system76-edk2/MdeModulePkg/Universal/Disk/UdfDxe/File.c

/** @file
  Handle operations in files and directories from UDF/ECMA-167 file systems.

  Copyright (C) 2014-2017 Paulo Alcantara <pcacjr@zytor.com>
  Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>

  SPDX-License-Identifier: BSD-2-Clause-Patent
**/

#include "Udf.h"

EFI_FILE_PROTOCOL  gUdfFileIoOps = {
  EFI_FILE_PROTOCOL_REVISION,
  UdfOpen,
  UdfClose,
  UdfDelete,
  UdfRead,
  UdfWrite,
  UdfGetPosition,
  UdfSetPosition,
  UdfGetInfo,
  UdfSetInfo,
  UdfFlush,
  NULL,
  NULL,
  NULL,
  NULL
};

#define _ROOT_FILE(_PrivData)  (_PrivData)->Root
#define _PARENT_FILE(_PrivData) \
  ((_PrivData)->IsRootDirectory ? (_PrivData)->Root : &(_PrivData)->File)
#define _FILE(_PrivData)  _PARENT_FILE(_PrivData)

/**
  Open the root directory on a volume.

  @param  This Protocol instance pointer.
  @param  Root Returns an Open file handle for the root directory

  @retval EFI_SUCCESS          The device was opened.
  @retval EFI_UNSUPPORTED      This volume does not support the file system.
  @retval EFI_NO_MEDIA         The device has no media.
  @retval EFI_DEVICE_ERROR     The device reported an error.
  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
  @retval EFI_ACCESS_DENIED    The service denied access to the file.
  @retval EFI_OUT_OF_RESOURCES The volume was not opened due to lack of
                               resources.

**/
EFI_STATUS
EFIAPI
UdfOpenVolume (
  IN   EFI_SIMPLE_FILE_SYSTEM_PROTOCOL  *This,
  OUT  EFI_FILE_PROTOCOL                **Root
  )
{
  EFI_TPL                     OldTpl;
  EFI_STATUS                  Status;
  PRIVATE_UDF_SIMPLE_FS_DATA  *PrivFsData;
  PRIVATE_UDF_FILE_DATA       *PrivFileData;

  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);

  if ((This == NULL) || (Root == NULL)) {
    Status = EFI_INVALID_PARAMETER;
    goto Error_Invalid_Params;
  }

  PrivFsData = PRIVATE_UDF_SIMPLE_FS_DATA_FROM_THIS (This);

  if (PrivFsData->OpenFiles == 0) {
    //
    // There is no more open files. Read volume information again since it was
    // cleaned up on the last UdfClose() call.
    //
    Status = ReadUdfVolumeInformation (
               PrivFsData->BlockIo,
               PrivFsData->DiskIo,
               &PrivFsData->Volume
               );
    if (EFI_ERROR (Status)) {
      goto Error_Read_Udf_Volume;
    }
  }

  CleanupFileInformation (&PrivFsData->Root);

  //
  // Find root directory file.
  //
  Status = FindRootDirectory (
             PrivFsData->BlockIo,
             PrivFsData->DiskIo,
             &PrivFsData->Volume,
             &PrivFsData->Root
             );
  if (EFI_ERROR (Status)) {
    goto Error_Find_Root_Dir;
  }

  PrivFileData =
    (PRIVATE_UDF_FILE_DATA *)AllocateZeroPool (sizeof (PRIVATE_UDF_FILE_DATA));
  if (PrivFileData == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto Error_Alloc_Priv_File_Data;
  }

  PrivFileData->Signature       = PRIVATE_UDF_FILE_DATA_SIGNATURE;
  PrivFileData->SimpleFs        = This;
  PrivFileData->Root            = &PrivFsData->Root;
  PrivFileData->IsRootDirectory = TRUE;

