// Fill in the response that should be sent to the kernel, or set noResponse if
// the op requires no response.
func (c *Connection) kernelResponse(
m *buffer.OutMessage,
fuseID uint64,
op interface{},
opErr error) (noResponse bool) {
h := m.OutHeader()
h.Unique = fuseID
// Special case: handle the ops for which the kernel expects no response.
// interruptOp .
switch op.(type) {
case *fuseops.ForgetInodeOp:
noResponse = true
return
case *interruptOp:
noResponse = true
return
}
// If the user returned the error, fill in the error field of the outgoing
// message header.
if opErr != nil {
m.OutHeader().Error = -int32(syscall.EIO)
if errno, ok := opErr.(syscall.Errno); ok {
m.OutHeader().Error = -int32(errno)
}
// Special case: for some types, convertInMessage grew the message in order
// to obtain a destination buffer. Make sure that we shrink back to just
// the header, because on OS X the kernel otherwise returns EINVAL when we
// attempt to write an error response with a length that extends beyond the
// header.
m.ShrinkTo(buffer.OutMessageInitialSize)
}
// Otherwise, fill in the rest of the response.
if opErr == nil {
c.kernelResponseForOp(m, op)
}
h.Len = uint32(m.Len())
return
}
// Like kernelResponse, but assumes the user replied with a nil error to the
// op.
func (c *Connection) kernelResponseForOp(
m *buffer.OutMessage,
op interface{}) {
// Create the appropriate output message
switch o := op.(type) {
case *fuseops.LookUpInodeOp:
size := fusekernel.EntryOutSize(c.protocol)
out := (*fusekernel.EntryOut)(m.Grow(size))
convertChildInodeEntry(&o.Entry, out)
case *fuseops.GetInodeAttributesOp:
size := fusekernel.AttrOutSize(c.protocol)
out := (*fusekernel.AttrOut)(m.Grow(size))
out.AttrValid, out.AttrValidNsec = convertExpirationTime(
o.AttributesExpiration)
convertAttributes(o.Inode, &o.Attributes, &out.Attr)
case *fuseops.SetInodeAttributesOp:
size := fusekernel.AttrOutSize(c.protocol)
out := (*fusekernel.AttrOut)(m.Grow(size))
out.AttrValid, out.AttrValidNsec = convertExpirationTime(
o.AttributesExpiration)
convertAttributes(o.Inode, &o.Attributes, &out.Attr)
case *fuseops.MkDirOp:
size := fusekernel.EntryOutSize(c.protocol)
out := (*fusekernel.EntryOut)(m.Grow(size))
convertChildInodeEntry(&o.Entry, out)
case *fuseops.CreateFileOp:
eSize := fusekernel.EntryOutSize(c.protocol)
e := (*fusekernel.EntryOut)(m.Grow(eSize))
convertChildInodeEntry(&o.Entry, e)
oo := (*fusekernel.OpenOut)(m.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
oo.Fh = uint64(o.Handle)
case *fuseops.CreateSymlinkOp:
size := fusekernel.EntryOutSize(c.protocol)
out := (*fusekernel.EntryOut)(m.Grow(size))
convertChildInodeEntry(&o.Entry, out)
case *fuseops.RenameOp:
// Empty response
case *fuseops.RmDirOp:
// Empty response
case *fuseops.UnlinkOp:
// Empty response
case *fuseops.OpenDirOp:
out := (*fusekernel.OpenOut)(m.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
out.Fh = uint64(o.Handle)
case *fuseops.ReadDirOp:
// convertInMessage already set up the destination buffer to be at the end
// of the out message. We need only shrink to the right size based on how
// much the user read.
m.ShrinkTo(buffer.OutMessageInitialSize + uintptr(o.BytesRead))
case *fuseops.ReleaseDirHandleOp:
// Empty response
case *fuseops.OpenFileOp:
out := (*fusekernel.OpenOut)(m.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
out.Fh = uint64(o.Handle)
if o.KeepPageCache {
out.OpenFlags |= uint32(fusekernel.OpenKeepCache)
}
case *fuseops.ReadFileOp:
// convertInMessage already set up the destination buffer to be at the end
// of the out message. We need only shrink to the right size based on how
// much the user read.
