Let a tracker with live sync built in run without a cluster

3 files changed, 49 insertions, 7 deletions

diff --git a/Mk/tests.mk b/Mk/tests.mk
index a7d4fbc..2efdd72 100644
--- a/Mk/tests.mk
+++ b/Mk/tests.mk
@@ -70,11 +70,10 @@ check-integration: opentracker.integration
 check-tsan: opentracker.tsan
         OPENTRACKER=./opentracker.tsan $(PYTHON) -m unittest discover -s tests/integration
 
-# Only the live sync tests: a build with WANT_SYNC_LIVE refuses to start
-# without a live sync address, so it cannot stand in for the plain binary in
-# the rest of the suite.
+# The whole suite against a build that has live sync, which is also the only
+# way the live sync tests stop skipping.
 check-livesync: opentracker.livesync
-        OPENTRACKER=./opentracker.livesync $(PYTHON) -m unittest discover -s tests/integration -p 'test_livesync.py'
+        OPENTRACKER=./opentracker.livesync $(PYTHON) -m unittest discover -s tests/integration
 
 # Cheapest first, so a quick failure comes back quickly.
 check-all:
diff --git a/src/ot_livesync.c b/src/ot_livesync.c
index 18dae0d..9770bbc 100644
--- a/src/ot_livesync.c
+++ b/src/ot_livesync.c
@@ -60,7 +60,7 @@ void livesync_init(void) {
   uint32_t packet_type4 = htonl(OT_SYNC_PEER4);
 
   if (g_socket_in == -1)
-    exerr("No socket address for live sync specified.");
+    return;
 
   /* Prepare outgoing peers buffer */
   memcpy(g_v6_buf.data, &g_tracker_id, sizeof(g_tracker_id));
@@ -160,6 +160,9 @@ static void livesync_handle_peersync(struct ot_workstruct *ws, size_t peer_size)
    stuck when there's not enough traffic to fill udp packets fast
    enough */
 void livesync_ticker(void) {
+  if (g_socket_out == -1)
+    return;
+
   /* livesync_issue_peersync sets g_next_packet_time */
   pthread_mutex_lock(&g_outbuf_mutex);
   if (time_now_seconds() > g_v6_buf.next_packet_time && g_v6_buf.fill > sizeof(g_tracker_id) + sizeof(uint32_t))
@@ -177,8 +180,14 @@ void livesync_ticker(void) {
 /* Inform live sync about whats going on. */
 void livesync_tell(struct ot_workstruct *ws) {
   size_t       peer_size; /* initialized in next line */
-  ot_peer     *peer_src = peer_from_peer6(&ws->peer, &peer_size);
-  sync_buffer *dest_buf = peer_size == OT_PEER_SIZE6 ? &g_v6_buf : &g_v4_buf;
+  ot_peer     *peer_src;
+  sync_buffer *dest_buf;
+
+  if (g_socket_out == -1)
+    return;
+
+  peer_src = peer_from_peer6(&ws->peer, &peer_size);
+  dest_buf = peer_size == OT_PEER_SIZE6 ? &g_v6_buf : &g_v4_buf;
 
   pthread_mutex_lock(&g_outbuf_mutex);
 
diff --git a/tests/integration/test_livesync.py b/tests/integration/test_livesync.py
index 1659a41..3a9ee58 100644
--- a/tests/integration/test_livesync.py
+++ b/tests/integration/test_livesync.py
@@ -130,3 +130,37 @@ class LiveSyncAccess(TrackerTestCase):
         info_hash = self.hash_for("sync-unblessed")
         self.tracker.livesync_send(packet(SYNC_PEER4, [(info_hash, peer4("10.1.2.12", 6881, FLAG_SEEDING))]))
         self.assertFalse(self.tracker.wait_until(lambda: self.tracker.torrent_count() != 0, timeout=1))
+
+
+@unittest.skipUnless(has_livesync(), "this build has no WANT_SYNC_LIVE")
+class LiveSyncUnconfigured(TrackerTestCase):
+    """A binary that has the feature but no cluster to join. Somebody whose
+    packager turned WANT_SYNC_LIVE on did not ask for live sync and should
+    not be able to tell that it is there."""
+
+    config = ""
+
+    def test_the_tracker_runs_anyway(self):
+        info_hash = self.hash_for("no-cluster")
+        self.tracker.announce(info_hash, port=6881, left=0)
+        self.assertEqual(self.tracker.torrent_count(), 1)
+
+    def test_nothing_is_said_about_the_missing_cluster(self):
+        self.assertNotIn("sync", self.tracker.output().lower())
+
+    def test_no_socket_is_bound_for_it(self):
+        """A configured tracker holds the wildcard address on that port, so
+        taking it here proves nothing was started."""
+        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        try:
+            sock.bind(("0.0.0.0", self.tracker.livesync_port))
+        finally:
+            sock.close()
+
+    def test_announcing_stays_clean(self):
+        """Enough announces to pass the watermark that would flush an
+        outgoing buffer, if there were one to flush. The sanitizers in this
+        build turn anything the attempt touched into a failure."""
+        for i in range(200):
+            self.tracker.announce(self.hash_for("no-cluster-%d" % i), port=6881 + i, left=0)
+        self.assertEqual(self.tracker.torrent_count(), 200)