libgocryptfs/daemonize.go

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package main
import (
"fmt"
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"os"
"os/exec"
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"os/signal"
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"syscall"
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)
// The child sends us USR1 if the mount was successful
func exitOnUsr1() {
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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()
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name := os.Args[0]
notifyArg := fmt.Sprintf("-notifypid=%d", os.Getpid())
newArgs := []string{"-f", notifyArg}
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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)
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os.Exit(1)
}
err = c.Wait()
if err != nil {
if exiterr, ok := err.(*exec.ExitError); ok {
if waitstat, ok := exiterr.Sys().(syscall.WaitStatus); ok {
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os.Exit(waitstat.ExitStatus())
}
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}
fmt.Printf("forkChild: wait returned an unknown error: %v\n", err)
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os.Exit(1)
}
// The child exited with 0 - let's do the same.
os.Exit(0)
}