fix ts2phc to correctly handle leap seconds (RHEL-54721)

Resolves: RHEL-54721

linuxptp-nmealeap.patch

@@ -0,0 +1,80 @@
+commit a3d3f4687f25688140f5a391b437af1dca8e0d5c
+Author: Miroslav Lichvar <mlichvar@redhat.com>
+Date:   Tue Jun 11 16:17:37 2024 +0200
+
+    nmea: Fix conversion of leap second.
+    
+    When a leap second is inserted, the RMC message reports time of
+    23:59:60, which overflows in mktime() to 0:00:00 after the leap second
+    with an incremented TAI-UTC offset. This causes a one-second error in
+    the offset meaured by ts2phc.
+    
+    Check the seconds field of the RMC message and convert 60 to 59 to make
+    the timestamp ambiguous per is_utc_ambiguous() and ignored by ts2phc to
+    avoid updating the clock with the one-second error.
+    
+    Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
+    Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
+
+diff --git a/nmea.c b/nmea.c
+index 7f1d9a2..b84b42e 100644
+--- a/nmea.c
++++ b/nmea.c
+@@ -155,6 +155,9 @@ static int nmea_scan_rmc(struct nmea_parser *np, struct nmea_rmc *result)
+ 	if (cnt != 3) {
+ 		return -1;
+ 	}
++	/* Convert an inserted leap second to ambiguous 23:59:59 */
++	if (tm.tm_sec == 60)
++		tm.tm_sec = 59;
+ 	tm.tm_year += 100;
+ 	tm.tm_mon--;
+ 	tm.tm_isdst = 0;
+
+commit 6dcb8eda9fa7b2e3d486a3903c5c7b2568b30605
+Author: Miroslav Lichvar <mlichvar@redhat.com>
+Date:   Tue Jun 11 16:17:38 2024 +0200
+
+    ts2phc: Fix timestamp conversion for leap seconds.
+    
+    The UTC timestamp parsed from the RMC message needs to be converted to
+    TAI in order to calculate the PHC offset. This conversion was done after
+    adjusting the timestamp for the measured delay between the reception of
+    the message and the following pulse, which caused the offset measured by
+    ts2phc to have a one-second error if the message expected during or
+    after a leap second was missed.
+    
+    Apply the TAI-UTC offset to the timestamp parsed from the RMC message
+    before any adjustments are made to avoid the error.
+    
+    Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
+    Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
+
+diff --git a/ts2phc_nmea_pps_source.c b/ts2phc_nmea_pps_source.c
+index 3385e39..e345969 100644
+--- a/ts2phc_nmea_pps_source.c
++++ b/ts2phc_nmea_pps_source.c
+@@ -187,11 +187,9 @@ static int ts2phc_nmea_pps_source_getppstime(struct ts2phc_pps_source *src,
+ 		pr_err("nmea: rmc time stamp stale");
+ 		return -1;
+ 	}
+-	rmc = tmv_add(rmc, duration_since_rmc);
+-	rmc = tmv_add(rmc, m->delay_correction);
++
+ 	utc_time = tmv_to_nanoseconds(rmc);
+ 	utc_time /= (int64_t) 1000000000;
+-	*ts = tmv_to_timespec(rmc);
+ 
+ 	result = lstab_utc2tai(m->lstab, utc_time, &tai_offset);
+ 	switch (result) {
+@@ -208,6 +206,10 @@ static int ts2phc_nmea_pps_source_getppstime(struct ts2phc_pps_source *src,
+ 		pr_err("nmea: utc time stamp is ambiguous");
+ 		break;
+ 	}
++
++	rmc = tmv_add(rmc, duration_since_rmc);
++	rmc = tmv_add(rmc, m->delay_correction);
++	*ts = tmv_to_timespec(rmc);
+ 	ts->tv_sec += tai_offset;
+ 
+ 	return lstab_error;

linuxptp.spec

@@ -35,6 +35,8 @@ Patch2:		linuxptp-holdover.patch
 Patch3:		linuxptp-nmeareset.patch
 # fix ts2phc to handle large NMEA delay
 Patch4:		linuxptp-nmeadelay.patch
+# fix ts2phc to correctly handle leap seconds
+Patch5:		linuxptp-nmealeap.patch
 
 BuildRequires:	gcc gcc-c++ gnutls-devel make systemd