Rewrite mount_darwin.go, obviating CGO.

The strategy was inspired by the mount code for Darwin in
bazil.org/fuse.

Unfortunately, OSX must have the event loop started before mounting
can be completed. This means that WaitMount() must be maintained for
use on OSX.

Change-Id: Ie53425f306b4575b3e94e45407bab05017f5ce14

fuse/mount_darwin.go

-// Copyright 2011 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// TODO: Rewrite using package syscall not cgo
-
 package fuse
 
-/*
-
-// Adapted from Plan 9 from User Space's src/cmd/9pfuse/fuse.c,
-// which carries this notice:
-//
-// The files in this directory are subject to the following license.
-//
-// The author of this software is Russ Cox.
-//
-//         Copyright (c) 2006 Russ Cox
-//
-// Permission to use, copy, modify, and distribute this software for any
-// purpose without fee is hereby granted, provided that this entire notice
-// is included in all copies of any software which is or includes a copy
-// or modification of this software and in all copies of the supporting
-// documentation for such software.
-//
-// THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
-// WARRANTY.  IN PARTICULAR, THE AUTHOR MAKES NO REPRESENTATION OR WARRANTY
-// OF ANY KIND CONCERNING THE MERCHANTABILITY OF THIS SOFTWARE OR ITS
-// FITNESS FOR ANY PARTICULAR PURPOSE.
-
-#include <stdlib.h>
-#include <sys/param.h>
-#include <sys/mount.h>
-#include <unistd.h>
-#include <string.h>
-#include <stdio.h>
-#include <errno.h>
-#include <fcntl.h>
-
-#define nil ((void*)0)
-
-static int
-mountfuse(char *mtpt, char **err)
-{
-	int i, pid, fd, r;
-	char buf[200];
-	struct vfsconf vfs;
-	char *f;
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"syscall"
+)
 
-	if(getvfsbyname("osxfusefs", &vfs) < 0){
-		if(access(f="/Library/Filesystems/osxfusefs.fs/Support/load_osxfusefs", 0) < 0){
-		         *err = strdup("cannot find load_fusefs");
-		   	return -1;
-		}
-		if((r=system(f)) < 0){
-			snprintf(buf, sizeof buf, "%s: %s", f, strerror(errno));
-			*err = strdup(buf);
-			return -1;
-		}
-		if(r != 0){
-			snprintf(buf, sizeof buf, "load_fusefs failed: exit %d", r);
-			*err = strdup(buf);
-			return -1;
-		}
-		if(getvfsbyname("osxfusefs", &vfs) < 0){
-			snprintf(buf, sizeof buf, "getvfsbyname osxfusefs: %s", strerror(errno));
-			*err = strdup(buf);
-			return -1;
-		}
+func openFUSEDevice() (*os.File, error) {
+	fs, err := filepath.Glob("/dev/osxfuse*")
+	if err != nil {
+		return nil, err
 	}
-
-	// Look for available FUSE device.
-	for(i=0;; i++){
-		snprintf(buf, sizeof buf, "/dev/osxfuse%d", i);
-		if(access(buf, 0) < 0){
-			*err = strdup("no available fuse devices");
-			return -1;
+	if len(fs) == 0 {
+		// TODO(hanwen): run the load_osxfuse command.
+		return nil, fmt.Errorf("no FUSE devices found")
+	}
+	for _, fn := range fs {
+		f, err := os.OpenFile(fn, os.O_RDWR, 0)
+		if err != nil {
+			continue
 		}
-		if((fd = open(buf, O_RDWR)) >= 0)
-			break;
+		return f, nil
 	}
 
-	pid = fork();
-	if(pid < 0)
-		return -1;
-	if(pid == 0){
-		snprintf(buf, sizeof buf, "%d", fd);
-		setenv("MOUNT_FUSEFS_CALL_BY_LIB", "", 1);
-		// Different versions of MacFUSE put the
-		// mount_fusefs binary in different places.
-		// Try all.
-		// Leopard location
-		setenv("MOUNT_FUSEFS_DAEMON_PATH", "/Library/Filesystems/osxfusefs.fs/Support/mount_osxfusefs", 1);
-		execl("/Library/Filesystems/osxfusefs.fs/Support/mount_osxfusefs", "mount_osxfusefs", "-o", "iosize=4096", buf, mtpt, nil);
-		fprintf(stderr, "exec mount_osxfusefs: %s\n", strerror(errno));
-		_exit(1);
-	}
-	return fd;
+	return nil, fmt.Errorf("all FUSE devices busy")
 }
 
