Fix a bug in the error handling when blocking system call is in place.

When a blocking system call is ongoing, the error message shown was
wrong. It was indicated that a blocking system call is on-going when
the program terminates. This is correct, but hides the error message
which describes why packetdrill is terminating.

Sponsored by:	Netflix

gtests/net/packetdrill/code.c

@@ -619,7 +619,7 @@ void run_code_event(struct state *state, struct event *event,
 
 error_out:
 	script_path = strdup(state->config->script_path);
-	state_free(state);
+	state_free(state, 1);
 	die("%s:%d: runtime error in code: %s\n",
 	    script_path, event->line_number, error);
 	free(script_path);

gtests/net/packetdrill/run.c

@@ -128,12 +128,12 @@ static void close_all_sockets(struct state *state)
 	}
 }
 
-void state_free(struct state *state)
+void state_free(struct state *state, int about_to_die)
 {
 	/* We have to stop the system call thread first, since it's using
 	 * sockets that we want to close and reset.
 	 */
-	syscalls_free(state, state->syscalls);
+	syscalls_free(state, state->syscalls, about_to_die);
 
 	/* Then we close the sockets and reset the connections, while
 	 * we still have a netdev for injecting reset packets to free
@@ -402,7 +402,7 @@ static void run_local_packet_event(struct state *state, struct event *event,
 		fprintf(stderr, "%s", error);
 		free(error);
 	} else if (result == STATUS_ERR) {
-		state_free(state);
+		state_free(state, 1);
 		die("%s\n", error);
 	}
 }
@@ -553,7 +553,7 @@ void run_script(struct config *config, struct script *script)
 
 	while (1) {
 		if (get_next_event(state, &error)) {
-			state_free(state);
+			state_free(state, 1);
 			die("%s\n", error);
 		}
 		event = state->event;
@@ -603,14 +603,14 @@ void run_script(struct config *config, struct script *script)
 
 	if (code_execute(state->code, &error)) {
 		char *script_path = strdup(state->config->script_path);
-		state_free(state);
+		state_free(state, 1);
 		die("%s: error executing code: %s\n",
 		    script_path, error);
 		free(script_path);
 		free(error);
 	}
 
-	state_free(state);
+	state_free(state, 0);
 
 	DEBUGP("run_script: done running\n");
 }

gtests/net/packetdrill/run.h

@@ -110,7 +110,7 @@ extern struct state *state_new(struct config *config,
 			       struct netdev *netdev);
 
 /* Free all run-time state for a test. */
-void state_free(struct state *state);
+void state_free(struct state *state, int about_to_die);
 
 /* Grab the global lock for all global state. */
 static inline void run_lock(struct state *state)

gtests/net/packetdrill/run_command.c

@@ -50,7 +50,7 @@ void run_command_event(
 
 error_out:
 	script_path = strdup(state->config->script_path);
-	state_free(state);
+	state_free(state, 1);
 	die("%s:%d: error executing `%s` command: %s\n",
 	    script_path, event->line_number,
 	    command->command_line, error);

gtests/net/packetdrill/run_system_call.c

@@ -6125,7 +6125,7 @@ static void invoke_system_call(
 
 error_out:
 	script_path = strdup(state->config->script_path);
-	state_free(state);
+	state_free(state, 1);
 	die("%s:%d: runtime error in %s call: %s\n",
 	    script_path, event->line_number,
 	    syscall->name, error);
@@ -6236,7 +6236,7 @@ static void enqueue_system_call(
 
 error_out:
 	script_path = strdup(state->config->script_path);
-	state_free(state);
+	state_free(state, 1);
 	die("%s:%d: runtime error in %s call: %s\n",
 	    script_path, event->line_number,
 	    syscall->name, error);
@@ -6378,31 +6378,35 @@ struct syscalls *syscalls_new(struct state *state)
 	return syscalls;
 }
 
-void syscalls_free(struct state *state, struct syscalls *syscalls)
+void syscalls_free(struct state *state, struct syscalls *syscalls, int about_to_die)
 {
+	int status;
+
 	/* Wait a bit for the thread to go idle. */
-	if (await_idle_thread(state)) {
+	status = await_idle_thread(state);
+	if ((status == STATUS_ERR) && (about_to_die == 0)) {
 		die("%s:%d: runtime error: exiting while "
 		    "a blocking system call is in progress\n",
 		    state->config->script_path,
 		    syscalls->event->line_number);
 	}
 
-	/* Send a request to terminate the thread. */
-	DEBUGP("main thread: signaling syscall thread to exit\n");
-	syscalls->state = SYSCALL_EXITING;
-	if (pthread_cond_signal(&syscalls->enqueued) != 0)
-		die_perror("pthread_cond_signal");
-
-	/* Release the lock briefly and wait for syscall thread to finish. */
-	run_unlock(state);
-	DEBUGP("main thread: unlocking, waiting for syscall thread exit\n");
-	void *thread_result = NULL;
-	if (pthread_join(syscalls->thread, &thread_result) != 0)
-		die_perror("pthread_cancel");
-	DEBUGP("main thread: joined syscall thread; relocking\n");
-	run_lock(state);
+	if (status == STATUS_OK) {
+		/* Send a request to terminate the thread. */
+		DEBUGP("main thread: signaling syscall thread to exit\n");
+		syscalls->state = SYSCALL_EXITING;
+		if (pthread_cond_signal(&syscalls->enqueued) != 0)
+			die_perror("pthread_cond_signal");
 
+		/* Release the lock briefly and wait for syscall thread to finish. */
+		run_unlock(state);
+		DEBUGP("main thread: unlocking, waiting for syscall thread exit\n");
+		void *thread_result = NULL;
+		if (pthread_join(syscalls->thread, &thread_result) != 0)
+			die_perror("pthread_cancel");
+		DEBUGP("main thread: joined syscall thread; relocking\n");
+		run_lock(state);
+	}
 	if ((pthread_cond_destroy(&syscalls->idle) != 0) ||
 	    (pthread_cond_destroy(&syscalls->enqueued) != 0) ||
 	    (pthread_cond_destroy(&syscalls->dequeued) != 0)) {

gtests/net/packetdrill/run_system_call.h

@@ -88,7 +88,8 @@ extern struct syscalls *syscalls_new(struct state *state);
 
 /* Tear down a syscalls and free up the resources it has allocated. */
 extern void syscalls_free(struct state *state,
-			  struct syscalls *syscalls);
+			  struct syscalls *syscalls,
+			  int about_to_die);
 
 /* Execute the given system call event. The system call may be
  * expected to block for a while, or it may be expected to return

gtests/net/packetdrill/wire_server.c

@@ -491,7 +491,7 @@ error_done:
 		fprintf(stderr, "%s\n", error);
 
 	if (wire_server->state != NULL)
-		state_free(wire_server->state);
+		state_free(wire_server->state, 0);
 
 	DEBUGP("wire_server_thread: connection is done\n");
 	wire_server_free(wire_server);