94 lines
2.7 KiB

// Copyright 2015 Google Inc. All Rights Reserved.
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package fuseutil
import (
type DirentType uint32
const (
DT_Unknown DirentType = 0
DT_Socket DirentType = syscall.DT_SOCK
DT_Link DirentType = syscall.DT_LNK
DT_File DirentType = syscall.DT_REG
DT_Block DirentType = syscall.DT_BLK
DT_Directory DirentType = syscall.DT_DIR
DT_Char DirentType = syscall.DT_CHR
DT_FIFO DirentType = syscall.DT_FIFO
// A struct representing an entry within a directory file, describing a child.
// See notes on fuse.ReadDirResponse and on AppendDirent for details.
type Dirent struct {
// The (opaque) offset within the directory file of the entry following this
// one. See notes on fuse.ReadDirRequest.Offset for details.
Offset fuse.DirOffset
// The inode of the child file or directory, and its name within the parent.
Inode fuse.InodeID
Name string
// The type of the child. The zero value (DT_Unknown) is legal, but means
// that the kernel will need to call GetAttr when the type is needed.
Type DirentType
// Append the supplied directory entry to the given buffer in the format
// expected in fuse.ReadResponse.Data, returning the resulting buffer.
func AppendDirent(input []byte, d Dirent) (output []byte) {
// We want to append bytes with the layout of fuse_dirent
// (http://goo.gl/BmFxob) in host order. The struct must be aligned according
// to FUSE_DIRENT_ALIGN (http://goo.gl/UziWvH), which dictates 8-byte
// alignment.
type fuse_dirent struct {
ino uint64
off uint64
namelen uint32
type_ uint32
name [0]byte
const alignment = 8
const nameOffset = 8 + 8 + 4 + 4
// Write the header into the buffer.
de := fuse_dirent{
ino: uint64(d.Inode),
off: uint64(d.Offset),
namelen: uint32(len(d.Name)),
type_: uint32(d.Type),
output = append(input, (*[nameOffset]byte)(unsafe.Pointer(&de))[:]...)
// Write the name afterward.
output = append(output, d.Name...)
// Add any necessary padding.
if len(d.Name)%alignment != 0 {
padLen := alignment - (len(d.Name) % alignment)
var padding [alignment]byte
output = append(output, padding[:padLen]...)