copy of the current device path instance and returns a pointer to the next device path
169 This function creates a new device node in a newly allocated buffer of size NodeLength and
170 initializes the device path node header with NodeType and NodeSubType. The new device path node
172 If NodeLength is smaller than a device path header, then NULL is returned.
173 If there is not enough memory to allocate space for the new device path, then NULL is returned.
174 The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
175 free the memory allocated.
177 @param NodeType The device node type for the new device node.
178 @param NodeSubType The device node sub-type for the new device node.
179 @param NodeLength The length of the new device node.
181 @return The new device path.
184 EFI_DEVICE_PATH_PROTOCOL
*
188 IN UINT8 NodeSubType
,
193 Determines if a device path is single or multi-instance.
195 This function returns TRUE if the device path specified by DevicePath is multi-instance.
196 Otherwise, FALSE is returned. If DevicePath is NULL, then FALSE is returned.
198 @param DevicePath A pointer to a device path data structure.
200 @retval TRUE DevicePath is multi-instance.
201 @retval FALSE DevicePath is not multi-instance or DevicePath is NULL.
206 IsDevicePathMultiInstance (
207 IN CONST EFI_DEVICE_PATH_PROTOCOL
*DevicePath
211 Retrieves the device path protocol from a handle.
213 This function returns the device path protocol from the handle specified by Handle. If Handle is
214 NULL or Handle does not contain a device path protocol, then NULL is returned.
216 @param Handle The handle from which to retrieve the device path protocol.
218 @return The device path protocol from the handle specified by Handle.
221 EFI_DEVICE_PATH_PROTOCOL
*
223 DevicePathFromHandle (
228 Allocates a device path for a file and appends it to an existing device path.
230 If Device is a valid device handle that contains a device path protocol, then a device path for
231 the file specified by FileName is allocated and appended to the device path associated with the
232 handle Device. The allocated device path is returned. If Device is NULL or Device is a handle
233 that does not support the device path protocol, then a device path containing a single device
234 path node for the file specified by FileName is allocated and returned.
235 If FileName is NULL, then ASSERT().
237 @param Device A pointer to a device handle. This parameter is optional and
239 @param FileName A pointer to a Null-terminated Unicode string.
241 @return The allocated device path.
244 EFI_DEVICE_PATH_PROTOCOL
*
247 IN EFI_HANDLE Device
, OPTIONAL
248 IN CONST CHAR16
*FileName