// FUSE service loop, for servers that wish to use it.
package fs // import "bazil.org/fuse/fs"
import (
"encoding/binary"
"fmt"
"hash/fnv"
"io"
"log"
"reflect"
"runtime"
"strings"
"sync"
"time"
"golang.org/x/net/context"
)
import (
"bytes"
"bazil.org/fuse"
"bazil.org/fuse/fuseutil"
)
const (
attrValidTime = 1 * time.Minute
entryValidTime = 1 * time.Minute
)
// TODO: FINISH DOCS
// An FS is the interface required of a file system.
//
// Other FUSE requests can be handled by implementing methods from the
// FS* interfaces, for example FSStatfser.
type FS interface {
// Root is called to obtain the Node for the file system root.
Root() (Node, error)
}
type FSStatfser interface {
// Statfs is called to obtain file system metadata.
// It should write that data to resp.
Statfs(ctx context.Context, req *fuse.StatfsRequest, resp *fuse.StatfsResponse) error
}
type FSDestroyer interface {
// Destroy is called when the file system is shutting down.
//
// Linux only sends this request for block device backed (fuseblk)
// filesystems, to allow them to flush writes to disk before the
// unmount completes.
Destroy()
}
type FSInodeGenerator interface {
// GenerateInode is called to pick a dynamic inode number when it
// would otherwise be 0.
//
// Not all filesystems bother tracking inodes, but FUSE requires
// the inode to be set, and fewer duplicates in general makes UNIX
// tools work better.
//
// Operations where the nodes may return 0 inodes include Getattr,
// Setattr and ReadDir.
//
// If FS does not implement FSInodeGenerator, GenerateDynamicInode
// is used.
//
// Implementing this is useful to e.g. constrain the range of
// inode values used for dynamic inodes.
GenerateInode(parentInode uint64, name string) uint64
}
// A Node is the interface required of a file or directory.
// See the documentation for type FS for general information
// pertaining to all methods.
//
// A Node must be usable as a map key, that is, it cannot be a
// function, map or slice.
//
// Other FUSE requests can be handled by implementing methods from the
// Node* interfaces, for example NodeOpener.
//
// Methods returning Node should take care to return the same Node
// when the result is logically the same instance. Without this, each
// Node will get a new NodeID, causing spurious cache invalidations,
// extra lookups and aliasing anomalies. This may not matter for a
// simple, read-only filesystem.
type Node interface {
// Attr fills attr with the standard metadata for the node.
//
// Fields with reasonable defaults are prepopulated. For example,
// all times are set to a fixed moment when the program started.
//
// If Inode is left as 0, a dynamic inode number is chosen.
//
// The result may be cached for the duration set in Valid.
Attr(ctx context.Context, attr *fuse.Attr) error
}
type NodeGetattrer interface {
// Getattr obtains the standard metadata for the receiver.
// It should store that metadata in resp.
//
// If this method is not implemented, the attributes will be
// generated based on Attr(), with zero values filled in.
Getattr(ctx context.Context, req *fuse.GetattrRequest, resp *fuse.GetattrResponse) error
}
type NodeSetattrer interface {
// Setattr sets the standard metadata for the receiver.
//
// Note, this is also used to communicate changes in the size of
// the file, outside of Writes.
//
// req.Valid is a bitmask of what fields are actually being set.
// For example, the method should not change the mode of the file
// unless req.Valid.Mode() is true.
Setattr(ctx context.Context, req *fuse.SetattrRequest, resp *fuse.SetattrResponse) error
}
type NodeSymlinker interface {
// Symlink creates a new symbolic link in the receiver, which must be a directory.
//
// TODO is the above true about directories?
Symlink(ctx context.Context, req *fuse.SymlinkRequest) (Node, error)
}
// This optional request will be called only for symbolic link nodes.
type NodeReadlinker interface {
// Readlink reads a symbolic link.
Readlink(ctx context.Context, req *fuse.ReadlinkRequest) (string, error)
}
type NodeLinker interface {
// Link creates a new directory entry in the receiver based on an
// existing Node. Receiver must be a directory.
Link(ctx context.Context, req *fuse.LinkRequest, old Node) (Node, error)
}
type NodeRemover interface {
// Remove removes the entry with the given name from
// the receiver, which must be a directory. The entry to be removed
// may correspond to a file (unlink) or to a directory (rmdir).
Remove(ctx context.Context, req *fuse.RemoveRequest) error
}
type NodeAccesser interface {
// Access checks whether the calling context has permission for
// the given operations on the receiver. If so, Access should
// return nil. If not, Access should return EPERM.
//
// Note that this call affects the result of the access(2) system
// call but not the open(2) system call. If Access is not
// implemented, the Node behaves as if it always returns nil
// (permission granted), relying on checks in Open instead.
Access(ctx context.Context, req *fuse.AccessRequest) error
}
type NodeStringLookuper interface {
// Lookup looks up a specific entry in the receiver,
// which must be a directory. Lookup should return a Node
// corresponding to the entry. If the name does not exist in
// the directory, Lookup should return ENOENT.
//
// Lookup need not to handle the names "." and "..".
Lookup(ctx context.Context, name string) (Node, error)
}
type NodeRequestLookuper interface {
// Lookup looks up a specific entry in the receiver.
