go daemon

daemon.go

//Change from http://www.mysqlab.net/blog/2011/12/daemon-function-for-go-language/
//For go 1.0.2
package daemon

import (
	"syscall"
	"os"
	"log"
)

func Daemon(nochdir, noclose int) int {
	var ret, ret2 uintptr
	var err syscall.Errno

	if syscall.Getppid() == 1 {
		return 0
	}

	ret, ret2, err = syscall.RawSyscall(syscall.SYS_FORK, 0, 0, 0)
	if err != 0 {
		return -1
	}

	if ret2 < 0 {
		os.Exit(-1)
	}

	if ret > 0 {
		os.Exit(0)
	}

	syscall.Umask(0)

	s_ret, s_errno := syscall.Setsid()
	if s_errno != nil {
		log.Printf("Error: syscall.Setsid error: %s", s_errno)
	}

	if s_ret < 0 {
		return -1
	}

	if nochdir == 0 {
		os.Chdir("/")
	}

	if noclose == 0 {
		f, e := os.OpenFile("/dev/null", os.O_RDWR, 0)
		if e == nil {
			fd := f.Fd()
			syscall.Dup2(int(fd), int(os.Stdin.Fd()))
			syscall.Dup2(int(fd), int(os.Stdout.Fd()))
			syscall.Dup2(int(fd), int(os.Stderr.Fd()))
		}
	}

	return 0
}