624 lines
16 KiB
C
624 lines
16 KiB
C
/*
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chronyd/chronyc - Programs for keeping computer clocks accurate.
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**********************************************************************
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* Copyright (C) Richard P. Curnow 1997-2003
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* Copyright (C) Miroslav Lichvar 2011, 2014
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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**********************************************************************
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=======================================================================
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The routines in this file present a common local (system) clock
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interface to the rest of the software.
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They interface with the system specific driver files in sys_*.c
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*/
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#include "config.h"
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#include "sysincl.h"
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#include "conf.h"
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#include "local.h"
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#include "localp.h"
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#include "memory.h"
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#include "util.h"
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#include "logging.h"
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/* ================================================== */
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/* Variable to store the current frequency, in ppm */
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static double current_freq_ppm;
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/* Temperature compensation, in ppm */
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static double temp_comp_ppm;
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/* ================================================== */
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/* Store the system dependent drivers */
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static lcl_ReadFrequencyDriver drv_read_freq;
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static lcl_SetFrequencyDriver drv_set_freq;
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static lcl_AccrueOffsetDriver drv_accrue_offset;
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static lcl_ApplyStepOffsetDriver drv_apply_step_offset;
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static lcl_OffsetCorrectionDriver drv_offset_convert;
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static lcl_SetLeapDriver drv_set_leap;
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/* ================================================== */
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/* Types and variables associated with handling the parameter change
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list */
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typedef struct _ChangeListEntry {
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struct _ChangeListEntry *next;
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struct _ChangeListEntry *prev;
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LCL_ParameterChangeHandler handler;
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void *anything;
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} ChangeListEntry;
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static ChangeListEntry change_list;
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/* ================================================== */
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/* Types and variables associated with handling the parameter change
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list */
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typedef struct _DispersionNotifyListEntry {
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struct _DispersionNotifyListEntry *next;
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struct _DispersionNotifyListEntry *prev;
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LCL_DispersionNotifyHandler handler;
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void *anything;
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} DispersionNotifyListEntry;
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static DispersionNotifyListEntry dispersion_notify_list;
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/* ================================================== */
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static int precision_log;
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static double precision_quantum;
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static double max_clock_error;
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/* ================================================== */
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/* Define the number of increments of the system clock that we want
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to see to be fairly sure that we've got something approaching
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the minimum increment. Even on a crummy implementation that can't
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interpolate between 10ms ticks, we should get this done in
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under 1s of busy waiting. */
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#define NITERS 100
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static void
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calculate_sys_precision(void)
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{
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struct timeval tv, old_tv;
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int dusec, best_dusec;
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int iters;
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gettimeofday(&old_tv, NULL);
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best_dusec = 1000000; /* Assume we must be better than a second */
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iters = 0;
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do {
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gettimeofday(&tv, NULL);
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dusec = 1000000*(tv.tv_sec - old_tv.tv_sec) + (tv.tv_usec - old_tv.tv_usec);
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old_tv = tv;
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if (dusec > 0) {
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if (dusec < best_dusec) {
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best_dusec = dusec;
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}
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iters++;
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}
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} while (iters < NITERS);
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assert(best_dusec > 0);
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precision_quantum = best_dusec * 1.0e-6;
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/* Get rounded log2 value of the measured precision */
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precision_log = 0;
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while (best_dusec < 707107) {
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precision_log--;
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best_dusec *= 2;
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}
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DEBUG_LOG(LOGF_Local, "Clock precision %.9f (%d)", precision_quantum, precision_log);
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}
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/* ================================================== */
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void
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LCL_Initialise(void)
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{
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change_list.next = change_list.prev = &change_list;
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dispersion_notify_list.next = dispersion_notify_list.prev = &dispersion_notify_list;
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/* Null out the system drivers, so that we die
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if they never get defined before use */
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drv_read_freq = NULL;
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drv_set_freq = NULL;
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drv_accrue_offset = NULL;
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drv_offset_convert = NULL;
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/* This ought to be set from the system driver layer */
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current_freq_ppm = 0.0;
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temp_comp_ppm = 0.0;
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calculate_sys_precision();
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max_clock_error = CNF_GetMaxClockError() * 1e-6;
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}
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/* ================================================== */
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void
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LCL_Finalise(void)
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{
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}
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/* ================================================== */
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/* Routine to read the system precision as a log to base 2 value. */
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int
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LCL_GetSysPrecisionAsLog(void)
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{
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return precision_log;
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}
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/* ================================================== */
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/* Routine to read the system precision in terms of the actual time step */
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double
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LCL_GetSysPrecisionAsQuantum(void)
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{
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return precision_quantum;
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}
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/* ================================================== */
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double
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LCL_GetMaxClockError(void)
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{
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return max_clock_error;
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}
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/* ================================================== */
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void
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LCL_AddParameterChangeHandler(LCL_ParameterChangeHandler handler, void *anything)
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{
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ChangeListEntry *ptr, *new_entry;
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/* Check that the handler is not already registered */
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for (ptr = change_list.next; ptr != &change_list; ptr = ptr->next) {
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if (!(ptr->handler != handler || ptr->anything != anything)) {
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assert(0);
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}
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}
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new_entry = MallocNew(ChangeListEntry);
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new_entry->handler = handler;
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new_entry->anything = anything;
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/* Chain it into the list */
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new_entry->next = &change_list;
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new_entry->prev = change_list.prev;
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change_list.prev->next = new_entry;
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change_list.prev = new_entry;
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}
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/* ================================================== */
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/* Remove a handler */
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void LCL_RemoveParameterChangeHandler(LCL_ParameterChangeHandler handler, void *anything)
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{
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ChangeListEntry *ptr;
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int ok;
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ptr = NULL;
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ok = 0;
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for (ptr = change_list.next; ptr != &change_list; ptr = ptr->next) {
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if (ptr->handler == handler && ptr->anything == anything) {
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ok = 1;
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break;
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}
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}
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assert(ok);
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/* Unlink entry from the list */
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ptr->next->prev = ptr->prev;
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ptr->prev->next = ptr->next;
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free(ptr);
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}
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/* ================================================== */
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static void
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invoke_parameter_change_handlers(struct timeval *raw, struct timeval *cooked,
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double dfreq, double doffset,
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LCL_ChangeType change_type)
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{
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ChangeListEntry *ptr;
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for (ptr = change_list.next; ptr != &change_list; ptr = ptr->next) {
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(ptr->handler)(raw, cooked, dfreq, doffset, change_type, ptr->anything);
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}
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}
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/* ================================================== */
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void
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LCL_AddDispersionNotifyHandler(LCL_DispersionNotifyHandler handler, void *anything)
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{
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DispersionNotifyListEntry *ptr, *new_entry;
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/* Check that the handler is not already registered */
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for (ptr = dispersion_notify_list.next; ptr != &dispersion_notify_list; ptr = ptr->next) {
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if (!(ptr->handler != handler || ptr->anything != anything)) {
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assert(0);
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}
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}
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new_entry = MallocNew(DispersionNotifyListEntry);
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new_entry->handler = handler;
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new_entry->anything = anything;
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/* Chain it into the list */
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new_entry->next = &dispersion_notify_list;
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new_entry->prev = dispersion_notify_list.prev;
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dispersion_notify_list.prev->next = new_entry;
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dispersion_notify_list.prev = new_entry;
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}
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/* ================================================== */
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/* Remove a handler */
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extern
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void LCL_RemoveDispersionNotifyHandler(LCL_DispersionNotifyHandler handler, void *anything)
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{
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DispersionNotifyListEntry *ptr;