// See NodeStringLookuper for more.
Lookup(ctx context.Context, req *fuse.LookupRequest, resp *fuse.LookupResponse) (Node, error)
}
type NodeMkdirer interface {
Mkdir(ctx context.Context, req *fuse.MkdirRequest) (Node, error)
}
type NodeOpener interface {
// Open opens the receiver. After a successful open, a client
// process has a file descriptor referring to this Handle.
//
// Open can also be also called on non-files. For example,
// directories are Opened for ReadDir or fchdir(2).
//
// If this method is not implemented, the open will always
// succeed, and the Node itself will be used as the Handle.
//
// XXX note about access. XXX OpenFlags.
Open(ctx context.Context, req *fuse.OpenRequest, resp *fuse.OpenResponse) (Handle, error)
}
type NodeCreater interface {
// Create creates a new directory entry in the receiver, which
// must be a directory.
Create(ctx context.Context, req *fuse.CreateRequest, resp *fuse.CreateResponse) (Node, Handle, error)
}
type NodeForgetter interface {
// Forget about this node. This node will not receive further
// method calls.
//
// Forget is not necessarily seen on unmount, as all nodes are
// implicitly forgotten as part part of the unmount.
Forget()
}
type NodeRenamer interface {
Rename(ctx context.Context, req *fuse.RenameRequest, newDir Node) error
}
type NodeMknoder interface {
Mknod(ctx context.Context, req *fuse.MknodRequest) (Node, error)
}
// TODO this should be on Handle not Node
type NodeFsyncer interface {
Fsync(ctx context.Context, req *fuse.FsyncRequest) error
}
type NodeGetxattrer interface {
// Getxattr gets an extended attribute by the given name from the
// node.
//
// If there is no xattr by that name, returns fuse.ErrNoXattr.
Getxattr(ctx context.Context, req *fuse.GetxattrRequest, resp *fuse.GetxattrResponse) error
}
type NodeListxattrer interface {
// Listxattr lists the extended attributes recorded for the node.
Listxattr(ctx context.Context, req *fuse.ListxattrRequest, resp *fuse.ListxattrResponse) error
}
type NodeSetxattrer interface {
// Setxattr sets an extended attribute with the given name and
// value for the node.
Setxattr(ctx context.Context, req *fuse.SetxattrRequest) error
}
type NodeRemovexattrer interface {
// Removexattr removes an extended attribute for the name.
//
// If there is no xattr by that name, returns fuse.ErrNoXattr.
Removexattr(ctx context.Context, req *fuse.RemovexattrRequest) error
}
var startTime = time.Now()
func nodeAttr(ctx context.Context, n Node, attr *fuse.Attr) error {
attr.Valid = attrValidTime
attr.Nlink = 1
attr.Atime = startTime
attr.Mtime = startTime
attr.Ctime = startTime
attr.Crtime = startTime
if err := n.Attr(ctx, attr); err != nil {
return err
}
return nil
}
// A Handle is the interface required of an opened file or directory.
// See the documentation for type FS for general information
// pertaining to all methods.
//
// Other FUSE requests can be handled by implementing methods from the
// Handle* interfaces. The most common to implement are HandleReader,
// HandleReadDirer, and HandleWriter.
//
// TODO implement methods: Getlk, Setlk, Setlkw
type Handle interface {
}
type HandleFlusher interface {
// Flush is called each time the file or directory is closed.
// Because there can be multiple file descriptors referring to a
// single opened file, Flush can be called multiple times.
Flush(ctx context.Context, req *fuse.FlushRequest) error
}
type HandleReadAller interface {
ReadAll(ctx context.Context) ([]byte, error)
}
type HandleReadDirAller interface {
ReadDirAll(ctx context.Context) ([]fuse.Dirent, error)
}
type HandleReader interface {
// Read requests to read data from the handle.
//
// There is a page cache in the kernel that normally submits only
// page-aligned reads spanning one or more pages. However, you
// should not rely on this. To see individual requests as
// submitted by the file system clients, set OpenDirectIO.
//
// Note that reads beyond the size of the file as reported by Attr
// are not even attempted (except in OpenDirectIO mode).
Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error
}
type HandleWriter interface {
// Write requests to write data into the handle at the given offset.
// Store the amount of data written in resp.Size.
//
// There is a writeback page cache in the kernel that normally submits
// only page-aligned writes spanning one or more pages. However,
// you should not rely on this. To see individual requests as
// submitted by the file system clients, set OpenDirectIO.
//
// Writes that grow the file are expected to update the file size
// (as seen through Attr). Note that file size changes are
// communicated also through Setattr.
Write(ctx context.Context, req *fuse.WriteRequest, resp *fuse.WriteResponse) error
}
type HandleReleaser interface {
Release(ctx context.Context, req *fuse.ReleaseRequest) error
}
type Config struct {
// Function to send debug log messages to. If nil, use fuse.Debug.
// Note that changing this or fuse.Debug may not affect existing
// calls to Serve.
//
// See fuse.Debug for the rules that log functions must follow.
Debug func(msg interface{})
// Function to put things into context for processing the request.
// The returned context must have ctx as its parent.
