148 lines
2.8 KiB
Go
148 lines
2.8 KiB
Go
package main
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import (
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"flag"
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"log"
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"os"
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"os/exec"
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"os/signal"
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"path/filepath"
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"strings"
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"syscall"
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)
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const etcService = "/etc/service"
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func main() {
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reap := flag.Bool("reap", true, "reap orphan children")
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flag.Parse()
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log.SetFlags(0)
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runsvdir, err := exec.LookPath("runsvdir")
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if err != nil {
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log.Fatal(err)
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}
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sv, err := exec.LookPath("sv")
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if err != nil {
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log.Fatal(err)
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}
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if fi, err := os.Stat(etcService); err != nil {
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log.Fatal(err)
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} else if !fi.IsDir() {
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log.Fatalf("%s is not a directory", etcService)
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}
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if pid := os.Getpid(); pid != 1 {
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log.Printf("warning: I'm not PID 1, I'm PID %d", pid)
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}
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if *reap {
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log.Print("reaping zombies")
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go reapLoop()
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} else {
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log.Print("NOT reaping zombies")
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}
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supervisor := cmd(runsvdir, etcService)
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if err := supervisor.Start(); err != nil {
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log.Fatal(err)
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}
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log.Printf("%s started", runsvdir)
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go shutdown(sv, supervisor.Process)
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if err := supervisor.Wait(); err != nil {
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log.Printf("%s exited with error: %v", runsvdir, err)
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} else {
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log.Printf("%s exited cleanly", runsvdir)
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}
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}
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// From https://github.com/ramr/go-reaper/blob/master/reaper.go
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func reapLoop() {
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c := make(chan os.Signal)
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signal.Notify(c, syscall.SIGCHLD)
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for range c {
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reapChildren()
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}
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}
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func reapChildren() {
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for {
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var (
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ws syscall.WaitStatus
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pid int
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err error
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)
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for {
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pid, err = syscall.Wait4(-1, &ws, 0, nil)
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if err != syscall.EINTR {
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break
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}
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}
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if err == syscall.ECHILD {
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return // done
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}
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log.Printf("reaped child process %d (%+v)", pid, ws)
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}
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}
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type signaler interface {
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Signal(os.Signal) error
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}
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func shutdown(sv string, s signaler) {
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c := make(chan os.Signal)
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signal.Notify(c, syscall.SIGTERM, syscall.SIGINT)
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sig := <-c
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log.Printf("received %s", sig)
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matches, err := filepath.Glob(filepath.Join(etcService, "*"))
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if err != nil {
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log.Printf("when shutting down services: %v", err)
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return
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}
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var stopped []string
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for _, match := range matches {
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fi, err := os.Stat(match)
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if err != nil {
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log.Printf("%s: %v", match, err)
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continue
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}
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if !fi.IsDir() {
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log.Printf("%s: not a directory", match)
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continue
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}
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service := filepath.Base(match)
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stop := cmd(sv, "stop", service)
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if err := stop.Run(); err != nil {
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log.Printf("%s: %v", strings.Join(stop.Args, " "), err)
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continue
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}
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stopped = append(stopped, service)
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}
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log.Printf("stopped %d: %s", len(stopped), strings.Join(stopped, ", "))
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log.Printf("stopping supervisor with signal %s...", sig)
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if err := s.Signal(sig); err != nil {
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log.Print(err)
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}
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log.Printf("shutdown handler exiting")
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}
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func cmd(path string, args ...string) *exec.Cmd {
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return &exec.Cmd{
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Path: path,
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Args: append([]string{path}, args...),
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Env: os.Environ(),
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Stdin: os.Stdin,
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Stdout: os.Stdout,
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Stderr: os.Stderr,
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}
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}
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