72 lines
1.9 KiB
Go
72 lines
1.9 KiB
Go
// Copyright 2015 Google Inc. All Rights Reserved.
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// Author: jacobsa@google.com (Aaron Jacobs)
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package fuseutil
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import (
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"unsafe"
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bazilfuse "bazil.org/fuse"
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"github.com/jacobsa/fuse"
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)
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type DirentType bazilfuse.DirentType
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// A struct representing an entry within a directory file, describing a child.
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// See notes on fuse.ReadDirResponse and on AppendDirent for details.
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type Dirent struct {
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// The (opaque) offset within the directory file of the entry following this
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// one. See notes on fuse.ReadDirRequest.Offset for details.
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Offset fuse.DirOffset
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// The inode of the child file or directory, and its name within the parent.
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Inode fuse.InodeID
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Name string
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// The type of the child. The zero value (DT_Unknown) is legal, but means
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// that the kernel will need to call GetAttr when the type is needed.
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Type DirentType
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}
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// Append the supplied directory entry to the given buffer in the format
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// expected in fuse.ReadResponse.Data, returning the resulting buffer.
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func AppendDirent(input []byte, d Dirent) (output []byte) {
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// We want to append bytes with the layout of fuse_dirent
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// (http://goo.gl/BmFxob) in host order. The struct must be aligned according
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// to FUSE_DIRENT_ALIGN (http://goo.gl/UziWvH), which dictates 8-byte
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// alignment.
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type fuse_dirent struct {
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ino uint64
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off uint64
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namelen uint32
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type_ uint32
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name [0]byte
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}
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const alignment = 8
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const nameOffset = 8 + 8 + 4 + 4
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// Write the header into the buffer.
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de := fuse_dirent{
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ino: uint64(d.Inode),
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off: uint64(d.Offset),
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namelen: uint32(len(d.Name)),
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type_: uint32(d.Type),
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}
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output = append(input, (*[nameOffset]byte)(unsafe.Pointer(&de))[:]...)
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// Write the name afterward.
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output = append(output, d.Name...)
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// Add any necessary padding.
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if len(d.Name)%alignment != 0 {
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padLen := alignment - (len(d.Name) % alignment)
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var padding [alignment]byte
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output = append(output, padding[:padLen]...)
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}
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return
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}
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