Issue #1382: Do not send data to backend when there are no listeners …

…(+ tests)

.gitignore

@@ -74,6 +74,7 @@ test_linger
 test_security_null
 test_security_plain
 test_proxy
+test_proxy_terminate
 test_abstract_ipc
 test_filter_ipc
 test_connect_delay_tipc

AUTHORS

@@ -86,6 +86,7 @@ Philip Kovacs
 Pieter Hintjens 
 Piotr Trojanek 
 Richard Newton 
+Rik van der Heijden
 Robert G. Jakabosky 
 Sebastian Otaegui 
 Stefan Radomski 

Makefile.am

@@ -340,6 +340,7 @@ test_apps = \
 	tests/test_inproc_connect \
 	tests/test_issue_566 \
 	tests/test_proxy \
+	tests/test_proxy_terminate \
 	tests/test_many_sockets \
 	tests/test_ipc_wildcard \
 	tests/test_diffserv \

src/proxy.cpp

@@ -159,14 +159,16 @@ int zmq::proxy (
         }
         //  Process a request
         if (state == active
-        &&  items [0].revents & ZMQ_POLLIN) {
+        &&  items [0].revents & ZMQ_POLLIN
+        &&  items [1].revents & ZMQ_POLLOUT) {
             rc = forward(frontend_, backend_, capture_,msg);
             if (unlikely (rc < 0))
                 return -1;
         }
         //  Process a reply
         if (state == active
-        &&  items [1].revents & ZMQ_POLLIN) {
+        &&  items [1].revents & ZMQ_POLLIN
+        &&  items [0].revents & ZMQ_POLLOUT) {
             rc = forward(backend_, frontend_, capture_,msg);
             if (unlikely (rc < 0))
                 return -1;

tests/CMakeLists.txt

@@ -55,6 +55,7 @@ if(NOT WIN32)
           test_reqrep_ipc
           test_abstract_ipc
           test_proxy
+          test_proxy_terminate
           test_filter_ipc
   )
   if(HAVE_FORK)

tests/test_proxy_terminate.cpp

@@ -0,0 +1,113 @@
+/*
+    Copyright (c) 2007-2015 Contributors as noted in the AUTHORS file
+
+    This file is part of 0MQ.
+
+    0MQ is free software; you can redistribute it and/or modify it under
+    the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    0MQ is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "testutil.hpp"
+#include "../include/zmq_utils.h"
+
+// This is a test for issue #1382. The server thread creates a SUB-PUSH
+// steerable proxy. The main process then sends messages to the SUB
+// but there is no pull on the other side, previously the proxy blocks
+// in writing to the backend, preventing the proxy from terminating
+
+void
+server_task (void *ctx)
+{
+    // Frontend socket talks to main process
+    void *frontend = zmq_socket (ctx, ZMQ_SUB);
+    assert (frontend);
+    int rc = zmq_setsockopt (frontend, ZMQ_SUBSCRIBE, "", 0);
+    assert (rc == 0);
+    rc = zmq_bind (frontend, "tcp://127.0.0.1:15564");
+    assert (rc == 0);
+
+    // Nice socket which is never read
+    void *backend = zmq_socket (ctx, ZMQ_PUSH);
+    assert (backend);
+    rc = zmq_bind (backend, "tcp://127.0.0.1:15563");
+    assert (rc == 0);
+
+    // Control socket receives terminate command from main over inproc
+    void *control = zmq_socket (ctx, ZMQ_SUB);
+    assert (control);
+    rc = zmq_setsockopt (control, ZMQ_SUBSCRIBE, "", 0);
+    assert (rc == 0);
+    rc = zmq_connect (control, "inproc://control");
+    assert (rc == 0);
+
+    // Connect backend to frontend via a proxy
+    zmq_proxy_steerable (frontend, backend, NULL, control);
+
+    rc = zmq_close (frontend);
+    assert (rc == 0);
+    rc = zmq_close (backend);
+    assert (rc == 0);
+    rc = zmq_close (control);
+    assert (rc == 0);
+}
+
+
+// The main thread simply starts a basic steerable proxy server, publishes some messages, and then
+// waits for the server to terminate.
+
+int main (void)
+{
+    setup_test_environment ();
+
+    void *ctx = zmq_ctx_new ();
+    assert (ctx);
+    // Control socket receives terminate command from main over inproc
+    void *control = zmq_socket (ctx, ZMQ_PUB);
+    assert (control);
+    int rc = zmq_bind (control, "inproc://control");
+    assert (rc == 0);
+
+    void *thread = zmq_threadstart(&server_task, ctx);
+    msleep (500); // Run for 500 ms
+
+    // Start a secondary publisher which writes data to the SUB-PUSH server socket
+    void *publisher = zmq_socket (ctx, ZMQ_PUB);
+    assert (publisher);
+    rc = zmq_connect (publisher, "tcp://127.0.0.1:15564");
+    assert (rc == 0);
+
+    msleep (50);
+    rc = zmq_send (publisher, "This is a test", 14, 0);
+    assert (rc == 14);
+
+    msleep (50);
+    rc = zmq_send (publisher, "This is a test", 14, 0);
+    assert (rc == 14);
+
+    msleep (50);
+    rc = zmq_send (publisher, "This is a test", 14, 0);
+    assert (rc == 14);
+    rc = zmq_send (control, "TERMINATE", 9, 0);
+    assert (rc == 9);
+
+    rc = zmq_close (publisher);
+    assert (rc == 0);
+    rc = zmq_close (control);
+    assert (rc == 0);
+
+    zmq_threadclose (thread);
+
+    rc = zmq_ctx_term (ctx);
+    assert (rc == 0);
+    return 0;
+}