1 files changed, 133 insertions, 0 deletions
diff --git a/pkg/sentry/fsimpl/fuse/file.go b/pkg/sentry/fsimpl/fuse/file.go
new file mode 100644
index 000000000..991efcda4
--- /dev/null
+++ b/pkg/sentry/fsimpl/fuse/file.go
@@ -0,0 +1,133 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fuse
+
+import (
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+// fileDescription implements vfs.FileDescriptionImpl for fuse.
+type fileDescription struct {
+	vfsfd vfs.FileDescription
+	vfs.FileDescriptionDefaultImpl
+	vfs.DentryMetadataFileDescriptionImpl
+	vfs.NoLockFD
+
+	// the file handle used in userspace.
+	Fh uint64
+
+	// Nonseekable is indicate cannot perform seek on a file.
+	Nonseekable bool
+
+	// DirectIO suggest fuse to use direct io operation.
+	DirectIO bool
+
+	// OpenFlag is the flag returned by open.
+	OpenFlag uint32
+
+	// off is the file offset.
+	off int64
+}
+
+func (fd *fileDescription) dentry() *kernfs.Dentry {
+	return fd.vfsfd.Dentry().Impl().(*kernfs.Dentry)
+}
+
+func (fd *fileDescription) inode() *inode {
+	return fd.dentry().Inode().(*inode)
+}
+
+func (fd *fileDescription) filesystem() *vfs.Filesystem {
+	return fd.vfsfd.VirtualDentry().Mount().Filesystem()
+}
+
+func (fd *fileDescription) statusFlags() uint32 {
+	return fd.vfsfd.StatusFlags()
+}
+
+// Release implements vfs.FileDescriptionImpl.Release.
+func (fd *fileDescription) Release(ctx context.Context) {
+	// no need to release if FUSE server doesn't implement Open.
+	conn := fd.inode().fs.conn
+	if conn.noOpen {
+		return
+	}
+
+	in := linux.FUSEReleaseIn{
+		Fh:    fd.Fh,
+		Flags: fd.statusFlags(),
+	}
+	// TODO(gvisor.dev/issue/3245): add logic when we support file lock owner.
+	var opcode linux.FUSEOpcode
+	if fd.inode().Mode().IsDir() {
+		opcode = linux.FUSE_RELEASEDIR
+	} else {
+		opcode = linux.FUSE_RELEASE
+	}
+	kernelTask := kernel.TaskFromContext(ctx)
+	// ignoring errors and FUSE server reply is analogous to Linux's behavior.
+	req, err := conn.NewRequest(auth.CredentialsFromContext(ctx), uint32(kernelTask.ThreadID()), fd.inode().nodeID, opcode, &in)
+	if err != nil {
+		// No way to invoke Call() with an errored request.
+		return
+	}
+	req.noReply = true
+	conn.CallAsync(kernelTask, req)
+}
+
+// PRead implements vfs.FileDescriptionImpl.PRead.
+func (fd *fileDescription) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
+	return 0, nil
+}
+
+// Read implements vfs.FileDescriptionImpl.Read.
+func (fd *fileDescription) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
+	return 0, nil
+}
+
+// PWrite implements vfs.FileDescriptionImpl.PWrite.
+func (fd *fileDescription) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
+	return 0, nil
+}
+
+// Write implements vfs.FileDescriptionImpl.Write.
+func (fd *fileDescription) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
+	return 0, nil
+}
+
+// Seek implements vfs.FileDescriptionImpl.Seek.
+func (fd *fileDescription) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
+	return 0, nil
+}
+
+// Stat implements vfs.FileDescriptionImpl.Stat.
+func (fd *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) {
+	fs := fd.filesystem()
+	inode := fd.inode()
+	return inode.Stat(ctx, fs, opts)
+}
+
+// SetStat implements vfs.FileDescriptionImpl.SetStat.
+func (fd *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) error {
+	fs := fd.filesystem()
+	creds := auth.CredentialsFromContext(ctx)
+	return fd.inode().setAttr(ctx, fs, creds, opts, true, fd.Fh)
+}