[or-cvs] r16994: {tor} Fix 0/0 calculation in get_weighted_fractional_uptime(). (in tor/trunk: . src/or)

[nickm@xxxxxxxx]

Author: nickm
Date: 2008-09-28 11:48:36 -0400 (Sun, 28 Sep 2008)
New Revision: 16994

Modified:
   tor/trunk/ChangeLog
   tor/trunk/src/or/rephist.c
Log:
Fix 0/0 calculation in get_weighted_fractional_uptime().

Modified: tor/trunk/ChangeLog
===================================================================
--- tor/trunk/ChangeLog	2008-09-28 15:42:56 UTC (rev 16993)
+++ tor/trunk/ChangeLog	2008-09-28 15:48:36 UTC (rev 16994)
@@ -66,6 +66,8 @@
       directory writes.  Previously, we had only counted this when we
       had met our limits precisely. Fixes bug 824. Patch from by rovv.
       Bugfix on 0.2.0.x (??).
+    - Avoid a 0/0 calculation when calculating router uptime at directory
+      authorities.  Bugfix on 0.2.0.8-alpha.
 
   o Minor bugfixes (controller):
     - Make DNS resolved events into "CLOSED", not "FAILED".  Bugfix on

Modified: tor/trunk/src/or/rephist.c
===================================================================
--- tor/trunk/src/or/rephist.c	2008-09-28 15:42:56 UTC (rev 16993)
+++ tor/trunk/src/or/rephist.c	2008-09-28 15:48:36 UTC (rev 16994)
@@ -462,6 +462,14 @@
   } else if (hist->start_of_downtime) {
     total += (when - hist->start_of_downtime);
   }
+
+  if (!total) {
+    /* Avoid calling anybody's uptime infinity (which should be impossible if
+     * the code is working), or NaN (which can happen for any router we haven't
+     * observed up or down yet). */
+    return 0.0;
+  }
+
   return ((double) up) / total;
 }