m.ShrinkTo(buffer.OutMessageInitialSize + uintptr(o.BytesRead))
case *fuseops.WriteFileOp:
out := (*fusekernel.WriteOut)(m.Grow(unsafe.Sizeof(fusekernel.WriteOut{})))
out.Size = uint32(len(o.Data))
case *fuseops.SyncFileOp:
// Empty response
case *fuseops.FlushFileOp:
// Empty response
case *fuseops.ReleaseFileHandleOp:
// Empty response
case *fuseops.ReadSymlinkOp:
m.AppendString(o.Target)
case *statFSOp:
m.Grow(unsafe.Sizeof(fusekernel.StatfsOut{}))
case *initOp:
out := (*fusekernel.InitOut)(m.Grow(unsafe.Sizeof(fusekernel.InitOut{})))
out.Major = o.Library.Major
out.Minor = o.Library.Minor
out.MaxReadahead = o.MaxReadahead
out.Flags = uint32(o.Flags)
out.MaxWrite = o.MaxWrite
default:
panic(fmt.Sprintf("Unexpected op: %#v", op))
}
return
}
// Convert a kernel message to an appropriate op. If the op is unknown, a
// special unexported type will be used.
//
// The caller is responsible for arranging for the message to be destroyed.
func convertInMessage(
inMsg *buffer.InMessage,
outMsg *buffer.OutMessage,
protocol fusekernel.Protocol) (o interface{}, err error) {
switch inMsg.Header().Opcode {
case fusekernel.OpLookup:
buf := inMsg.ConsumeBytes(inMsg.Len())
n := len(buf)
if n == 0 || buf[n-1] != '\x00' {
err = errors.New("Corrupt OpLookup")
return
}
o = &fuseops.LookUpInodeOp{
Parent: fuseops.InodeID(inMsg.Header().Nodeid),
Name: string(buf[:n-1]),
}
case fusekernel.OpGetattr:
o = &fuseops.GetInodeAttributesOp{
Inode: fuseops.InodeID(inMsg.Header().Nodeid),
}
case fusekernel.OpSetattr:
type input fusekernel.SetattrIn
in := (*input)(inMsg.Consume(unsafe.Sizeof(input{})))
if in == nil {
err = errors.New("Corrupt OpSetattr")
return
}
to := &fuseops.SetInodeAttributesOp{
Inode: fuseops.InodeID(inMsg.Header().Nodeid),
}
o = to
valid := fusekernel.SetattrValid(in.Valid)
if valid&fusekernel.SetattrSize != 0 {
to.Size = &in.Size
}
if valid&fusekernel.SetattrMode != 0 {
mode := convertFileMode(in.Mode)
to.Mode = &mode
}
if valid&fusekernel.SetattrAtime != 0 {
t := time.Unix(int64(in.Atime), int64(in.AtimeNsec))
to.Atime = &t
}
if valid&fusekernel.SetattrMtime != 0 {
t := time.Unix(int64(in.Mtime), int64(in.MtimeNsec))
to.Mtime = &t
}
case fusekernel.OpForget:
type input fusekernel.ForgetIn
in := (*input)(inMsg.Consume(unsafe.Sizeof(input{})))
if in == nil {
err = errors.New("Corrupt OpForget")
return
}
o = &fuseops.ForgetInodeOp{
Inode: fuseops.InodeID(inMsg.Header().Nodeid),
N: in.Nlookup,
}
case fusekernel.OpMkdir:
in := (*fusekernel.MkdirIn)(inMsg.Consume(fusekernel.MkdirInSize(protocol)))
if in == nil {
err = errors.New("Corrupt OpMkdir")
return
}
name := inMsg.ConsumeBytes(inMsg.Len())
i := bytes.IndexByte(name, '\x00')
if i < 0 {
err = errors.New("Corrupt OpMkdir")
return
}
name = name[:i]
o = &fuseops.MkDirOp{
Parent: fuseops.InodeID(inMsg.Header().Nodeid),
Name: string(name),
// On Linux, vfs_mkdir calls through to the inode with at most
// permissions and sticky bits set (cf. https://goo.gl/WxgQXk), and fuse
// passes that on directly (cf. https://goo.gl/f31aMo). In other words,
// the fact that this is a directory is implicit in the fact that the
// opcode is mkdir. But we want the correct mode to go through, so ensure
// that os.ModeDir is set.
