MdePkg/Library/UefiDevicePathLibDevicePathProtocol/UefiDevicePathLib.c

   1 /** @file
   2   UEFI Device Path Library.
   3
   4   Copyright (c) 2006, Intel Corporation<BR>
   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
  16 #include <Uefi.h>
  17
  18 #include <Protocol/DevicePathUtilities.h>
  19 #include <Protocol/DevicePath.h>
  20
  21 #include <Library/DevicePathLib.h>
  22 #include <Library/DebugLib.h>
  23 #include <Library/BaseLib.h>
  24 #include <Library/MemoryAllocationLib.h>
  25 #include <Library/BaseMemoryLib.h>
  26 #include <Library/UefiBootServicesTableLib.h>
  27
  28 #include "UefiDevicePathLibInternal.h"
  29
  30 STATIC EFI_DEVICE_PATH_UTILITIES_PROTOCOL          *mDevicePathUtilities = NULL;
  31
  32 /**
  33   The constructor function caches the pointer to DevicePathUtilites protocol.
  34
  35   The constructor function locates DevicePathUtilities protocol from protocol database.
  36   It will ASSERT() if that operation fails and it will always return EFI_SUCCESS.
  37
  38   @param  ImageHandle   The firmware allocated handle for the EFI image.
  39   @param  SystemTable   A pointer to the EFI System Table.
  40
  41   @retval EFI_SUCCESS   The constructor always returns EFI_SUCCESS.
  42
  43 **/
  44 EFI_STATUS
  45 EFIAPI
  46 DevicePathLibConstructor (
  47   IN      EFI_HANDLE                ImageHandle,
  48   IN      EFI_SYSTEM_TABLE          *SystemTable
  49   )
  50 {
  51   EFI_STATUS                        Status;
  52
  53   Status = gBS->LocateProtocol (
  54                   &gEfiDevicePathUtilitiesProtocolGuid,
  55                   NULL,
  56                   (VOID**) &mDevicePathUtilities
  57                   );
  58   ASSERT_EFI_ERROR (Status);
  59   ASSERT (mDevicePathUtilities != NULL);
  60
  61   return Status;
  62 }
  63
  64 /**
  65   Returns the size of a device path in bytes.
  66
  67   This function returns the size, in bytes, of the device path data structure specified by
  68   DevicePath including the end of device path node.  If DevicePath is NULL, then 0 is returned.
  69
  70   @param  DevicePath                 A pointer to a device path data structure.
  71
  72   @return The size of a device path in bytes.
  73
  74 **/
  75 UINTN
  76 EFIAPI
  77 GetDevicePathSize (
  78   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath
  79   )
  80 {
  81   return mDevicePathUtilities->GetDevicePathSize (DevicePath);
  82 }
  83
  84 /**
  85   Creates a new device path by appending a second device path to a first device path.
  86
  87   This function allocates space for a new copy of the device path specified by DevicePath.  If
  88   DevicePath is NULL, then NULL is returned.  If the memory is successfully allocated, then the
  89   contents of DevicePath are copied to the newly allocated buffer, and a pointer to that buffer
  90   is returned.  Otherwise, NULL is returned.
  91
  92   @param  DevicePath                 A pointer to a device path data structure.
  93
  94   @return A pointer to the duplicated device path.
  95
  96 **/
  97 EFI_DEVICE_PATH_PROTOCOL *
  98 EFIAPI
  99 DuplicateDevicePath (
 100   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath
 101   )
 102 {
 103   return mDevicePathUtilities->DuplicateDevicePath (DevicePath);
 104 }
 105
 106 /**
 107   Creates a new device path by appending a second device path to a first device path.
 108
 109   This function creates a new device path by appending a copy of SecondDevicePath to a copy of
 110   FirstDevicePath in a newly allocated buffer.  Only the end-of-device-path device node from
 111   SecondDevicePath is retained. The newly created device path is returned.
 112   If FirstDevicePath is NULL, then it is ignored, and a duplicate of SecondDevicePath is returned.
 113   If SecondDevicePath is NULL, then it is ignored, and a duplicate of FirstDevicePath is returned.
 114   If both FirstDevicePath and SecondDevicePath are NULL, then a copy of an end-of-device-path is
 115   returned.
 116   If there is not enough memory for the newly allocated buffer, then NULL is returned.
 117   The memory for the new device path is allocated from EFI boot services memory. It is the
 118   responsibility of the caller to free the memory allocated.
 119
 120   @param  FirstDevicePath            A pointer to a device path data structure.
 121   @param  SecondDevicePath           A pointer to a device path data structure.
 122
 123   @return A pointer to the new device path.