  CopyMem (
    (VOID *)&PrivFileData->FileIo,
    (VOID *)&gUdfFileIoOps,
    sizeof (EFI_FILE_PROTOCOL)
    );

  *Root = &PrivFileData->FileIo;

  PrivFsData->OpenFiles++;

  gBS->RestoreTPL (OldTpl);

  return EFI_SUCCESS;

Error_Alloc_Priv_File_Data:
  CleanupFileInformation (&PrivFsData->Root);

Error_Find_Root_Dir:

Error_Read_Udf_Volume:
Error_Invalid_Params:
  gBS->RestoreTPL (OldTpl);

  return Status;
}

/**
  Opens a new file relative to the source file's location.

  @param  This       The protocol instance pointer.
  @param  NewHandle  Returns File Handle for FileName.
  @param  FileName   Null terminated string. "\", ".", and ".." are supported.
  @param  OpenMode   Open mode for file.
  @param  Attributes Only used for EFI_FILE_MODE_CREATE.

  @retval EFI_SUCCESS          The device was opened.
  @retval EFI_NOT_FOUND        The specified file could not be found on the
                               device.
  @retval EFI_NO_MEDIA         The device has no media.
  @retval EFI_MEDIA_CHANGED    The media has changed.
  @retval EFI_DEVICE_ERROR     The device reported an error.
  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
  @retval EFI_ACCESS_DENIED    The service denied access to the file.
  @retval EFI_OUT_OF_RESOURCES The volume was not opened due to lack of
                               resources.
  @retval EFI_VOLUME_FULL      The volume is full.

**/
EFI_STATUS
EFIAPI
UdfOpen (
  IN   EFI_FILE_PROTOCOL  *This,
  OUT  EFI_FILE_PROTOCOL  **NewHandle,
  IN   CHAR16             *FileName,
  IN   UINT64             OpenMode,
  IN   UINT64             Attributes
  )
{
  EFI_TPL                     OldTpl;
  EFI_STATUS                  Status;
  PRIVATE_UDF_FILE_DATA       *PrivFileData;
  PRIVATE_UDF_SIMPLE_FS_DATA  *PrivFsData;
  CHAR16                      FilePath[UDF_PATH_LENGTH];
  UDF_FILE_INFO               File;
  PRIVATE_UDF_FILE_DATA       *NewPrivFileData;
  CHAR16                      *TempFileName;

  ZeroMem (FilePath, sizeof FilePath);
  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);

  if ((This == NULL) || (NewHandle == NULL) || (FileName == NULL)) {
    Status = EFI_INVALID_PARAMETER;
    goto Error_Invalid_Params;
  }

  if (OpenMode != EFI_FILE_MODE_READ) {
    Status = EFI_WRITE_PROTECTED;
    goto Error_Invalid_Params;
  }

  PrivFileData = PRIVATE_UDF_FILE_DATA_FROM_THIS (This);

  PrivFsData = PRIVATE_UDF_SIMPLE_FS_DATA_FROM_THIS (PrivFileData->SimpleFs);

  //
  // Build full path
  //
  if (*FileName == L'\\') {
    StrCpyS (FilePath, UDF_PATH_LENGTH, FileName);
  } else {
    StrCpyS (FilePath, UDF_PATH_LENGTH, PrivFileData->AbsoluteFileName);
    StrCatS (FilePath, UDF_PATH_LENGTH, L"\\");
    StrCatS (FilePath, UDF_PATH_LENGTH, FileName);
  }

  MangleFileName (FilePath);
  if (FilePath[0] == L'\0') {
    Status = EFI_NOT_FOUND;
    goto Error_Bad_FileName;
  }

  Status = FindFile (
             PrivFsData->BlockIo,
             PrivFsData->DiskIo,
             &PrivFsData->Volume,
             FilePath,
             _ROOT_FILE (PrivFileData),
             _PARENT_FILE (PrivFileData),
             &_PARENT_FILE (PrivFileData)->FileIdentifierDesc->Icb,
             &File
             );
  if (EFI_ERROR (Status)) {
    goto Error_Find_File;
  }

