OvmfPkg/VirtioFsDxe/SimpleFsSetPosition.c

   1 /** @file
   2   EFI_FILE_PROTOCOL.SetPosition() member function for the Virtio Filesystem
   3   driver.
   4
   5   Copyright (C) 2020, Red Hat, Inc.
   6
   7   SPDX-License-Identifier: BSD-2-Clause-Patent
   8 **/
   9
  10 #include <Library/MemoryAllocationLib.h> // FreePool()
  11
  12 #include "VirtioFsDxe.h"
  13
  14 EFI_STATUS
  15 EFIAPI
  16 VirtioFsSimpleFileSetPosition (
  17   IN EFI_FILE_PROTOCOL  *This,
  18   IN UINT64             Position
  19   )
  20 {
  21   VIRTIO_FS_FILE                      *VirtioFsFile;
  22   VIRTIO_FS                           *VirtioFs;
  23   EFI_STATUS                          Status;
  24   VIRTIO_FS_FUSE_ATTRIBUTES_RESPONSE  FuseAttr;
  25
  26   VirtioFsFile = VIRTIO_FS_FILE_FROM_SIMPLE_FILE (This);
  27
  28   //
  29   // Directories can only be rewound, per spec.
  30   //
  31   if (VirtioFsFile->IsDirectory) {
  32     if (Position != 0) {
  33       return EFI_UNSUPPORTED;
  34     }
  35
  36     VirtioFsFile->FilePosition = 0;
  37     if (VirtioFsFile->FileInfoArray != NULL) {
  38       FreePool (VirtioFsFile->FileInfoArray);
  39       VirtioFsFile->FileInfoArray = NULL;
  40     }
  41
  42     VirtioFsFile->SingleFileInfoSize = 0;
  43     VirtioFsFile->NumFileInfo        = 0;
  44     VirtioFsFile->NextFileInfo       = 0;
  45     return EFI_SUCCESS;
  46   }
  47
  48   //
  49   // Regular file.
  50   //
  51   if (Position < MAX_UINT64) {
  52     //
  53     // Caller is requesting absolute file position.
  54     //
  55     VirtioFsFile->FilePosition = Position;
  56     return EFI_SUCCESS;
  57   }
  58
  59   //
  60   // Caller is requesting a seek to EOF.
  61   //
  62   VirtioFs = VirtioFsFile->OwnerFs;
  63   Status   = VirtioFsFuseGetAttr (VirtioFs, VirtioFsFile->NodeId, &FuseAttr);
  64   if (EFI_ERROR (Status)) {
  65     return Status;
  66   }
  67
  68   VirtioFsFile->FilePosition = FuseAttr.Size;
  69   return EFI_SUCCESS;
  70 }