Use blocking Pipe_pull. Wake pipe on interrupt.

prrt/proto/processes/dataTransmitter.c

@@ -131,7 +131,7 @@ void *send_data_loop(void *ptr) {
     while (1) {
         ListNode *job;
         do {
-            job = Pipe_poll(sock_ptr->sendDataQueue);
+            job = Pipe_pull(sock_ptr->sendDataQueue);
             if (PrrtSocket_closing(sock_ptr)) {
                 if (block != NULL) {
                     PrrtBlock_destroy(block);

prrt/proto/socket.c

@@ -380,6 +380,10 @@ int PrrtSocket_interrupt(PrrtSocket *s) {
         PrrtReceiver_interrupt(s->receiver);
     }
 
+    if(s->sendDataQueue != NULL) {
+      Pipe_wake(s->sendDataQueue);
+    }
+
     void **res = NULL;
     if (s->sendDataThread != 0) {
         check(pthread_join(s->sendDataThread, res) == 0, "Join failed.");