MdePkg/Include/Library/DevicePathLib.h

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