-*/
-import "C"
-import (
-	"fmt"
-	"log"
-	"os/exec"
-	"syscall"
-	"unsafe"
-)
+const bin = "/Library/Filesystems/osxfusefs.fs/Support/mount_osxfusefs"
 
-func mount(dir string, options string) (int, error) {
-	errp := (**C.char)(C.malloc(16))
-	*errp = nil
-	defer C.free(unsafe.Pointer(errp))
-	cdir := C.CString(dir)
-	defer C.free(unsafe.Pointer(cdir))
-	fd := C.mountfuse(cdir, errp)
-	if *errp != nil {
-		return -1, mountError(C.GoString(*errp))
+func mount(mountPoint, options string, ready chan<- error) (fd int, err error) {
+	f, err := openFUSEDevice()
+	if err != nil {
+		return 0, err
 	}
-	return int(fd), nil
-}
 
-type mountError string
+	cmd := exec.Command(bin, "-o", options, "-o", fmt.Sprintf("iosize=%d", MAX_KERNEL_WRITE), "3", mountPoint)
+	cmd.ExtraFiles = []*os.File{f}
+	cmd.Env = append(os.Environ(), "MOUNT_FUSEFS_CALL_BY_LIB=", "MOUNT_OSXFUSE_CALL_BY_LIB=",
+		"MOUNT_OSXFUSE_DAEMON_PATH="+os.Args[0],
+		"MOUNT_FUSEFS_DAEMON_PATH="+os.Args[0])
 
-func (m mountError) Error() string {
-	return string(m)
-}
+	var out, errOut bytes.Buffer
+	cmd.Stdout = &out
+	cmd.Stderr = &errOut
 
-func unmount(mountPoint string) error {
-	if err := syscall.Unmount(mountPoint, 0); err != nil {
-		return fmt.Errorf("umount(%q): %v", mountPoint, err)
+	if err := cmd.Start(); err != nil {
+		f.Close()
+		return 0, err
 	}
-	return nil
-}
+	go func() {
+		err := cmd.Wait()
+		if err != nil {
+			err = fmt.Errorf("mount_osxfusefs failed: %v. Stderr: %s, Stdout: %s", err, errOut.String(), out.String())
+		}
 
-var umountBinary string
+		ready <- err
+		close(ready)
+	}()
+	return int(f.Fd()), nil
+}
 
-func init() {
-	var err error
-	umountBinary, err = exec.LookPath("umount")
-	if err != nil {
-		log.Fatalf("Could not find umount binary: %v", err)
-	}
+func unmount(dir string) error {
+	return syscall.Unmount(dir, 0)
 }

fuse/mount_linux.go

@@ -24,7 +24,7 @@ func unixgramSocketpair() (l, r *os.File, err error) {
 
 // Create a FUSE FS on the specified mount point.  The returned
 // mount point is always absolute.
-func mount(mountPoint string, options string) (fd int, err error) {
+func mount(mountPoint string, options string, ready chan<- error) (fd int, err error) {
 	local, remote, err := unixgramSocketpair()
 	if err != nil {
 		return
@@ -62,7 +62,13 @@ func mount(mountPoint string, options string) (fd int, err error) {
 		return
 	}
 
-	return getConnection(local)
+	fd, err = getConnection(local)
+	if err != nil {
+		return -1, err
+	}
+
+	close(ready)
+	return fd, err
 }
 
 func privilegedUnmount(mountPoint string) error {

fuse/nodefs/fileless_test.go

@@ -68,8 +68,10 @@ func TestNoOpen(t *testing.T) {
 	}
 	defer s.Unmount()
 	go s.Serve()
+	if err := s.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 
-	s.WaitMount()
 	if s.KernelSettings().Minor < 23 {
 		t.Skip("Kernel does not support open-less read/writes. Skipping test.")
 	}
@@ -109,6 +111,9 @@ func TestNodeRead(t *testing.T) {
 	}
 	defer s.Unmount()
 	go s.Serve()
+	if err := s.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 	content, err := ioutil.ReadFile(dir + "/file")
 	if err != nil {
 		t.Fatalf("ReadFile: %v", err)

fuse/nodefs/memnode_test.go

@@ -36,18 +36,21 @@ func setupMemNodeTest(t *testing.T) (wd string, root Node, clean func()) {
 
