Follow-up to 10b72f1: periodically age service crash counter

Traditionally we've reset the service restart counter on two occasions:

  1) when a service reaches its max crash count (default 10), and
  2) when a service somehow "stabilizes"

In the second case the service is restored to normal running state and
we "forget" its bad previous behavior.  Meaning we cannot catch daemons
that act in an unstable manner outside the "rage quit" scenario.

This patch allows for slowing aging (decrementing) the restart counter
once every five minutes.  Meaning we still catch rage quitters but now
are also able catch other types of misbehavior.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/conf.c

@@ -41,6 +41,7 @@
 #include "finit.h"
 #include "cond.h"
 #include "iwatch.h"
+#include "private.h"
 #include "service.h"
 #include "tty.h"
 #include "helpers.h"
@@ -572,6 +573,26 @@ static void parse_static(char *line, int is_rcsd)
 			cfglevel = 2; /* Fallback */
 		return;
 	}
+
+	/*
+	 * Periodic check and instability index leveler, seconds
+	 */
+	if (MATCH_CMD(line, "service-interval ", x)) {
+		char *token = strip_line(x);
+		const char *err = NULL;
+		int val;
+
+		/* 0 min to 1 day, should check at least daily */
+		val = strtonum(token, 0, 1440, &err);
+		if (!err) {
+			int disabled = !service_interval;
+
+			service_interval = val * 1000; /* to milliseconds */
+			if (disabled)
+				service_init();
+		}
+		return;
+	}
 }
 
 static void parse_dynamic(char *line, struct rlimit rlimit[], char *file)