//
// Note that changing this may not affect existing calls to Serve.
//
// Must not retain req.
WithContext func(ctx context.Context, req fuse.Request) context.Context
}
// New returns a new FUSE server ready to serve this kernel FUSE
// connection.
//
// Config may be nil.
func New(conn *fuse.Conn, config *Config) *Server {
s := &Server{
conn: conn,
req: map[fuse.RequestID]*serveRequest{},
nodeRef: map[Node]fuse.NodeID{},
dynamicInode: GenerateDynamicInode,
}
if config != nil {
s.debug = config.Debug
s.context = config.WithContext
}
if s.debug == nil {
s.debug = fuse.Debug
}
return s
}
type Server struct {
// set in New
conn *fuse.Conn
debug func(msg interface{})
context func(ctx context.Context, req fuse.Request) context.Context
// set once at Serve time
fs FS
dynamicInode func(parent uint64, name string) uint64
// state, protected by meta
meta sync.Mutex
req map[fuse.RequestID]*serveRequest
node []*serveNode
nodeRef map[Node]fuse.NodeID
handle []*serveHandle
freeNode []fuse.NodeID
freeHandle []fuse.HandleID
nodeGen uint64
// Used to ensure worker goroutines finish before Serve returns
wg sync.WaitGroup
}
// Serve serves the FUSE connection by making calls to the methods
// of fs and the Nodes and Handles it makes available. It returns only
// when the connection has been closed or an unexpected error occurs.
func (s *Server) Serve(fs FS) error {
defer s.wg.Wait() // Wait for worker goroutines to complete before return
s.fs = fs
if dyn, ok := fs.(FSInodeGenerator); ok {
s.dynamicInode = dyn.GenerateInode
}
root, err := fs.Root()
if err != nil {
return fmt.Errorf("cannot obtain root node: %v", err)
}
// Recognize the root node if it's ever returned from Lookup,
// passed to Invalidate, etc.
s.nodeRef[root] = 1
s.node = append(s.node, nil, &serveNode{
inode: 1,
generation: s.nodeGen,
node: root,
refs: 1,
})
s.handle = append(s.handle, nil)
for {
req, err := s.conn.ReadRequest()
if err != nil {
if err == io.EOF {
break
}
return err
}
s.wg.Add(1)
go func() {
defer s.wg.Done()
s.serve(req)
}()
}
return nil
}
// Serve serves a FUSE connection with the default settings. See
// Server.Serve.
func Serve(c *fuse.Conn, fs FS) error {
server := New(c, nil)
return server.Serve(fs)
}
type nothing struct{}
type serveRequest struct {
Request fuse.Request
cancel func()
}
type serveNode struct {
inode uint64
generation uint64
node Node
refs uint64
// Delay freeing the NodeID until waitgroup is done. This allows
// using the NodeID for short periods of time without holding the
// Server.meta lock.
//
// Rules:
//
// - hold Server.meta while calling wg.Add, then unlock
// - do NOT try to reacquire Server.meta
wg sync.WaitGroup
}
func (sn *serveNode) attr(ctx context.Context, attr *fuse.Attr) error {
err := nodeAttr(ctx, sn.node, attr)
if attr.Inode == 0 {
attr.Inode = sn.inode
}
return err
}
type serveHandle struct {
handle Handle
readData []byte
nodeID fuse.NodeID
}
// NodeRef is deprecated. It remains here to decrease code churn on
// FUSE library users. You may remove it from your program now;
// returning the same Node values are now recognized automatically,
// without needing NodeRef.
type NodeRef struct{}
func (c *Server) saveNode(inode uint64, node Node) (id fuse.NodeID, gen uint64) {
c.meta.Lock()
defer c.meta.Unlock()
if id, ok := c.nodeRef[node]; ok {
sn := c.node[id]
sn.refs++
return id, sn.generation
}
sn := &serveNode{inode: inode, node: node, refs: 1}
if n := len(c.freeNode); n > 0 {
id = c.freeNode[n-1]
c.freeNode = c.freeNode[:n-1]
c.node[id] = sn
c.nodeGen++
} else {
id = fuse.NodeID(len(c.node))
c.node = append(c.node, sn)
}
sn.generation = c.nodeGen
c.nodeRef[node] = id
return id, sn.generation
}
func (c *Server) saveHandle(handle Handle, nodeID fuse.NodeID) (id fuse.HandleID) {
c.meta.Lock()
shandle := &serveHandle{handle: handle, nodeID: nodeID}
if n := len(c.freeHandle); n > 0 {
id = c.freeHandle[n-1]
c.freeHandle = c.freeHandle[:n-1]
c.handle[id] = shandle
} else {
id = fuse.HandleID(len(c.handle))
c.handle = append(c.handle, shandle)
}
c.meta.Unlock()
return
}
type nodeRefcountDropBug struct {
N uint64
Refs uint64
Node fuse.NodeID
}
func (n *nodeRefcountDropBug) String() string {
return fmt.Sprintf("bug: trying to drop %d of %d references to %v", n.N, n.Refs, n.Node)
}
func (c *Server) dropNode(id fuse.NodeID, n uint64) (forget bool) {
c.meta.Lock()
defer c.meta.Unlock()
snode := c.node[id]
if snode == nil {
// this should only happen if refcounts kernel<->us disagree
// *and* two ForgetRequests for the same node race each other;
// this indicates a bug somewhere
c.debug(nodeRefcountDropBug{N: n, Node: id})
// we may end up triggering Forget twice, but that's better
// than not even once, and that's the best we can do
return true
}
if n > snode.refs {
c.debug(nodeRefcountDropBug{N: n, Refs: snode.refs, Node: id})
n = snode.refs
}
snode.refs -= n
if snode.refs == 0 {
snode.wg.Wait()
c.node[id] = nil
delete(c.nodeRef, snode.node)
c.freeNode = append(c.freeNode, id)
return true
}
return false
}
func (c *Server) dropHandle(id fuse.HandleID) {
c.meta.Lock()
c.handle[id] = nil
c.freeHandle = append(c.freeHandle, id)
c.meta.Unlock()
}
type missingHandle struct {
Handle fuse.HandleID
MaxHandle fuse.HandleID
}
func (m missingHandle) String() string {
return fmt.Sprint("missing handle: ", m.Handle, m.MaxHandle)
}
// Returns nil for invalid handles.
