// Read the next op from the kernel process, returning the op and a context
// that should be used for work related to the op. Return io.EOF if the kernel
// has closed the connection.
//
// If err != nil, the user is responsible for later calling c.Reply with the
// returned context.
//
// This function delivers ops in exactly the order they are received from
// /dev/fuse. It must not be called multiple times concurrently.
//
// LOCKS_EXCLUDED(c.mu)
func (c *Connection) ReadOp() (ctx context.Context, op interface{}, err error) {
// Keep going until we find a request we know how to convert.
for {
// Read the next message from the kernel.
var inMsg *buffer.InMessage
inMsg, err = c.readMessage()
if err != nil {
return
}
// Convert the message to an op.
outMsg := c.getOutMessage()
op, err = convertInMessage(inMsg, outMsg, c.protocol)
if err != nil {
c.putOutMessage(outMsg)
err = fmt.Errorf("convertInMessage: %v", err)
return
}
// Choose an ID for this operation for the purposes of logging, and log it.
if c.debugLogger != nil {
c.debugLog(inMsg.Header().Unique, 1, "<- %s", describeRequest(op))
}
// Special case: handle interrupt requests inline.
if interruptOp, ok := op.(*interruptOp); ok {
c.handleInterrupt(interruptOp.FuseID)
continue
}
// Set up a context that remembers information about this op.
ctx = c.beginOp(inMsg.Header().Opcode, inMsg.Header().Unique)
ctx = context.WithValue(ctx, contextKey, opState{inMsg, outMsg, op})
// Special case: responding to statfs is required to make mounting work on
// OS X. We don't currently expose the capability for the file system to
// intercept this.
if _, ok := op.(*statFSOp); ok {
c.Reply(ctx, nil)
continue
}
// Return the op to the user.
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
}