  NewPrivFileData =
    (PRIVATE_UDF_FILE_DATA *)AllocateZeroPool (sizeof (PRIVATE_UDF_FILE_DATA));
  if (NewPrivFileData == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto Error_Alloc_New_Priv_File_Data;
  }

  CopyMem (
    (VOID *)NewPrivFileData,
    (VOID *)PrivFileData,
    sizeof (PRIVATE_UDF_FILE_DATA)
    );
  CopyMem ((VOID *)&NewPrivFileData->File, &File, sizeof (UDF_FILE_INFO));

  NewPrivFileData->IsRootDirectory = FALSE;

  StrCpyS (NewPrivFileData->AbsoluteFileName, UDF_PATH_LENGTH, FilePath);
  FileName = NewPrivFileData->AbsoluteFileName;

  while ((TempFileName = StrStr (FileName, L"\\")) != NULL) {
    FileName = TempFileName + 1;
  }

  StrCpyS (NewPrivFileData->FileName, UDF_FILENAME_LENGTH, FileName);

  Status = GetFileSize (
             PrivFsData->BlockIo,
             PrivFsData->DiskIo,
             &PrivFsData->Volume,
             &NewPrivFileData->File,
             &NewPrivFileData->FileSize
             );
  if (EFI_ERROR (Status)) {
    DEBUG ((
      DEBUG_ERROR,
      "%a: GetFileSize() fails with status - %r.\n",
      __FUNCTION__,
      Status
      ));
    goto Error_Get_File_Size;
  }

  NewPrivFileData->FilePosition = 0;
  ZeroMem (
    (VOID *)&NewPrivFileData->ReadDirInfo,
    sizeof (UDF_READ_DIRECTORY_INFO)
    );

  *NewHandle = &NewPrivFileData->FileIo;

  PrivFsData->OpenFiles++;

  gBS->RestoreTPL (OldTpl);

  return Status;

Error_Get_File_Size:
  FreePool ((VOID *)NewPrivFileData);

Error_Alloc_New_Priv_File_Data:
  CleanupFileInformation (&File);

Error_Find_File:
Error_Bad_FileName:
Error_Invalid_Params:
  gBS->RestoreTPL (OldTpl);

  return Status;
}

/**
  Read data from the file.

  @param  This       Protocol instance pointer.
  @param  BufferSize On input size of buffer, on output amount of data in
                     buffer.
  @param  Buffer     The buffer in which data is read.

  @retval EFI_SUCCESS          Data was read.
  @retval EFI_NO_MEDIA         The device has no media.
  @retval EFI_DEVICE_ERROR     The device reported an error.
  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
  @retval EFI_BUFFER_TO_SMALL  BufferSize is too small. BufferSize contains
                               required size.

**/
EFI_STATUS
EFIAPI
UdfRead (
  IN      EFI_FILE_PROTOCOL  *This,
  IN OUT  UINTN              *BufferSize,
  OUT     VOID               *Buffer
  )
{
  EFI_TPL                         OldTpl;
  EFI_STATUS                      Status;
  PRIVATE_UDF_FILE_DATA           *PrivFileData;
  PRIVATE_UDF_SIMPLE_FS_DATA      *PrivFsData;
  UDF_VOLUME_INFO                 *Volume;
  UDF_FILE_INFO                   *Parent;
  UDF_READ_DIRECTORY_INFO         *ReadDirInfo;
  EFI_BLOCK_IO_PROTOCOL           *BlockIo;
  EFI_DISK_IO_PROTOCOL            *DiskIo;
  UDF_FILE_INFO                   FoundFile;
  UDF_FILE_IDENTIFIER_DESCRIPTOR  *NewFileIdentifierDesc;
  VOID                            *NewFileEntryData;
  CHAR16                          FileName[UDF_FILENAME_LENGTH];
  UINT64                          FileSize;
  UINT64                          BufferSizeUint64;

