/*
chronyd/chronyc - Programs for keeping computer clocks accurate.
**********************************************************************
* Copyright (C) Richard P. Curnow 1997-2003
* Copyright (C) Miroslav Lichvar 2011, 2014-2015
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
**********************************************************************
=======================================================================
The routines in this file present a common local (system) clock
interface to the rest of the software.
They interface with the system specific driver files in sys_*.c
*/
#include "config.h"
#include "sysincl.h"
#include "conf.h"
#include "local.h"
#include "localp.h"
#include "memory.h"
#include "smooth.h"
#include "util.h"
#include "logging.h"
/* ================================================== */
/* Variable to store the current frequency, in ppm */
static double current_freq_ppm;
/* Maximum allowed frequency, in ppm */
static double max_freq_ppm;
/* Temperature compensation, in ppm */
static double temp_comp_ppm;
/* ================================================== */
/* Store the system dependent drivers */
static lcl_ReadFrequencyDriver drv_read_freq;
static lcl_SetFrequencyDriver drv_set_freq;
static lcl_AccrueOffsetDriver drv_accrue_offset;
static lcl_ApplyStepOffsetDriver drv_apply_step_offset;
static lcl_OffsetCorrectionDriver drv_offset_convert;
static lcl_SetLeapDriver drv_set_leap;
static lcl_SetSyncStatusDriver drv_set_sync_status;
/* ================================================== */
/* Types and variables associated with handling the parameter change
list */
typedef struct _ChangeListEntry {
struct _ChangeListEntry *next;
struct _ChangeListEntry *prev;
LCL_ParameterChangeHandler handler;
void *anything;
} ChangeListEntry;
static ChangeListEntry change_list;
/* ================================================== */
/* Types and variables associated with handling the parameter change
list */
typedef struct _DispersionNotifyListEntry {
struct _DispersionNotifyListEntry *next;
struct _DispersionNotifyListEntry *prev;
LCL_DispersionNotifyHandler handler;
void *anything;
} DispersionNotifyListEntry;
static DispersionNotifyListEntry dispersion_notify_list;
/* ================================================== */
static int precision_log;
static double precision_quantum;
static double max_clock_error;
/* ================================================== */
/* Define the number of increments of the system clock that we want
to see to be fairly sure that we've got something approaching
the minimum increment. Even on a crummy implementation that can't
interpolate between 10ms ticks, we should get this done in
under 1s of busy waiting. */
#define NITERS 100
#define NSEC_PER_SEC 1000000000
static void
calculate_sys_precision(void)
{
struct timespec ts, old_ts;
int iters, diff, best;
LCL_ReadRawTime(&old_ts);
/* Assume we must be better than a second */
best = NSEC_PER_SEC;
iters = 0;
do {
LCL_ReadRawTime(&ts);
diff = NSEC_PER_SEC * (ts.tv_sec - old_ts.tv_sec) + (ts.tv_nsec - old_ts.tv_nsec);
old_ts = ts;
if (diff > 0) {
if (diff < best)
best = diff;
iters++;
}
} while (iters < NITERS);
assert(best > 0);
precision_quantum = 1.0e-9 * best;
/* Get rounded log2 value of the measured precision */
precision_log = 0;
while (best < 707106781) {
precision_log--;
best *= 2;
}
assert(precision_log >= -30);
DEBUG_LOG("Clock precision %.9f (%d)", precision_quantum, precision_log);
}
/* ================================================== */
void
LCL_Initialise(void)
{
change_list.next = change_list.prev = &change_list;
dispersion_notify_list.next = dispersion_notify_list.prev = &dispersion_notify_list;
/* Null out the system drivers, so that we die
if they never get defined before use */
drv_read_freq = NULL;
drv_set_freq = NULL;
drv_accrue_offset = NULL;
drv_offset_convert = NULL;
/* This ought to be set from the system driver layer */
current_freq_ppm = 0.0;
temp_comp_ppm = 0.0;
calculate_sys_precision();
/* This is the maximum allowed frequency offset in ppm, the time must
never stop or run backwards */
max_freq_ppm = CNF_GetMaxDrift();
max_freq_ppm = CLAMP(0.0, max_freq_ppm, 500000.0);
max_clock_error = CNF_GetMaxClockError() * 1e-6;
}
/* ================================================== */
void
LCL_Finalise(void)
{
while (change_list.next != &change_list)
LCL_RemoveParameterChangeHandler(change_list.next->handler,
change_list.next->anything);
while (dispersion_notify_list.next != &dispersion_notify_list)
LCL_RemoveDispersionNotifyHandler(dispersion_notify_list.next->handler,
dispersion_notify_list.next->anything);
}
/* ================================================== */
/* Routine to read the system precision as a log to base 2 value. */
int
LCL_GetSysPrecisionAsLog(void)
{
return precision_log;
}
/* ================================================== */
/* Routine to read the system precision in terms of the actual time step */
double
LCL_GetSysPrecisionAsQuantum(void)
{
return precision_quantum;
}
/* ================================================== */
double
LCL_GetMaxClockError(void)
{
return max_clock_error;
}
/* ================================================== */
void
LCL_AddParameterChangeHandler(LCL_ParameterChangeHandler handler, void *anything)
{
ChangeListEntry *ptr, *new_entry;
/* Check that the handler is not already registered */
for (ptr = change_list.next; ptr != &change_list; ptr = ptr->next) {
if (!(ptr->handler != handler || ptr->anything != anything)) {
assert(0);
}
}
new_entry = MallocNew(ChangeListEntry);
new_entry->handler = handler;
new_entry->anything = anything;
/* Chain it into the list */
new_entry->next = &change_list;
new_entry->prev = change_list.prev;
change_list.prev->next = new_entry;
change_list.prev = new_entry;
}
/* ================================================== */
/* Remove a handler */
void LCL_RemoveParameterChangeHandler(LCL_ParameterChangeHandler handler, void *anything)
{
ChangeListEntry *ptr;
int ok;
ptr = NULL;
ok = 0;
for (ptr = change_list.next; ptr != &change_list; ptr = ptr->next) {
if (ptr->handler == handler && ptr->anything == anything) {
ok = 1;
break;
}
}
assert(ok);
/* Unlink entry from the list */
ptr->next->prev = ptr->prev;
ptr->prev->next = ptr->next;
Free(ptr);
}
/* ================================================== */
int
LCL_IsFirstParameterChangeHandler(LCL_ParameterChangeHandler handler)
{
return change_list.next->handler == handler;
}
/* ================================================== */
static void
invoke_parameter_change_handlers(struct timespec *raw, struct timespec *cooked,
double dfreq, double doffset,
LCL_ChangeType change_type)
{
ChangeListEntry *ptr;
for (ptr = change_list.next; ptr != &change_list; ptr = ptr->next) {
(ptr->handler)(raw, cooked, dfreq, doffset, change_type, ptr->anything);
}
}
/* ================================================== */
void
LCL_AddDispersionNotifyHandler(LCL_DispersionNotifyHandler handler, void *anything)
{
DispersionNotifyListEntry *ptr, *new_entry;
