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// Copyright 2016 the Go-FUSE Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package fuse
import (
"bytes"
"fmt"
"os"
"os/exec"
"strings"
"syscall"
"unsafe"
)
func unixgramSocketpair() (l, r *os.File, err error) {
fd, err := syscall.Socketpair(syscall.AF_UNIX, syscall.SOCK_STREAM, 0)
if err != nil {
return nil, nil, os.NewSyscallError("socketpair",
err.(syscall.Errno))
}
l = os.NewFile(uintptr(fd[0]), "socketpair-half1")
r = os.NewFile(uintptr(fd[1]), "socketpair-half2")
return
}
// Create a FUSE FS on the specified mount point. The returned
// mount point is always absolute.
func mount(mountPoint string, opts *MountOptions, ready chan<- error) (fd int, err error) {
local, remote, err := unixgramSocketpair()
if err != nil {
return
}
defer local.Close()
defer remote.Close()
bin, err := fusermountBinary()
if err != nil {
return 0, err
}
cmd := exec.Command(bin,
"-o", strings.Join(opts.optionsStrings(), ","),
"-o", fmt.Sprintf("iosize=%d", opts.MaxWrite),
mountPoint)
cmd.ExtraFiles = []*os.File{remote} // fd would be (index + 3)
cmd.Env = append(os.Environ(),
"_FUSE_CALL_BY_LIB=",
"_FUSE_DAEMON_PATH="+os.Args[0],
"_FUSE_COMMFD=3",
"_FUSE_COMMVERS=2",
"MOUNT_OSXFUSE_CALL_BY_LIB=",
"MOUNT_OSXFUSE_DAEMON_PATH="+os.Args[0])
var out, errOut bytes.Buffer
cmd.Stdout = &out
cmd.Stderr = &errOut
if err = cmd.Start(); err != nil {
return
}
fd, err = getConnection(local)
if err != nil {
return -1, err
}
go func() {
// wait inside a goroutine or otherwise it would block forever for unknown reasons
if err := cmd.Wait(); err != nil {
err = fmt.Errorf("mount_osxfusefs failed: %v. Stderr: %s, Stdout: %s",
err, errOut.String(), out.String())
}
ready <- err
close(ready)
}()
// golang sets CLOEXEC on file descriptors when they are
// acquired through normal operations (e.g. open).
// Buf for fd, we have to set CLOEXEC manually
syscall.CloseOnExec(fd)
return fd, err
}
func unmount(dir string, opts *MountOptions) error {
return syscall.Unmount(dir, 0)
}
func getConnection(local *os.File) (int, error) {
var data [4]byte
control := make([]byte, 4*256)
// n, oobn, recvflags, from, errno - todo: error checking.
_, oobn, _, _,
err := syscall.Recvmsg(
int(local.Fd()), data[:], control[:], 0)
if err != nil {
return 0, err
}
message := *(*syscall.Cmsghdr)(unsafe.Pointer(&control[0]))
fd := *(*int32)(unsafe.Pointer(uintptr(unsafe.Pointer(&control[0])) + syscall.SizeofCmsghdr))
if message.Type != syscall.SCM_RIGHTS {
return 0, fmt.Errorf("getConnection: recvmsg returned wrong control type: %d", message.Type)
}
if oobn <= syscall.SizeofCmsghdr {
return 0, fmt.Errorf("getConnection: too short control message. Length: %d", oobn)
}
if fd < 0 {
return 0, fmt.Errorf("getConnection: fd < 0: %d", fd)
}
return int(fd), nil
}
func fusermountBinary() (string, error) {
binPaths := []string{
"/Library/Filesystems/macfuse.fs/Contents/Resources/mount_macfuse",
"/Library/Filesystems/osxfuse.fs/Contents/Resources/mount_osxfuse",
}
for _, path := range binPaths {
if _, err := os.Stat(path); err == nil {
return path, nil
}
}
return "", fmt.Errorf("no FUSE mount utility found")
}
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