OvmfPkg/VirtioFsDxe: implement EFI_FILE_PROTOCOL.GetInfo()

Using the functions introduced previously, we can now implement
VirtioFsSimpleFileGetInfo().

This allows the "VOL" command to work in the UEFI shell.

Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3097
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20201216211125.19496-31-lersek@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>

OvmfPkg/VirtioFsDxe/SimpleFsGetInfo.c

@@ -6,8 +6,184 @@
   SPDX-License-Identifier: BSD-2-Clause-Patent
 **/
 
+#include <Guid/FileSystemInfo.h>            // gEfiFileSystemInfoGuid
+#include <Guid/FileSystemVolumeLabelInfo.h> // gEfiFileSystemVolumeLabelInfo...
+#include <Library/BaseLib.h>                // StrSize()
+#include <Library/BaseMemoryLib.h>          // CompareGuid()
+
 #include "VirtioFsDxe.h"
 
+/**
+  Provide EFI_FILE_INFO about this particular file.
+**/
+STATIC
+EFI_STATUS
+GetFileInfo (
+  IN     EFI_FILE_PROTOCOL *This,
+  IN OUT UINTN             *BufferSize,
+     OUT VOID              *Buffer
+  )
+{
+  VIRTIO_FS_FILE                     *VirtioFsFile;
+  VIRTIO_FS                          *VirtioFs;
+  UINTN                              AllocSize;
+  UINTN                              BasenameSize;
+  EFI_STATUS                         Status;
+  EFI_FILE_INFO                      *FileInfo;
+  VIRTIO_FS_FUSE_ATTRIBUTES_RESPONSE FuseAttr;
+
+  VirtioFsFile = VIRTIO_FS_FILE_FROM_SIMPLE_FILE (This);
+  VirtioFs     = VirtioFsFile->OwnerFs;
+
+  AllocSize = *BufferSize;
+
+  //
+  // Calculate the needed size.
+  //
+  BasenameSize = 0;
+  Status = VirtioFsGetBasename (VirtioFsFile->CanonicalPathname, NULL,
+             &BasenameSize);
+  ASSERT (Status == EFI_BUFFER_TOO_SMALL);
+  *BufferSize = OFFSET_OF (EFI_FILE_INFO, FileName) + BasenameSize;
+
+  if (*BufferSize > AllocSize) {
+    return EFI_BUFFER_TOO_SMALL;
+  }
+
+  //
+  // Set the structure size, and store the basename.
+  //
+  FileInfo = Buffer;
+  FileInfo->Size = *BufferSize;
+  Status = VirtioFsGetBasename (VirtioFsFile->CanonicalPathname,
+             FileInfo->FileName, &BasenameSize);
+  ASSERT_EFI_ERROR (Status);
+
+  //
+  // Fetch the file attributes, and convert them into the caller's buffer.
+  //
+  Status = VirtioFsFuseGetAttr (VirtioFs, VirtioFsFile->NodeId, &FuseAttr);
+  if (!EFI_ERROR (Status)) {
+    Status = VirtioFsFuseAttrToEfiFileInfo (&FuseAttr, FileInfo);
+  }
+  return (Status == EFI_BUFFER_TOO_SMALL) ? EFI_DEVICE_ERROR : Status;
+}
+
+/**
+  Provide EFI_FILE_SYSTEM_INFO about the filesystem this file lives on.
+**/
+STATIC
+EFI_STATUS
+GetFileSystemInfo (
+  IN     EFI_FILE_PROTOCOL *This,
+  IN OUT UINTN             *BufferSize,
+     OUT VOID              *Buffer
+  )
+{
+  VIRTIO_FS_FILE                 *VirtioFsFile;
+  VIRTIO_FS                      *VirtioFs;
+  UINTN                          AllocSize;
+  UINTN                          LabelSize;
+  EFI_STATUS                     Status;
+  VIRTIO_FS_FUSE_STATFS_RESPONSE FilesysAttr;
+  UINT64                         MaxBlocks;
+  EFI_FILE_SYSTEM_INFO           *FilesysInfo;
+
+  VirtioFsFile = VIRTIO_FS_FILE_FROM_SIMPLE_FILE (This);
+  VirtioFs     = VirtioFsFile->OwnerFs;
+
+  AllocSize = *BufferSize;
+
+  //
+  // Calculate the needed size.
+  //
+  LabelSize = StrSize (VirtioFs->Label);