/* Check that the handler is not already registered */
for (ptr = dispersion_notify_list.next; ptr != &dispersion_notify_list; ptr = ptr->next) {
if (!(ptr->handler != handler || ptr->anything != anything)) {
assert(0);
}
}
new_entry = MallocNew(DispersionNotifyListEntry);
new_entry->handler = handler;
new_entry->anything = anything;
/* Chain it into the list */
new_entry->next = &dispersion_notify_list;
new_entry->prev = dispersion_notify_list.prev;
dispersion_notify_list.prev->next = new_entry;
dispersion_notify_list.prev = new_entry;
}
/* ================================================== */
/* Remove a handler */
extern
void LCL_RemoveDispersionNotifyHandler(LCL_DispersionNotifyHandler handler, void *anything)
{
DispersionNotifyListEntry *ptr;
int ok;
ptr = NULL;
ok = 0;
for (ptr = dispersion_notify_list.next; ptr != &dispersion_notify_list; ptr = ptr->next) {
if (ptr->handler == handler && ptr->anything == anything) {
ok = 1;
break;
}
}
assert(ok);
/* Unlink entry from the list */
ptr->next->prev = ptr->prev;
ptr->prev->next = ptr->next;
Free(ptr);
}
/* ================================================== */
void
LCL_ReadRawTime(struct timespec *ts)
{
#if HAVE_CLOCK_GETTIME
if (clock_gettime(CLOCK_REALTIME, ts) < 0)
LOG_FATAL("clock_gettime() failed : %s", strerror(errno));
#else
struct timeval tv;
if (gettimeofday(&tv, NULL) < 0)
LOG_FATAL("gettimeofday() failed : %s", strerror(errno));
UTI_TimevalToTimespec(&tv, ts);
#endif
}
/* ================================================== */
void
LCL_ReadCookedTime(struct timespec *result, double *err)
{
struct timespec raw;
LCL_ReadRawTime(&raw);
LCL_CookTime(&raw, result, err);
}
/* ================================================== */
void
LCL_CookTime(struct timespec *raw, struct timespec *cooked, double *err)
{
double correction;
LCL_GetOffsetCorrection(raw, &correction, err);
UTI_AddDoubleToTimespec(raw, correction, cooked);
}
/* ================================================== */
void
LCL_GetOffsetCorrection(struct timespec *raw, double *correction, double *err)
{
/* Call system specific driver to get correction */
(*drv_offset_convert)(raw, correction, err);
}
/* ================================================== */
/* Return current frequency */
double
LCL_ReadAbsoluteFrequency(void)
{
double freq;
freq = current_freq_ppm;
/* Undo temperature compensation */
if (temp_comp_ppm != 0.0) {
freq = (freq + temp_comp_ppm) / (1.0 - 1.0e-6 * temp_comp_ppm);
}
return freq;
}
/* ================================================== */
static double
clamp_freq(double freq)
{
if (freq <= max_freq_ppm && freq >= -max_freq_ppm)
return freq;
LOG(LOGS_WARN, "Frequency %.1f ppm exceeds allowed maximum", freq);
return CLAMP(-max_freq_ppm, freq, max_freq_ppm);
}
/* ================================================== */
static int
check_offset(struct timespec *now, double offset)
{
/* Check if the time will be still sane with accumulated offset */
if (UTI_IsTimeOffsetSane(now, -offset))
return 1;
LOG(LOGS_WARN, "Adjustment of %.1f seconds is invalid", -offset);
return 0;
}
/* ================================================== */
/* This involves both setting the absolute frequency with the
system-specific driver, as well as calling all notify handlers */
void
LCL_SetAbsoluteFrequency(double afreq_ppm)
{
struct timespec raw, cooked;
double dfreq;
afreq_ppm = clamp_freq(afreq_ppm);
/* Apply temperature compensation */
if (temp_comp_ppm != 0.0) {
afreq_ppm = afreq_ppm * (1.0 - 1.0e-6 * temp_comp_ppm) - temp_comp_ppm;
}