 124
 125 **/
 126 EFI_DEVICE_PATH_PROTOCOL *
 127 EFIAPI
 128 AppendDevicePath (
 129   IN CONST EFI_DEVICE_PATH_PROTOCOL  *FirstDevicePath,  OPTIONAL
 130   IN CONST EFI_DEVICE_PATH_PROTOCOL  *SecondDevicePath  OPTIONAL
 131   )
 132 {
 133   return mDevicePathUtilities->AppendDevicePath (FirstDevicePath, SecondDevicePath);
 134 }
 135
 136 /**
 137   Creates a new path by appending the device node to the device path.
 138
 139   This function creates a new device path by appending a copy of the device node specified by
 140   DevicePathNode to a copy of the device path specified by DevicePath in an allocated buffer.
 141   The end-of-device-path device node is moved after the end of the appended device node.
 142   If DeviceNode is NULL then a copy of DevicePath is returned.
 143   If DevicePathNode is NULL then a copy of DevicePath is returned.
 144   If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path device node
 145   is returned.
 146   If there is not enough memory to allocate space for the new device path, then NULL is returned.
 147   The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
 148   free the memory allocated.
 149
 150   @param  DevicePath                 A pointer to a device path data structure.
 151   @param  DevicePathNode             A pointer to a single device path node.
 152
 153   @return A pointer to the new device path.
 154
 155 **/
 156 EFI_DEVICE_PATH_PROTOCOL *
 157 EFIAPI
 158 AppendDevicePathNode (
 159   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath,     OPTIONAL
 160   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePathNode  OPTIONAL
 161   )
 162 {
 163   return mDevicePathUtilities->AppendDeviceNode (DevicePath, DevicePathNode);
 164 }
 165
 166 /**
 167   Creates a new device path by appending the specified device path instance to the specified device
 168   path.
 169
 170   This function creates a new device path by appending a copy of the device path instance specified
 171   by DevicePathInstance to a copy of the device path secified by DevicePath in a allocated buffer.
 172   The end-of-device-path device node is moved after the end of the appended device path instance
 173   and a new end-of-device-path-instance node is inserted between.
 174   If DevicePath is NULL, then a copy if DevicePathInstance is returned.
 175   If DevicePathInstance is NULL, then NULL is returned.
 176   If there is not enough memory to allocate space for the new device path, then NULL is returned.
 177   The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
 178   free the memory allocated.
 179
 180   @param  DevicePath                 A pointer to a device path data structure.
 181   @param  DevicePathInstance         A pointer to a device path instance.
 182
 183   @return A pointer to the new device path.
 184
 185 **/
 186 EFI_DEVICE_PATH_PROTOCOL *
 187 EFIAPI
 188 AppendDevicePathInstance (
 189   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath,        OPTIONAL
 190   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePathInstance OPTIONAL
 191   )
 192 {
 193   return mDevicePathUtilities->AppendDevicePathInstance (DevicePath, DevicePathInstance);
 194 }
 195
 196 /**
 197   Creates a copy of the current device path instance and returns a pointer to the next device path
 198   instance.
 199
 200   This function creates a copy of the current device path instance. It also updates DevicePath to
 201   point to the next device path instance in the device path (or NULL if no more) and updates Size
 202   to hold the size of the device path instance copy.
 203   If DevicePath is NULL, then NULL is returned.
 204   If there is not enough memory to allocate space for the new device path, then NULL is returned.
 205   The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
 206   free the memory allocated.
 207   If Size is NULL, then ASSERT().
 208
 209   @param  DevicePath                 On input, this holds the pointer to the current device path
 210                                      instance. On output, this holds the pointer to the next device
 211                                      path instance or NULL if there are no more device path
 212                                      instances in the device path pointer to a device path data
 213                                      structure.
 214   @param  Size                       On output, this holds the size of the device path instance, in
 215                                      bytes or zero, if DevicePath is NULL.
 216
 217   @return A pointer to the current device path instance.
 218
 219 **/
 220 EFI_DEVICE_PATH_PROTOCOL *
 221 EFIAPI
 222 GetNextDevicePathInstance (
 223   IN OUT EFI_DEVICE_PATH_PROTOCOL    **DevicePath,
 224   OUT UINTN                          *Size
 225   )
 226 {
 227   ASSERT (Size != NULL);
 228   return mDevicePathUtilities->GetNextDevicePathInstance (DevicePath, Size);
 229 }
 230
 231 /**
 232   Creates a copy of the current device path instance and returns a pointer to the next device path
 233   instance.
 234
 235   This function creates a new device node in a newly allocated buffer of size NodeLength and
 236   initializes the device path node header with NodeType and NodeSubType.  The new device path node
 237   is returned.
 238   If NodeLength is smaller than a device path header, then NULL is returned.
 239   If there is not enough memory to allocate space for the new device path, then NULL is returned.
 240   The memory is allocated from EFI boot services memory. It is the responsibility of the caller to
 241   free the memory allocated.
 242
 243   @param  NodeType                   The device node type for the new device node.