+  *BufferSize = OFFSET_OF (EFI_FILE_SYSTEM_INFO, VolumeLabel) + LabelSize;
+
+  if (*BufferSize > AllocSize) {
+    return EFI_BUFFER_TOO_SMALL;
+  }
+
+  //
+  // Fetch the filesystem attributes.
+  //
+  Status = VirtioFsFuseStatFs (VirtioFs, VirtioFsFile->NodeId, &FilesysAttr);
+  if (EFI_ERROR (Status)) {
+    return (Status == EFI_BUFFER_TOO_SMALL) ? EFI_DEVICE_ERROR : Status;
+  }
+  //
+  // Sanity checks...
+  //
+  if (FilesysAttr.Frsize != FilesysAttr.Bsize) {
+    return EFI_UNSUPPORTED;
+  }
+  if (FilesysAttr.Frsize == 0 || FilesysAttr.Blocks == 0 ||
+      FilesysAttr.Bavail > FilesysAttr.Blocks) {
+    return EFI_DEVICE_ERROR;
+  }
+  MaxBlocks = DivU64x32 (MAX_UINT64, FilesysAttr.Frsize);
+  if (FilesysAttr.Blocks > MaxBlocks || FilesysAttr.Bavail > MaxBlocks) {
+    return EFI_DEVICE_ERROR;
+  }
+
+  //
+  // Fill in EFI_FILE_SYSTEM_INFO.
+  //
+  FilesysInfo             = Buffer;
+  FilesysInfo->Size       = *BufferSize;
+  FilesysInfo->ReadOnly   = FALSE;
+  FilesysInfo->VolumeSize = MultU64x32 (FilesysAttr.Blocks,
+                              FilesysAttr.Frsize);
+  FilesysInfo->FreeSpace  = MultU64x32 (FilesysAttr.Bavail,
+                              FilesysAttr.Frsize);
+  FilesysInfo->BlockSize  = FilesysAttr.Frsize;
+  CopyMem (FilesysInfo->VolumeLabel, VirtioFs->Label, LabelSize);
+
+  return EFI_SUCCESS;
+}
+
+/**
+  Return the filesystem label as EFI_FILE_SYSTEM_VOLUME_LABEL.
+**/
+STATIC
+EFI_STATUS
+GetFileSystemVolumeLabelInfo (
+  IN     EFI_FILE_PROTOCOL *This,
+  IN OUT UINTN             *BufferSize,
+     OUT VOID              *Buffer
+  )
+{
+  VIRTIO_FS_FILE               *VirtioFsFile;
+  VIRTIO_FS                    *VirtioFs;
+  UINTN                        AllocSize;
+  UINTN                        LabelSize;
+  EFI_FILE_SYSTEM_VOLUME_LABEL *FilesysVolumeLabel;
+
+  VirtioFsFile = VIRTIO_FS_FILE_FROM_SIMPLE_FILE (This);
+  VirtioFs     = VirtioFsFile->OwnerFs;
+
+  AllocSize = *BufferSize;
+
+  //
+  // Calculate the needed size.
+  //
+  LabelSize = StrSize (VirtioFs->Label);
+  *BufferSize = (OFFSET_OF (EFI_FILE_SYSTEM_VOLUME_LABEL, VolumeLabel) +
+                 LabelSize);
+
+  if (*BufferSize > AllocSize) {
+    return EFI_BUFFER_TOO_SMALL;
+  }
+
+  //
+  // Store the label.
+  //
+  FilesysVolumeLabel = Buffer;
+  CopyMem (FilesysVolumeLabel->VolumeLabel, VirtioFs->Label, LabelSize);
+
+  return EFI_SUCCESS;
+}
+
 EFI_STATUS
 EFIAPI
 VirtioFsSimpleFileGetInfo (
@@ -17,5 +193,17 @@ VirtioFsSimpleFileGetInfo (
      OUT VOID              *Buffer
   )
 {
-  return EFI_NO_MEDIA;
+  if (CompareGuid (InformationType, &gEfiFileInfoGuid)) {
+    return GetFileInfo (This, BufferSize, Buffer);
+  }
+
+  if (CompareGuid (InformationType, &gEfiFileSystemInfoGuid)) {
+    return GetFileSystemInfo (This, BufferSize, Buffer);
+  }
+
+  if (CompareGuid (InformationType, &gEfiFileSystemVolumeLabelInfoIdGuid)) {
+    return GetFileSystemVolumeLabelInfo (This, BufferSize, Buffer);
+  }
+
+  return EFI_UNSUPPORTED;
 }

OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf

@@ -125,3 +125,8 @@
   gEfiDriverBindingProtocolGuid         ## PRODUCES
   gEfiSimpleFileSystemProtocolGuid      ## BY_START
   gVirtioDeviceProtocolGuid             ## TO_START
+
+[Guids]
+  gEfiFileInfoGuid
+  gEfiFileSystemInfoGuid
+  gEfiFileSystemVolumeLabelInfoIdGuid