journalctl: make --rotate synchronous, too

Of course, ideally we'd just use normal synchronous bus calls, but this
is out of the question as long as we rely on dbus-daemon (which logs to
journald, and thus cannot use to avoid cyclic sync loops). Hence,
instead, reuse the wait logic already implemented for --sync, and use a
signal in one direction, and a mtime watch file for the reply.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/journal/journald-server.c b/src/journal/journald-server.c
index f0a3c82d98..70ff101d5f 100644
--- a/src/journal/journald-server.c
+++ b/src/journal/journald-server.c
@@ -1263,6 +1263,9 @@ static int dispatch_sigusr2(sd_event_source *es, const struct signalfd_siginfo *
         server_rotate(s);
         server_vacuum(s, true, true);
 
+        /* Let clients know when the most recent rotation happened. */
+        (void) touch("/run/systemd/journal/rotated");
+
         return 0;
 }