Mode: convertFileMode(in.Mode) | os.ModeDir,
}
case fusekernel.OpCreate:
in := (*fusekernel.CreateIn)(inMsg.Consume(fusekernel.CreateInSize(protocol)))
if in == nil {
err = errors.New("Corrupt OpCreate")
return
}
name := inMsg.ConsumeBytes(inMsg.Len())
i := bytes.IndexByte(name, '\x00')
if i < 0 {
err = errors.New("Corrupt OpCreate")
return
}
name = name[:i]
o = &fuseops.CreateFileOp{
Parent: fuseops.InodeID(inMsg.Header().Nodeid),
Name: string(name),
Mode: convertFileMode(in.Mode),
}
case fusekernel.OpSymlink:
// The message is "newName\0target\0".
names := inMsg.ConsumeBytes(inMsg.Len())
if len(names) == 0 || names[len(names)-1] != 0 {
err = errors.New("Corrupt OpSymlink")
return
}
i := bytes.IndexByte(names, '\x00')
if i < 0 {
err = errors.New("Corrupt OpSymlink")
return
}
newName, target := names[0:i], names[i+1:len(names)-1]
o = &fuseops.CreateSymlinkOp{
Parent: fuseops.InodeID(inMsg.Header().Nodeid),
Name: string(newName),
Target: string(target),
}
case fusekernel.OpRename:
type input fusekernel.RenameIn
in := (*input)(inMsg.Consume(unsafe.Sizeof(input{})))
if in == nil {
err = errors.New("Corrupt OpRename")
return
}
names := inMsg.ConsumeBytes(inMsg.Len())
// names should be "old\x00new\x00"
if len(names) < 4 {
err = errors.New("Corrupt OpRename")
return
}
if names[len(names)-1] != '\x00' {
err = errors.New("Corrupt OpRename")
return
}
i := bytes.IndexByte(names, '\x00')
if i < 0 {
err = errors.New("Corrupt OpRename")
return
}
oldName, newName := names[:i], names[i+1:len(names)-1]
o = &fuseops.RenameOp{
OldParent: fuseops.InodeID(inMsg.Header().Nodeid),
OldName: string(oldName),
NewParent: fuseops.InodeID(in.Newdir),
NewName: string(newName),
}
case fusekernel.OpUnlink:
buf := inMsg.ConsumeBytes(inMsg.Len())
n := len(buf)
if n == 0 || buf[n-1] != '\x00' {
err = errors.New("Corrupt OpUnlink")
return
}
o = &fuseops.UnlinkOp{
Parent: fuseops.InodeID(inMsg.Header().Nodeid),
Name: string(buf[:n-1]),
}
case fusekernel.OpRmdir:
buf := inMsg.ConsumeBytes(inMsg.Len())
n := len(buf)
if n == 0 || buf[n-1] != '\x00' {
err = errors.New("Corrupt OpRmdir")
return
}
o = &fuseops.RmDirOp{
Parent: fuseops.InodeID(inMsg.Header().Nodeid),
Name: string(buf[:n-1]),
}
case fusekernel.OpOpen:
o = &fuseops.OpenFileOp{
Inode: fuseops.InodeID(inMsg.Header().Nodeid),
}
case fusekernel.OpOpendir:
o = &fuseops.OpenDirOp{
Inode: fuseops.InodeID(inMsg.Header().Nodeid),
}
case fusekernel.OpRead:
in := (*fusekernel.ReadIn)(inMsg.Consume(fusekernel.ReadInSize(protocol)))
if in == nil {
err = errors.New("Corrupt OpRead")
return
}
to := &fuseops.ReadFileOp{
Inode: fuseops.InodeID(inMsg.Header().Nodeid),
Handle: fuseops.HandleID(in.Fh),
Offset: int64(in.Offset),
}
o = to
readSize := int(in.Size)
p := outMsg.GrowNoZero(uintptr(readSize))
if p == nil {
err = fmt.Errorf("Can't grow for %d-byte read", readSize)
return
}
sh := (*reflect.SliceHeader)(unsafe.Pointer(&to.Dst))
sh.Data = uintptr(p)
sh.Len = readSize
