File ntp-sntp-dst.patch of Package ntp

Index: ntp-4.2.8p4/sntp/utilities.c
===================================================================
--- ntp-4.2.8p4.orig/sntp/utilities.c
+++ ntp-4.2.8p4/sntp/utilities.c
@@ -139,34 +139,36 @@ tv_to_str(
 {
 	const size_t bufsize = 48;
 	char *buf;
-	time_t gmt_time, local_time;
-	struct tm *p_tm_local;
+	time_t time_gmt, time_local;
+	struct tm tm_gmt, tm_local;
 	int hh, mm, lto;
 
-	/*
-	 * convert to struct tm in UTC, then intentionally feed
-	 * that tm to mktime() which expects local time input, to
-	 * derive the offset from UTC to local time.
+	/* Get local time, convert it to GMT, adjust the tm_isdst to the
+	 * current local DST value.  Then call mktime which will not adjust
+	 * for DST allowing us to calculate the offset from local to GMT
 	 */
-	gmt_time = tv->tv_sec;
-	local_time = mktime(gmtime(&gmt_time));
-	p_tm_local = localtime(&gmt_time);
+	time_gmt = tv->tv_sec;
+	localtime_r(&time_gmt, &tm_local);
+	time_local = mktime(&tm_local);
+	gmtime_r(&time_local, &tm_gmt);
+	tm_gmt.tm_isdst=tm_local.tm_isdst;
+	time_gmt = mktime(&tm_gmt);
 
 	/* Local timezone offsets should never cause an overflow.  Yeah. */
-	lto = difftime(local_time, gmt_time);
+	lto = difftime(time_local, time_gmt);
 	lto /= 60;
 	hh = lto / 60;
 	mm = abs(lto % 60);
 
-	buf = emalloc(bufsize);
+	buf = malloc(bufsize);
 	snprintf(buf, bufsize,
 		 "%d-%.2d-%.2d %.2d:%.2d:%.2d.%.6d (%+03d%02d)",
-		 p_tm_local->tm_year + 1900,
-		 p_tm_local->tm_mon + 1,
-		 p_tm_local->tm_mday,
-		 p_tm_local->tm_hour,
-		 p_tm_local->tm_min,
-		 p_tm_local->tm_sec,
+		 tm_local.tm_year + 1900,
+		 tm_local.tm_mon + 1,
+		 tm_local.tm_mday,
+		 tm_local.tm_hour,
+		 tm_local.tm_min,
+		 tm_local.tm_sec,
 		 (int)tv->tv_usec,
 		 hh,
 		 mm);