From e60a92e93e8aaccdb4edbb5e417870fc52cf2dee Mon Sep 17 00:00:00 2001
From: Cuong Manh Le <cuong@windscribe.com>
Date: Mon, 24 Feb 2025 23:57:45 +0700
Subject: [PATCH] cmd/cli: improving IPC when try listening failed

So the "ctrld start" should know earlier that "ctrld run" failed to
listen on certain port, and terminate earlier instead of waiting for
timeout happened.
---
 cmd/cli/cli.go | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/cmd/cli/cli.go b/cmd/cli/cli.go
index 3b13992..de2945b 100644
--- a/cmd/cli/cli.go
+++ b/cmd/cli/cli.go
@@ -325,7 +325,7 @@ func run(appCallback *AppCallback, stopCh chan struct{}) {
 		}
 	}
 
-	updated := updateListenerConfig(&cfg)
+	updated := updateListenerConfig(&cfg, notifyExitToLogServer)
 
 	if cdUID != "" {
 		processLogAndCacheFlags()
@@ -488,7 +488,7 @@ func readConfigFile(writeDefaultConfig, notice bool) bool {
 			mainLog.Load().Fatal().Msgf("failed to unmarshal default config: %v", err)
 		}
 		nop := zerolog.Nop()
-		_, _ = tryUpdateListenerConfig(&cfg, &nop, true)
+		_, _ = tryUpdateListenerConfig(&cfg, &nop, func() {}, true)
 		addExtraSplitDnsRule(&cfg)
 		if err := writeConfigFile(&cfg); err != nil {
 			mainLog.Load().Fatal().Msgf("failed to write default config file: %v", err)
@@ -1167,8 +1167,8 @@ func mobileListenerIp() string {
 // updateListenerConfig updates the config for listeners if not defined,
 // or defined but invalid to be used, e.g: using loopback address other
 // than 127.0.0.1 with systemd-resolved.
-func updateListenerConfig(cfg *ctrld.Config) bool {
-	updated, _ := tryUpdateListenerConfig(cfg, nil, true)
+func updateListenerConfig(cfg *ctrld.Config, notifyToLogServerFunc func()) bool {
+	updated, _ := tryUpdateListenerConfig(cfg, nil, notifyToLogServerFunc, true)
 	if addExtraSplitDnsRule(cfg) {
 		updated = true
 	}
@@ -1178,7 +1178,7 @@ func updateListenerConfig(cfg *ctrld.Config) bool {
 // tryUpdateListenerConfig tries updating listener config with a working one.
 // If fatal is true, and there's listen address conflicted, the function do
 // fatal error.
-func tryUpdateListenerConfig(cfg *ctrld.Config, infoLogger *zerolog.Logger, fatal bool) (updated, ok bool) {
+func tryUpdateListenerConfig(cfg *ctrld.Config, infoLogger *zerolog.Logger, notifyFunc func(), fatal bool) (updated, ok bool) {
 	ok = true
 	lcc := make(map[string]*listenerConfigCheck)
 	cdMode := cdUID != ""
@@ -1310,6 +1310,7 @@ func tryUpdateListenerConfig(cfg *ctrld.Config, infoLogger *zerolog.Logger, fata
 		maxAttempts := 10
 		for {
 			if attempts == maxAttempts {
+				notifyFunc()
 				logMsg(mainLog.Load().Fatal(), n, "could not find available listen ip and port")
 			}
 			addr := net.JoinHostPort(listener.IP, strconv.Itoa(listener.Port))
@@ -1322,6 +1323,7 @@ func tryUpdateListenerConfig(cfg *ctrld.Config, infoLogger *zerolog.Logger, fata
 
 			if !check.IP && !check.Port {
 				if fatal {
+					notifyFunc()
 					logMsg(mainLog.Load().Fatal(), n, "failed to listen: %v", err)
 				}
 				ok = false
@@ -1389,6 +1391,7 @@ func tryUpdateListenerConfig(cfg *ctrld.Config, infoLogger *zerolog.Logger, fata
 			}
 			if listener.IP == oldIP && listener.Port == oldPort {
 				if fatal {
+					notifyFunc()
 					logMsg(mainLog.Load().Fatal(), n, "could not listen on %s: %v", net.JoinHostPort(listener.IP, strconv.Itoa(listener.Port)), err)
 				}
 				ok = false
@@ -1427,6 +1430,7 @@ func tryUpdateListenerConfig(cfg *ctrld.Config, infoLogger *zerolog.Logger, fata
 					}
 				}
 				if !found {
+					notifyFunc()
 					logMsg(mainLog.Load().Fatal(), n, "could not use %q as DNS nameserver with systemd resolved", listener.IP)
 				}
 			}
@@ -1631,7 +1635,7 @@ func doGenerateNextDNSConfig(uid string) error {
 	}
 	mainLog.Load().Notice().Msgf("Generating nextdns config: %s", defaultConfigFile)
 	generateNextDNSConfig(uid)
-	updateListenerConfig(&cfg)
+	updateListenerConfig(&cfg, func() {})
 	return writeConfigFile(&cfg)
 }