  ZeroMem (FileName, sizeof FileName);
  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);

  if ((This == NULL) || (BufferSize == NULL) || ((*BufferSize != 0) &&
                                                 (Buffer == NULL)))
  {
    Status = EFI_INVALID_PARAMETER;
    goto Error_Invalid_Params;
  }

  PrivFileData = PRIVATE_UDF_FILE_DATA_FROM_THIS (This);
  PrivFsData   = PRIVATE_UDF_SIMPLE_FS_DATA_FROM_THIS (PrivFileData->SimpleFs);

  BlockIo               = PrivFsData->BlockIo;
  DiskIo                = PrivFsData->DiskIo;
  Volume                = &PrivFsData->Volume;
  ReadDirInfo           = &PrivFileData->ReadDirInfo;
  NewFileIdentifierDesc = NULL;
  NewFileEntryData      = NULL;

  Parent = _PARENT_FILE (PrivFileData);

  Status = EFI_VOLUME_CORRUPTED;

  if (IS_FID_NORMAL_FILE (Parent->FileIdentifierDesc)) {
    if (PrivFileData->FilePosition > PrivFileData->FileSize) {
      //
      // File's position is beyond the EOF
      //
      Status = EFI_DEVICE_ERROR;
      goto Error_File_Beyond_The_Eof;
    }

    if (PrivFileData->FilePosition == PrivFileData->FileSize) {
      *BufferSize = 0;
      Status      = EFI_SUCCESS;
      goto Done;
    }

    BufferSizeUint64 = *BufferSize;

    Status = ReadFileData (
               BlockIo,
               DiskIo,
               Volume,
               Parent,
               PrivFileData->FileSize,
               &PrivFileData->FilePosition,
               Buffer,
               &BufferSizeUint64
               );
    ASSERT (BufferSizeUint64 <= MAX_UINTN);
    *BufferSize = (UINTN)BufferSizeUint64;
  } else if (IS_FID_DIRECTORY_FILE (Parent->FileIdentifierDesc)) {
    if ((ReadDirInfo->FidOffset == 0) && (PrivFileData->FilePosition > 0)) {
      Status      = EFI_DEVICE_ERROR;
      *BufferSize = 0;
      goto Done;
    }

    for ( ; ;) {
      Status = ReadDirectoryEntry (
                 BlockIo,
                 DiskIo,
                 Volume,
                 &Parent->FileIdentifierDesc->Icb,
                 Parent->FileEntry,
                 ReadDirInfo,
                 &NewFileIdentifierDesc
                 );
      if (EFI_ERROR (Status)) {
        if (Status == EFI_DEVICE_ERROR) {
          FreePool (ReadDirInfo->DirectoryData);
          ZeroMem ((VOID *)ReadDirInfo, sizeof (UDF_READ_DIRECTORY_INFO));

          *BufferSize = 0;
          Status      = EFI_SUCCESS;
        }

        goto Done;
      }

      //
      // After calling function ReadDirectoryEntry(), if 'NewFileIdentifierDesc'
      // is NULL, then the 'Status' must be EFI_OUT_OF_RESOURCES. Hence, if the
      // code reaches here, 'NewFileIdentifierDesc' must be not NULL.
      //
      // The ASSERT here is for addressing a false positive NULL pointer
      // dereference issue raised from static analysis.
      //
      ASSERT (NewFileIdentifierDesc != NULL);

      if (!IS_FID_PARENT_FILE (NewFileIdentifierDesc)) {
        break;
      }

      FreePool ((VOID *)NewFileIdentifierDesc);
    }

    Status = FindFileEntry (
               BlockIo,
               DiskIo,
               Volume,
               &NewFileIdentifierDesc->Icb,
               &NewFileEntryData
               );
    if (EFI_ERROR (Status)) {
      goto Error_Find_Fe;
    }