 244   @param  NodeSubType                The device node sub-type for the new device node.
 245   @param  NodeLength                 The length of the new device node.
 246
 247   @return The new device path.
 248
 249 **/
 250 EFI_DEVICE_PATH_PROTOCOL *
 251 EFIAPI
 252 CreateDeviceNode (
 253   IN UINT8                           NodeType,
 254   IN UINT8                           NodeSubType,
 255   IN UINT16                          NodeLength
 256   )
 257 {
 258   return mDevicePathUtilities->CreateDeviceNode (NodeType, NodeSubType, NodeLength);
 259 }
 260
 261 /**
 262   Determines if a device path is single or multi-instance.
 263
 264   This function returns TRUE if the device path specified by DevicePath is multi-instance.
 265   Otherwise, FALSE is returned.  If DevicePath is NULL, then FALSE is returned.
 266
 267   @param  DevicePath                 A pointer to a device path data structure.
 268
 269   @retval  TRUE                      DevicePath is multi-instance.
 270   @retval  FALSE                     DevicePath is not multi-instance or DevicePath is NULL.
 271
 272 **/
 273 BOOLEAN
 274 EFIAPI
 275 IsDevicePathMultiInstance (
 276   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath
 277   )
 278 {
 279   return mDevicePathUtilities->IsDevicePathMultiInstance (DevicePath);
 280 }
 281
 282 /**
 283   Retrieves the device path protocol from a handle.
 284
 285   This function returns the device path protocol from the handle specified by Handle.  If Handle is
 286   NULL or Handle does not contain a device path protocol, then NULL is returned.
 287
 288   @param  Handle                     The handle from which to retrieve the device path protocol.
 289
 290   @return The device path protocol from the handle specified by Handle.
 291
 292 **/
 293 EFI_DEVICE_PATH_PROTOCOL *
 294 EFIAPI
 295 DevicePathFromHandle (
 296   IN EFI_HANDLE                      Handle
 297   )
 298 {
 299   EFI_DEVICE_PATH_PROTOCOL  *DevicePath;
 300   EFI_STATUS                Status;
 301
 302   Status = gBS->HandleProtocol (
 303                   Handle,
 304                   &gEfiDevicePathProtocolGuid,
 305                   (VOID *) &DevicePath
 306                   );
 307   if (EFI_ERROR (Status)) {
 308     DevicePath = NULL;
 309   }
 310   return DevicePath;
 311 }
 312
 313 /**
 314   Allocates a device path for a file and appends it to an existing device path.
 315
 316   If Device is a valid device handle that contains a device path protocol, then a device path for
 317   the file specified by FileName  is allocated and appended to the device path associated with the
 318   handle Device.  The allocated device path is returned.  If Device is NULL or Device is a handle
 319   that does not support the device path protocol, then a device path containing a single device
 320   path node for the file specified by FileName is allocated and returned.
 321   If FileName is NULL, then ASSERT().
 322
 323   @param  Device                     A pointer to a device handle.  This parameter is optional and
 324                                      may be NULL.
 325   @param  FileName                   A pointer to a Null-terminated Unicode string.
 326
 327   @return The allocated device path.
 328
 329 **/
 330 EFI_DEVICE_PATH_PROTOCOL *
 331 EFIAPI
 332 FileDevicePath (
 333   IN EFI_HANDLE                      Device,     OPTIONAL
 334   IN CONST CHAR16                    *FileName
 335   )
 336 {
 337   UINTN                     Size;
 338   FILEPATH_DEVICE_PATH      *FilePath;
 339   EFI_DEVICE_PATH_PROTOCOL  *DevicePath;
 340   EFI_DEVICE_PATH_PROTOCOL  *FileDevicePath;
 341
 342   DevicePath = NULL;
 343
 344   Size = StrSize (FileName);
 345   FileDevicePath = AllocatePool (Size + SIZE_OF_FILEPATH_DEVICE_PATH + EFI_END_DEVICE_PATH_LENGTH);
 346   if (FileDevicePath != NULL) {
 347     FilePath = (FILEPATH_DEVICE_PATH *) FileDevicePath;
 348     FilePath->Header.Type    = MEDIA_DEVICE_PATH;
 349     FilePath->Header.SubType = MEDIA_FILEPATH_DP;
 350     CopyMem (&FilePath->PathName, FileName, Size);
 351     SetDevicePathNodeLength (&FilePath->Header, Size + SIZE_OF_FILEPATH_DEVICE_PATH);
 352     SetDevicePathEndNode (NextDevicePathNode (&FilePath->Header));
 353
 354     if (Device != NULL) {
 355       DevicePath = DevicePathFromHandle (Device);
 356     }
 357
 358     DevicePath = AppendDevicePath (DevicePath, FileDevicePath);
 359     FreePool (FileDevicePath);
 360   }
 361
 362   return DevicePath;
 363 }
 364