[PATCH] lib/util: fix timespec normalization

[Philipp Gesang]

Hi,

please consider the attached patch.

CI: https://gitlab.com/samba-team/devel/samba/pipelines/43706542

Best,
Philipp

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From 422f5832e1174995e5e0349ad05263f292761fe3 Mon Sep 17 00:00:00 2001
From: Philipp Gesang <philipp.gesang at intra2net.com>
Date: Thu, 17 Jan 2019 11:06:26 +0100
Subject: [PATCH] lib/util: fix timespec normalization

When fixing up timespec structs, negative values for the ns part
should be taken into account. Also, the range for a valid ns part
is [0, 1000000000), not [0, 1000000000].

Signed-off-by: Philipp Gesang <philipp.gesang at intra2net.com>
---
 lib/util/time.c | 27 +++++++++++++++++++--------
 lib/util/time.h |  1 +
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/lib/util/time.c b/lib/util/time.c
index bd067f84e8e..140fe5e8b63 100644
--- a/lib/util/time.c
+++ b/lib/util/time.c
@@ -39,6 +39,7 @@
 #endif
 
 
+#define NSEC_PER_SEC 1000000000
 
 /**
  External access to time_t_min and time_t_max.
@@ -88,10 +89,7 @@ _PUBLIC_ time_t time_mono(time_t *t)
 time_t convert_timespec_to_time_t(struct timespec ts)
 {
 	/* Ensure tv_nsec is less than 1sec. */
-	while (ts.tv_nsec > 1000000000) {
-		ts.tv_sec += 1;
-		ts.tv_nsec -= 1000000000;
-	}
+	normalize_timespec(&ts);
 
 	/* 1 ns == 1,000,000,000 - one thousand millionths of a second.
 	   increment if it's greater than 500 millionth of a second. */
@@ -950,10 +948,7 @@ void round_timespec_to_usec(struct timespec *ts)
 {
 	struct timeval tv = convert_timespec_to_timeval(*ts);
 	*ts = convert_timeval_to_timespec(tv);
-	while (ts->tv_nsec > 1000000000) {
-		ts->tv_sec += 1;
-		ts->tv_nsec -= 1000000000;
-	}
+	normalize_timespec(ts);
 }
 
 /****************************************************************************
@@ -982,3 +977,19 @@ _PUBLIC_ NTTIME unix_timespec_to_nt_time(struct timespec ts)
 
 	return d;
 }
+
+/****************************************************************************
+ Deal with nanoseconds overflow.
+****************************************************************************/
+
+void normalize_timespec(struct timespec *ts)
+{
+	while (ts->tv_nsec >= NSEC_PER_SEC) {
+		++ts->tv_sec;
+		ts->tv_nsec -= NSEC_PER_SEC;
+	}
+	while (ts->tv_nsec < 0) {
+		--ts->tv_sec;
+		ts->tv_nsec += NSEC_PER_SEC;
+	}
+}
diff --git a/lib/util/time.h b/lib/util/time.h
index 1988b330576..2cfa1fa9039 100644
--- a/lib/util/time.h
+++ b/lib/util/time.h
@@ -329,5 +329,6 @@ int timespec_compare(const struct timespec *ts1, const struct timespec *ts2);
 void round_timespec_to_sec(struct timespec *ts);
 void round_timespec_to_usec(struct timespec *ts);
 NTTIME unix_timespec_to_nt_time(struct timespec ts);
+void normalize_timespec(struct timespec *ts);
 
 #endif /* _SAMBA_TIME_H_ */
-- 
2.17.2

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