module svcshutdownbug

go 1.14

require golang.org/x/sys v0.0.0-20200625212154-ddb9806d33ae

package main

import (
	"fmt"
	"log"
	"os"
	"strings"
	"time"
	"strconv"
	"path/filepath"
	"golang.org/x/sys/windows/svc"
	"golang.org/x/sys/windows/svc/eventlog"
	"golang.org/x/sys/windows/svc/mgr"
)

// Log interface allows different log implementations to be used.
type Log interface {
	Close() error
	Info(eid uint32, msg string) error
	Warning(eid uint32, msg string) error
	Error(eid uint32, msg string) error
}

// ConsoleLog provides access to the console.
type ConsoleLog struct {
	Name string
}

// New creates new ConsoleLog.
func New(source string) *ConsoleLog {
	return &ConsoleLog{Name: source}
}

// Close closes console log l.
func (l *ConsoleLog) Close() error {
	return nil
}

func (l *ConsoleLog) report(kind string, eid uint32, msg string) error {
	s := l.Name + "." + kind + "(" + strconv.Itoa(int(eid)) + "): " + msg + "\n"
	_, err := os.Stdout.Write([]byte(s))
	return err
}

// Info writes an information event msg with event id eid to the console l.
func (l *ConsoleLog) Info(eid uint32, msg string) error {
	return l.report("info", eid, msg)
}

// Warning writes an warning event msg with event id eid to the console l.
func (l *ConsoleLog) Warning(eid uint32, msg string) error {
	return l.report("warn", eid, msg)
}

// Error writes an error event msg with event id eid to the console l.
func (l *ConsoleLog) Error(eid uint32, msg string) error {
	return l.report("error", eid, msg)
}

func exePath() (string, error) {
	prog := os.Args[0]
	p, err := filepath.Abs(prog)
	if err != nil {
		return "", err
	}
	fi, err := os.Stat(p)
	if err == nil {
		if !fi.Mode().IsDir() {
			return p, nil
		}
		err = fmt.Errorf("%s is directory", p)
	}
	if filepath.Ext(p) == "" {
		p += ".exe"
		fi, err := os.Stat(p)
		if err == nil {
			if !fi.Mode().IsDir() {
				return p, nil
			}
			err = fmt.Errorf("%s is directory", p)
		}
	}
	return "", err
}

func installService(name, desc string) error {
	exepath, err := exePath()
	if err != nil {
		return err
	}
	m, err := mgr.Connect()
	if err != nil {
		return err
	}
	defer m.Disconnect()
	s, err := m.OpenService(name)
	if err == nil {
		s.Close()
		return fmt.Errorf("service %s already exists", name)
	}
	s, err = m.CreateService(name, exepath, mgr.Config{DisplayName: desc}, "is", "auto-started")
	if err != nil {
		return err
	}
	defer s.Close()
	err = eventlog.InstallAsEventCreate(name, eventlog.Error|eventlog.Warning|eventlog.Info)
	if err != nil {
		s.Delete()
		return fmt.Errorf("SetupEventLogSource() failed: %s", err)
	}
	return nil
}

func removeService(name string) error {
	m, err := mgr.Connect()
	if err != nil {
		return err
	}
	defer m.Disconnect()
	s, err := m.OpenService(name)
	if err != nil {
		return fmt.Errorf("service %s is not installed", name)
	}
	defer s.Close()
	err = s.Delete()
	if err != nil {
		return err
	}
	err = eventlog.Remove(name)
	if err != nil {
		return fmt.Errorf("RemoveEventLogSource() failed: %s", err)
	}
	return nil
}



