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sys_solaris: disable kernel dosynctodr

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The dosynctodr kernel variable needs to be set to 0 to block automatic
synchronization of the system clock to the hardware clock. chronyd used
to disable dosynctodr on Solaris versions before 2.6, but it seems it is
now needed even on current versions as the clock driver sets frequency
only without calling adjtime() or setting the ntp_adjtime() PLL offset.

This issue was reproduced and fix tested on current OpenIndiana.

Fixes: 8feb37df2b ("sys_solaris: use timex driver")
This commit is contained in:
Miroslav Lichvar 2021-12-07 11:32:54 +01:00
parent 264957a443
commit ebc610fcb3
2 changed files with 32 additions and 1 deletions
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2
configure vendored
View file

@ -467,7 +467,7 @@ case $OPERATINGSYSTEM in
;;
SunOS)
EXTRA_OBJECTS="sys_generic.o sys_solaris.o sys_timex.o sys_posix.o"
LIBS="$LIBS -lsocket -lnsl -lresolv"
LIBS="$LIBS -lsocket -lnsl -lkvm -lelf -lresolv"
try_setsched=1
try_lockmem=1
add_def SOLARIS

31
sys_solaris.c
View file

@ -28,16 +28,47 @@
#include "sysincl.h"
#include "logging.h"
#include "privops.h"
#include "sys_solaris.h"
#include "sys_timex.h"
#include "util.h"
#include <kvm.h>
#include <nlist.h>
/* ================================================== */
static void
set_dosynctodr(int on_off)
{
struct nlist nl[] = { {"dosynctodr"}, {NULL} };
kvm_t *kt;
kt = kvm_open(NULL, NULL, NULL, O_RDWR, NULL);
if (!kt)
LOG_FATAL("Could not open kvm");
if (kvm_nlist(kt, nl) < 0 || !nl[0].n_value)
LOG_FATAL("Could not get dosynctodr address");
if (kvm_kwrite(kt, nl[0].n_value, &on_off, sizeof (on_off)) < 0)
LOG_FATAL("Could not write to dosynctodr");
kvm_close(kt);
}
/* ================================================== */
void
SYS_Solaris_Initialise(void)
{
/* The kernel keeps the system clock and hardware clock synchronised to each
other. The dosynctodr variable needs to be set to zero to prevent the
the system clock from following the hardware clock when the system clock
is not adjusted by adjtime() or ntp_adjtime(modes=MOD_OFFSET). */
set_dosynctodr(0);
/* The kernel allows the frequency to be set in the full range off int32_t */
SYS_Timex_InitialiseWithFunctions(32500, 1.0 / 100, NULL, NULL, NULL,
0.0, 0.0, NULL, NULL);