func (c *Server) getHandle(id fuse.HandleID) (shandle *serveHandle) {
c.meta.Lock()
defer c.meta.Unlock()
if id < fuse.HandleID(len(c.handle)) {
shandle = c.handle[uint(id)]
}
if shandle == nil {
c.debug(missingHandle{
Handle: id,
MaxHandle: fuse.HandleID(len(c.handle)),
})
}
return
}
type request struct {
Op string
Request *fuse.Header
In interface{} `json:",omitempty"`
}
func (r request) String() string {
return fmt.Sprintf("<- %s", r.In)
}
type logResponseHeader struct {
ID fuse.RequestID
}
func (m logResponseHeader) String() string {
return fmt.Sprintf("ID=%v", m.ID)
}
type response struct {
Op string
Request logResponseHeader
Out interface{} `json:",omitempty"`
// Errno contains the errno value as a string, for example "EPERM".
Errno string `json:",omitempty"`
// Error may contain a free form error message.
Error string `json:",omitempty"`
}
func (r response) errstr() string {
s := r.Errno
if r.Error != "" {
// prefix the errno constant to the long form message
s = s + ": " + r.Error
}
return s
}
func (r response) String() string {
switch {
case r.Errno != "" && r.Out != nil:
return fmt.Sprintf("-> [%v] %v error=%s", r.Request, r.Out, r.errstr())
case r.Errno != "":
return fmt.Sprintf("-> [%v] %s error=%s", r.Request, r.Op, r.errstr())
case r.Out != nil:
// make sure (seemingly) empty values are readable
switch r.Out.(type) {
case string:
return fmt.Sprintf("-> [%v] %s %q", r.Request, r.Op, r.Out)
case []byte:
return fmt.Sprintf("-> [%v] %s [% x]", r.Request, r.Op, r.Out)
default:
return fmt.Sprintf("-> [%v] %v", r.Request, r.Out)
}
default:
return fmt.Sprintf("-> [%v] %s", r.Request, r.Op)
}
}
type notification struct {
Op string
Node fuse.NodeID
Out interface{} `json:",omitempty"`
Err string `json:",omitempty"`
}
func (n notification) String() string {
var buf bytes.Buffer
fmt.Fprintf(&buf, "=> %s %v", n.Op, n.Node)
if n.Out != nil {
// make sure (seemingly) empty values are readable
switch n.Out.(type) {
case string:
fmt.Fprintf(&buf, " %q", n.Out)
case []byte:
fmt.Fprintf(&buf, " [% x]", n.Out)
default:
fmt.Fprintf(&buf, " %s", n.Out)
}
}
if n.Err != "" {
fmt.Fprintf(&buf, " Err:%v", n.Err)
}
return buf.String()
}
type logMissingNode struct {
MaxNode fuse.NodeID
}
func opName(req fuse.Request) string {
t := reflect.Indirect(reflect.ValueOf(req)).Type()
s := t.Name()
s = strings.TrimSuffix(s, "Request")
return s
}
type logLinkRequestOldNodeNotFound struct {
Request *fuse.Header
In *fuse.LinkRequest
}
func (m *logLinkRequestOldNodeNotFound) String() string {
return fmt.Sprintf("In LinkRequest (request %v), node %d not found", m.Request.Hdr().ID, m.In.OldNode)
}
type renameNewDirNodeNotFound struct {
Request *fuse.Header
In *fuse.RenameRequest
}
func (m *renameNewDirNodeNotFound) String() string {
return fmt.Sprintf("In RenameRequest (request %v), node %d not found", m.Request.Hdr().ID, m.In.NewDir)
}
type handlerPanickedError struct {
Request interface{}
Err interface{}
}
var _ error = handlerPanickedError{}
func (h handlerPanickedError) Error() string {
return fmt.Sprintf("handler panicked: %v", h.Err)
}
var _ fuse.ErrorNumber = handlerPanickedError{}
func (h handlerPanickedError) Errno() fuse.Errno {
if err, ok := h.Err.(fuse.ErrorNumber); ok {
return err.Errno()
}
return fuse.DefaultErrno
}
// handlerTerminatedError happens when a handler terminates itself
// with runtime.Goexit. This is most commonly because of incorrect use
// of testing.TB.FailNow, typically via t.Fatal.
type handlerTerminatedError struct {
Request interface{}
}
var _ error = handlerTerminatedError{}
func (h handlerTerminatedError) Error() string {
return fmt.Sprintf("handler terminated (called runtime.Goexit)")
}
var _ fuse.ErrorNumber = handlerTerminatedError{}
func (h handlerTerminatedError) Errno() fuse.Errno {
return fuse.DefaultErrno
}
type handleNotReaderError struct {
handle Handle
}
var _ error = handleNotReaderError{}
func (e handleNotReaderError) Error() string {
return fmt.Sprintf("handle has no Read: %T", e.handle)
}
var _ fuse.ErrorNumber = handleNotReaderError{}
func (e handleNotReaderError) Errno() fuse.Errno {
return fuse.ENOTSUP
}
func initLookupResponse(s *fuse.LookupResponse) {
s.EntryValid = entryValidTime
}
func (c *Server) serve(r fuse.Request) {
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
parentCtx := ctx
if c.context != nil {
ctx = c.context(ctx, r)
}
req := &serveRequest{Request: r, cancel: cancel}
c.debug(request{
Op: opName(r),
Request: r.Hdr(),
In: r,
})
var node Node
var snode *serveNode
c.meta.Lock()
hdr := r.Hdr()
if id := hdr.Node; id != 0 {
if id < fuse.NodeID(len(c.node)) {
snode = c.node[uint(id)]
}
if snode == nil {
c.meta.Unlock()
c.debug(response{
Op: opName(r),
Request: logResponseHeader{ID: hdr.ID},
Error: fuse.ESTALE.ErrnoName(),
// this is the only place that sets both Error and
// Out; not sure if i want to do that; might get rid
// of len(c.node) things altogether
Out: logMissingNode{
MaxNode: fuse.NodeID(len(c.node)),
},
})
r.RespondError(fuse.ESTALE)
return
}
node = snode.node
}
if c.req[hdr.ID] != nil {
// This happens with OSXFUSE. Assume it's okay and
// that we'll never see an interrupt for this one.
// Otherwise everything wedges. TODO: Report to OSXFUSE?
//
// TODO this might have been because of missing done() calls
} else {
c.req[hdr.ID] = req
}
c.meta.Unlock()
// Call this before responding.
// After responding is too late: we might get another request
// with the same ID and be very confused.
done := func(resp interface{}) {
msg := response{
Op: opName(r),
Request: logResponseHeader{ID: hdr.ID},
}
if err, ok := resp.(error); ok {
msg.Error = err.Error()
if ferr, ok := err.(fuse.ErrorNumber); ok {
errno := ferr.Errno()
msg.Errno = errno.ErrnoName()
if errno == err {
// it's just a fuse.Errno with no extra detail;
// skip the textual message for log readability
msg.Error = ""
}
} else {
msg.Errno = fuse.DefaultErrno.ErrnoName()
}
} else {
msg.Out = resp
}
c.debug(msg)
c.meta.Lock()
delete(c.req, hdr.ID)
c.meta.Unlock()
}
var responded bool
defer func() {
if rec := recover(); rec != nil {
const size = 1 << 16
buf := make([]byte, size)
n := runtime.Stack(buf, false)
buf = buf[:n]
log.Printf("fuse: panic in handler for %v: %v\n%s", r, rec, buf)
err := handlerPanickedError{
Request: r,
Err: rec,
}
done(err)
r.RespondError(err)
return
}
if !responded {
err := handlerTerminatedError{
Request: r,
}
done(err)
r.RespondError(err)
}
}()
if err := c.handleRequest(ctx, node, snode, r, done); err != nil {
if err == context.Canceled {
select {
case <-parentCtx.Done():
// We canceled the parent context because of an
// incoming interrupt request, so return EINTR
// to trigger the right behavior in the client app.
//
// Only do this when it's the parent context that was
// canceled, not a context controlled by the program
// using this library, so we don't return EINTR too
// eagerly -- it might cause busy loops.
//
// Decent write-up on role of EINTR:
// http://250bpm.com/blog:12
err = fuse.EINTR
default:
// nothing
}
}
done(err)
r.RespondError(err)
}
// disarm runtime.Goexit protection
responded = true
}
// handleRequest will either a) call done(s) and r.Respond(s) OR b) return an error.
func (c *Server) handleRequest(ctx context.Context, node Node, snode *serveNode, r fuse.Request, done func(resp interface{})) error {
switch r := r.(type) {
default:
// Note: To FUSE, ENOSYS means "this server never implements this request."
