From ecef9ffb8afa3c7b20c87642d8e9ae99f9541d79 Mon Sep 17 00:00:00 2001
From: claudio <claudio@openbsd.org>
Date: Thu, 30 Jun 2022 07:42:50 +0000
Subject: [PATCH] Fix interval timers by forcing TZ to UTC, else some strftime
 formats print strange offsets.

While there rework the main loop to only use localtime and now.
Calculate the relative time offset for -m mode just once at startup.
OK sthen@ job@
---
 usr.bin/ts/ts.c | 49 +++++++++++++++++++++----------------------------
 1 file changed, 21 insertions(+), 28 deletions(-)

diff --git a/usr.bin/ts/ts.c b/usr.bin/ts/ts.c
index d2067e48d68..6f0e7be3fab 100644
--- a/usr.bin/ts/ts.c
+++ b/usr.bin/ts/ts.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ts.c,v 1.2 2022/06/29 16:01:10 job Exp $	*/
+/*	$OpenBSD: ts.c,v 1.3 2022/06/30 07:42:50 claudio Exp $	*/
 /*
  * Copyright (c) 2022 Job Snijders <job@openbsd.org>
  * Copyright (c) 2022 Claudio Jeker <claudio@openbsd.org>
@@ -40,8 +40,8 @@ main(int argc, char *argv[])
 {
 	int iflag, mflag, sflag;
 	int ch, prev;
-	struct timespec rstart, start, now, elapsed;
-	struct tm *lt, tm;
+	struct timespec roff, start, now;
+	struct tm *tm;
 	int clock = CLOCK_REALTIME;
 
 	if (pledge("stdio", NULL) == -1)
@@ -88,34 +88,27 @@ main(int argc, char *argv[])
 	if ((outbuf = calloc(1, bufsize)) == NULL)
 		err(1, NULL);
 
-	clock_gettime(CLOCK_REALTIME, &rstart);
-	clock_gettime(CLOCK_MONOTONIC, &start);
+	/* force UTC for interval calculations */
+	if (iflag || sflag)
+		if (setenv("TZ", "UTC", 1) == -1)
+			err(1, "setenv UTC");
+
+	clock_gettime(CLOCK_REALTIME, &roff);
+	clock_gettime(clock, &start);
+	timespecsub(&roff, &start, &roff);
 
 	for (prev = '\n'; (ch = getchar()) != EOF; prev = ch) {
 		if (prev == '\n') {
-			if (clock_gettime(clock, &now))
-				err(1, "clock_gettime");
-			if (iflag || sflag) {
-				timespecsub(&now, &start, &elapsed);
-				if (gmtime_r(&elapsed.tv_sec, &tm) == NULL)
-					err(1, "gmtime_r");
-				if (iflag)
-					if (clock_gettime(clock, &start))
-						err(1, "clock_gettime");
-				fmtfmt(&tm, elapsed.tv_nsec);
-			} else if (mflag) {
-				timespecsub(&now, &start, &elapsed);
-				timespecadd(&rstart, &elapsed, &now);
-				lt = localtime(&now.tv_sec);
-				if (lt == NULL)
-					err(1, "localtime");
-				fmtfmt(lt, now.tv_nsec);
-			} else {
-				lt = localtime(&now.tv_sec);
-				if (lt == NULL)
-					err(1, "localtime");
-				fmtfmt(lt, now.tv_nsec);
-			}
+			clock_gettime(clock, &now);
+			if (iflag || sflag)
+				timespecsub(&now, &start, &now);
+			else if (mflag)
+				timespecadd(&now, &roff, &now);
+			if (iflag)
+				clock_gettime(clock, &start);
+			if ((tm = localtime(&now.tv_sec)) == NULL)
+				err(1, "localtime/gmtime");
+			fmtfmt(tm, now.tv_nsec);
 		}
 		if (putchar(ch) == EOF)
 			break;
-- 
2.20.1