mdmon: recreate socket/pid file on SIGHUP

Allow mdmon to start while /var/run/mdadm is readonly.  Later a SIGHUP
can trigger mdmon to drop its pid and socket once /var/run/mdadm is
writable.  Of course one needs the pid to send a HUP, that can be stored
in a distribution specific rw-init directory... For now, rely on a
killall -HUP mdmon to get the files dumped.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/managemon.c b/managemon.c
index fc5da71..779cb23 100644
--- a/managemon.c
+++ b/managemon.c
@@ -605,6 +605,7 @@ void do_manager(struct supertype *container)
 
 	sigprocmask(SIG_UNBLOCK, NULL, &set);
 	sigdelset(&set, SIGUSR1);
+	sigdelset(&set, SIGHUP);
 
 	do {
 
@@ -622,6 +623,13 @@ void do_manager(struct supertype *container)
 
 			read_sock(container);
 
+			if (socket_hup_requested) {
+				close(container->sock);
+				container->sock = make_control_sock(container->devname);
+				make_pidfile(container->devname, 0);
+				socket_hup_requested = 0;
+			}
+
 			free_mdstat(mdstat);
 		}
 		remove_old();