/* Call the system-specific driver for setting the frequency */
afreq_ppm = (*drv_set_freq)(afreq_ppm);
dfreq = (afreq_ppm - current_freq_ppm) / (1.0e6 - current_freq_ppm);
LCL_ReadRawTime(&raw);
LCL_CookTime(&raw, &cooked, NULL);
/* Dispatch to all handlers */
invoke_parameter_change_handlers(&raw, &cooked, dfreq, 0.0, LCL_ChangeAdjust);
current_freq_ppm = afreq_ppm;
}
/* ================================================== */
void
LCL_AccumulateDeltaFrequency(double dfreq)
{
struct timespec raw, cooked;
double old_freq_ppm;
old_freq_ppm = current_freq_ppm;
/* Work out new absolute frequency. Note that absolute frequencies
are handled in units of ppm, whereas the 'dfreq' argument is in
terms of the gradient of the (offset) v (local time) function. */
current_freq_ppm += dfreq * (1.0e6 - current_freq_ppm);
current_freq_ppm = clamp_freq(current_freq_ppm);
/* Call the system-specific driver for setting the frequency */
current_freq_ppm = (*drv_set_freq)(current_freq_ppm);
dfreq = (current_freq_ppm - old_freq_ppm) / (1.0e6 - old_freq_ppm);
LCL_ReadRawTime(&raw);
LCL_CookTime(&raw, &cooked, NULL);
/* Dispatch to all handlers */
invoke_parameter_change_handlers(&raw, &cooked, dfreq, 0.0, LCL_ChangeAdjust);
}
/* ================================================== */
void
LCL_AccumulateOffset(double offset, double corr_rate)
{
struct timespec raw, cooked;
/* In this case, the cooked time to be passed to the notify clients
has to be the cooked time BEFORE the change was made */
LCL_ReadRawTime(&raw);
LCL_CookTime(&raw, &cooked, NULL);
if (!check_offset(&cooked, offset))
return;
(*drv_accrue_offset)(offset, corr_rate);
/* Dispatch to all handlers */
invoke_parameter_change_handlers(&raw, &cooked, 0.0, offset, LCL_ChangeAdjust);
}
/* ================================================== */
int
LCL_ApplyStepOffset(double offset)
{
struct timespec raw, cooked;
/* In this case, the cooked time to be passed to the notify clients
has to be the cooked time BEFORE the change was made */
LCL_ReadRawTime(&raw);
LCL_CookTime(&raw, &cooked, NULL);
if (!check_offset(&raw, offset))
return 0;
if (!(*drv_apply_step_offset)(offset)) {
LOG(LOGS_ERR, "Could not step system clock");
return 0;
}
/* Reset smoothing on all clock steps */
SMT_Reset(&cooked);
/* Dispatch to all handlers */
invoke_parameter_change_handlers(&raw, &cooked, 0.0, offset, LCL_ChangeStep);
return 1;
}
/* ================================================== */
void
LCL_NotifyExternalTimeStep(struct timespec *raw, struct timespec *cooked,
double offset, double dispersion)
{
/* Dispatch to all handlers */
invoke_parameter_change_handlers(raw, cooked, 0.0, offset, LCL_ChangeUnknownStep);
lcl_InvokeDispersionNotifyHandlers(dispersion);
}
/* ================================================== */
void
LCL_NotifyLeap(int leap)
{
struct timespec raw, cooked;
LCL_ReadRawTime(&raw);
LCL_CookTime(&raw, &cooked, NULL);
/* Smooth the leap second out */
SMT_Leap(&cooked, leap);
/* Dispatch to all handlers as if the clock was stepped */
invoke_parameter_change_handlers(&raw, &cooked, 0.0, -leap, LCL_ChangeStep);
}
/* ================================================== */
void
LCL_AccumulateFrequencyAndOffset(double dfreq, double doffset, double corr_rate)
{
struct timespec raw, cooked;
double old_freq_ppm;
LCL_ReadRawTime(&raw);
/* Due to modifying the offset, this has to be the cooked time prior
to the change we are about to make */
LCL_CookTime(&raw, &cooked, NULL);
if (!check_offset(&cooked, doffset))
return;
old_freq_ppm = current_freq_ppm;
