package fuse
import (
"errors"
"fmt"
"log"
"os"
"os/exec"
"path"
"strconv"
"strings"
"sync"
"syscall"
)
var (
errNoAvail = errors.New("no available fuse devices")
errNotLoaded = errors.New("osxfuse is not loaded")
)
func loadOSXFUSE(bin string) error {
cmd := exec.Command(bin)
cmd.Dir = "/"
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err := cmd.Run()
return err
}
func openOSXFUSEDev(devPrefix string) (*os.File, error) {
var f *os.File
var err error
for i := uint64(0); ; i++ {
path := devPrefix + strconv.FormatUint(i, 10)
f, err = os.OpenFile(path, os.O_RDWR, 0000)
if os.IsNotExist(err) {
if i == 0 {
// not even the first device was found -> fuse is not loaded
return nil, errNotLoaded
}
// we've run out of kernel-provided devices
return nil, errNoAvail
}
if err2, ok := err.(*os.PathError); ok && err2.Err == syscall.EBUSY {
// try the next one
continue
}
if err != nil {
return nil, err
}
return f, nil
}
}
func handleMountOSXFUSE(helperName string, errCh chan<- error) func(line string) (ignore bool) {
var noMountpointPrefix = helperName + `: `
const noMountpointSuffix = `: No such file or directory`
return func(line string) (ignore bool) {
if strings.HasPrefix(line, noMountpointPrefix) && strings.HasSuffix(line, noMountpointSuffix) {
// re-extract it from the error message in case some layer
// changed the path
mountpoint := line[len(noMountpointPrefix) : len(line)-len(noMountpointSuffix)]
err := &MountpointDoesNotExistError{
Path: mountpoint,
}
select {
case errCh <- err:
return true
default:
// not the first error; fall back to logging it
return false
}
}
return false
}
}
// isBoringMountOSXFUSEError returns whether the Wait error is
// uninteresting; exit status 64 is.
func isBoringMountOSXFUSEError(err error) bool {
if err, ok := err.(*exec.ExitError); ok && err.Exited() {
if status, ok := err.Sys().(syscall.WaitStatus); ok && status.ExitStatus() == 64 {
return true
}
}
return false
}
func callMount(bin string, daemonVar string, dir string, conf *mountConfig, f *os.File, ready chan<- struct{}, errp *error) error {
for k, v := range conf.options {
if strings.Contains(k, ",") || strings.Contains(v, ",") {
// Silly limitation but the mount helper does not
// understand any escaping. See TestMountOptionCommaError.
return fmt.Errorf("mount options cannot contain commas on darwin: %q=%q", k, v)
}
}
cmd := exec.Command(
bin,
"-o", conf.getOptions(),
// Tell osxfuse-kext how large our buffer is. It must split
// writes larger than this into multiple writes.
//
// OSXFUSE seems to ignore InitResponse.MaxWrite, and uses
// this instead.
"-o", "iosize="+strconv.FormatUint(maxWrite, 10),
// refers to fd passed in cmd.ExtraFiles
"3",
dir,
)
cmd.ExtraFiles = []*os.File{f}
cmd.Env = os.Environ()
// OSXFUSE <3.3.0
cmd.Env = append(cmd.Env, "MOUNT_FUSEFS_CALL_BY_LIB=")
// OSXFUSE >=3.3.0
cmd.Env = append(cmd.Env, "MOUNT_OSXFUSE_CALL_BY_LIB=")
daemon := os.Args[0]
if daemonVar != "" {
cmd.Env = append(cmd.Env, daemonVar+"="+daemon)
}
stdout, err := cmd.StdoutPipe()
if err != nil {
return fmt.Errorf("setting up mount_osxfusefs stderr: %v", err)
}
stderr, err := cmd.StderrPipe()
if err != nil {
return fmt.Errorf("setting up mount_osxfusefs stderr: %v", err)
}
if err := cmd.Start(); err != nil {
return fmt.Errorf("mount_osxfusefs: %v", err)
}
helperErrCh := make(chan error, 1)
go func() {
var wg sync.WaitGroup
wg.Add(2)
go lineLogger(&wg, "mount helper output", neverIgnoreLine, stdout)
helperName := path.Base(bin)
go lineLogger(&wg, "mount helper error", handleMountOSXFUSE(helperName, helperErrCh), stderr)
wg.Wait()
if err := cmd.Wait(); err != nil {
// see if we have a better error to report
select {
case helperErr := <-helperErrCh:
// log the Wait error if it's not what we expected
if !isBoringMountOSXFUSEError(err) {
log.Printf("mount helper failed: %v", err)
}
// and now return what we grabbed from stderr as the real
// error
*errp = helperErr
close(ready)
return
default:
// nope, fall back to generic message
}
*errp = fmt.Errorf("mount_osxfusefs: %v", err)
close(ready)
return
}
*errp = nil
close(ready)
}()
return nil
}
func mount(dir string, conf *mountConfig, ready chan<- struct{}, errp *error) (*os.File, error) {
locations := conf.osxfuseLocations
if locations == nil {
locations = []OSXFUSEPaths{
OSXFUSELocationV3,
OSXFUSELocationV2,
}
}
for _, loc := range locations {
if _, err := os.Stat(loc.Mount); os.IsNotExist(err) {
// try the other locations
continue
}
f, err := openOSXFUSEDev(loc.DevicePrefix)
if err == errNotLoaded {
err = loadOSXFUSE(loc.Load)
if err != nil {
return nil, err
}
// try again
f, err = openOSXFUSEDev(loc.DevicePrefix)
}
if err != nil {
return nil, err
}
err = callMount(loc.Mount, loc.DaemonVar, dir, conf, f, ready, errp)
if err != nil {
f.Close()
return nil, err
}
return f, nil
}
return nil, ErrOSXFUSENotFound
}
