Hello,
After running ntpd for the first time on a machine with a bad clock, I
got the following in syslog:
ntpd[24277]: adjusting local clock by 369307689.625505s
ntpd[24277]: adjtime failed: Invalid argument
I think adjtime limits its argument to a maximum value. Apparently on
Unix this is 2 hours, and on Linux: (INT_MAX / 1000000 - 2).
If you're interested, below is a patch for 3.9p1 to limit the argument
to adjtime to 2000 seconds, so that it works bit by bit instead of
failing over and over again.
Mansour
diff -uprN openntpd-3.9p1.orig/ntpd.c openntpd-3.9p1/ntpd.c
--- openntpd-3.9p1.orig/ntpd.c 2012-09-17 02:41:45.615802521 -0400
+++ openntpd-3.9p1/ntpd.c 2001-01-03 15:04:58.250151486 -0500
@@ -35,6 +35,7 @@ RCSID("$Release: OpenNTPD "OPENNTPD_VERS
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
+#include <math.h>
#include "ntpd.h"
@@ -332,6 +333,11 @@ ntpd_adjtime(double d)
int synced = 0;
static int firstadj = 1;
+ if (fabs(d) > (double)ADJTIME_MAX) {
+ log_debug("adjusting local clock by %fs (of %fs)",
+ (double)ADJTIME_MAX, d);
+ d = copysign((double)ADJTIME_MAX, d);
+ }
if (d >= (double)LOG_NEGLIGEE / 1000 ||
d <= -1 * (double)LOG_NEGLIGEE / 1000)
log_info("adjusting local clock by %fs", d);
diff -uprN openntpd-3.9p1.orig/ntpd.h openntpd-3.9p1/ntpd.h
--- openntpd-3.9p1.orig/ntpd.h 2012-09-17 02:41:45.575800776 -0400
+++ openntpd-3.9p1/ntpd.h 2012-09-17 02:41:29.084800742 -0400
@@ -59,6 +59,7 @@
#define SETTIME_MIN_OFFSET 180 /* min offset for settime at
start */
#define SETTIME_TIMEOUT 15 /* max seconds to wait with -s
*/
#define LOG_NEGLIGEE 128 /* negligible drift to not log
(ms) */
+#define ADJTIME_MAX 2000
enum client_state {
STATE_NONE,
