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 DeviceNode is NULL then a copy of DevicePath is returned.
  88   If DevicePathNode is NULL then a copy of DevicePath is returned.
  89   If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path device node
  90   is returned.
  91   If there is not enough memory to allocate space for the new device path, then NULL is returned.
  92   The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
  93   free the memory allocated.
  94
  95   @param  DevicePath                 A pointer to a device path data structure.
  96   @param  DevicePathNode             A pointer to a single device path node.
  97
  98   @return A pointer to the new device path.
  99
 100 **/
 101 EFI_DEVICE_PATH_PROTOCOL *
 102 EFIAPI
 103 AppendDevicePathNode (
 104   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath,     OPTIONAL
 105   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePathNode  OPTIONAL
 106   );
 107
 108 /**
 109   Creates a new device path by appending the specified device path instance to the specified device
 110   path.
 111
 112   This function creates a new device path by appending a copy of the device path instance specified
 113   by DevicePathInstance to a copy of the device path secified by DevicePath in a allocated buffer.
 114   The end-of-device-path device node is moved after the end of the appended device path instance
 115   and a new end-of-device-path-instance node is inserted between.
 116   If DevicePath is NULL, then a copy if DevicePathInstance is returned.
 117   If DevicePathInstance is NULL, then NULL is returned.
 118   If there is not enough memory to allocate space for the new device path, then NULL is returned.
 119   The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
 120   free the memory allocated.
 121
 122   @param  DevicePath                 A pointer to a device path data structure.
 123   @param  DevicePathInstance         A pointer to a device path instance.
 124
 125   @return A pointer to the new device path.
 126
 127 **/
 128 EFI_DEVICE_PATH_PROTOCOL *
 129 EFIAPI
 130 AppendDevicePathInstance (
 131   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath,        OPTIONAL
 132   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePathInstance OPTIONAL
 133   );
 134
 135 /**
 136   Creates a copy of the current device path instance and returns a pointer to the next device path
 137   instance.
 138
 139   This function creates a copy of the current device path instance. It also updates DevicePath to
 140   point to the next device path instance in the device path (or NULL if no more) and updates Size
 141   to hold the size of the device path instance copy.
 142   If DevicePath is NULL, then NULL is returned.
 143   If there is not enough memory to allocate space for the new device path, then NULL is returned.
 144   The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
 145   free the memory allocated.
 146   If Size is NULL, then ASSERT().
 147
 148   @param  DevicePath                 On input, this holds the pointer to the current device path
 149                                      instance. On output, this holds the pointer to the next device
 150                                      path instance or NULL if there are no more device path
 151                                      instances in the device path pointer to a device path data
 152                                      structure.
 153   @param  Size                       On output, this holds the size of the device path instance, in
 154                                      bytes or zero, if DevicePath is NULL.
 155
 156   @return A pointer to the current device path instance.
 157
 158 **/
 159 EFI_DEVICE_PATH_PROTOCOL *
 160 EFIAPI
 161 GetNextDevicePathInstance (
 162   IN OUT EFI_DEVICE_PATH_PROTOCOL    **DevicePath,
 163   OUT UINTN                          *Size
 164   );
 165
 166 /**
 167   Creates a copy of the current device path instance and returns a pointer to the next device path
 168   instance.
 169
 170   This function creates a new device node in a newly allocated buffer of size NodeLength and
 171   initializes the device path node header with NodeType and NodeSubType.  The new device path node
 172   is returned.
 173   If NodeLength is smaller than a device path header, then NULL is returned.
 174   If there is not enough memory to allocate space for the new device path, then NULL is returned.
 175   The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
 176   free the memory allocated.
 177
 178   @param  NodeType                   The device node type for the new device node.
 179   @param  NodeSubType                The device node sub-type for the new device node.
 180   @param  NodeLength                 The length of the new device node.
 181
 182   @return The new device path.
 183
 184 **/
 185 EFI_DEVICE_PATH_PROTOCOL *
 186 EFIAPI
 187 CreateDeviceNode (
 188   IN UINT8                           NodeType,
 189   IN UINT8                           NodeSubType,
 190   IN UINT16                          NodeLength
 191   );
 192
 193 /**
 194   Determines if a device path is single or multi-instance.
 195
 196   This function returns TRUE if the device path specified by DevicePath is multi-instance.
 197   Otherwise, FALSE is returned.  If DevicePath is NULL, then FALSE is returned.
 198
 199   @param  DevicePath                 A pointer to a device path data structure.
 200
 201   @retval  TRUE                      DevicePath is multi-instance.
 202   @retval  FALSE                     DevicePath is not multi-instance or DevicePath is NULL.
 203
 204 **/
 205 BOOLEAN
 206 EFIAPI
 207 IsDevicePathMultiInstance (
 208   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath
 209   );
 210
 211 /**
 212   Retrieves the device path protocol from a handle.
 213
 214   This function returns the device path protocol from the handle specified by Handle.  If Handle is
 215   NULL or Handle does not contain a device path protocol, then NULL is returned.
 216
 217   @param  Handle                     The handle from which to retrieve the device path protocol.
 218
 219   @return The device path protocol from the handle specified by Handle.
 220
 221 **/
 222 EFI_DEVICE_PATH_PROTOCOL *
 223 EFIAPI
 224 DevicePathFromHandle (
 225   IN EFI_HANDLE                      Handle
 226   );
 227
 228 /**
 229   Allocates a device path for a file and appends it to an existing device path.
 230
 231   If Device is a valid device handle that contains a device path protocol, then a device path for
 232   the file specified by FileName  is allocated and appended to the device path associated with the
 233   handle Device.  The allocated device path is returned.  If Device is NULL or Device is a handle
 234   that does not support the device path protocol, then a device path containing a single device
 235   path node for the file specified by FileName is allocated and returned.
 236   If FileName is NULL, then ASSERT().
 237
 238   @param  Device                     A pointer to a device handle.  This parameter is optional and
 239                                      may be NULL.
 240   @param  FileName                   A pointer to a Null-terminated Unicode string.
 241
 242   @return The allocated device path.
 243
 244 **/
 245 EFI_DEVICE_PATH_PROTOCOL *
 246 EFIAPI
 247 FileDevicePath (
 248   IN EFI_HANDLE                      Device,     OPTIONAL
 249   IN CONST CHAR16                    *FileName
 250   );
 251
 252 #endif