MdePkg/Include/Library/DevicePathLib.h

   1 /** @file
   2   Device Path services.
   3
   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
   9
  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.
  12
  13 **/
  14
  15 #ifndef __DEVICE_PATH_LIB_H__
  16 #define __DEVICE_PATH_LIB_H__
  17
  18 /**
  19   Returns the size of a device path in bytes.
  20
  21   This function returns the size, in bytes, of the device path data structure specified by
  22   DevicePath including the end of device path node.  If DevicePath is NULL, then 0 is returned.
  23
  24   @param  DevicePath                 A pointer to a device path data structure.
  25
  26   @return The size of a device path in bytes.
  27
  28 **/
  29 UINTN
  30 EFIAPI
  31 GetDevicePathSize (
  32   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath
  33   );
  34
  35 /**
  36   Creates a new device path by appending a second device path to a first device path.
  37
  38   This function allocates space for a new copy of the device path specified by DevicePath.  If
  39   DevicePath is NULL, then NULL is returned.  If the memory is successfully allocated, then the
  40   contents of DevicePath are copied to the newly allocated buffer, and a pointer to that buffer
  41   is returned.  Otherwise, NULL is returned.
  42
  43   @param  DevicePath                 A pointer to a device path data structure.
  44
  45   @return A pointer to the duplicated device path.
  46
  47 **/
  48 EFI_DEVICE_PATH_PROTOCOL *
  49 EFIAPI
  50 DuplicateDevicePath (
  51   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath
  52   );
  53
  54 /**
  55   Creates a new device path by appending a second device path to a first device path.
  56
  57   This function creates a new device path by appending a copy of SecondDevicePath to a copy of
  58   FirstDevicePath in a newly allocated buffer.  Only the end-of-device-path device node from
  59   SecondDevicePath is retained. The newly created device path is returned.
  60   If FirstDevicePath is NULL, then it is ignored, and a duplicate of SecondDevicePath is returned.
  61   If SecondDevicePath is NULL, then it is ignored, and a duplicate of FirstDevicePath is returned.
  62   If both FirstDevicePath and SecondDevicePath are NULL, then a copy of an end-of-device-path is
  63   returned.
  64   If there is not enough memory for the newly allocated buffer, then NULL is returned.
  65   The memory for the new device path is allocated from EFI boot services memory. It is the
  66   responsibility of the caller to free the memory allocated.
  67
  68   @param  FirstDevicePath            A pointer to a device path data structure.
  69   @param  SecondDevicePath           A pointer to a device path data structure.
  70
  71   @return A pointer to the new device path.
  72
  73 **/
  74 EFI_DEVICE_PATH_PROTOCOL *
  75 EFIAPI
  76 AppendDevicePath (
  77   IN CONST EFI_DEVICE_PATH_PROTOCOL  *FirstDevicePath,  OPTIONAL
  78   IN CONST EFI_DEVICE_PATH_PROTOCOL  *SecondDevicePath  OPTIONAL
  79   );
  80
  81 /**
  82   Creates a new path by appending the device node to the device path.
  83
  84   This function creates a new device path by appending a copy of the device node specified by
  85   DevicePathNode to a copy of the device path specified by DevicePath in an allocated buffer.
  86   The end-of-device-path device node is moved after the end of the appended device node.
  87   If DevicePathNode is NULL then a copy of DevicePath is returned.
  88   If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device path device
  89   node is returned.
  90   If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path device node
  91   is returned.
  92   If there is not enough memory to allocate space for the new device path, then NULL is returned.
  93   The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
  94   free the memory allocated.
  95
  96   @param  DevicePath                 A pointer to a device path data structure.
  97   @param  DevicePathNode             A pointer to a single device path node.
  98
  99   @return A pointer to the new device path.
 100
 101 **/
 102 EFI_DEVICE_PATH_PROTOCOL *
 103 EFIAPI
 104 AppendDevicePathNode (
 105   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath,     OPTIONAL
 106   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePathNode  OPTIONAL
 107   );
 108
 109 /**
 110   Creates a new device path by appending the specified device path instance to the specified device
 111   path.
 112
 113   This function creates a new device path by appending a copy of the device path instance specified
 114   by DevicePathInstance to a copy of the device path secified by DevicePath in a allocated buffer.
 115   The end-of-device-path device node is moved after the end of the appended device path instance
 116   and a new end-of-device-path-instance node is inserted between.
 117   If DevicePath is NULL, then a copy if DevicePathInstance is returned.
 118   If DevicePathInstance is NULL, then NULL is returned.
 119   If there is not enough memory to allocate space for the new device path, then NULL is returned.
 120   The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
 121   free the memory allocated.
 122
 123   @param  DevicePath                 A pointer to a device path data structure.
 124   @param  DevicePathInstance         A pointer to a device path instance.
