Add comment to explain use of the types "int" and "unsigned int" in the implementatio...

[mirror_edk2.git] / MdePkg / Library / UefiDevicePathLibDevicePathProtocol / UefiDevicePathLib.c

/** @file\r
  Library instance that implement UEFI Device Path Library class based on protocol\r
  gEfiDevicePathUtilitiesProtocolGuid.\r
\r
  Copyright (c) 2006 - 2008, Intel Corporation<BR>\r
  All rights reserved. This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
\r
#include <Uefi.h>\r
\r
#include <Protocol/DevicePathUtilities.h>\r
#include <Protocol/DevicePath.h>\r
\r
#include <Library/DevicePathLib.h>\r
#include <Library/DebugLib.h>\r
#include <Library/BaseLib.h>\r
#include <Library/MemoryAllocationLib.h>\r
#include <Library/BaseMemoryLib.h>\r
#include <Library/UefiBootServicesTableLib.h>\r
\r
EFI_DEVICE_PATH_UTILITIES_PROTOCOL          *mDevicePathUtilities = NULL;\r
\r
/**\r
  The constructor function caches the pointer to DevicePathUtilites protocol.\r
  \r
  The constructor function locates DevicePathUtilities protocol from protocol database.\r
  It will ASSERT() if that operation fails and it will always return EFI_SUCCESS. \r
\r
  @param  ImageHandle   The firmware allocated handle for the EFI image.\r
  @param  SystemTable   A pointer to the EFI System Table.\r
  \r
  @retval EFI_SUCCESS   The constructor always returns EFI_SUCCESS.\r
\r
**/\r
EFI_STATUS\r
EFIAPI\r
DevicePathLibConstructor (\r
  IN      EFI_HANDLE                ImageHandle,\r
  IN      EFI_SYSTEM_TABLE          *SystemTable\r
  )\r
{\r
  EFI_STATUS                        Status;\r
\r
  Status = gBS->LocateProtocol (\r
                  &gEfiDevicePathUtilitiesProtocolGuid,\r
                  NULL,\r
                  (VOID**) &mDevicePathUtilities\r
                  );\r
  ASSERT_EFI_ERROR (Status);\r
  ASSERT (mDevicePathUtilities != NULL);\r
\r
  return Status;\r
}\r
\r
/**\r
  Returns the size of a device path in bytes.\r
\r
  This function returns the size, in bytes, of the device path data structure specified by\r
  DevicePath including the end of device path node.  If DevicePath is NULL, then 0 is returned.\r
\r
  @param  DevicePath                 A pointer to a device path data structure.\r
  \r
  @retval 0       If DevicePath is NULL.\r
  @retval Others  The size of a device path in bytes.\r
\r
**/\r
UINTN\r
EFIAPI\r
GetDevicePathSize (\r
  IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath\r
  )\r
{\r
  return mDevicePathUtilities->GetDevicePathSize (DevicePath);\r
}\r
\r
/**\r
  Creates a new copy of an existing device path.\r
\r
  This function allocates space for a new copy of the device path specified by DevicePath.  If\r
  DevicePath is NULL, then NULL is returned.  If the memory is successfully allocated, then the\r
  contents of DevicePath are copied to the newly allocated buffer, and a pointer to that buffer\r
  is returned.  Otherwise, NULL is returned.  \r
  The memory for the new device path is allocated from EFI boot services memory. \r
  It is the responsibility of the caller to free the memory allocated. \r
  \r
  @param  DevicePath                 A pointer to a device path data structure.\r
\r
  @retval NULL    If DevicePath is NULL.\r
  @retval Others  A pointer to the duplicated device path.\r
  \r
**/\r
EFI_DEVICE_PATH_PROTOCOL *\r
EFIAPI\r
DuplicateDevicePath (\r
  IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath\r
  )\r
{\r
  return mDevicePathUtilities->DuplicateDevicePath (DevicePath);\r
}\r
\r
/**\r
  Creates a new device path by appending a second device path to a first device path.\r
\r
  This function creates a new device path by appending a copy of SecondDevicePath to a copy of\r
  FirstDevicePath in a newly allocated buffer.  Only the end-of-device-path device node from\r
