"connections, and will shut down in %d seconds. Interrupt "
"again to exit now.", options->ShutdownWaitLength);
shutdown_time = time(NULL) + options->ShutdownWaitLength;
+#ifdef HAVE_SYSTEMD
+ /* tell systemd that we may need more than the default 90 seconds to shut
+ * down so they don't kill us. add some extra time to actually finish
+ * shutting down, otherwise systemd will kill us immediately after the
+ * EXTEND_TIMEOUT_USEC expires. this is an *upper* limit; tor will probably
+ * only take one or two more seconds, but assume that maybe we got swapped
+ * out and it takes a little while longer.
+ *
+ * as of writing, this is a no-op with all-defaults: ShutdownWaitLength is
+ * 30 seconds, so this will extend the timeout to 60 seconds.
+ * default systemd DefaultTimeoutStopSec is 90 seconds, so systemd will
+ * wait (up to) 90 seconds anyways.
+ *
+ * 2^31 usec = ~2147 sec = ~35 min. probably nobody will actually set
+ * ShutdownWaitLength to more than that, but use a longer type so we don't
+ * need to think about UB on overflow
+ */
+ sd_notifyf(0, "EXTEND_TIMEOUT_USEC=%" PRIu64,
+ ((uint64_t)(options->ShutdownWaitLength) + 30) * TOR_USEC_PER_SEC);
+#endif
} else { /* soft limit reached */
hibernate_end_time = interval_end_time;
}