// It would be inappropriate to return ENOSYS for other operations in this
// switch that might only be unavailable in some contexts, not all.
return fuse.ENOSYS
case *fuse.StatfsRequest:
s := &fuse.StatfsResponse{}
if fs, ok := c.fs.(FSStatfser); ok {
if err := fs.Statfs(ctx, r, s); err != nil {
return err
}
}
done(s)
r.Respond(s)
return nil
// Node operations.
case *fuse.GetattrRequest:
s := &fuse.GetattrResponse{}
if n, ok := node.(NodeGetattrer); ok {
if err := n.Getattr(ctx, r, s); err != nil {
return err
}
} else {
if err := snode.attr(ctx, &s.Attr); err != nil {
return err
}
}
done(s)
r.Respond(s)
return nil
case *fuse.SetattrRequest:
s := &fuse.SetattrResponse{}
if n, ok := node.(NodeSetattrer); ok {
if err := n.Setattr(ctx, r, s); err != nil {
return err
}
}
if err := snode.attr(ctx, &s.Attr); err != nil {
return err
}
done(s)
r.Respond(s)
return nil
case *fuse.SymlinkRequest:
s := &fuse.SymlinkResponse{}
initLookupResponse(&s.LookupResponse)
n, ok := node.(NodeSymlinker)
if !ok {
return fuse.EIO // XXX or EPERM like Mkdir?
}
n2, err := n.Symlink(ctx, r)
if err != nil {
return err
}
if err := c.saveLookup(ctx, &s.LookupResponse, snode, r.NewName, n2); err != nil {
return err
}
done(s)
r.Respond(s)
return nil
case *fuse.ReadlinkRequest:
n, ok := node.(NodeReadlinker)
if !ok {
return fuse.EIO /// XXX or EPERM?
}
target, err := n.Readlink(ctx, r)
if err != nil {
return err
}
done(target)
r.Respond(target)
return nil
case *fuse.LinkRequest:
n, ok := node.(NodeLinker)
if !ok {
return fuse.EIO /// XXX or EPERM?
}
c.meta.Lock()
var oldNode *serveNode
if int(r.OldNode) < len(c.node) {
oldNode = c.node[r.OldNode]
}
c.meta.Unlock()
if oldNode == nil {
c.debug(logLinkRequestOldNodeNotFound{
Request: r.Hdr(),
In: r,
})
return fuse.EIO
}
n2, err := n.Link(ctx, r, oldNode.node)
if err != nil {
return err
}
s := &fuse.LookupResponse{}
initLookupResponse(s)
if err := c.saveLookup(ctx, s, snode, r.NewName, n2); err != nil {
return err
}
done(s)
r.Respond(s)
return nil
case *fuse.RemoveRequest:
n, ok := node.(NodeRemover)
if !ok {
return fuse.EIO /// XXX or EPERM?
}
err := n.Remove(ctx, r)
if err != nil {
return err
}
done(nil)
r.Respond()
return nil
case *fuse.AccessRequest:
if n, ok := node.(NodeAccesser); ok {
if err := n.Access(ctx, r); err != nil {
return err
}
}
done(nil)
r.Respond()
return nil
case *fuse.LookupRequest:
var n2 Node
var err error
s := &fuse.LookupResponse{}
initLookupResponse(s)
if n, ok := node.(NodeStringLookuper); ok {
n2, err = n.Lookup(ctx, r.Name)
} else if n, ok := node.(NodeRequestLookuper); ok {
n2, err = n.Lookup(ctx, r, s)
} else {
return fuse.ENOENT
}
if err != nil {
return err
}
if err := c.saveLookup(ctx, s, snode, r.Name, n2); err != nil {
return err
}
done(s)
r.Respond(s)
return nil
case *fuse.MkdirRequest:
s := &fuse.MkdirResponse{}
initLookupResponse(&s.LookupResponse)
n, ok := node.(NodeMkdirer)
if !ok {
return fuse.EPERM
}
n2, err := n.Mkdir(ctx, r)
if err != nil {
return err
}
if err := c.saveLookup(ctx, &s.LookupResponse, snode, r.Name, n2); err != nil {
return err
}
done(s)
r.Respond(s)
return nil
case *fuse.OpenRequest:
s := &fuse.OpenResponse{}
var h2 Handle
if n, ok := node.(NodeOpener); ok {
hh, err := n.Open(ctx, r, s)
if err != nil {
return err
}
h2 = hh
} else {
h2 = node
}
s.Handle = c.saveHandle(h2, r.Hdr().Node)
done(s)
r.Respond(s)
return nil
case *fuse.CreateRequest:
n, ok := node.(NodeCreater)
if !ok {
// If we send back ENOSYS, FUSE will try mknod+open.
