event: hook up sd-event with the service watchdog logic

Adds a new call sd_event_set_watchdog() that can be used to hook up the
event loop with the watchdog supervision logic of systemd. If enabled
and $WATCHDOG_USEC is set the event loop will ping the invoking systemd
daemon right after coming back from epoll_wait() but not more often than
$WATCHDOG_USEC/4. The epoll_wait() will sleep no longer than
$WATCHDOG_USEC/4*3, to make sure the service manager is called in time.

This means that setting WatchdogSec= in a .service file and calling
sd_event_set_watchdog() in your daemon is enough to hook it up with the
watchdog logic.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/libsystemd-bus/libsystemd-bus.sym b/src/libsystemd-bus/libsystemd-bus.sym
index 7bc1ef9ad2..4a849b382a 100644
--- a/src/libsystemd-bus/libsystemd-bus.sym
+++ b/src/libsystemd-bus/libsystemd-bus.sym
@@ -238,6 +238,7 @@ global:
         sd_event_request_quit;
         sd_event_get_now_realtime;
         sd_event_get_now_monotonic;
+        sd_event_set_watchdog;
 
         sd_event_source_ref;
         sd_event_source_unref;