lstab: Add LSTAB_EXPIRED result

LSTAB_UNKNOWN is too generic, add LSTAB_EXPIRED result to return the latest lstab correction and indicate that the tab used to resolve it is expired. This is useful for more precise reporting of lstab file state and will enable an override of expired table. Signed-off-by: Maciek Machnikowski <[email protected]> Reviewed-by: Jacob Keller <[email protected]> Signed-off-by: Maciek Machnikowski <[email protected]>
lichenAAA · Feb 12, 2023 · 30d1db5 · 30d1db5
1 parent b2ef98f
commit 30d1db5
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Showing 3 changed files with 15 additions and 7 deletions.
diff --git a/lstab.c b/lstab.c
@@ -182,10 +182,6 @@ enum lstab_result lstab_utc2tai(struct lstab *lstab, uint64_t utctime,
 {
 	int epoch = -1, index, next;
 
-	if (utctime > lstab->expiration_utc) {
-		return LSTAB_UNKNOWN;
-	}
-
 	for (index = lstab->length - 1; index > -1; index--) {
 		if (utctime >= lstab->lstab[index].utc) {
 			epoch = index;
@@ -203,5 +199,10 @@ enum lstab_result lstab_utc2tai(struct lstab *lstab, uint64_t utctime,
 	if (next < lstab->length && utctime == lstab->lstab[next].utc - 1) {
 		return LSTAB_AMBIGUOUS;
 	}
+
+	if (utctime > lstab->expiration_utc) {
+		return LSTAB_EXPIRED;
+	}
+
 	return LSTAB_OK;
 }
diff --git a/lstab.h b/lstab.h
@@ -41,6 +41,12 @@ enum lstab_result {
 	 */
 	LSTAB_UNKNOWN,
 
+	/**
+	 * The given lstab is past its expiry date and the tai_offset return
+	 * value may not be correct.
+	 */
+	LSTAB_EXPIRED,
+
 	/**
 	 * The given UTC value is ambiguous.  The corresponding TAI time is either
 	 *

diff --git a/ts2phc_nmea_pps_source.c b/ts2phc_nmea_pps_source.c
@@ -188,7 +188,7 @@ static int ts2phc_nmea_pps_source_getppstime(struct ts2phc_pps_source *src,
 	struct ts2phc_nmea_pps_source *m =
 		container_of(src, struct ts2phc_nmea_pps_source, pps_source);
 	tmv_t delay_t1, delay_t2, duration_since_rmc, local_t1, local_t2, rmc;
-	int lstab_error = 0, tai_offset = 0;
+	int lstab_error = -1, tai_offset = 0;
 	enum lstab_result result;
 	struct timespec now;
 	int64_t utc_time;
@@ -237,11 +237,12 @@ static int ts2phc_nmea_pps_source_getppstime(struct ts2phc_pps_source *src,
 		break;
 	case LSTAB_UNKNOWN:
 		pr_err("nmea: unable to find utc time in leap second table");
-		lstab_error = -1;
+		break;
+	case LSTAB_EXPIRED:
+		pr_err("nmea: utc time is past leap second table expiry date");
 		break;
 	case LSTAB_AMBIGUOUS:
 		pr_err("nmea: utc time stamp is ambiguous");
-		lstab_error = -1;
 		break;
 	}
 	ts->tv_sec += tai_offset;