[MEDIUM] implement a monotonic internal clock
If the system date is set backwards while haproxy is running,
some scheduled events are delayed by the amount of time the
clock went backwards. This is particularly problematic on
systems where the date is set at boot, because it seldom
happens that health-checks do not get sent for a few hours.
Before switching to use clock_gettime() on systems which
provide it, we can at least ensure that the clock is not
going backwards and maintain two clocks : the "date" which
represents what the user wants to see (mostly for logs),
and an internal date stored in "now", used for scheduled
events.
diff --git a/include/common/time.h b/include/common/time.h
index 2a4a142..d615526 100644
--- a/include/common/time.h
+++ b/include/common/time.h
@@ -2,7 +2,7 @@
include/common/time.h
Time calculation functions and macros.
- Copyright (C) 2000-2007 Willy Tarreau - w@1wt.eu
+ Copyright (C) 2000-2008 Willy Tarreau - w@1wt.eu
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
@@ -49,7 +49,8 @@
#define MINTIME(old, new) (((new)<0)?(old):(((old)<0||(new)<(old))?(new):(old)))
#define SETNOW(a) (*a=now)
-extern struct timeval now; /* the current date at any moment */
+extern struct timeval now; /* internal date is a monotonic function of real clock */
+extern struct timeval date; /* the real current date */
extern struct timeval start_date; /* the process's start date */
@@ -83,13 +84,19 @@
return tv;
}
+/* tv_now_mono: sets <date> to the current time (wall clock), <mono> to a value
+ * following a monotonic function, and applies any required correction if the
+ * time goes backwards. Note that while we could improve it a bit by checking
+ * that the new date is not too far in the future, it is not much necessary to
+ * do so.
+ */
+REGPRM2 struct timeval *tv_now_mono(struct timeval *mono, struct timeval *wall);
+
/*
* sets a struct timeval to its highest value so that it can never happen
* note that only tv_usec is necessary to detect it since a tv_usec > 999999
* is normally not possible.
- *
*/
-
REGPRM1 static inline struct timeval *tv_eternity(struct timeval *tv)
{
tv->tv_sec = tv->tv_usec = TV_ETERNITY;