dmeventd: handle signal from plugin

Add support to unmonitor device when monitor recognizes there is
nothing to monitor anymore.

TODO: possibly API change with return value could be also used.

2 files changed, 13 insertions, 1 deletions

diff --git a/WHATS_NEW_DM b/WHATS_NEW_DM
index 8c271391d..8524a6de8 100644
--- a/WHATS_NEW_DM
+++ b/WHATS_NEW_DM
@@ -1,6 +1,7 @@
 Version 1.02.110 - 
 ======================================
-  New design for thread cooperation in dmeventd.
+  Add support to allow unmonitor device from plugin itself.
+  New design for thread co-operation in dmeventd.
   Dmeventd read device status with 'noflush'.
   Dmeventd closes control device when no device is monitored.
   Thin plugin for dmeventd improved percentage usage.
diff --git a/daemons/dmeventd/dmeventd.c b/daemons/dmeventd/dmeventd.c
index d8c317e8e..2706ad60f 100644
--- a/daemons/dmeventd/dmeventd.c
+++ b/daemons/dmeventd/dmeventd.c
@@ -973,6 +973,17 @@ static void *_monitor_thread(void *arg)
 
 			_lock_mutex();
 			thread->processing = 0;
+
+			/*
+			 * Thread can terminate itself from plugin via SIGALRM
+			 * Timer thread will not send signal while processing
+			 * TODO: maybe worth API change and return value for
+			 *       _do_process_event() instead of this signal solution
+			 */
+			if (sigpending(&pendmask) < 0)
+				log_sys_error("sigpending", "");
+			else if (sigismember(&pendmask, SIGALRM))
+				break;
 		} else {
 			_unlock_mutex();