    ASSERT (NewFileEntryData != NULL);

    if (FE_ICB_FILE_TYPE (NewFileEntryData) == UdfFileEntrySymlink) {
      Status = ResolveSymlink (
                 BlockIo,
                 DiskIo,
                 Volume,
                 Parent,
                 NewFileEntryData,
                 &FoundFile
                 );
      if (EFI_ERROR (Status)) {
        goto Error_Resolve_Symlink;
      }

      FreePool ((VOID *)NewFileEntryData);
      NewFileEntryData = FoundFile.FileEntry;

      Status = GetFileNameFromFid (NewFileIdentifierDesc, ARRAY_SIZE (FileName), FileName);
      if (EFI_ERROR (Status)) {
        FreePool ((VOID *)FoundFile.FileIdentifierDesc);
        goto Error_Get_FileName;
      }

      FreePool ((VOID *)NewFileIdentifierDesc);
      NewFileIdentifierDesc = FoundFile.FileIdentifierDesc;
    } else {
      FoundFile.FileIdentifierDesc = NewFileIdentifierDesc;
      FoundFile.FileEntry          = NewFileEntryData;

      Status = GetFileNameFromFid (FoundFile.FileIdentifierDesc, ARRAY_SIZE (FileName), FileName);
      if (EFI_ERROR (Status)) {
        goto Error_Get_FileName;
      }
    }

    Status = GetFileSize (
               BlockIo,
               DiskIo,
               Volume,
               &FoundFile,
               &FileSize
               );
    if (EFI_ERROR (Status)) {
      goto Error_Get_File_Size;
    }

    Status = SetFileInfo (
               &FoundFile,
               FileSize,
               FileName,
               BufferSize,
               Buffer
               );
    if (EFI_ERROR (Status)) {
      goto Error_Set_File_Info;
    }

    PrivFileData->FilePosition++;
    Status = EFI_SUCCESS;
  } else if (IS_FID_DELETED_FILE (Parent->FileIdentifierDesc)) {
    //
    // Code should never reach here.
    //
    ASSERT (FALSE);
    Status = EFI_DEVICE_ERROR;
  }

Error_Set_File_Info:
Error_Get_File_Size:
Error_Get_FileName:
Error_Resolve_Symlink:
  if (NewFileEntryData != NULL) {
    FreePool (NewFileEntryData);
  }

Error_Find_Fe:
  if (NewFileIdentifierDesc != NULL) {
    FreePool ((VOID *)NewFileIdentifierDesc);
  }

Done:
Error_File_Beyond_The_Eof:
Error_Invalid_Params:
  gBS->RestoreTPL (OldTpl);

  return Status;
}

/**
  Close the file handle.

  @param  This Protocol instance pointer.

  @retval EFI_SUCCESS The file was closed.

**/
EFI_STATUS
EFIAPI
UdfClose (
  IN EFI_FILE_PROTOCOL  *This
  )
{
  EFI_TPL                OldTpl;
  EFI_STATUS             Status;
  PRIVATE_UDF_FILE_DATA  *PrivFileData;

  OldTpl = gBS->RaiseTPL (TPL_CALLBACK);

  Status = EFI_SUCCESS;

  if (This == NULL) {
    Status = EFI_INVALID_PARAMETER;
    goto Exit;
  }

  PrivFileData = PRIVATE_UDF_FILE_DATA_FROM_THIS (This);

  if (!PrivFileData->IsRootDirectory) {
    CleanupFileInformation (&PrivFileData->File);

    if (PrivFileData->ReadDirInfo.DirectoryData != NULL) {
      FreePool (PrivFileData->ReadDirInfo.DirectoryData);
    }
  }

  FreePool ((VOID *)PrivFileData);

Exit:
  gBS->RestoreTPL (OldTpl);

  return Status;
}

/**
  Close and delete the file handle.

  @param  This                     Protocol instance pointer.