 	// Unthreaded, but in background.
 	go state.Serve()
+
+	if err := state.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 	return mnt, root, func() {
 		state.Unmount()
 		os.RemoveAll(tmp)
 	}
-
 }
 
 func TestMemNodeFsWrite(t *testing.T) {
 	wd, _, clean := setupMemNodeTest(t)
 	defer clean()
-
 	want := "hello"
+
 	err := ioutil.WriteFile(wd+"/test", []byte(want), 0644)
 	if err != nil {
 		t.Fatalf("WriteFile failed: %v", err)
@@ -59,7 +62,7 @@ func TestMemNodeFsWrite(t *testing.T) {
 	}
 }
 
-func TestMemNodeFs(t *testing.T) {
+func TestMemNodeFsBasic(t *testing.T) {
 	wd, _, clean := setupMemNodeTest(t)
 	defer clean()
 

fuse/pathfs/owner_test.go

@@ -40,6 +40,9 @@ func setupOwnerTest(t *testing.T, opts *nodefs.Options) (workdir string, cleanup
 		t.Fatalf("MountNodeFileSystem failed: %v", err)
 	}
 	go state.Serve()
+	if err := state.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 	return wd, func() {
 		state.Unmount()
 		os.RemoveAll(wd)

fuse/server.go

@@ -47,6 +47,8 @@ type Server struct {
 	singleReader bool
 	canSplice    bool
 	loops        sync.WaitGroup
+
+	ready chan error
 }
 
 // SetDebug is deprecated. Use MountOptions.Debug instead.
@@ -173,7 +175,8 @@ func NewServer(fs RawFileSystem, mountPoint string, opts *MountOptions) (*Server
 		}
 		mountPoint = filepath.Clean(filepath.Join(cwd, mountPoint))
 	}
-	fd, err := mount(mountPoint, strings.Join(optStrs, ","))
+	ms.ready = make(chan error, 1)
+	fd, err := mount(mountPoint, strings.Join(optStrs, ","), ms.ready)
 	if err != nil {
 		return nil, err
 	}
@@ -181,8 +184,11 @@ func NewServer(fs RawFileSystem, mountPoint string, opts *MountOptions) (*Server
 	ms.mountPoint = mountPoint
 	ms.mountFd = fd
 
-	ms.handleInit()
-
+	if code := ms.handleInit(); !code.Ok() {
+		syscall.Close(fd)
+		// TODO - unmount as well?
+		return nil, fmt.Errorf("init: %s", code)
+	}
 	return ms, nil
 }
 
@@ -308,7 +314,7 @@ func (ms *Server) Serve() {
 	ms.writeMu.Unlock()
 }
 
-func (ms *Server) handleInit() {
+func (ms *Server) handleInit() Status {
 	// The first request should be INIT; read it synchronously,
 	// and don't spawn new readers.
 	orig := ms.singleReader
@@ -317,13 +323,16 @@ func (ms *Server) handleInit() {
 	ms.singleReader = orig
 
 	if errNo != OK || req == nil {
-		return
+		return errNo
+	}
+	if code := ms.handleRequest(req); !code.Ok() {
+		return code
 	}
-	ms.handleRequest(req)
 
 	// INIT is handled. Init the file system, but don't accept
 	// incoming requests, so the file system can setup itself.
 	ms.fileSystem.Init(ms)
+	return OK
 }
 
 func (ms *Server) loop(exitIdle bool) {
@@ -354,7 +363,7 @@ exit:
 	}
 }
 
-func (ms *Server) handleRequest(req *request) {
+func (ms *Server) handleRequest(req *request) Status {
 	req.parse()
 	if req.handler == nil {
 		req.status = ENOSYS
@@ -379,6 +388,7 @@ func (ms *Server) handleRequest(req *request) {
 			errNo, operationName(req.inHeader.Opcode))
 	}
 	ms.returnRequest(req)
+	return Status(errNo)
 }
 
 func (ms *Server) allocOut(req *request, size uint32) []byte {
@@ -524,8 +534,10 @@ func init() {
 }
 
