OvmfPkg/VirtioFsDxe/SimpleFsOpenVolume.c

   1 /** @file
   2   EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.OpenVolume() member function for the Virtio
   3   Filesystem driver.
   4
   5   Copyright (C) 2020, Red Hat, Inc.
   6
   7   SPDX-License-Identifier: BSD-2-Clause-Patent
   8 **/
   9
  10 #include <Library/BaseLib.h>             // InsertTailList()
  11 #include <Library/MemoryAllocationLib.h> // AllocatePool()
  12
  13 #include "VirtioFsDxe.h"
  14
  15 /**
  16   Open the root directory on the Virtio Filesystem.
  17
  18   Refer to EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_OPEN_VOLUME for the interface
  19   contract.
  20 **/
  21 EFI_STATUS
  22 EFIAPI
  23 VirtioFsOpenVolume (
  24   IN  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *This,
  25   OUT EFI_FILE_PROTOCOL               **Root
  26   )
  27 {
  28   VIRTIO_FS      *VirtioFs;
  29   VIRTIO_FS_FILE *VirtioFsFile;
  30   EFI_STATUS     Status;
  31   CHAR8          *CanonicalPathname;
  32   UINT64         RootDirHandle;
  33
  34   VirtioFs = VIRTIO_FS_FROM_SIMPLE_FS (This);
  35
  36   VirtioFsFile = AllocatePool (sizeof *VirtioFsFile);
  37   if (VirtioFsFile == NULL) {
  38     return EFI_OUT_OF_RESOURCES;
  39   }
  40
  41   CanonicalPathname = AllocateCopyPool (sizeof "/", "/");
  42   if (CanonicalPathname == NULL) {
  43     Status = EFI_OUT_OF_RESOURCES;
  44     goto FreeVirtioFsFile;
  45   }
  46
  47   //
  48   // Open the root directory.
  49   //
  50   Status = VirtioFsFuseOpenDir (VirtioFs, VIRTIO_FS_FUSE_ROOT_DIR_NODE_ID,
  51              &RootDirHandle);
  52   if (EFI_ERROR (Status)) {
  53     goto FreeCanonicalPathname;
  54   }
  55
  56   //
  57   // Populate the new VIRTIO_FS_FILE object.
  58   //
  59   VirtioFsFile->Signature              = VIRTIO_FS_FILE_SIG;
  60   VirtioFsFile->SimpleFile.Revision    = EFI_FILE_PROTOCOL_REVISION;
  61   VirtioFsFile->SimpleFile.Open        = VirtioFsSimpleFileOpen;
  62   VirtioFsFile->SimpleFile.Close       = VirtioFsSimpleFileClose;
  63   VirtioFsFile->SimpleFile.Delete      = VirtioFsSimpleFileDelete;
  64   VirtioFsFile->SimpleFile.Read        = VirtioFsSimpleFileRead;
  65   VirtioFsFile->SimpleFile.Write       = VirtioFsSimpleFileWrite;
  66   VirtioFsFile->SimpleFile.GetPosition = VirtioFsSimpleFileGetPosition;
  67   VirtioFsFile->SimpleFile.SetPosition = VirtioFsSimpleFileSetPosition;
  68   VirtioFsFile->SimpleFile.GetInfo     = VirtioFsSimpleFileGetInfo;
  69   VirtioFsFile->SimpleFile.SetInfo     = VirtioFsSimpleFileSetInfo;
  70   VirtioFsFile->SimpleFile.Flush       = VirtioFsSimpleFileFlush;
  71   VirtioFsFile->IsDirectory            = TRUE;
  72   VirtioFsFile->IsOpenForWriting       = FALSE;
  73   VirtioFsFile->OwnerFs                = VirtioFs;
  74   VirtioFsFile->CanonicalPathname      = CanonicalPathname;
  75   VirtioFsFile->FilePosition           = 0;
  76   VirtioFsFile->NodeId                 = VIRTIO_FS_FUSE_ROOT_DIR_NODE_ID;
  77   VirtioFsFile->FuseHandle             = RootDirHandle;
  78
  79   //
  80   // One more file open for the filesystem.
  81   //
  82   InsertTailList (&VirtioFs->OpenFiles, &VirtioFsFile->OpenFilesEntry);
  83
  84   *Root = &VirtioFsFile->SimpleFile;
  85   return EFI_SUCCESS;
  86
  87 FreeCanonicalPathname:
  88   FreePool (CanonicalPathname);
  89
  90 FreeVirtioFsFile:
  91   FreePool (VirtioFsFile);
  92
  93   return Status;
  94 }