From 3f6c423e76f0c33bcb926b0d69168734951db23f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=96=E7=95=8C?= <i@sekai.icu>
Date: Tue, 26 Mar 2024 20:40:59 +0800
Subject: [PATCH] Merge time service to library

---
 common/ntp/service.go      | 62 ++++++++++++++++++++++++++------------
 common/ntp/time_stub.go    | 12 ++++++++
 common/ntp/time_unix.go    | 14 +++++++++
 common/ntp/time_windows.go | 32 ++++++++++++++++++++
 4 files changed, 101 insertions(+), 19 deletions(-)
 create mode 100644 common/ntp/time_stub.go
 create mode 100644 common/ntp/time_unix.go
 create mode 100644 common/ntp/time_windows.go

diff --git a/common/ntp/service.go b/common/ntp/service.go
index 21f9467..cbf34b3 100644
--- a/common/ntp/service.go
+++ b/common/ntp/service.go
@@ -10,6 +10,8 @@ import (
 	"github.com/sagernet/sing/common/logger"
 	M "github.com/sagernet/sing/common/metadata"
 	N "github.com/sagernet/sing/common/network"
+	"github.com/sagernet/sing/service"
+	"github.com/sagernet/sing/service/pause"
 )
 
 const TimeLayout = "2006-01-02 15:04:05 -0700"
@@ -19,23 +21,26 @@ type TimeService interface {
 }
 
 type Options struct {
-	Context  context.Context
-	Server   M.Socksaddr
-	Interval time.Duration
-	Dialer   N.Dialer
-	Logger   logger.Logger
+	Context       context.Context
+	Dialer        N.Dialer
+	Logger        logger.Logger
+	Server        M.Socksaddr
+	Interval      time.Duration
+	WriteToSystem bool
 }
 
 var _ TimeService = (*Service)(nil)
 
 type Service struct {
-	ctx         context.Context
-	cancel      common.ContextCancelCauseFunc
-	server      M.Socksaddr
-	dialer      N.Dialer
-	logger      logger.Logger
-	ticker      *time.Ticker
-	clockOffset time.Duration
+	ctx           context.Context
+	cancel        common.ContextCancelCauseFunc
+	dialer        N.Dialer
+	logger        logger.Logger
+	server        M.Socksaddr
+	writeToSystem bool
+	ticker        *time.Ticker
+	clockOffset   time.Duration
+	pause         pause.Manager
 }
 
 func NewService(options Options) *Service {
@@ -47,9 +52,12 @@ func NewService(options Options) *Service {
 	destination := options.Server
 	if !destination.IsValid() {
 		destination = M.Socksaddr{
-			Fqdn: "time.google.com",
+			Fqdn: "time.apple.com",
 		}
 	}
+	if options.Logger == nil {
+		options.Logger = logger.NOP()
+	}
 	if destination.Port == 0 {
 		destination.Port = 123
 	}
@@ -66,12 +74,14 @@ func NewService(options Options) *Service {
 		dialer = N.SystemDialer
 	}
 	return &Service{
-		ctx:    ctx,
-		cancel: cancel,
-		server: destination,
-		dialer: dialer,
-		logger: options.Logger,
-		ticker: time.NewTicker(interval),
+		ctx:           ctx,
+		cancel:        cancel,
+		dialer:        dialer,
+		logger:        options.Logger,
+		writeToSystem: options.WriteToSystem,
+		server:        destination,
+		ticker:        time.NewTicker(interval),
+		pause:         service.FromContext[pause.Manager](ctx),
 	}
 }
 
@@ -104,6 +114,14 @@ func (s *Service) loopUpdate() {
 			return
 		case <-s.ticker.C:
 		}
+		if s.pause != nil {
+			s.pause.WaitActive()
+			select {
+			case <-s.ctx.Done():
+				return
+			default:
+			}
+		}
 		err := s.update()
 		if err == nil {
 			s.logger.Debug("updated time: ", s.TimeFunc()().Local().Format(TimeLayout))
@@ -119,5 +137,11 @@ func (s *Service) update() error {
 		return err
 	}
 	s.clockOffset = response.ClockOffset
+	if s.writeToSystem {
+		writeErr := SetSystemTime(s.TimeFunc()())
+		if writeErr != nil {
+			s.logger.Warn("write time to system: ", writeErr)
+		}
+	}
 	return nil
 }
diff --git a/common/ntp/time_stub.go b/common/ntp/time_stub.go
new file mode 100644
index 0000000..a168625
--- /dev/null
+++ b/common/ntp/time_stub.go
@@ -0,0 +1,12 @@
+//go:build !(windows || linux || darwin)
+
+package ntp
+
+import (
+	"os"
+	"time"
+)
+
+func SetSystemTime(nowTime time.Time) error {
+	return os.ErrInvalid
+}
diff --git a/common/ntp/time_unix.go b/common/ntp/time_unix.go
new file mode 100644
index 0000000..6b4226f
--- /dev/null
+++ b/common/ntp/time_unix.go
@@ -0,0 +1,14 @@
+//go:build linux || darwin
+
+package ntp
+
+import (
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+func SetSystemTime(nowTime time.Time) error {
+	timeVal := unix.NsecToTimeval(nowTime.UnixNano())
+	return unix.Settimeofday(&timeVal)
+}
diff --git a/common/ntp/time_windows.go b/common/ntp/time_windows.go
new file mode 100644
index 0000000..c17fea1
--- /dev/null
+++ b/common/ntp/time_windows.go
@@ -0,0 +1,32 @@
+package ntp
+
+import (
+	"time"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+func SetSystemTime(nowTime time.Time) error {
+	var systemTime windows.Systemtime
+	systemTime.Year = uint16(nowTime.Year())
+	systemTime.Month = uint16(nowTime.Month())
+	systemTime.Day = uint16(nowTime.Day())
+	systemTime.Hour = uint16(nowTime.Hour())
+	systemTime.Minute = uint16(nowTime.Minute())
+	systemTime.Second = uint16(nowTime.Second())
+	systemTime.Milliseconds = uint16(nowTime.UnixMilli() - nowTime.Unix()*1000)
+
+	dllKernel32 := windows.NewLazySystemDLL("kernel32.dll")
+	proc := dllKernel32.NewProc("SetSystemTime")
+
+	_, _, err := proc.Call(
+		uintptr(unsafe.Pointer(&systemTime)),
+	)
+
+	if err != nil && err.Error() != "The operation completed successfully." {
+		return err
+	}
+
+	return nil
+}