Your message dated Mon, 28 Dec 2020 00:17:22 +0100
with message-id <[email protected]>
and subject line Re: Bug#528968: hwclock: pay attention to ongoing correction
has caused the Debian Bug report #528968,
regarding hwclock: pay attention to ongoing correction
to be marked as done.
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--
528968: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=528968
Debian Bug Tracking System
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--- Begin Message ---
Package: util-linux
Version: 2.13.1.1-1
Severity: normal
Tags: patch
Hi,
when comparing with or setting the hardware clock hwclock should pay
attention to an ongoing correction. If the outstanding correction of the
system clock is more than a second, hwclock may calculate a wrong drift
of the hardware clock.
Bye, Jörg.
-- System Information:
Debian Release: unstable/experimental
APT prefers unstable
APT policy: (900, 'unstable'), (700, 'experimental')
Architecture: powerpc (ppc)
Kernel: Linux 2.6.29
Locale: LANG=C, LC_CTYPE=C (charmap=UTF-8) (ignored: LC_ALL set to de_DE.UTF-8)
Shell: /bin/sh linked to /bin/dash
Versions of packages util-linux depends on:
ii libc6 2.9-12 GNU C Library: Shared libraries
ii libncurses5 5.7+20090510-1 shared libraries for terminal hand
ii libselinux1 2.0.71-1 SELinux shared libraries
ii libslang2 2.1.4-3 The S-Lang programming library - r
ii libuuid1 1.41.5-1 universally unique id library
ii lsb-base 3.2-22 Linux Standard Base 3.2 init scrip
ii tzdata 2009g-1 time zone and daylight-saving time
ii zlib1g 1:1.2.3.3.dfsg-13 compression library - runtime
util-linux recommends no packages.
Versions of packages util-linux suggests:
ii dosfstools 3.0.2-1 utilities for making and checking
ii kbd 1.15-1 Linux console font and keytable ut
pn util-linux-locales <none> (no description available)
-- no debconf information
--- hwclock.c+ 2009-05-16 18:49:20.931695536 +0200
+++ hwclock.c 2009-05-16 19:49:42.411706841 +0200
@@ -490,6 +490,26 @@
}
+static int
+gettimeofday_with_adjtime(struct timeval *tv, struct timezone *tz) {
+ struct timeval ongoing_correction;
+
+ const int rc = gettimeofday(tv, tz);
+ if (rc)
+ return rc;
+
+ if ( !adjtime(NULL, &ongoing_correction) ) {
+ tv->tv_sec += ongoing_correction.tv_sec;
+ tv->tv_usec += ongoing_correction.tv_usec;
+ if (tv->tv_usec >= 1000000) {
+ ++tv->tv_sec;
+ tv->tv_usec -= 1000000;
+ }
+ }
+
+ return rc;
+}
+
static void
set_hardware_clock_exact(const time_t sethwtime,
@@ -519,7 +539,7 @@
struct timeval beginsystime, nowsystime;
time_resync:
- gettimeofday(&beginsystime, NULL);
+ gettimeofday_with_adjtime(&beginsystime, NULL);
newhwtime = sethwtime + (int) time_diff(beginsystime, refsystime) + 1;
if (debug)
printf(_("Time elapsed since reference time has been %.6f seconds.\n"
@@ -534,7 +554,7 @@
*/
do {
float tdiff;
- gettimeofday(&nowsystime, NULL);
+ gettimeofday_with_adjtime(&nowsystime, NULL);
tdiff = time_diff(nowsystime, beginsystime);
if (tdiff < 0)
goto time_resync; /* probably time was reset */
@@ -1092,7 +1112,7 @@
Defined only if hclock_valid is true.
*/
- gettimeofday(&read_time, NULL);
+ gettimeofday_with_adjtime(&read_time, NULL);
read_hardware_clock(universal, &hclock_valid, &hclocktime);
if (show) {
@@ -1112,7 +1132,7 @@
time, so we set it with reference to the most recent
whole seconds time.
*/
- gettimeofday(&nowtime, NULL);
+ gettimeofday_with_adjtime(&nowtime, NULL);
reftime.tv_sec = nowtime.tv_sec;
reftime.tv_usec = 0;
@@ -1315,7 +1335,7 @@
char *date_opt;
/* Remember what time we were invoked */
- gettimeofday(&startup_time, NULL);
+ gettimeofday_with_adjtime(&startup_time, NULL);
#ifdef HAVE_LIBAUDIT
hwaudit_fd = audit_open();
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--- End Message ---
--- Begin Message ---
* Jörg Sommer <[email protected]> [201227 23:16]:
> when comparing with or setting the hardware clock hwclock should pay
> attention to an ongoing correction. If the outstanding correction of the
> system clock is more than a second, hwclock may calculate a wrong drift
> of the hardware clock.
hwclock(8) documents quite clearly that hwclock --systohc requires
that nothing else except hwclock modifies the hardware clock. I
believe this includes any drift adjustments.
Chris
--- End Message ---