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int ok;
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ptr = NULL;
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ok = 0;
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for (ptr = dispersion_notify_list.next; ptr != &dispersion_notify_list; ptr = ptr->next) {
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if (ptr->handler == handler && ptr->anything == anything) {
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ok = 1;
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break;
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}
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}
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assert(ok);
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/* Unlink entry from the list */
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ptr->next->prev = ptr->prev;
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ptr->prev->next = ptr->next;
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free(ptr);
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}
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/* ================================================== */
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/* At the moment, this is just gettimeofday(), because
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I can't think of a Unix system where it would not be */
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void
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LCL_ReadRawTime(struct timeval *result)
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{
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if (gettimeofday(result, NULL) < 0) {
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LOG_FATAL(LOGF_Local, "gettimeofday() failed");
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}
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}
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/* ================================================== */
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void
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LCL_ReadCookedTime(struct timeval *result, double *err)
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{
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struct timeval raw;
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LCL_ReadRawTime(&raw);
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LCL_CookTime(&raw, result, err);
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}
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/* ================================================== */
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void
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LCL_CookTime(struct timeval *raw, struct timeval *cooked, double *err)
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{
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double correction;
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LCL_GetOffsetCorrection(raw, &correction, err);
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UTI_AddDoubleToTimeval(raw, correction, cooked);
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}
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/* ================================================== */
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void
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LCL_GetOffsetCorrection(struct timeval *raw, double *correction, double *err)
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{
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/* Call system specific driver to get correction */
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(*drv_offset_convert)(raw, correction, err);
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}
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/* ================================================== */
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/* Return current frequency */
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double
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LCL_ReadAbsoluteFrequency(void)
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{
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double freq;
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freq = current_freq_ppm;
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/* Undo temperature compensation */
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if (temp_comp_ppm != 0.0) {
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freq = (freq + temp_comp_ppm) / (1.0 - 1.0e-6 * temp_comp_ppm);
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}
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return freq;
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}
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/* ================================================== */
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/* This involves both setting the absolute frequency with the
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system-specific driver, as well as calling all notify handlers */
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void
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LCL_SetAbsoluteFrequency(double afreq_ppm)
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{
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struct timeval raw, cooked;
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double dfreq;
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/* Apply temperature compensation */
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if (temp_comp_ppm != 0.0) {
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afreq_ppm = afreq_ppm * (1.0 - 1.0e-6 * temp_comp_ppm) - temp_comp_ppm;
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}
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/* Call the system-specific driver for setting the frequency */
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afreq_ppm = (*drv_set_freq)(afreq_ppm);
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dfreq = (afreq_ppm - current_freq_ppm) / (1.0e6 - current_freq_ppm);
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LCL_ReadRawTime(&raw);
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LCL_CookTime(&raw, &cooked, NULL);
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/* Dispatch to all handlers */
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invoke_parameter_change_handlers(&raw, &cooked, dfreq, 0.0, LCL_ChangeAdjust);
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current_freq_ppm = afreq_ppm;
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}
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/* ================================================== */
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void
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LCL_AccumulateDeltaFrequency(double dfreq)
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{
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struct timeval raw, cooked;
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double old_freq_ppm;
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old_freq_ppm = current_freq_ppm;
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/* Work out new absolute frequency. Note that absolute frequencies
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are handled in units of ppm, whereas the 'dfreq' argument is in
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terms of the gradient of the (offset) v (local time) function. */
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current_freq_ppm += dfreq * (1.0e6 - current_freq_ppm);
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/* Call the system-specific driver for setting the frequency */
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current_freq_ppm = (*drv_set_freq)(current_freq_ppm);
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dfreq = (current_freq_ppm - old_freq_ppm) / (1.0e6 - old_freq_ppm);
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LCL_ReadRawTime(&raw);
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LCL_CookTime(&raw, &cooked, NULL);
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/* Dispatch to all handlers */
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invoke_parameter_change_handlers(&raw, &cooked, dfreq, 0.0, LCL_ChangeAdjust);
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}
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/* ================================================== */
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void
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LCL_AccumulateOffset(double offset, double corr_rate)
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{
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struct timeval raw, cooked;
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/* In this case, the cooked time to be passed to the notify clients