 // WaitMount waits for the first request to be served. Use this to
-// avoid racing between accessing the (empty) mountpoint, and the OS
-// trying to setup the user-space mount.
-func (ms *Server) WaitMount() {
-	// TODO(hanwen): see if this can safely be removed.
+// avoid racing between accessing the (empty or not yet mounted)
+// mountpoint, and the OS trying to setup the user-space mount.
+// Currently, this call only necessary on OSX.
+func (ms *Server) WaitMount() error {
+	err := <-ms.ready
+	return err
 }

fuse/test/cache_test.go

@@ -48,7 +48,9 @@ func setupCacheTest(t *testing.T) (string, *pathfs.PathNodeFs, func()) {
 		t.Fatalf("MountNodeFileSystem failed: %v", err)
 	}
 	go state.Serve()
-
+	if err := state.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 	return dir, pfs, func() {
 		err := state.Unmount()
 		if err == nil {
@@ -149,6 +151,9 @@ func TestNonseekable(t *testing.T) {
 	defer state.Unmount()
 
 	go state.Serve()
+	if err := state.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 
 	f, err := os.Open(dir + "/file")
 	if err != nil {
@@ -180,6 +185,9 @@ func TestGetAttrRace(t *testing.T) {
 		t.Fatalf("MountNodeFileSystem failed: %v", err)
 	}
 	go state.Serve()
+	if err := state.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 
 	defer state.Unmount()
 

fuse/test/defaultread_test.go

@@ -49,7 +49,9 @@ func defaultReadTest(t *testing.T) (root string, cleanup func()) {
 		t.Fatalf("MountNodeFileSystem failed: %v", err)
 	}
 	go state.Serve()
-
+	if err := state.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 	return dir, func() {
 		state.Unmount()
 		os.Remove(dir)

fuse/test/delete_linux_test.go

@@ -51,6 +51,9 @@ func TestDeleteNotify(t *testing.T) {
 	}
 	go state.Serve()
 	defer state.Unmount()
+	if err := state.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 
 	_, code := root.Mkdir("testdir", 0755, nil)
 	if !code.Ok() {

fuse/test/fsetattr_test.go

@@ -153,6 +153,9 @@ func setupFAttrTest(t *testing.T, fs pathfs.FileSystem) (dir string, clean func(
 	}
 
 	go state.Serve()
+	if err := state.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 
 	// Trigger INIT.
 	os.Lstat(dir)

fuse/test/loopback_test.go

@@ -107,10 +107,10 @@ func NewTestCase(t *testing.T) *testCase {
 		t.Fatal("NewServer:", err)
 	}
 
-	// Unthreaded, but in background.
 	go tc.state.Serve()
-
-	tc.state.WaitMount()
+	if err := tc.state.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 	return tc
 }
 
@@ -875,6 +875,9 @@ func TestOriginalIsSymlink(t *testing.T) {
 	defer state.Unmount()
 
 	go state.Serve()
+	if err := state.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 
 	if _, err := os.Lstat(mnt); err != nil {
 		t.Fatalf("Lstat failed: %v", err)

fuse/test/mount_test.go

@@ -176,6 +176,9 @@ func TestDefaultNodeMount(t *testing.T) {
 		t.Fatalf("MountRoot: %v", err)
 	}
 	go s.Serve()
+	if err := s.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 	defer s.Unmount()
 
 	if err := conn.Mount(root.Inode(), "sub", nodefs.NewDefaultNode(), nil); !err.Ok() {

fuse/test/notify_linux_test.go

@@ -93,6 +93,9 @@ func NewNotifyTest(t *testing.T) *NotifyTest {
 		t.Fatalf("MountNodeFileSystem failed: %v", err)
 	}
 	go me.state.Serve()
+	if err := me.state.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
 
 	return me
 }

fuse/test/xattr_test.go

@@ -49,6 +49,10 @@ func TestDefaultXAttr(t *testing.T) {
 		t.Fatalf("MountRoot: %v", err)
 	}
 	go s.Serve()
+	if err := s.WaitMount(); err != nil {
+		t.Fatal("WaitMount", err)
+	}
+
 	defer s.Unmount()
 
 	var data [1024]byte