  @retval EFI_SUCCESS              The file was closed and deleted.
  @retval EFI_WARN_DELETE_FAILURE  The handle was closed but the file was not
                                   deleted.

**/
EFI_STATUS
EFIAPI
UdfDelete (
  IN EFI_FILE_PROTOCOL  *This
  )
{
  PRIVATE_UDF_FILE_DATA  *PrivFileData;

  if (This == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  PrivFileData = PRIVATE_UDF_FILE_DATA_FROM_THIS (This);

  (VOID)PrivFileData->FileIo.Close (This);

  return EFI_WARN_DELETE_FAILURE;
}

/**
  Write data to a file.

  @param  This       Protocol instance pointer.
  @param  BufferSize On input size of buffer, on output amount of data in
                     buffer.
  @param  Buffer     The buffer in which data to write.

  @retval EFI_SUCCESS          Data was written.
  @retval EFI_UNSUPPORTED      Writes to Open directory are not supported.
  @retval EFI_NO_MEDIA         The device has no media.
  @retval EFI_DEVICE_ERROR     The device reported an error.
  @retval EFI_DEVICE_ERROR     An attempt was made to write to a deleted file.
  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
  @retval EFI_WRITE_PROTECTED  The device is write protected.
  @retval EFI_ACCESS_DENIED    The file was open for read only.
  @retval EFI_VOLUME_FULL      The volume is full.

**/
EFI_STATUS
EFIAPI
UdfWrite (
  IN      EFI_FILE_PROTOCOL  *This,
  IN OUT  UINTN              *BufferSize,
  IN      VOID               *Buffer
  )
{
  return EFI_UNSUPPORTED;
}

/**
  Get file's current position.

  @param  This      Protocol instance pointer.
  @param  Position  Byte position from the start of the file.

  @retval EFI_SUCCESS      Position was updated.
  @retval EFI_UNSUPPORTED  Seek request for directories is not valid.

**/
EFI_STATUS
EFIAPI
UdfGetPosition (
  IN   EFI_FILE_PROTOCOL  *This,
  OUT  UINT64             *Position
  )
{
  PRIVATE_UDF_FILE_DATA  *PrivFileData;

  if ((This == NULL) || (Position == NULL)) {
    return EFI_INVALID_PARAMETER;
  }

  PrivFileData = PRIVATE_UDF_FILE_DATA_FROM_THIS (This);

  //
  // As per UEFI spec, if the file handle is a directory, then the current file
  // position has no meaning and the operation is not supported.
  //
  if (IS_FID_DIRECTORY_FILE (PrivFileData->File.FileIdentifierDesc)) {
    return EFI_UNSUPPORTED;
  }

  //
  // The file is not a directory. So, return its position.
  //
  *Position = PrivFileData->FilePosition;

  return EFI_SUCCESS;
}

/**
  Set file's current position.

  @param  This      Protocol instance pointer.
  @param  Position  Byte position from the start of the file.

  @retval EFI_SUCCESS      Position was updated.
  @retval EFI_UNSUPPORTED  Seek request for non-zero is not valid on open.

**/
EFI_STATUS
EFIAPI
UdfSetPosition (
  IN EFI_FILE_PROTOCOL  *This,
  IN UINT64             Position
  )
{
  EFI_STATUS                      Status;
  PRIVATE_UDF_FILE_DATA           *PrivFileData;
  UDF_FILE_IDENTIFIER_DESCRIPTOR  *FileIdentifierDesc;

  if (This == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  Status = EFI_UNSUPPORTED;

  PrivFileData = PRIVATE_UDF_FILE_DATA_FROM_THIS (This);