  SecondDevicePath is retained. The newly created device path is returned.  \r
  If FirstDevicePath is NULL, then it is ignored, and a duplicate of SecondDevicePath is returned.  \r
  If SecondDevicePath is NULL, then it is ignored, and a duplicate of FirstDevicePath is returned.  \r
  If both FirstDevicePath and SecondDevicePath are NULL, then a copy of an end-of-device-path is\r
  returned.  \r
  If there is not enough memory for the newly allocated buffer, then NULL is returned.\r
  The memory for the new device path is allocated from EFI boot services memory. It is the\r
  responsibility of the caller to free the memory allocated.\r
\r
  @param  FirstDevicePath            A pointer to a device path data structure.\r
  @param  SecondDevicePath           A pointer to a device path data structure.\r
  \r
  @retval NULL      If there is not enough memory for the newly allocated buffer.\r
  @retval Others    A pointer to the new device path if success.\r
                    Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.\r
\r
**/\r
EFI_DEVICE_PATH_PROTOCOL *\r
EFIAPI\r
AppendDevicePath (\r
  IN CONST EFI_DEVICE_PATH_PROTOCOL  *FirstDevicePath,  OPTIONAL\r
  IN CONST EFI_DEVICE_PATH_PROTOCOL  *SecondDevicePath  OPTIONAL\r
  )\r
{\r
  return mDevicePathUtilities->AppendDevicePath (FirstDevicePath, SecondDevicePath);\r
}\r
\r
/**\r
  Creates a new path by appending the device node to the device path.\r
\r
  This function creates a new device path by appending a copy of the device node specified by\r
  DevicePathNode to a copy of the device path specified by DevicePath in an allocated buffer.\r
  The end-of-device-path device node is moved after the end of the appended device node.\r
  If DevicePathNode is NULL then a copy of DevicePath is returned.\r
  If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device path device\r
  node is returned.\r
  If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path device node\r
  is returned.\r
  If there is not enough memory to allocate space for the new device path, then NULL is returned.  \r
  The memory is allocated from EFI boot services memory. It is the responsibility of the caller to\r
  free the memory allocated.\r
\r
  @param  DevicePath                 A pointer to a device path data structure.\r
  @param  DevicePathNode             A pointer to a single device path node.\r
\r
  @retval NULL      If there is not enough memory for the new device path.\r
  @retval Others    A pointer to the new device path if success.\r
                    A copy of DevicePathNode followed by an end-of-device-path node \r
                    if both FirstDevicePath and SecondDevicePath are NULL.\r
                    A copy of an end-of-device-path node if both FirstDevicePath and SecondDevicePath are NULL.\r
\r
**/\r
EFI_DEVICE_PATH_PROTOCOL *\r
EFIAPI\r
AppendDevicePathNode (\r
  IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath,     OPTIONAL\r
  IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePathNode  OPTIONAL\r
  )\r
{\r
  return mDevicePathUtilities->AppendDeviceNode (DevicePath, DevicePathNode);\r
}\r
\r
/**\r
  Creates a new device path by appending the specified device path instance to the specified device\r
  path.\r
 \r
  This function creates a new device path by appending a copy of the device path instance specified\r
  by DevicePathInstance to a copy of the device path secified by DevicePath in a allocated buffer.\r
  The end-of-device-path device node is moved after the end of the appended device path instance\r
  and a new end-of-device-path-instance node is inserted between. \r
  If DevicePath is NULL, then a copy if DevicePathInstance is returned.\r
  If DevicePathInstance is NULL, then NULL is returned.\r
  If there is not enough memory to allocate space for the new device path, then NULL is returned.  \r
  The memory is allocated from EFI boot services memory. It is the responsibility of the caller to\r
  free the memory allocated.\r
  \r
  @param  DevicePath                 A pointer to a device path data structure.\r
  @param  DevicePathInstance         A pointer to a device path instance.\r
\r
  @return A pointer to the new device path.\r
\r
**/\r
EFI_DEVICE_PATH_PROTOCOL *\r
EFIAPI\r
AppendDevicePathInstance (\r
  IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath,        OPTIONAL\r
  IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePathInstance OPTIONAL\r
  )\r
{\r
  return mDevicePathUtilities->AppendDevicePathInstance (DevicePath, DevicePathInstance);\r
}\r
\r
/**\r
  Creates a copy of the current device path instance and returns a pointer to the next device path\r
  instance.\r
\r
  This function creates a copy of the current device path instance. It also updates DevicePath to\r
  point to the next device path instance in the device path (or NULL if no more) and updates Size\r
  to hold the size of the device path instance copy.\r
  If DevicePath is NULL, then NULL is returned.\r
  If there is not enough memory to allocate space for the new device path, then NULL is returned.  \r
  The memory is allocated from EFI boot services memory. It is the responsibility of the caller to\r
  free the memory allocated.\r
  If Size is NULL, then ASSERT().\r
 \r
  @param  DevicePath                 On input, this holds the pointer to the current device path\r
                                     instance. On output, this holds the pointer to the next device\r
                                     path instance or NULL if there are no more device path\r
                                     instances in the device path pointer to a device path data\r
                                     structure.\r
  @param  Size                       On output, this holds the size of the device path instance, in\r
                                     bytes or zero, if DevicePath is NULL.\r
\r
  @return A pointer to the current device path instance.\r
\r
**/\r
EFI_DEVICE_PATH_PROTOCOL *\r
EFIAPI\r
GetNextDevicePathInstance (\r
  IN OUT EFI_DEVICE_PATH_PROTOCOL    **DevicePath,\r
  OUT UINTN                          *Size\r
  )\r
{\r
  ASSERT (Size != NULL);\r
  return mDevicePathUtilities->GetNextDevicePathInstance (DevicePath, Size);\r
}\r
\r
/**\r
  Creates a device node.\r
\r
  This function creates a new device node in a newly allocated buffer of size NodeLength and\r
  initializes the device path node header with NodeType and NodeSubType.  The new device path node\r
  is returned.\r
  If NodeLength is smaller than a device path header, then NULL is returned.  \r
  If there is not enough memory to allocate space for the new device path, then NULL is returned.  \r
  The memory is allocated from EFI boot services memory. It is the responsibility of the caller to\r
  free the memory allocated.\r
\r
  @param  NodeType                   The device node type for the new device node.\r
  @param  NodeSubType                The device node sub-type for the new device node.\r
  @param  NodeLength                 The length of the new device node.\r
\r
  @return The new device path.\r
\r
**/\r
EFI_DEVICE_PATH_PROTOCOL *\r
EFIAPI\r
CreateDeviceNode (\r
  IN UINT8                           NodeType,\r
  IN UINT8                           NodeSubType,\r
  IN UINT16                          NodeLength\r
  )\r
{\r
  return mDevicePathUtilities->CreateDeviceNode (NodeType, NodeSubType, NodeLength);\r
}\r
\r
/**\r
  Determines if a device path is single or multi-instance.\r
\r
