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|
package fuse
import (
"fmt"
"log"
"os"
"os/exec"
"strings"
"sync"
"syscall"
)
func handleMountFusefsStderr(errCh chan<- error) func(line string) (ignore bool) {
return func(line string) (ignore bool) {
const (
noMountpointPrefix = `mount_fusefs: `
noMountpointSuffix = `: No such file or directory`
)
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
}
}
// isBoringMountFusefsError returns whether the Wait error is
// uninteresting; exit status 1 is.
func isBoringMountFusefsError(err error) bool {
if err, ok := err.(*exec.ExitError); ok && err.Exited() {
if status, ok := err.Sys().(syscall.WaitStatus); ok && status.ExitStatus() == 1 {
return true
}
}
return false
}
func mount(dir string, conf *mountConfig, ready chan<- struct{}, errp *error) (*os.File, 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 nil, fmt.Errorf("mount options cannot contain commas on FreeBSD: %q=%q", k, v)
}
}
f, err := os.OpenFile("/dev/fuse", os.O_RDWR, 0000)
if err != nil {
*errp = err
return nil, err
}
cmd := exec.Command(
"/sbin/mount_fusefs",
"--safe",
"-o", conf.getOptions(),
"3",
dir,
)
cmd.ExtraFiles = []*os.File{f}
stdout, err := cmd.StdoutPipe()
if err != nil {
return nil, fmt.Errorf("setting up mount_fusefs stderr: %v", err)
}
stderr, err := cmd.StderrPipe()
if err != nil {
return nil, fmt.Errorf("setting up mount_fusefs stderr: %v", err)
}
if err := cmd.Start(); err != nil {
return nil, fmt.Errorf("mount_fusefs: %v", err)
}
helperErrCh := make(chan error, 1)
var wg sync.WaitGroup
wg.Add(2)
go lineLogger(&wg, "mount helper output", neverIgnoreLine, stdout)
go lineLogger(&wg, "mount helper error", handleMountFusefsStderr(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 !isBoringMountFusefsError(err) {
log.Printf("mount helper failed: %v", err)
}
// and now return what we grabbed from stderr as the real
// error
return nil, helperErr
default:
// nope, fall back to generic message
}
return nil, fmt.Errorf("mount_fusefs: %v", err)
}
close(ready)
return f, nil
}
|