/* Work out new absolute frequency. Note that absolute frequencies
are handled in units of ppm, whereas the 'dfreq' argument is in
terms of the gradient of the (offset) v (local time) function. */
current_freq_ppm += dfreq * (1.0e6 - current_freq_ppm);
current_freq_ppm = clamp_freq(current_freq_ppm);
DEBUG_LOG("old_freq=%.3fppm new_freq=%.3fppm offset=%.6fsec",
old_freq_ppm, current_freq_ppm, doffset);
/* Call the system-specific driver for setting the frequency */
current_freq_ppm = (*drv_set_freq)(current_freq_ppm);
dfreq = (current_freq_ppm - old_freq_ppm) / (1.0e6 - old_freq_ppm);
(*drv_accrue_offset)(doffset, corr_rate);
/* Dispatch to all handlers */
invoke_parameter_change_handlers(&raw, &cooked, dfreq, doffset, LCL_ChangeAdjust);
}
/* ================================================== */
void
lcl_InvokeDispersionNotifyHandlers(double dispersion)
{
DispersionNotifyListEntry *ptr;
for (ptr = dispersion_notify_list.next; ptr != &dispersion_notify_list; ptr = ptr->next) {
(ptr->handler)(dispersion, ptr->anything);
}
}
/* ================================================== */
void
lcl_RegisterSystemDrivers(lcl_ReadFrequencyDriver read_freq,
lcl_SetFrequencyDriver set_freq,
lcl_AccrueOffsetDriver accrue_offset,
lcl_ApplyStepOffsetDriver apply_step_offset,
lcl_OffsetCorrectionDriver offset_convert,
lcl_SetLeapDriver set_leap,
lcl_SetSyncStatusDriver set_sync_status)
{
drv_read_freq = read_freq;
drv_set_freq = set_freq;
drv_accrue_offset = accrue_offset;
drv_apply_step_offset = apply_step_offset;
drv_offset_convert = offset_convert;
drv_set_leap = set_leap;
drv_set_sync_status = set_sync_status;
current_freq_ppm = (*drv_read_freq)();
DEBUG_LOG("Local freq=%.3fppm", current_freq_ppm);
}
/* ================================================== */
/* Look at the current difference between the system time and the NTP
time, and make a step to cancel it. */
int
LCL_MakeStep(void)
{
struct timespec raw;
double correction;
LCL_ReadRawTime(&raw);
LCL_GetOffsetCorrection(&raw, &correction, NULL);
if (!check_offset(&raw, -correction))
return 0;
/* Cancel remaining slew and make the step */
LCL_AccumulateOffset(correction, 0.0);
if (!LCL_ApplyStepOffset(-correction))
return 0;
LOG(LOGS_WARN, "System clock was stepped by %.6f seconds", correction);
return 1;
}
/* ================================================== */
int
LCL_CanSystemLeap(void)
{
return drv_set_leap ? 1 : 0;
}
/* ================================================== */
void
LCL_SetSystemLeap(int leap, int tai_offset)
{
if (drv_set_leap) {
(drv_set_leap)(leap, tai_offset);
}
}
/* ================================================== */
double
LCL_SetTempComp(double comp)
{
double uncomp_freq_ppm;
if (temp_comp_ppm == comp)
return comp;
/* Undo previous compensation */
current_freq_ppm = (current_freq_ppm + temp_comp_ppm) /
(1.0 - 1.0e-6 * temp_comp_ppm);
uncomp_freq_ppm = current_freq_ppm;
/* Apply new compensation */
current_freq_ppm = current_freq_ppm * (1.0 - 1.0e-6 * comp) - comp;
/* Call the system-specific driver for setting the frequency */
current_freq_ppm = (*drv_set_freq)(current_freq_ppm);
temp_comp_ppm = (uncomp_freq_ppm - current_freq_ppm) /
(1.0e-6 * uncomp_freq_ppm + 1.0);
return temp_comp_ppm;
}
/* ================================================== */
void
LCL_SetSyncStatus(int synchronised, double est_error, double max_error)
{
if (drv_set_sync_status) {
(drv_set_sync_status)(synchronised, est_error, max_error);
}
}
/* ================================================== */