  FileIdentifierDesc = _FILE (PrivFileData)->FileIdentifierDesc;
  ASSERT (FileIdentifierDesc != NULL);
  if (IS_FID_DIRECTORY_FILE (FileIdentifierDesc)) {
    //
    // If the file handle is a directory, the _only_ position that may be set is
    // zero. This has no effect of starting the read proccess of the directory
    // entries over.
    //
    if (Position == 0) {
      PrivFileData->FilePosition          = Position;
      PrivFileData->ReadDirInfo.FidOffset = 0;
      Status                              = EFI_SUCCESS;
    }
  } else if (IS_FID_NORMAL_FILE (FileIdentifierDesc)) {
    //
    // Seeking to position 0xFFFFFFFFFFFFFFFF causes the current position to be
    // set to the EOF.
    //
    if (Position == 0xFFFFFFFFFFFFFFFF) {
      PrivFileData->FilePosition = PrivFileData->FileSize;
    } else {
      PrivFileData->FilePosition = Position;
    }

    Status = EFI_SUCCESS;
  }

  return Status;
}

/**
  Get information about a file.

  @param  This            Protocol instance pointer.
  @param  InformationType Type of information to return in Buffer.
  @param  BufferSize      On input size of buffer, on output amount of data in
                          buffer.
  @param  Buffer          The buffer to return data.

  @retval EFI_SUCCESS          Data was returned.
  @retval EFI_UNSUPPORTED      InformationType is not supported.
  @retval EFI_NO_MEDIA         The device has no media.
  @retval EFI_DEVICE_ERROR     The device reported an error.
  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
  @retval EFI_WRITE_PROTECTED  The device is write protected.
  @retval EFI_ACCESS_DENIED    The file was open for read only.
  @retval EFI_BUFFER_TOO_SMALL Buffer was too small; required size returned in
                               BufferSize.

**/
EFI_STATUS
EFIAPI
UdfGetInfo (
  IN      EFI_FILE_PROTOCOL  *This,
  IN      EFI_GUID           *InformationType,
  IN OUT  UINTN              *BufferSize,
  OUT     VOID               *Buffer
  )
{
  EFI_STATUS                    Status;
  PRIVATE_UDF_FILE_DATA         *PrivFileData;
  PRIVATE_UDF_SIMPLE_FS_DATA    *PrivFsData;
  EFI_FILE_SYSTEM_INFO          *FileSystemInfo;
  UINTN                         FileSystemInfoLength;
  UINT64                        VolumeSize;
  UINT64                        FreeSpaceSize;
  EFI_FILE_SYSTEM_VOLUME_LABEL  *FileSystemVolumeLabel;
  UINTN                         FileSystemVolumeLabelLength;
  CHAR16                        VolumeLabel[64];

  if ((This == NULL) || (InformationType == NULL) || (BufferSize == NULL) ||
      ((*BufferSize != 0) && (Buffer == NULL)))
  {
    return EFI_INVALID_PARAMETER;
  }

  PrivFileData = PRIVATE_UDF_FILE_DATA_FROM_THIS (This);

  PrivFsData = PRIVATE_UDF_SIMPLE_FS_DATA_FROM_THIS (PrivFileData->SimpleFs);

  Status = EFI_UNSUPPORTED;

  if (CompareGuid (InformationType, &gEfiFileInfoGuid)) {
    Status = SetFileInfo (
               _FILE (PrivFileData),
               PrivFileData->FileSize,
               PrivFileData->FileName,
               BufferSize,
               Buffer
               );
  } else if (CompareGuid (InformationType, &gEfiFileSystemInfoGuid)) {
    Status = GetVolumeLabel (&PrivFsData->Volume, ARRAY_SIZE (VolumeLabel), VolumeLabel);
    if (EFI_ERROR (Status)) {
      return Status;
    }

    FileSystemInfoLength = StrSize (VolumeLabel) +
                           sizeof (EFI_FILE_SYSTEM_INFO);
    if (*BufferSize < FileSystemInfoLength) {
      *BufferSize = FileSystemInfoLength;
      return EFI_BUFFER_TOO_SMALL;
    }

