test_fork: update test to verify communication between parent and child

tests/test_fork.cpp

@@ -26,49 +26,90 @@
 #include <signal.h>
 
 const char* address = "tcp://127.0.0.1:6571";
-void my_handler(int, siginfo_t *info, void *uap);
-volatile int child_exited = 0;
-volatile int child_exit_code = 0;
+
+#define NUM_MESSAGES 5
 
 int main (void)
 {
     int rc;
-    
+
     setup_test_environment();
-    
+
     printf("parent: process id = %d\n", (int)getpid());
     void *ctx = zmq_ctx_new ();
     assert (ctx);
-    
+
     void* sock = zmq_socket(ctx, ZMQ_PULL);
     assert(sock);
-    
-    rc = zmq_connect(sock, address);
+
+    rc = zmq_bind(sock, address);
     assert(rc == 0);
-    
+
     // wait for io threads to be running
     usleep(100000);
-    
+
+    printf("about to fork()\n");
     int pid = fork();
     if (pid == 0) {
-        sleep(1);
+        // this is the child process
+
+        usleep(100000);
         printf("child: process id = %d\n", (int)getpid());
         printf("child: terminating inherited context...\n");
         // close the socket, or the context gets stuck indefinitely
-        zmq_close(sock);
+        // zmq_close(sock);
         zmq_term(ctx);
-        printf("child done\n");
+
+        // create new context, socket, connect and send some messages
+        void *ctx2 = zmq_ctx_new ();
+        assert (ctx2);
+
+        void* push = zmq_socket(ctx2, ZMQ_PUSH);
+        assert(push);
+
+        rc = zmq_connect(push, address);
+        assert(rc == 0);
+
+        const char* message = "hello";
+
+        int i;
+        for (i = 0; i < NUM_MESSAGES; i += 1) {
+            printf("child: send message #%d\n", i);
+            zmq_send(push, message, strlen(message), 0);
+            usleep(100000);
+        }
+
+        printf("child: closing push socket\n");
+        zmq_close(push);
+        printf("child: destroying child context\n");
+        zmq_ctx_destroy(ctx2);
+        printf("child: done\n");
         exit(0);
     } else {
+        // this is the parent process
+        printf("parent: waiting for %d messages\n", NUM_MESSAGES);
+
+        char buffer[1024];
+
+        int i;
+        for (i = 0; i < NUM_MESSAGES; i += 1) {
+            int num_bytes = zmq_recv(sock, buffer, 1024, 0);
+            assert(num_bytes > 0);
+            buffer[num_bytes] = 0;
+            printf("parent: received #%d: %s\n", i, buffer);
+        }
+
         int child_status;
         while (true) {
             rc = waitpid(pid, &child_status, 0);
             if (rc == -1 && errno == EINTR) continue;
             printf("parent: child exit code = %d, rc = %d, errno = %d\n", WEXITSTATUS(child_status), rc, errno);
+            assert(rc > 0);
+            // verify the status code of the child was zero.
             assert(WEXITSTATUS(child_status) == 0);
             break;
         }
-        printf("parent done.\n");
+        printf("parent: done.\n");
         exit(0);
     }
     return 0;