send more details about daemon status to supervisor

  If running under systemd, send back information when reloading
configuration and gracefully shutting down.  This gives administator
more information about current Tor daemon state.

src/or/main.c

@@ -2169,6 +2169,9 @@ process_signal(uintptr_t sig)
         tor_cleanup();
         exit(0);
       }
+#ifdef HAVE_SYSTEMD
+      sd_notify(0, "STOPPING=1");
+#endif
       hibernate_begin_shutdown();
       break;
 #ifdef SIGPIPE
@@ -2188,11 +2191,17 @@ process_signal(uintptr_t sig)
       control_event_signal(sig);
       break;
     case SIGHUP:
+#ifdef HAVE_SYSTEMD
+      sd_notify(0, "RELOADING=1");
+#endif
       if (do_hup() < 0) {
         log_warn(LD_CONFIG,"Restart failed (config error?). Exiting.");
         tor_cleanup();
         exit(1);
       }
+#ifdef HAVE_SYSTEMD
+      sd_notify(0, "READY=1");
+#endif
       control_event_signal(sig);
       break;
 #ifdef SIGCHLD