sh.Cap = readSize
case fusekernel.OpReaddir:
in := (*fusekernel.ReadIn)(inMsg.Consume(fusekernel.ReadInSize(protocol)))
if in == nil {
err = errors.New("Corrupt OpReaddir")
return
}
to := &fuseops.ReadDirOp{
Inode: fuseops.InodeID(inMsg.Header().Nodeid),
Handle: fuseops.HandleID(in.Fh),
Offset: fuseops.DirOffset(in.Offset),
}
o = to
readSize := int(in.Size)
p := outMsg.GrowNoZero(uintptr(readSize))
if p == nil {
err = fmt.Errorf("Can't grow for %d-byte read", readSize)
return
}
sh := (*reflect.SliceHeader)(unsafe.Pointer(&to.Dst))
sh.Data = uintptr(p)
sh.Len = readSize
sh.Cap = readSize
case fusekernel.OpRelease:
type input fusekernel.ReleaseIn
in := (*input)(inMsg.Consume(unsafe.Sizeof(input{})))
if in == nil {
err = errors.New("Corrupt OpRelease")
return
}
o = &fuseops.ReleaseFileHandleOp{
Handle: fuseops.HandleID(in.Fh),
}
case fusekernel.OpReleasedir:
type input fusekernel.ReleaseIn
in := (*input)(inMsg.Consume(unsafe.Sizeof(input{})))
if in == nil {
err = errors.New("Corrupt OpReleasedir")
return
}
o = &fuseops.ReleaseDirHandleOp{
Handle: fuseops.HandleID(in.Fh),
}
case fusekernel.OpWrite:
in := (*fusekernel.WriteIn)(inMsg.Consume(fusekernel.WriteInSize(protocol)))
if in == nil {
err = errors.New("Corrupt OpWrite")
return
}
buf := inMsg.ConsumeBytes(inMsg.Len())
if len(buf) < int(in.Size) {
err = errors.New("Corrupt OpWrite")
return
}
o = &fuseops.WriteFileOp{
Inode: fuseops.InodeID(inMsg.Header().Nodeid),
Handle: fuseops.HandleID(in.Fh),
Data: buf,
Offset: int64(in.Offset),
}
case fusekernel.OpFsync:
type input fusekernel.FsyncIn
in := (*input)(inMsg.Consume(unsafe.Sizeof(input{})))
if in == nil {
err = errors.New("Corrupt OpFsync")
return
}
o = &fuseops.SyncFileOp{
Inode: fuseops.InodeID(inMsg.Header().Nodeid),
Handle: fuseops.HandleID(in.Fh),
}
case fusekernel.OpFlush:
type input fusekernel.FlushIn
in := (*input)(inMsg.Consume(unsafe.Sizeof(input{})))
if in == nil {
err = errors.New("Corrupt OpFlush")
return
}
o = &fuseops.FlushFileOp{
Inode: fuseops.InodeID(inMsg.Header().Nodeid),
Handle: fuseops.HandleID(in.Fh),
}
case fusekernel.OpReadlink:
o = &fuseops.ReadSymlinkOp{
Inode: fuseops.InodeID(inMsg.Header().Nodeid),
}
case fusekernel.OpStatfs:
o = &statFSOp{}
case fusekernel.OpInterrupt:
type input fusekernel.InterruptIn
in := (*input)(inMsg.Consume(unsafe.Sizeof(input{})))
if in == nil {
err = errors.New("Corrupt OpInterrupt")
return
}
o = &interruptOp{
FuseID: in.Unique,
}
case fusekernel.OpInit:
type input fusekernel.InitIn
in := (*input)(inMsg.Consume(unsafe.Sizeof(input{})))
if in == nil {
err = errors.New("Corrupt OpInit")
return
}
o = &initOp{
Kernel: fusekernel.Protocol{in.Major, in.Minor},
MaxReadahead: in.MaxReadahead,
Flags: fusekernel.InitFlags(in.Flags),
}
default:
o = &unknownOp{
OpCode: inMsg.Header().Opcode,
Inode: fuseops.InodeID(inMsg.Header().Nodeid),
}
}
return
}
// Like kernelResponse, but assumes the user replied with a nil error to the
// op.
func (c *Connection) kernelResponseForOp(
m *buffer.OutMessage,
op interface{}) {
// Create the appropriate output message
switch o := op.(type) {
case *fuseops.LookUpInodeOp:
size := fusekernel.EntryOutSize(c.protocol)
out := (*fusekernel.EntryOut)(m.Grow(size))
convertChildInodeEntry(&o.Entry, out)
case *fuseops.GetInodeAttributesOp:
size := fusekernel.AttrOutSize(c.protocol)
out := (*fusekernel.AttrOut)(m.Grow(size))
out.AttrValid, out.AttrValidNsec = convertExpirationTime(
o.AttributesExpiration)
convertAttributes(o.Inode, &o.Attributes, &out.Attr)
case *fuseops.SetInodeAttributesOp:
size := fusekernel.AttrOutSize(c.protocol)
out := (*fusekernel.AttrOut)(m.Grow(size))
out.AttrValid, out.AttrValidNsec = convertExpirationTime(
o.AttributesExpiration)
convertAttributes(o.Inode, &o.Attributes, &out.Attr)
case *fuseops.MkDirOp:
size := fusekernel.EntryOutSize(c.protocol)
out := (*fusekernel.EntryOut)(m.Grow(size))
convertChildInodeEntry(&o.Entry, out)
case *fuseops.CreateFileOp:
eSize := fusekernel.EntryOutSize(c.protocol)
e := (*fusekernel.EntryOut)(m.Grow(eSize))
convertChildInodeEntry(&o.Entry, e)
oo := (*fusekernel.OpenOut)(m.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
oo.Fh = uint64(o.Handle)
case *fuseops.CreateSymlinkOp:
size := fusekernel.EntryOutSize(c.protocol)
out := (*fusekernel.EntryOut)(m.Grow(size))
convertChildInodeEntry(&o.Entry, out)
case *fuseops.RenameOp:
// Empty response
case *fuseops.RmDirOp:
// Empty response
case *fuseops.UnlinkOp:
// Empty response
case *fuseops.OpenDirOp:
out := (*fusekernel.OpenOut)(m.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
out.Fh = uint64(o.Handle)
case *fuseops.ReadDirOp:
// convertInMessage already set up the destination buffer to be at the end
// of the out message. We need only shrink to the right size based on how
// much the user read.
m.ShrinkTo(buffer.OutMessageInitialSize + uintptr(o.BytesRead))
case *fuseops.ReleaseDirHandleOp:
// Empty response
case *fuseops.OpenFileOp:
out := (*fusekernel.OpenOut)(m.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
out.Fh = uint64(o.Handle)
if o.KeepPageCache {
out.OpenFlags |= uint32(fusekernel.OpenKeepCache)
}
case *fuseops.ReadFileOp:
// convertInMessage already set up the destination buffer to be at the end
// of the out message. We need only shrink to the right size based on how
// much the user read.
m.ShrinkTo(buffer.OutMessageInitialSize + uintptr(o.BytesRead))
case *fuseops.WriteFileOp:
out := (*fusekernel.WriteOut)(m.Grow(unsafe.Sizeof(fusekernel.WriteOut{})))
out.Size = uint32(len(o.Data))
case *fuseops.SyncFileOp:
// Empty response
case *fuseops.FlushFileOp:
// Empty response
case *fuseops.ReleaseFileHandleOp:
// Empty response
case *fuseops.ReadSymlinkOp:
m.AppendString(o.Target)
case *fuseops.StatFSOp:
out := (*fusekernel.StatfsOut)(m.Grow(unsafe.Sizeof(fusekernel.StatfsOut{})))
out.St.Blocks = o.Blocks
out.St.Bfree = o.BlocksFree
out.St.Bavail = o.BlocksAvailable
out.St.Files = o.Inodes
out.St.Ffree = o.InodesFree
// The posix spec for sys/statvfs.h (http://goo.gl/LktgrF) defines the
// following fields of statvfs, among others:
//
// f_bsize File system block size.
// f_frsize Fundamental file system block size.
// f_blocks Total number of blocks on file system in units of f_frsize.
//
// It appears as though f_bsize was the only thing supported by most unixes
// originally, but then f_frsize was added when new sorts of file systems
// came about. Quoth The Linux Programming Interface by Michael Kerrisk
// (https://goo.gl/5LZMxQ):
//
// For most Linux file systems, the values of f_bsize and f_frsize are
// the same. However, some file systems support the notion of block
// fragments, which can be used to allocate a smaller unit of storage
// at the end of the file if if a full block is not required. This
// avoids the waste of space that would otherwise occur if a full block
// was allocated. On such file systems, f_frsize is the size of a
// fragment, and f_bsize is the size of a whole block. (The notion of
// fragments in UNIX file systems first appeared in the early 1980s
// with the 4.2BSD Fast File System.)
//
// Confusingly, it appears as though osxfuse surfaces fuse_kstatfs::bsize
// as statfs::f_iosize (of advisory use only), and fuse_kstatfs::frsize as
// statfs::f_bsize (which affects free space display in the Finder).
out.St.Bsize = o.IoSize
out.St.Frsize = o.BlockSize
case *initOp:
out := (*fusekernel.InitOut)(m.Grow(unsafe.Sizeof(fusekernel.InitOut{})))
out.Major = o.Library.Major
out.Minor = o.Library.Minor
out.MaxReadahead = o.MaxReadahead
out.Flags = uint32(o.Flags)
out.MaxWrite = o.MaxWrite
default:
panic(fmt.Sprintf("Unexpected op: %#v", op))
}
return
}