return fuse.EPERM
}
s := &fuse.CreateResponse{OpenResponse: fuse.OpenResponse{}}
initLookupResponse(&s.LookupResponse)
n2, h2, err := n.Create(ctx, r, s)
if err != nil {
return err
}
if err := c.saveLookup(ctx, &s.LookupResponse, snode, r.Name, n2); err != nil {
return err
}
s.Handle = c.saveHandle(h2, r.Hdr().Node)
done(s)
r.Respond(s)
return nil
case *fuse.GetxattrRequest:
n, ok := node.(NodeGetxattrer)
if !ok {
return fuse.ENOTSUP
}
s := &fuse.GetxattrResponse{}
err := n.Getxattr(ctx, r, s)
if err != nil {
return err
}
if r.Size != 0 && uint64(len(s.Xattr)) > uint64(r.Size) {
return fuse.ERANGE
}
done(s)
r.Respond(s)
return nil
case *fuse.ListxattrRequest:
n, ok := node.(NodeListxattrer)
if !ok {
return fuse.ENOTSUP
}
s := &fuse.ListxattrResponse{}
err := n.Listxattr(ctx, r, s)
if err != nil {
return err
}
if r.Size != 0 && uint64(len(s.Xattr)) > uint64(r.Size) {
return fuse.ERANGE
}
done(s)
r.Respond(s)
return nil
case *fuse.SetxattrRequest:
n, ok := node.(NodeSetxattrer)
if !ok {
return fuse.ENOTSUP
}
err := n.Setxattr(ctx, r)
if err != nil {
return err
}
done(nil)
r.Respond()
return nil
case *fuse.RemovexattrRequest:
n, ok := node.(NodeRemovexattrer)
if !ok {
return fuse.ENOTSUP
}
err := n.Removexattr(ctx, r)
if err != nil {
return err
}
done(nil)
r.Respond()
return nil
case *fuse.ForgetRequest:
forget := c.dropNode(r.Hdr().Node, r.N)
if forget {
n, ok := node.(NodeForgetter)
if ok {
n.Forget()
}
}
done(nil)
r.Respond()
return nil
// Handle operations.
case *fuse.ReadRequest:
shandle := c.getHandle(r.Handle)
if shandle == nil {
return fuse.ESTALE
}
handle := shandle.handle
s := &fuse.ReadResponse{Data: make([]byte, 0, r.Size)}
if r.Dir {
if h, ok := handle.(HandleReadDirAller); ok {
// detect rewinddir(3) or similar seek and refresh
// contents
if r.Offset == 0 {
shandle.readData = nil
}
if shandle.readData == nil {
dirs, err := h.ReadDirAll(ctx)
if err != nil {
return err
}
var data []byte
for _, dir := range dirs {
if dir.Inode == 0 {
dir.Inode = c.dynamicInode(snode.inode, dir.Name)
}
data = fuse.AppendDirent(data, dir)
}
shandle.readData = data
}
fuseutil.HandleRead(r, s, shandle.readData)
done(s)
r.Respond(s)
return nil
}
} else {
if h, ok := handle.(HandleReadAller); ok {
if shandle.readData == nil {
data, err := h.ReadAll(ctx)
if err != nil {
return err
}
if data == nil {
data = []byte{}
}
shandle.readData = data
}
fuseutil.HandleRead(r, s, shandle.readData)
done(s)
r.Respond(s)
return nil
}
h, ok := handle.(HandleReader)
if !ok {
err := handleNotReaderError{handle: handle}
return err
}
if err := h.Read(ctx, r, s); err != nil {
return err
}
}
done(s)
r.Respond(s)
return nil
case *fuse.WriteRequest:
shandle := c.getHandle(r.Handle)
if shandle == nil {
return fuse.ESTALE
}
s := &fuse.WriteResponse{}
if h, ok := shandle.handle.(HandleWriter); ok {
if err := h.Write(ctx, r, s); err != nil {
return err
}
done(s)
r.Respond(s)
return nil
}
return fuse.EIO
case *fuse.FlushRequest:
shandle := c.getHandle(r.Handle)
if shandle == nil {
return fuse.ESTALE
}
handle := shandle.handle
if h, ok := handle.(HandleFlusher); ok {
if err := h.Flush(ctx, r); err != nil {
return err
}
}
done(nil)
r.Respond()
return nil
case *fuse.ReleaseRequest:
shandle := c.getHandle(r.Handle)
if shandle == nil {
return fuse.ESTALE
}
handle := shandle.handle
// No matter what, release the handle.
c.dropHandle(r.Handle)
if h, ok := handle.(HandleReleaser); ok {
if err := h.Release(ctx, r); err != nil {
return err
}
}
done(nil)
r.Respond()
return nil
case *fuse.DestroyRequest:
if fs, ok := c.fs.(FSDestroyer); ok {
fs.Destroy()
}
done(nil)
r.Respond()
return nil
case *fuse.RenameRequest:
c.meta.Lock()
var newDirNode *serveNode
if int(r.NewDir) < len(c.node) {
newDirNode = c.node[r.NewDir]
}
c.meta.Unlock()
if newDirNode == nil {
c.debug(renameNewDirNodeNotFound{
Request: r.Hdr(),
In: r,
})
return fuse.EIO
}
n, ok := node.(NodeRenamer)
if !ok {
return fuse.EIO // XXX or EPERM like Mkdir?
