From 09693ba1bf1b62645d6ebc16ffb879cb49ea8995 Mon Sep 17 00:00:00 2001
From: Martin Dosch <martin@mdosch.de>
Date: Sun, 31 Mar 2024 16:55:45 +0200
Subject: [PATCH] Further improvements to make race conditions less likely.

---
 CHANGELOG.md      | 3 +++
 main.go           | 4 ++++
 stanzahandling.go | 3 +++
 3 files changed, 10 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 42eae30..2052f1a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,9 @@
 # Changelog
 
 ## UNRELEASED
+### Changed
+- Fixed a race condition in receiving stanzas.
+
 ### Added
 - Add a warning when run by the user *root*.
 
diff --git a/main.go b/main.go
index e26a142..73f26c9 100644
--- a/main.go
+++ b/main.go
@@ -18,6 +18,7 @@ import (
 	osUser "os/user"
 	"runtime"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/ProtonMail/gopenpgp/v2/crypto" // MIT License
@@ -33,8 +34,11 @@ type configuration struct {
 	alias    string
 }
 
+var mutex sync.Mutex
+
 func closeAndExit(client *xmpp.Client, cancel context.CancelFunc, err error) {
 	cancel()
+	mutex.Lock()
 	client.Close()
 	if err != nil {
 		log.Fatal(err)
diff --git a/stanzahandling.go b/stanzahandling.go
index 386724c..8167e63 100644
--- a/stanzahandling.go
+++ b/stanzahandling.go
@@ -54,13 +54,16 @@ func rcvStanzas(client *xmpp.Client, iqc chan xmpp.IQ, msgc chan xmpp.Chat, ctx
 			return
 		default:
 			go func() {
+				mutex.Lock()
 				received, err = client.Recv()
 				r <- received
 			}()
 			select {
 			case <-ctx.Done():
+				mutex.Unlock()
 				return
 			case <-r:
+				mutex.Unlock()
 			}
 		}
 		// Don't print errors if the program is getting shut down,