 125
 126   @return A pointer to the new device path.
 127
 128 **/
 129 EFI_DEVICE_PATH_PROTOCOL *
 130 EFIAPI
 131 AppendDevicePathInstance (
 132   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath,        OPTIONAL
 133   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePathInstance OPTIONAL
 134   );
 135
 136 /**
 137   Creates a copy of the current device path instance and returns a pointer to the next device path
 138   instance.
 139
 140   This function creates a copy of the current device path instance. It also updates DevicePath to
 141   point to the next device path instance in the device path (or NULL if no more) and updates Size
 142   to hold the size of the device path instance copy.
 143   If DevicePath is NULL, then NULL is returned.
 144   If there is not enough memory to allocate space for the new device path, then NULL is returned.
 145   The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
 146   free the memory allocated.
 147   If Size is NULL, then ASSERT().
 148
 149   @param  DevicePath                 On input, this holds the pointer to the current device path
 150                                      instance. On output, this holds the pointer to the next device
 151                                      path instance or NULL if there are no more device path
 152                                      instances in the device path pointer to a device path data
 153                                      structure.
 154   @param  Size                       On output, this holds the size of the device path instance, in
 155                                      bytes or zero, if DevicePath is NULL.
 156
 157   @return A pointer to the current device path instance.
 158
 159 **/
 160 EFI_DEVICE_PATH_PROTOCOL *
 161 EFIAPI
 162 GetNextDevicePathInstance (
 163   IN OUT EFI_DEVICE_PATH_PROTOCOL    **DevicePath,
 164   OUT UINTN                          *Size
 165   );
 166
 167 /**
 168   Creates a copy of the current device path instance and returns a pointer to the next device path
 169   instance.
 170
 171   This function creates a new device node in a newly allocated buffer of size NodeLength and
 172   initializes the device path node header with NodeType and NodeSubType.  The new device path node
 173   is returned.
 174   If NodeLength is smaller than a device path header, then NULL is returned.
 175   If there is not enough memory to allocate space for the new device path, then NULL is returned.
 176   The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
 177   free the memory allocated.
 178
 179   @param  NodeType                   The device node type for the new device node.
 180   @param  NodeSubType                The device node sub-type for the new device node.
 181   @param  NodeLength                 The length of the new device node.
 182
 183   @return The new device path.
 184
 185 **/
 186 EFI_DEVICE_PATH_PROTOCOL *
 187 EFIAPI
 188 CreateDeviceNode (
 189   IN UINT8                           NodeType,
 190   IN UINT8                           NodeSubType,
 191   IN UINT16                          NodeLength
 192   );
 193
 194 /**
 195   Determines if a device path is single or multi-instance.
 196
 197   This function returns TRUE if the device path specified by DevicePath is multi-instance.
 198   Otherwise, FALSE is returned.  If DevicePath is NULL, then FALSE is returned.
 199
 200   @param  DevicePath                 A pointer to a device path data structure.
 201
 202   @retval  TRUE                      DevicePath is multi-instance.
 203   @retval  FALSE                     DevicePath is not multi-instance or DevicePath is NULL.
 204
 205 **/
 206 BOOLEAN
 207 EFIAPI
 208 IsDevicePathMultiInstance (
 209   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath
 210   );
 211
 212 /**
 213   Retrieves the device path protocol from a handle.
 214
 215   This function returns the device path protocol from the handle specified by Handle.  If Handle is
 216   NULL or Handle does not contain a device path protocol, then NULL is returned.
 217
 218   @param  Handle                     The handle from which to retrieve the device path protocol.
 219
 220   @return The device path protocol from the handle specified by Handle.
 221
 222 **/
 223 EFI_DEVICE_PATH_PROTOCOL *
 224 EFIAPI
 225 DevicePathFromHandle (
 226   IN EFI_HANDLE                      Handle
 227   );
 228
 229 /**
 230   Allocates a device path for a file and appends it to an existing device path.
 231
 232   If Device is a valid device handle that contains a device path protocol, then a device path for
 233   the file specified by FileName  is allocated and appended to the device path associated with the
 234   handle Device.  The allocated device path is returned.  If Device is NULL or Device is a handle
 235   that does not support the device path protocol, then a device path containing a single device
 236   path node for the file specified by FileName is allocated and returned.
 237   If FileName is NULL, then ASSERT().
 238
 239   @param  Device                     A pointer to a device handle.  This parameter is optional and
 240                                      may be NULL.
 241   @param  FileName                   A pointer to a Null-terminated Unicode string.
 242
 243   @return The allocated device path.
 244
 245 **/
 246 EFI_DEVICE_PATH_PROTOCOL *
 247 EFIAPI
 248 FileDevicePath (
 249   IN EFI_HANDLE                      Device,     OPTIONAL
 250   IN CONST CHAR16                    *FileName
 251   );
 252
 253 #endif