audk/OvmfPkg/VirtioFsDxe/SimpleFsGetPosition.c

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OvmfPkg/VirtioFsDxe: implement EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.OpenVolume() With the help of the VirtioFsFuseOpenDir() and VirtioFsFuseReleaseFileOrDir() functions introduced previously, we can now open and close the root directory. So let's implement EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.OpenVolume(). OpenVolume() creates a new EFI_FILE_PROTOCOL object -- a reference to the root directory of the filesystem. Thus, we have to start tracking references to EFI_SIMPLE_FILE_SYSTEM_PROTOCOL, lest we unbind the virtio-fs device while files are open. There are two methods that release an EFI_FILE_PROTOCOL object: the Close() and the Delete() member functions. In particular, they are not allowed to fail with regard to resource management -- they must release resources unconditionally. Thus, for rolling back the resource accounting that we do in EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.OpenVolume(), we have to implement the first versions of EFI_FILE_PROTOCOL.Close() and EFI_FILE_PROTOCOL.Delete() in this patch as well. With this patch applied, the UEFI shell can enter the root directory of the Virtio Filesystem (such as with the "FS3:" shell command), and the "DIR" shell command exercises FUSE_OPENDIR and FUSE_RELEASEDIR, according to the virtiofsd log. The "DIR" command reports the root directory as if it were empty; probably because at this time, we only allow the shell to open and to close the root directory, but not to read it. 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: <20201216211125.19496-12-lersek@redhat.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
2020-12-16 22:10:48 +01:00
/** @file
EFI_FILE_PROTOCOL.GetPosition() member function for the Virtio Filesystem
driver.
Copyright (C) 2020, Red Hat, Inc.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "VirtioFsDxe.h"
EFI_STATUS
EFIAPI
VirtioFsSimpleFileGetPosition (
IN EFI_FILE_PROTOCOL *This,
OUT UINT64 *Position
)
{
VIRTIO_FS_FILE *VirtioFsFile;
VirtioFsFile = VIRTIO_FS_FILE_FROM_SIMPLE_FILE (This);
if (VirtioFsFile->IsDirectory) {
return EFI_UNSUPPORTED;
}
*Position = VirtioFsFile->FilePosition;
return EFI_SUCCESS;
OvmfPkg/VirtioFsDxe: implement EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.OpenVolume() With the help of the VirtioFsFuseOpenDir() and VirtioFsFuseReleaseFileOrDir() functions introduced previously, we can now open and close the root directory. So let's implement EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.OpenVolume(). OpenVolume() creates a new EFI_FILE_PROTOCOL object -- a reference to the root directory of the filesystem. Thus, we have to start tracking references to EFI_SIMPLE_FILE_SYSTEM_PROTOCOL, lest we unbind the virtio-fs device while files are open. There are two methods that release an EFI_FILE_PROTOCOL object: the Close() and the Delete() member functions. In particular, they are not allowed to fail with regard to resource management -- they must release resources unconditionally. Thus, for rolling back the resource accounting that we do in EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.OpenVolume(), we have to implement the first versions of EFI_FILE_PROTOCOL.Close() and EFI_FILE_PROTOCOL.Delete() in this patch as well. With this patch applied, the UEFI shell can enter the root directory of the Virtio Filesystem (such as with the "FS3:" shell command), and the "DIR" shell command exercises FUSE_OPENDIR and FUSE_RELEASEDIR, according to the virtiofsd log. The "DIR" command reports the root directory as if it were empty; probably because at this time, we only allow the shell to open and to close the root directory, but not to read it. 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: <20201216211125.19496-12-lersek@redhat.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
2020-12-16 22:10:48 +01:00
}