var elog Log

type myservice struct{}

func (m *myservice) Execute(args []string, r <-chan svc.ChangeRequest, changes chan<- svc.Status) (ssec bool, errno uint32) {
	const cmdsAccepted = svc.AcceptStop | svc.AcceptShutdown | svc.AcceptPauseAndContinue
	changes <- svc.Status{State: svc.StartPending}
	changes <- svc.Status{State: svc.Running, Accepts: cmdsAccepted}
loop:
	for {
		select {
		case c := <-r:
			switch c.Cmd {
			case svc.Interrogate:
				changes <- c.CurrentStatus
				// Testing deadlock from https://code.google.com/p/winsvc/issues/detail?id=4
				time.Sleep(100 * time.Millisecond)
				changes <- c.CurrentStatus
			case svc.Stop:
				elog.Info(1337, "stop")
				break loop
			case svc.Shutdown:
				elog.Info(1337, "shutdown")
				break loop
			case svc.Pause:
				changes <- svc.Status{State: svc.Paused, Accepts: cmdsAccepted}
			case svc.Continue:
				changes <- svc.Status{State: svc.Running, Accepts: cmdsAccepted}
			default:
				elog.Error(1, fmt.Sprintf("unexpected control request #%d", c))
			}
		}
	}
	changes <- svc.Status{State: svc.StopPending}
	return
}

func runService(name string) {
	var err error
	elog, err = eventlog.Open(name)
	if err != nil {
		return
	}
	defer elog.Close()

	elog.Info(1337, fmt.Sprintf("starting %s service", name))
	run := svc.Run
	err = run(name, &myservice{})
	if err != nil {
		elog.Error(1337, fmt.Sprintf("%s service failed: %v", name, err))
		return
	}
	elog.Info(1337, fmt.Sprintf("%s service stopped", name))
}


func startService(name string) error {
	m, err := mgr.Connect()
	if err != nil {
		return err
	}
	defer m.Disconnect()
	s, err := m.OpenService(name)
	if err != nil {
		return fmt.Errorf("could not access service: %v", err)
	}
	defer s.Close()
	err = s.Start("is", "manual-started")
	if err != nil {
		return fmt.Errorf("could not start service: %v", err)
	}
	return nil
}

func controlService(name string, c svc.Cmd, to svc.State) error {
	m, err := mgr.Connect()
	if err != nil {
		return err
	}
	defer m.Disconnect()
	s, err := m.OpenService(name)
	if err != nil {
		return fmt.Errorf("could not access service: %v", err)
	}
	defer s.Close()
	status, err := s.Control(c)
	if err != nil {
		return fmt.Errorf("could not send control=%d: %v", c, err)
	}
	timeout := time.Now().Add(10 * time.Second)
	for status.State != to {
		if timeout.Before(time.Now()) {
			return fmt.Errorf("timeout waiting for service to go to state=%d", to)
		}
		time.Sleep(300 * time.Millisecond)
		status, err = s.Query()
		if err != nil {
			return fmt.Errorf("could not retrieve service status: %v", err)
		}
	}
	return nil
}

func usage(errmsg string) {
	fmt.Fprintf(os.Stderr,
		"%s\n\n"+
			"usage: %s <command>\n"+
			"       where <command> is one of\n"+
			"       install, remove, debug, start, stop, pause or continue.\n",
		errmsg, os.Args[0])
	os.Exit(2)
}

func main() {
	const svcName = "myservice"

	isIntSess, err := svc.IsAnInteractiveSession()
	if err != nil {
		log.Fatalf("failed to determine if we are running in an interactive session: %v", err)
	}
	if !isIntSess {
		runService(svcName)
		return
	}

	cmd := strings.ToLower(os.Args[1])
	switch cmd {
	default:
		runService(svcName)
		return
	case "install":
		err = installService(svcName, "my service")
	case "remove":
		err = removeService(svcName)
	case "start":
		err = startService(svcName)
	case "stop":
		err = controlService(svcName, svc.Stop, svc.Stopped)
	case "pause":
		err = controlService(svcName, svc.Pause, svc.Paused)
	case "continue":
		err = controlService(svcName, svc.Continue, svc.Running)
	}
	if err != nil {
		log.Fatalf("failed to %s %s: %v", cmd, svcName, err)
	}
	return
}