gvisor/pkg/sentry/fsimpl/ext/disklayout/dirent_new.go

62 lines
2.0 KiB
Go

// Copyright 2019 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 disklayout
import (
"fmt"
"gvisor.dev/gvisor/pkg/sentry/fs"
)
// DirentNew represents the ext4 directory entry struct. This emulates Linux's
// ext4_dir_entry_2 struct. The FileName can not be more than 255 bytes so we
// only need 8 bits to store the NameLength. As a result, NameLength has been
// shortened and the other 8 bits are used to encode the file type. Use the
// FileTypeRaw field only if the SbDirentFileType feature is set.
//
// Note: This struct can be of variable size on disk. The one described below
// is of maximum size and the FileName beyond NameLength bytes might contain
// garbage.
type DirentNew struct {
InodeNumber uint32
RecordLength uint16
NameLength uint8
FileTypeRaw uint8
FileNameRaw [MaxFileName]byte
}
// Compiles only if DirentNew implements Dirent.
var _ Dirent = (*DirentNew)(nil)
// Inode implements Dirent.Inode.
func (d *DirentNew) Inode() uint32 { return d.InodeNumber }
// RecordSize implements Dirent.RecordSize.
func (d *DirentNew) RecordSize() uint16 { return d.RecordLength }
// FileName implements Dirent.FileName.
func (d *DirentNew) FileName() string {
return string(d.FileNameRaw[:d.NameLength])
}
// FileType implements Dirent.FileType.
func (d *DirentNew) FileType() (fs.InodeType, bool) {
if inodeType, ok := inodeTypeByFileType[d.FileTypeRaw]; ok {
return inodeType, true
}
panic(fmt.Sprintf("unknown file type %v", d.FileTypeRaw))
}