diff mbox

[2/4] batctl: Use monotonic time source for icmp timing

Message ID 1468961051-6447-2-git-send-email-sven@narfation.org (mailing list archive)
State Accepted, archived
Delegated to: Sven Eckelmann
Headers

Commit Message

Sven Eckelmann July 19, 2016, 8:44 p.m. UTC 
  gettimeofday is not monotonic. It would give wrong results in some
situation like leap seconds, when switching between daylight saving time
and non-DST, NTP changes the time or when the administrator of the system
changes it manually. The function is also obsolete since POSIX.1-2008.

clock_gettime is recommended to get a monotonic timesource and as general
replacement of gettimeofday.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 Makefile    |  2 +-
 functions.c | 17 +++++++++--------
 2 files changed, 10 insertions(+), 9 deletions(-)

Comments

Sven Eckelmann Oct. 18, 2016, 12:25 p.m. UTC | #1 
On Dienstag, 19. Juli 2016 22:44:09 CEST Sven Eckelmann wrote:
> gettimeofday is not monotonic. It would give wrong results in some
> situation like leap seconds, when switching between daylight saving time
> and non-DST, NTP changes the time or when the administrator of the system
> changes it manually. The function is also obsolete since POSIX.1-2008.
> 
> clock_gettime is recommended to get a monotonic timesource and as general
> replacement of gettimeofday.
> 
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
>  Makefile    |  2 +-
>  functions.c | 17 +++++++++--------
>  2 files changed, 10 insertions(+), 9 deletions(-)

Applied in ef7cfaa81f72292f67afe50303ac657f41280853 [1].

Kind regards,
	Sven

[1] https://git.open-mesh.org/batctl.git/commit/ef7cfaa81f72292f67afe50303ac657f41280853
diff mbox

Patch

diff --git a/Makefile b/Makefile
index e980587..57d9a4e 100755
--- a/Makefile
+++ b/Makefile
@@ -46,7 +46,7 @@  MANPAGE = man/batctl.8
 # batctl flags and options
 CFLAGS += -Wall -W -std=gnu99 -fno-strict-aliasing -MD -MP
 CPPFLAGS += -D_GNU_SOURCE
-LDLIBS += -lm
+LDLIBS += -lm -lrt
 
 # disable verbose output
 ifneq ($(findstring $(MAKEFLAGS),s),s)
diff --git a/functions.c b/functions.c
index f9feca4..bc4f9f8 100644
--- a/functions.c
+++ b/functions.c
@@ -48,6 +48,7 @@ 
 #include <netlink/handlers.h>
 #include <netlink/msg.h>
 #include <netlink/attr.h>
+#include <time.h>
 
 #include "main.h"
 #include "functions.h"
@@ -59,7 +60,7 @@ 
 
 #define PATH_BUFF_LEN 200
 
-static struct timeval start_time;
+static struct timespec start_time;
 static char *host_name;
 char *line_ptr = NULL;
 
@@ -80,23 +81,23 @@  const char *fs_compile_out_param[] = {
 
 void start_timer(void)
 {
-	gettimeofday(&start_time, NULL);
+	clock_gettime(CLOCK_MONOTONIC, &start_time);
 }
 
 double end_timer(void)
 {
-	struct timeval end_time, diff;
+	struct timespec end_time, diff;
 
-	gettimeofday(&end_time, NULL);
+	clock_gettime(CLOCK_MONOTONIC, &end_time);
 	diff.tv_sec = end_time.tv_sec - start_time.tv_sec;
-	diff.tv_usec = end_time.tv_usec - start_time.tv_usec;
+	diff.tv_nsec = end_time.tv_nsec - start_time.tv_nsec;
 
-	if (diff.tv_usec < 0) {
+	if (diff.tv_nsec < 0) {
 		diff.tv_sec--;
-		diff.tv_usec += 1000000;
+		diff.tv_nsec += 1000000000;
 	}
 
-	return (((double)diff.tv_sec * 1000) + ((double)diff.tv_usec / 1000));
+	return (((double)diff.tv_sec * 1000) + ((double)diff.tv_nsec / 1000000));
 }
 
 char *ether_ntoa_long(const struct ether_addr *addr)