Close UART gracefully on SIGINT/SIGTERM in goTool.

Go exits on Ctrl+C without running defers, leaving the serial port locked; register shutdown hooks for serve and CLI commands.

Co-authored-by: Cursor <cursoragent@cursor.com>

goTool/cmd_serve.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"embed"
+	"errors"
 	"flag"
 	"fmt"
 	"io/fs"
@@ -34,21 +35,29 @@ func runServe(portName string, baud int, args []string) error {
 
 	link := newManagedSerial(portName, baud)
 	link.quiet = true
-	defer link.Close()
 
 	hub := newWSHub()
 	streamCtl := newAccelStreamCtl()
 	tapCtl := newTapNotifyCtl()
 	stop := make(chan struct{})
-	defer close(stop)
+
+	var dashSrv *http.Server
+	var apiSrv *http.Server
+	registerShutdown(func() {
+		close(stop)
+		shutdownHTTPServer(dashSrv)
+		shutdownAPIServer(apiSrv)
+		if err := link.Close(); err != nil {
+			log.Printf("UART close: %v", err)
+		}
+	})
+
 	go runPoller(link, portName, hub, streamCtl, tapCtl, *interval, stop)
 	go runBatteryPoller(link, hub, 5*time.Second, stop)
 	go runCacheStatusDashboardPoller(link, hub, *accelInterval, stop)
 
-	var apiSrv *http.Server
 	if *apiAddr != "" {
 		apiSrv = runAPIServer(portName, link, *apiAddr, *accelInterval, hub, streamCtl, tapCtl, stop)
-		defer shutdownAPIServer(apiSrv)
 	}
 
 	mux := http.NewServeMux()
@@ -81,5 +90,14 @@ func runServe(portName string, baud int, args []string) error {
 	if *apiAddr == "" {
 		log.Printf("external API disabled (-api-addr \"\")")
 	}
-	return http.ListenAndServe(*addr, mux)
+
+	dashSrv = &http.Server{Addr: *addr, Handler: mux}
+	go func() {
+		if err := dashSrv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+			log.Printf("dashboard server: %v", err)
+		}
+	}()
+
+	waitForShutdown()
+	return nil
 }