From 723b5d70813682ded26fbffcda30dcf6ca1fda4c Mon Sep 17 00:00:00 2001
From: Roger Light <roger@atchoo.org>
Date: Sun, 22 Aug 2021 08:23:13 +0100
Subject: [PATCH] Fix listener mount_point not being removed on outgoing
 messages.

Closes #2244. Thanks to alflexRH.
---
 ChangeLog.txt                          |  2 ++
 lib/send_publish.c                     |  9 +++++++
 test/broker/10-listener-mount-point.py | 35 +++++++++++++++++---------
 3 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/ChangeLog.txt b/ChangeLog.txt
index 92a0f8374a..c65c01be59 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -26,6 +26,8 @@ Broker:
   v3.1.1 protocol itself rather than an implementation, to be addressed.
 - Fix broker not quiting if e.g. the `password_file` is specified as a
   directory. Closes #2241.
+- Fix listener mount_point not being removed on outgoing messages.
+  Closes #2244.
 
 Client library:
 - If a client uses TLS-PSK then force the default cipher list to use "PSK"
diff --git a/lib/send_publish.c b/lib/send_publish.c
index 1d1842a0e8..8a434c0211 100644
--- a/lib/send_publish.c
+++ b/lib/send_publish.c
@@ -65,6 +65,15 @@ int send__publish(struct mosquitto *mosq, uint16_t mid, const char *topic, uint3
 	}
 
 #ifdef WITH_BROKER
+	if(mosq->listener && mosq->listener->mount_point){
+		len = strlen(mosq->listener->mount_point);
+		if(len < strlen(topic)){
+			topic += len;
+		}else{
+			/* Invalid topic string. Should never happen, but silently swallow the message anyway. */
+			return MOSQ_ERR_SUCCESS;
+		}
+	}
 #ifdef WITH_BRIDGE
 	if(mosq->bridge && mosq->bridge->topics && mosq->bridge->topic_remapping){
 		for(i=0; i<mosq->bridge->topic_count; i++){
diff --git a/test/broker/10-listener-mount-point.py b/test/broker/10-listener-mount-point.py
index 273aec6000..d3b639398c 100755
--- a/test/broker/10-listener-mount-point.py
+++ b/test/broker/10-listener-mount-point.py
@@ -4,7 +4,7 @@
 
 def write_config(filename, port1, port2):
     with open(filename, 'w') as f:
-        f.write("port %d\n" % (port1))
+        f.write("listener %d\n" % (port1))
         f.write("allow_anonymous true\n")
         f.write("\n")
         f.write("listener %d\n" % (port2))
@@ -31,29 +31,40 @@ def do_test(proto_ver):
     write_config(conf_file, port1, port2)
 
     rc = 1
-    keepalive = 60
-    connect_packet = mosq_test.gen_connect("test2", keepalive=keepalive, proto_ver=proto_ver)
-    connack_packet = mosq_test.gen_connack(rc=0, proto_ver=proto_ver)
-
     mid = 1
-    subscribe_packet = mosq_test.gen_subscribe(mid, "#", 0, proto_ver=proto_ver)
-    suback_packet = mosq_test.gen_suback(mid, 0, proto_ver=proto_ver)
 
-    publish_packet = mosq_test.gen_publish("mount/test", qos=0, payload="mount point", proto_ver=proto_ver)
+    # Subscriber for listener with mount point
+    connect_packet1 = mosq_test.gen_connect("test1", proto_ver=proto_ver)
+    connack_packet1 = mosq_test.gen_connack(rc=0, proto_ver=proto_ver)
+    subscribe_packet1 = mosq_test.gen_subscribe(mid, "#", 0, proto_ver=proto_ver)
+    suback_packet1 = mosq_test.gen_suback(mid, 0, proto_ver=proto_ver)
+    publish_packet1 = mosq_test.gen_publish("mount/test", qos=0, payload="mount point", proto_ver=proto_ver)
+
+    # Subscriber for listener without mount point
+    connect_packet2 = mosq_test.gen_connect("test2", proto_ver=proto_ver)
+    connack_packet2 = mosq_test.gen_connack(rc=0, proto_ver=proto_ver)
+    subscribe_packet2 = mosq_test.gen_subscribe(mid, "#", 0, proto_ver=proto_ver)
+    suback_packet2 = mosq_test.gen_suback(mid, 0, proto_ver=proto_ver)
+    publish_packet2 = mosq_test.gen_publish("test", qos=0, payload="mount point", proto_ver=proto_ver)
 
     broker = mosq_test.start_broker(filename=os.path.basename(__file__), use_conf=True, port=port1)
 
     try:
-        sock = mosq_test.do_client_connect(connect_packet, connack_packet, timeout=20, port=port1)
-        mosq_test.do_send_receive(sock, subscribe_packet, suback_packet, "suback")
+        sock1 = mosq_test.do_client_connect(connect_packet1, connack_packet1, timeout=20, port=port1)
+        mosq_test.do_send_receive(sock1, subscribe_packet1, suback_packet1, "suback1")
+
+        sock2 = mosq_test.do_client_connect(connect_packet2, connack_packet2, timeout=20, port=port2)
+        mosq_test.do_send_receive(sock2, subscribe_packet2, suback_packet2, "suback2")
 
         helper(port2, proto_ver)
         # Should have now received a publish command
 
-        mosq_test.expect_packet(sock, "publish", publish_packet)
+        mosq_test.expect_packet(sock1, "publish1", publish_packet1)
+        mosq_test.expect_packet(sock2, "publish2", publish_packet2)
         rc = 0
 
-        sock.close()
+        sock1.close()
+        sock2.close()
     except mosq_test.TestError:
         pass
     finally: