From abb090fdb929d2cd372fe2adcc8113b993a306fc Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Mon, 29 Apr 2019 13:30:28 +0200
Subject: service: improve state transitions

---
 service/install.go        |  6 +++---
 service/ipc_server.go     | 27 ++++++++++++++++++++++++---
 service/service_tunnel.go | 11 ++++++-----
 3 files changed, 33 insertions(+), 11 deletions(-)

diff --git a/service/install.go b/service/install.go
index 95c42b2f..e20658e9 100644
--- a/service/install.go
+++ b/service/install.go
@@ -129,17 +129,17 @@ func InstallTunnel(configPath string) error {
 	service, err := m.OpenService(serviceName)
 	if err == nil {
 		status, err := service.Query()
-		if err != nil {
+		if err != nil && err != syscall.Errno(serviceMARKED_FOR_DELETE) {
 			service.Close()
 			return err
 		}
-		if status.State != svc.Stopped {
+		if status.State != svc.Stopped && err != syscall.Errno(serviceMARKED_FOR_DELETE) {
 			service.Close()
 			return errors.New("Tunnel already installed and running")
 		}
 		err = service.Delete()
 		service.Close()
-		if err != nil {
+		if err != nil && err != syscall.Errno(serviceMARKED_FOR_DELETE) {
 			return err
 		}
 		for {
diff --git a/service/ipc_server.go b/service/ipc_server.go
index 6d576846..4dd36b2d 100644
--- a/service/ipc_server.go
+++ b/service/ipc_server.go
@@ -8,10 +8,12 @@ package service
 import (
 	"bytes"
 	"encoding/gob"
+	"fmt"
 	"github.com/Microsoft/go-winio"
 	"golang.org/x/sys/windows/svc"
 	"golang.zx2c4.com/wireguard/windows/conf"
 	"io/ioutil"
+	"log"
 	"net/rpc"
 	"os"
 	"sync"
@@ -74,13 +76,32 @@ func (s *ManagerService) Start(tunnelName string, unused *uintptr) error {
 	// For now, enforce only one tunnel at a time. Later we'll remove this silly restriction.
 	trackedTunnelsLock.Lock()
 	tt := make([]string, 0, len(trackedTunnels))
-	for t := range trackedTunnels {
+	var inTransition string
+	for t, state := range trackedTunnels {
 		tt = append(tt, t)
+		if len(t) > 0 && (state == TunnelStarting || state == TunnelUnknown) {
+			inTransition = t
+			break
+		}
 	}
 	trackedTunnelsLock.Unlock()
-	for _, t := range tt {
-		s.Stop(t, unused)
+	if len(inTransition) != 0 {
+		return fmt.Errorf("Please allow the tunnel \"%s\" to finish activating", inTransition)
 	}
+	go func() {
+		for _, t := range tt {
+			s.Stop(t, unused)
+		}
+		for _, t := range tt {
+			var state TunnelState
+			var unused uintptr
+			if s.State(t, &state) == nil && (state == TunnelStarted || state == TunnelStarting) {
+				log.Printf("[%s] Trying again to stop zombie tunnel", t)
+				s.Stop(t, &unused)
+				time.Sleep(time.Millisecond * 100)
+			}
+		}
+	}()
 
 	// After that process is started -- it's somewhat asynchronous -- we install the new one.
 	c, err := conf.LoadFromName(tunnelName)
diff --git a/service/service_tunnel.go b/service/service_tunnel.go
index dd681a33..12977d26 100644
--- a/service/service_tunnel.go
+++ b/service/service_tunnel.go
@@ -82,6 +82,12 @@ func (service *tunnelService) Execute(args []string, r <-chan svc.ChangeRequest,
 	logger.Info.Println("Starting wireguard-go version", device.WireGuardGoVersion)
 	logger.Debug.Println("Debug log enabled")
 
+	uapiConf, err := conf.ToUAPI()
+	if err != nil {
+		serviceError = ErrorDNSLookup
+		return
+	}
+
 	wintun, err := tun.CreateTUN(conf.Name)
 	if err != nil {
 		serviceError = ErrorCreateWintun
@@ -115,11 +121,6 @@ func (service *tunnelService) Execute(args []string, r <-chan svc.ChangeRequest,
 	}()
 	logger.Info.Println("UAPI listener started")
 
-	uapiConf, err := conf.ToUAPI()
-	if err != nil {
-		serviceError = ErrorDNSLookup
-		return
-	}
 	ipcErr := dev.IpcSetOperation(bufio.NewReader(strings.NewReader(uapiConf)))
 	if ipcErr != nil {
 		err = ipcErr
-- 
cgit v1.2.3-59-g8ed1b