}
err := n.Rename(ctx, r, newDirNode.node)
if err != nil {
return err
}
done(nil)
r.Respond()
return nil
case *fuse.MknodRequest:
n, ok := node.(NodeMknoder)
if !ok {
return fuse.EIO
}
n2, err := n.Mknod(ctx, r)
if err != nil {
return err
}
s := &fuse.LookupResponse{}
initLookupResponse(s)
if err := c.saveLookup(ctx, s, snode, r.Name, n2); err != nil {
return err
}
done(s)
r.Respond(s)
return nil
case *fuse.FsyncRequest:
n, ok := node.(NodeFsyncer)
if !ok {
return fuse.EIO
}
err := n.Fsync(ctx, r)
if err != nil {
return err
}
done(nil)
r.Respond()
return nil
case *fuse.InterruptRequest:
c.meta.Lock()
ireq := c.req[r.IntrID]
if ireq != nil && ireq.cancel != nil {
ireq.cancel()
ireq.cancel = nil
}
c.meta.Unlock()
done(nil)
r.Respond()
return nil
/* case *FsyncdirRequest:
return ENOSYS
case *GetlkRequest, *SetlkRequest, *SetlkwRequest:
return ENOSYS
case *BmapRequest:
return ENOSYS
case *SetvolnameRequest, *GetxtimesRequest, *ExchangeRequest:
return ENOSYS
*/
}
panic("not reached")
}
func (c *Server) saveLookup(ctx context.Context, s *fuse.LookupResponse, snode *serveNode, elem string, n2 Node) error {
if err := nodeAttr(ctx, n2, &s.Attr); err != nil {
return err
}
if s.Attr.Inode == 0 {
s.Attr.Inode = c.dynamicInode(snode.inode, elem)
}
s.Node, s.Generation = c.saveNode(s.Attr.Inode, n2)
return nil
}
type invalidateNodeDetail struct {
Off int64
Size int64
}
func (i invalidateNodeDetail) String() string {
return fmt.Sprintf("Off:%d Size:%d", i.Off, i.Size)
}
func errstr(err error) string {
if err == nil {
return ""
}
return err.Error()
}
func (s *Server) invalidateNode(node Node, off int64, size int64) error {
s.meta.Lock()
id, ok := s.nodeRef[node]
if ok {
snode := s.node[id]
snode.wg.Add(1)
defer snode.wg.Done()
}
s.meta.Unlock()
if !ok {
// This is what the kernel would have said, if we had been
// able to send this message; it's not cached.
return fuse.ErrNotCached
}
// Delay logging until after we can record the error too. We
// consider a /dev/fuse write to be instantaneous enough to not
// need separate before and after messages.
err := s.conn.InvalidateNode(id, off, size)
s.debug(notification{
Op: "InvalidateNode",
Node: id,
Out: invalidateNodeDetail{
Off: off,
Size: size,
},
Err: errstr(err),
})
return err
}
// InvalidateNodeAttr invalidates the kernel cache of the attributes
// of node.
//
// Returns fuse.ErrNotCached if the kernel is not currently caching
// the node.
func (s *Server) InvalidateNodeAttr(node Node) error {
return s.invalidateNode(node, 0, 0)
}
// InvalidateNodeData invalidates the kernel cache of the attributes
// and data of node.
//
// Returns fuse.ErrNotCached if the kernel is not currently caching
// the node.
func (s *Server) InvalidateNodeData(node Node) error {
return s.invalidateNode(node, 0, -1)
}
// InvalidateNodeDataRange invalidates the kernel cache of the
// attributes and a range of the data of node.
//
// Returns fuse.ErrNotCached if the kernel is not currently caching
// the node.
func (s *Server) InvalidateNodeDataRange(node Node, off int64, size int64) error {
return s.invalidateNode(node, off, size)
}
type invalidateEntryDetail struct {
Name string
}
func (i invalidateEntryDetail) String() string {
return fmt.Sprintf("%q", i.Name)
}
// InvalidateEntry invalidates the kernel cache of the directory entry
// identified by parent node and entry basename.
//
// Kernel may or may not cache directory listings. To invalidate
// those, use InvalidateNode to invalidate all of the data for a
// directory. (As of 2015-06, Linux FUSE does not cache directory
// listings.)
//
// Returns ErrNotCached if the kernel is not currently caching the
// node.
func (s *Server) InvalidateEntry(parent Node, name string) error {
s.meta.Lock()
id, ok := s.nodeRef[parent]
if ok {
snode := s.node[id]
snode.wg.Add(1)
defer snode.wg.Done()
}
s.meta.Unlock()
if !ok {
// This is what the kernel would have said, if we had been
// able to send this message; it's not cached.
return fuse.ErrNotCached
}
err := s.conn.InvalidateEntry(id, name)
s.debug(notification{
Op: "InvalidateEntry",
Node: id,
Out: invalidateEntryDetail{
Name: name,
},
Err: errstr(err),
})
return err
}
// DataHandle returns a read-only Handle that satisfies reads
// using the given data.
func DataHandle(data []byte) Handle {
return &dataHandle{data}
}
type dataHandle struct {
data []byte
}
func (d *dataHandle) ReadAll(ctx context.Context) ([]byte, error) {
return d.data, nil
}
// GenerateDynamicInode returns a dynamic inode.
//
// The parent inode and current entry name are used as the criteria
// for choosing a pseudorandom inode. This makes it likely the same
// entry will get the same inode on multiple runs.
func GenerateDynamicInode(parent uint64, name string) uint64 {
h := fnv.New64a()
var buf [8]byte
binary.LittleEndian.PutUint64(buf[:], parent)
_, _ = h.Write(buf[:])
_, _ = h.Write([]byte(name))
var inode uint64
for {
inode = h.Sum64()
if inode != 0 {
break
}
// there's a tiny probability that result is zero; change the
// input a little and try again
_, _ = h.Write([]byte{'x'})
}
return inode
}