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has to be the cooked time BEFORE the change was made */
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LCL_ReadRawTime(&raw);
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LCL_CookTime(&raw, &cooked, NULL);
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(*drv_accrue_offset)(offset, corr_rate);
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/* Dispatch to all handlers */
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invoke_parameter_change_handlers(&raw, &cooked, 0.0, offset, LCL_ChangeAdjust);
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}
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/* ================================================== */
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void
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LCL_ApplyStepOffset(double offset)
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{
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struct timeval raw, cooked;
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/* In this case, the cooked time to be passed to the notify clients
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has to be the cooked time BEFORE the change was made */
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LCL_ReadRawTime(&raw);
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LCL_CookTime(&raw, &cooked, NULL);
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(*drv_apply_step_offset)(offset);
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/* Dispatch to all handlers */
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invoke_parameter_change_handlers(&raw, &cooked, 0.0, offset, LCL_ChangeStep);
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}
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/* ================================================== */
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void
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LCL_NotifyExternalTimeStep(struct timeval *raw, struct timeval *cooked,
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double offset, double dispersion)
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{
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/* Dispatch to all handlers */
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invoke_parameter_change_handlers(raw, cooked, 0.0, offset, LCL_ChangeUnknownStep);
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lcl_InvokeDispersionNotifyHandlers(dispersion);
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}
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/* ================================================== */
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void
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LCL_AccumulateFrequencyAndOffset(double dfreq, double doffset, double corr_rate)
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{
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ChangeListEntry *ptr;
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struct timeval raw, cooked;
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double old_freq_ppm;
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LCL_ReadRawTime(&raw);
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/* Due to modifying the offset, this has to be the cooked time prior
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to the change we are about to make */
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LCL_CookTime(&raw, &cooked, NULL);
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old_freq_ppm = current_freq_ppm;
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/* Work out new absolute frequency. Note that absolute frequencies
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are handled in units of ppm, whereas the 'dfreq' argument is in
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terms of the gradient of the (offset) v (local time) function. */
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current_freq_ppm += dfreq * (1.0e6 - current_freq_ppm);
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DEBUG_LOG(LOGF_Local, "old_freq=%.3fppm new_freq=%.3fppm offset=%.6fsec",
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old_freq_ppm, current_freq_ppm, doffset);
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/* Call the system-specific driver for setting the frequency */
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current_freq_ppm = (*drv_set_freq)(current_freq_ppm);
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dfreq = (current_freq_ppm - old_freq_ppm) / (1.0e6 - old_freq_ppm);
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(*drv_accrue_offset)(doffset, corr_rate);
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/* Dispatch to all handlers */
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for (ptr = change_list.next; ptr != &change_list; ptr = ptr->next) {
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(ptr->handler)(&raw, &cooked, dfreq, doffset, 0, ptr->anything);
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}
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}
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/* ================================================== */
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void
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lcl_InvokeDispersionNotifyHandlers(double dispersion)
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{
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DispersionNotifyListEntry *ptr;
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for (ptr = dispersion_notify_list.next; ptr != &dispersion_notify_list; ptr = ptr->next) {
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(ptr->handler)(dispersion, ptr->anything);
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}
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}
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/* ================================================== */
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void
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lcl_RegisterSystemDrivers(lcl_ReadFrequencyDriver read_freq,
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lcl_SetFrequencyDriver set_freq,
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lcl_AccrueOffsetDriver accrue_offset,
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lcl_ApplyStepOffsetDriver apply_step_offset,
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lcl_OffsetCorrectionDriver offset_convert,
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lcl_SetLeapDriver set_leap)
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{
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drv_read_freq = read_freq;
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drv_set_freq = set_freq;
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drv_accrue_offset = accrue_offset;
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drv_apply_step_offset = apply_step_offset;
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drv_offset_convert = offset_convert;
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drv_set_leap = set_leap;
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current_freq_ppm = (*drv_read_freq)();
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DEBUG_LOG(LOGF_Local, "Local freq=%.3fppm", current_freq_ppm);
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}
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/* ================================================== */
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/* Look at the current difference between the system time and the NTP
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time, and make a step to cancel it. */
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int
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LCL_MakeStep(void)
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{
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struct timeval raw;
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double correction;
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LCL_ReadRawTime(&raw);
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LCL_GetOffsetCorrection(&raw, &correction, NULL);
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/* Cancel remaining slew and make the step */
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LCL_AccumulateOffset(correction, 0.0);
|
|
LCL_ApplyStepOffset(-correction);
|
|
|
|
LOG(LOGS_WARN, LOGF_Local, "System clock was stepped by %.6f seconds", correction);
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* ================================================== */
|
|
|
|
void
|
|
LCL_SetLeap(int leap)
|
|
{
|
|
if (drv_set_leap) {
|
|
(drv_set_leap)(leap);
|
|
}
|
|
}
|
|
|
|
/* ================================================== */
|
|
|
|
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;
|
|
}
|
|
|
|
/* ================================================== */
|