libgocryptfs/daemonize.go
Jakob Unterwurzacher d163169655 Wrap Logger to make disabling output more efficient
Instead of using SetOutput(ioutil.Discard), which means
that Printf is still called for every debug message,
use a simple and fast boolean check.

Streaming write performance improves from 86 to 93 MB/s.
2016-01-21 22:59:11 +01:00

49 lines
1.1 KiB
Go

package main
import (
"fmt"
"os"
"os/exec"
"os/signal"
"syscall"
)
// The child sends us USR1 if the mount was successful
func exitOnUsr1() {
c := make(chan os.Signal, 1)
signal.Notify(c, syscall.SIGUSR1)
<-c
os.Exit(0)
}
// forkChild - execute ourselves once again, this time with the "-f" flag, and
// wait for SIGUSR1 or child exit.
// This is a workaround for the missing true fork function in Go.
func forkChild() {
go exitOnUsr1()
name := os.Args[0]
newArgs := []string{"-f", fmt.Sprintf("-notifypid=%d", os.Getpid())}
newArgs = append(newArgs, os.Args[1:]...)
c := exec.Command(name, newArgs...)
c.Stdout = os.Stdout
c.Stderr = os.Stderr
c.Stdin = os.Stdin
err := c.Start()
if err != nil {
fmt.Printf("forkChild: starting %s failed: %v\n", name, err)
os.Exit(1)
}
err = c.Wait()
if err != nil {
if exiterr, ok := err.(*exec.ExitError); ok {
if waitstat, ok := exiterr.Sys().(syscall.WaitStatus); ok {
os.Exit(waitstat.ExitStatus())
}
}
fmt.Printf("forkChild: wait returned an unknown error: %v\n", err)
os.Exit(1)
}
// The child exited with 0 - let's do the same.
os.Exit(0)
}