    FileSystemInfo = (EFI_FILE_SYSTEM_INFO *)Buffer;
    StrCpyS (
      FileSystemInfo->VolumeLabel,
      (*BufferSize - SIZE_OF_EFI_FILE_SYSTEM_INFO) / sizeof (CHAR16),
      VolumeLabel
      );
    Status = GetVolumeSize (
               PrivFsData->BlockIo,
               PrivFsData->DiskIo,
               &PrivFsData->Volume,
               &VolumeSize,
               &FreeSpaceSize
               );
    if (EFI_ERROR (Status)) {
      return Status;
    }

    FileSystemInfo->Size      = FileSystemInfoLength;
    FileSystemInfo->ReadOnly  = TRUE;
    FileSystemInfo->BlockSize =
      PrivFsData->Volume.LogicalVolDesc.LogicalBlockSize;
    FileSystemInfo->VolumeSize = VolumeSize;
    FileSystemInfo->FreeSpace  = FreeSpaceSize;

    *BufferSize = FileSystemInfoLength;
    Status      = EFI_SUCCESS;
  } else if (CompareGuid (InformationType, &gEfiFileSystemVolumeLabelInfoIdGuid)) {
    Status = GetVolumeLabel (&PrivFsData->Volume, ARRAY_SIZE (VolumeLabel), VolumeLabel);
    if (EFI_ERROR (Status)) {
      return Status;
    }

    FileSystemVolumeLabelLength = StrSize (VolumeLabel) +
                                  sizeof (EFI_FILE_SYSTEM_VOLUME_LABEL);
    if (*BufferSize < FileSystemVolumeLabelLength) {
      *BufferSize = FileSystemVolumeLabelLength;
      return EFI_BUFFER_TOO_SMALL;
    }

    FileSystemVolumeLabel = (EFI_FILE_SYSTEM_VOLUME_LABEL *)Buffer;
    StrCpyS (
      FileSystemVolumeLabel->VolumeLabel,
      (*BufferSize - SIZE_OF_EFI_FILE_SYSTEM_VOLUME_LABEL) / sizeof (CHAR16),
      VolumeLabel
      );
    Status = EFI_SUCCESS;
  }

  return Status;
}

/**
  Set information about a file.

  @param  This            Protocol instance pointer.
  @param  InformationType Type of information in Buffer.
  @param  BufferSize      Size of buffer.
  @param  Buffer          The data to write.

  @retval EFI_SUCCESS          Data was set.
  @retval EFI_UNSUPPORTED      InformationType is not supported.
  @retval EFI_NO_MEDIA         The device has no media.
  @retval EFI_DEVICE_ERROR     The device reported an error.
  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
  @retval EFI_WRITE_PROTECTED  The device is write protected.
  @retval EFI_ACCESS_DENIED    The file was open for read only.

**/
EFI_STATUS
EFIAPI
UdfSetInfo (
  IN EFI_FILE_PROTOCOL  *This,
  IN EFI_GUID           *InformationType,
  IN UINTN              BufferSize,
  IN VOID               *Buffer
  )
{
  return EFI_WRITE_PROTECTED;
}

/**
  Flush data back for the file handle.

  @param  This Protocol instance pointer.

  @retval EFI_SUCCESS          Data was flushed.
  @retval EFI_UNSUPPORTED      Writes to Open directory are not supported.
  @retval EFI_NO_MEDIA         The device has no media.
  @retval EFI_DEVICE_ERROR     The device reported an error.
  @retval EFI_VOLUME_CORRUPTED The file system structures are corrupted.
  @retval EFI_WRITE_PROTECTED  The device is write protected.
  @retval EFI_ACCESS_DENIED    The file was open for read only.
  @retval EFI_VOLUME_FULL      The volume is full.

**/
EFI_STATUS
EFIAPI
UdfFlush (
  IN EFI_FILE_PROTOCOL  *This
  )
{
  return EFI_WRITE_PROTECTED;
}