  This function returns TRUE if the device path specified by DevicePath is multi-instance.\r
  Otherwise, FALSE is returned.  If DevicePath is NULL, then FALSE is returned.\r
\r
  @param  DevicePath                 A pointer to a device path data structure.\r
\r
  @retval  TRUE                      DevicePath is multi-instance.\r
  @retval  FALSE                     DevicePath is not multi-instance or DevicePath is NULL.\r
\r
**/\r
BOOLEAN\r
EFIAPI\r
IsDevicePathMultiInstance (\r
  IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath\r
  )\r
{\r
  return mDevicePathUtilities->IsDevicePathMultiInstance (DevicePath);\r
}\r
\r
/**\r
  Retrieves the device path protocol from a handle.\r
\r
  This function returns the device path protocol from the handle specified by Handle.  If Handle is\r
  NULL or Handle does not contain a device path protocol, then NULL is returned.\r
 \r
  @param  Handle                     The handle from which to retrieve the device path protocol.\r
\r
  @return The device path protocol from the handle specified by Handle.\r
\r
**/\r
EFI_DEVICE_PATH_PROTOCOL *\r
EFIAPI\r
DevicePathFromHandle (\r
  IN EFI_HANDLE                      Handle\r
  )\r
{\r
  EFI_DEVICE_PATH_PROTOCOL  *DevicePath;\r
  EFI_STATUS                Status;\r
\r
  Status = gBS->HandleProtocol (\r
                  Handle,\r
                  &gEfiDevicePathProtocolGuid,\r
                  (VOID *) &DevicePath\r
                  );\r
  if (EFI_ERROR (Status)) {\r
    DevicePath = NULL;\r
  }\r
  return DevicePath;\r
}\r
\r
/**\r
  Allocates a device path for a file and appends it to an existing device path.\r
\r
  If Device is a valid device handle that contains a device path protocol, then a device path for\r
  the file specified by FileName  is allocated and appended to the device path associated with the\r
  handle Device.  The allocated device path is returned.  If Device is NULL or Device is a handle\r
  that does not support the device path protocol, then a device path containing a single device\r
  path node for the file specified by FileName is allocated and returned.\r
  The memory for the new device path is allocated from EFI boot services memory. It is the responsibility\r
  of the caller to free the memory allocated.\r
  \r
  If FileName is NULL, then ASSERT().\r
  If FileName is not aligned on a 16-bit boundary, then ASSERT().\r
\r
  @param  Device                     A pointer to a device handle.  This parameter is optional and\r
                                     may be NULL.\r
  @param  FileName                   A pointer to a Null-terminated Unicode string.\r
\r
  @return The allocated device path.\r
\r
**/\r
EFI_DEVICE_PATH_PROTOCOL *\r
EFIAPI\r
FileDevicePath (\r
  IN EFI_HANDLE                      Device,     OPTIONAL\r
  IN CONST CHAR16                    *FileName\r
  )\r
{\r
  UINTN                     Size;\r
  FILEPATH_DEVICE_PATH      *FilePath;\r
  EFI_DEVICE_PATH_PROTOCOL  *DevicePath;\r
  EFI_DEVICE_PATH_PROTOCOL  *FileDevicePath;\r
\r
  DevicePath = NULL;\r
\r
  Size = StrSize (FileName);\r
  FileDevicePath = AllocatePool (Size + SIZE_OF_FILEPATH_DEVICE_PATH + END_DEVICE_PATH_LENGTH);\r
  if (FileDevicePath != NULL) {\r
    FilePath = (FILEPATH_DEVICE_PATH *) FileDevicePath;\r
    FilePath->Header.Type    = MEDIA_DEVICE_PATH;\r
    FilePath->Header.SubType = MEDIA_FILEPATH_DP;\r
    CopyMem (&FilePath->PathName, FileName, Size);\r
    SetDevicePathNodeLength (&FilePath->Header, Size + SIZE_OF_FILEPATH_DEVICE_PATH);\r
    SetDevicePathEndNode (NextDevicePathNode (&FilePath->Header));\r
\r
    if (Device != NULL) {\r
      DevicePath = DevicePathFromHandle (Device);\r
    }\r
\r
    DevicePath = AppendDevicePath (DevicePath, FileDevicePath);\r
    FreePool (FileDevicePath);\r
  }\r
\r
  return DevicePath;\r
}\r