[chrony-dev] [PATCH] Honour leap second flag in the PPS refclock

["Hattink, Tjalling [FINT]" <T.Hattink@xxxxxxxx>]

This patch fixes leap second handling for the PPS refclock. Without the
patch the PPS refclock will
always report LEAP_normal. But if a locked refclock (the SHM clock in my
case) does report a leap
state it should also be taken over by the PPS refclock, otherwise chrony
will still use LEAP_normal
when the PPS clock is used as reference source.

The patch will copy the leap state from the refclock. In case the PPS
clock is not specifically
locked to another refclock it will take over the leap state from the
local clock.

I've tested this patch by simulating a leap second through the samples
for the SHM clock, and with
the patch you will see chrony properly jump forward or backward on the
leap second. Without the
patch it will not do this and the clock becomes desynchronized and no
leap state is reported
upstream to other NTP clients.

Signed-off-by: Tjalling Hattink <t.hattink@xxxxxxxx>
---
 refclock.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/refclock.c b/refclock.c
index c9618aa..ae8134e 100644
--- a/refclock.c
+++ b/refclock.c
@@ -385,7 +385,9 @@ RCL_AddPulse(RCL_Instance instance, struct timeval
*pulse_time, double second)
   double correction, dispersion, offset;
   struct timeval cooked_time;
   int rate;
+  NTP_Leap leap;
 
+  leap = LEAP_Normal;
   LCL_GetOffsetCorrection(pulse_time, &correction, &dispersion);
   UTI_AddDoubleToTimeval(pulse_time, correction, &cooked_time);
   dispersion += instance->precision +
filter_get_avg_sample_dispersion(&instance->filter);
@@ -436,13 +438,14 @@ RCL_AddPulse(RCL_Instance instance, struct timeval
*pulse_time, double second)
       return 0;
     }
 
+    leap = refclocks[instance->lock_ref].leap_status;
+
     DEBUG_LOG(LOGF_Refclock, "refclock pulse second=%.9f offset=%.9f
offdiff=%.9f samplediff=%.9f",
         second, offset, ref_offset - offset, sample_diff);
   } else {
     struct timeval ref_time;
     int is_synchronised, stratum;
     double root_delay, root_dispersion, distance;
-    NTP_Leap leap;
     uint32_t ref_id;
 
     /* Ignore the pulse if we are not well synchronized */
@@ -461,7 +464,7 @@ RCL_AddPulse(RCL_Instance instance, struct timeval
*pulse_time, double second)
   }
 
   filter_add_sample(&instance->filter, &cooked_time, offset,
dispersion);
-  instance->leap_status = LEAP_Normal;
+  instance->leap_status = leap;
   instance->pps_active = 1;
 
   log_sample(instance, &cooked_time, 0, 1, offset + correction -
instance->offset, offset, dispersion);
-- 
1.9.1


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