bus: automatically flush bus queue when we exit the event loop

This way, we do not have to call it manually

src/hostname/hostnamed.c

@@ -665,7 +665,6 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
-        sd_bus_flush(bus);
         r = 0;
 
 finish:

src/libsystemd-bus/bus-internal.h

@@ -244,6 +244,7 @@ struct sd_bus {
         sd_event_source *input_io_event_source;
         sd_event_source *output_io_event_source;
         sd_event_source *time_event_source;
+        sd_event_source *quit_event_source;
         sd_event *event;
 };
 

src/libsystemd-bus/bus-util.c

@@ -83,7 +83,7 @@ int bus_event_loop_with_idle(sd_event *e, sd_bus *bus, const char *name, usec_t
                 if (r == SD_EVENT_FINISHED)
                         break;
 
-                r = sd_event_run(e, exiting ? (uint64_t) -1 : DEFAULT_EXIT_USEC);
+                r = sd_event_run(e, exiting ? (uint64_t) -1 : timeout);
                 if (r < 0)
                         return r;
 

src/libsystemd-bus/sd-bus.c

@@ -2208,6 +2208,16 @@ static int prepare_callback(sd_event_source *s, void *userdata) {
         return 1;
 }
 
+static int quit_callback(sd_event_source *event, void *userdata) {
+        sd_bus *bus = userdata;
+
+        assert(event);
+
+        sd_bus_flush(bus);
+
+        return 1;
+}
+
 int sd_bus_attach_event(sd_bus *bus, sd_event *event, int priority) {
         int r;
 
@@ -2251,6 +2261,10 @@ int sd_bus_attach_event(sd_bus *bus, sd_event *event, int priority) {
         if (r < 0)
                 goto fail;
 
+        r = sd_event_add_quit(event, quit_callback, bus, &bus->quit_event_source);
+        if (r < 0)
+                goto fail;
+
         return 0;
 
 fail:
@@ -2271,6 +2285,9 @@ int sd_bus_detach_event(sd_bus *bus) {
         if (bus->time_event_source)
                 bus->time_event_source = sd_event_source_unref(bus->time_event_source);
 
+        if (bus->quit_event_source)
+                bus->quit_event_source = sd_event_source_unref(bus->quit_event_source);
+
         if (bus->event)
                 bus->event = sd_event_unref(bus->event);
 

src/timedate/timedated.c

@@ -880,7 +880,6 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
-        sd_bus_flush(bus);
         r = 0;
 
 finish: