[dm-devel] [PATCH v2] multipath-tools: handle exit signal immediately

[Martin Wilck]

multipathd shouldn't try to service any more client connections
when it receives an exit signal. Moreover, ppoll() can return
success even if signals occured. So check for reconfigure or
log_reset signals after handling pending client requests.

Based on an analysis by Chongyun Wu.

Reported-by: Chongyun Wu <wu.chongyun at h3c.com>
Signed-off-by: Martin Wilck <mwilck at suse.com>
---
 multipathd/main.c   | 6 ++++--
 multipathd/main.h   | 2 +-
 multipathd/uxlsnr.c | 7 +++++--
 3 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/multipathd/main.c b/multipathd/main.c
index 27cf234623d0..8e96f5dd2d7f 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -2184,12 +2184,15 @@ signal_set(int signo, void (*func) (int))
 }
 
 void
-handle_signals(void)
+handle_signals(bool nonfatal)
 {
 	if (exit_sig) {
 		condlog(2, "exit (signal)");
+		exit_sig = 0;
 		exit_daemon();
 	}
+	if (!nonfatal)
+		return;
 	if (reconfig_sig) {
 		condlog(2, "reconfigure (signal)");
 		set_config_state(DAEMON_CONFIGURE);
@@ -2200,7 +2203,6 @@ handle_signals(void)
 		log_reset("multipathd");
 		pthread_mutex_unlock(&logq_lock);
 	}
-	exit_sig = 0;
 	reconfig_sig = 0;
 	log_reset_sig = 0;
 }
diff --git a/multipathd/main.h b/multipathd/main.h
index ededdaba32fe..e8140feaf291 100644
--- a/multipathd/main.h
+++ b/multipathd/main.h
@@ -38,6 +38,6 @@ int mpath_pr_event_handle(struct path *pp);
 void * mpath_pr_event_handler_fn (void * );
 int update_map_pr(struct multipath *mpp);
 void * mpath_pr_event_handler_fn (void * pathp );
-void handle_signals(void);
+void handle_signals(bool);
 
 #endif /* MAIN_H */
diff --git a/multipathd/uxlsnr.c b/multipathd/uxlsnr.c
index 98ac25a68c43..dc116cf2515b 100644
--- a/multipathd/uxlsnr.c
+++ b/multipathd/uxlsnr.c
@@ -221,9 +221,10 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, void * trigger_data)
 		/* most of our life is spent in this call */
 		poll_count = ppoll(polls, i, &sleep_time, &mask);
 
+		handle_signals(false);
 		if (poll_count == -1) {
 			if (errno == EINTR) {
-				handle_signals();
+				handle_signals(true);
 				continue;
 			}
 
@@ -233,7 +234,7 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, void * trigger_data)
 		}
 
 		if (poll_count == 0) {
-			handle_signals();
+			handle_signals(true);
 			continue;
 		}
 
@@ -292,6 +293,8 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, void * trigger_data)
 				FREE(inbuf);
 			}
 		}
+		/* see if we got a non-fatal signal */
+		handle_signals(true);
 
 		/* see if we got a new client */
 		if (polls[0].revents & POLLIN) {
-- 
2.16.1