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// 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/atomicbitops"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/usermem"
)
// fileDescription implements vfs.FileDescriptionImpl for fuse.
//
// +stateify savable
type fileDescription struct {
vfsfd vfs.FileDescription
vfs.FileDescriptionDefaultImpl
vfs.DentryMetadataFileDescriptionImpl
vfs.LockFD
// the file handle used in userspace.
Fh uint64
// Nonseekable indicates we cannot perform seek on a file.
Nonseekable bool
// DirectIO suggests that fuse use direct IO operations.
DirectIO bool
// OpenFlag is the flag returned by open.
OpenFlag uint32
// off is the file offset.
off atomicbitops.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 owners.
inode := fd.inode()
inode.attrMu.Lock()
defer inode.attrMu.Unlock()
var opcode linux.FUSEOpcode
if inode.filemode().IsDir() {
opcode = linux.FUSE_RELEASEDIR
} else {
opcode = linux.FUSE_RELEASE
}
// Ignoring errors and FUSE server replies is analogous to Linux's behavior.
req := conn.NewRequest(auth.CredentialsFromContext(ctx), pidFromContext(ctx), inode.nodeID, opcode, &in)
// The reply will be ignored since no callback is defined in asyncCallBack().
conn.CallAsync(ctx, req)
}
// OnClose implements vfs.FileDescriptionImpl.OnClose.
func (fd *fileDescription) OnClose(ctx context.Context) error {
inode := fd.inode()
conn := inode.fs.conn
inode.attrMu.Lock()
defer inode.attrMu.Unlock()
in := linux.FUSEFlushIn{
Fh: fd.Fh,
LockOwner: 0, // TODO(gvisor.dev/issue/3245): file lock
}
req := conn.NewRequest(auth.CredentialsFromContext(ctx), pidFromContext(ctx), inode.nodeID, linux.FUSE_FLUSH, &in)
return conn.CallAsync(ctx, 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)
inode := fd.inode()
inode.attrMu.Lock()
defer inode.attrMu.Unlock()
if err := vfs.CheckSetStat(ctx, creds, &opts, inode.filemode(), auth.KUID(inode.uid.Load()), auth.KGID(inode.gid.Load())); err != nil {
return err
}
return inode.setAttr(ctx, fs, creds, opts, fhOptions{useFh: true, fh: fd.Fh})
}
// Sync implements vfs.FileDescriptionImpl.Sync.
func (fd *fileDescription) Sync(ctx context.Context) error {
inode := fd.inode()
inode.attrMu.Lock()
defer inode.attrMu.Unlock()
conn := inode.fs.conn
// no need to proceed if FUSE server doesn't implement Open.
if conn.noOpen {
return linuxerr.EINVAL
}
in := linux.FUSEFsyncIn{
Fh: fd.Fh,
FsyncFlags: fd.statusFlags(),
}
// Ignoring errors and FUSE server replies is analogous to Linux's behavior.
req := conn.NewRequest(auth.CredentialsFromContext(ctx), pidFromContext(ctx), inode.nodeID, linux.FUSE_FSYNC, &in)
// The reply will be ignored since no callback is defined in asyncCallBack().
conn.CallAsync(ctx, req)
return nil
}
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