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-rw-r--r--sys_timex.c283
1 files changed, 283 insertions, 0 deletions
diff --git a/sys_timex.c b/sys_timex.c
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+/*
+ chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Richard P. Curnow 1997-2003
+ * Copyright (C) Miroslav Lichvar 2009-2012, 2014-2015, 2017
+ *
+ * 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.
+ *
+ **********************************************************************
+
+ =======================================================================
+
+ Driver for systems that implement the adjtimex()/ntp_adjtime() system call
+ */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "conf.h"
+#include "privops.h"
+#include "sys_generic.h"
+#include "sys_timex.h"
+#include "logging.h"
+
+#ifdef PRIVOPS_ADJUSTTIMEX
+#define NTP_ADJTIME PRV_AdjustTimex
+#define NTP_ADJTIME_NAME "ntp_adjtime"
+#else
+#ifdef LINUX
+#define NTP_ADJTIME adjtimex
+#define NTP_ADJTIME_NAME "adjtimex"
+#else
+#define NTP_ADJTIME ntp_adjtime
+#define NTP_ADJTIME_NAME "ntp_adjtime"
+#endif
+#endif
+
+/* Maximum frequency offset accepted by the kernel (in ppm) */
+#define MAX_FREQ 500.0
+
+/* Frequency scale to convert from ppm to the timex freq */
+#define FREQ_SCALE (double)(1 << 16)
+
+/* Threshold for the timex maxerror when the kernel sets the UNSYNC flag */
+#define MAX_SYNC_ERROR 16.0
+
+/* Minimum assumed rate at which the kernel updates the clock frequency */
+#define MIN_TICK_RATE 100
+
+/* Saved timex status */
+static int sys_status;
+
+/* Saved TAI-UTC offset */
+static int sys_tai_offset;
+
+/* ================================================== */
+
+static double
+convert_timex_frequency(const struct timex *txc)
+{
+ double freq_ppm;
+
+ freq_ppm = txc->freq / FREQ_SCALE;
+
+#ifdef MACOSX
+ /* Temporary workaround for Apple bug treating freq as unsigned number */
+ if (freq_ppm > 32767) {
+ freq_ppm -= 65536;
+ }
+#endif
+
+ return -freq_ppm;
+}
+
+/* ================================================== */
+
+static double
+read_frequency(void)
+{
+ struct timex txc;
+
+ txc.modes = 0;
+
+ SYS_Timex_Adjust(&txc, 0);
+
+ return convert_timex_frequency(&txc);
+}
+
+/* ================================================== */
+
+static double
+set_frequency(double freq_ppm)
+{
+ struct timex txc;
+
+ txc.modes = MOD_FREQUENCY;
+ txc.freq = freq_ppm * -FREQ_SCALE;
+
+ SYS_Timex_Adjust(&txc, 0);
+
+ return convert_timex_frequency(&txc);
+}
+
+/* ================================================== */
+
+static void
+set_leap(int leap, int tai_offset)
+{
+ struct timex txc;
+ int applied, prev_status;
+
+ txc.modes = 0;
+ applied = SYS_Timex_Adjust(&txc, 0) == TIME_WAIT;
+
+ prev_status = sys_status;
+ sys_status &= ~(STA_INS | STA_DEL);
+
+ if (leap > 0)
+ sys_status |= STA_INS;
+ else if (leap < 0)
+ sys_status |= STA_DEL;
+
+ txc.modes = MOD_STATUS;
+ txc.status = sys_status;
+
+#ifdef MOD_TAI
+ if (tai_offset) {
+ txc.modes |= MOD_TAI;
+ txc.constant = tai_offset;
+
+ if (applied && !(sys_status & (STA_INS | STA_DEL)))
+ sys_tai_offset += prev_status & STA_INS ? 1 : -1;
+
+ if (sys_tai_offset != tai_offset) {
+ sys_tai_offset = tai_offset;
+ LOG(LOGS_INFO, "System clock TAI offset set to %d seconds", tai_offset);
+ }
+ }
+#endif
+
+ SYS_Timex_Adjust(&txc, 0);
+
+ if (prev_status != sys_status) {
+ LOG(LOGS_INFO, "System clock status %s leap second",
+ leap ? (leap > 0 ? "set to insert" : "set to delete") :
+ (applied ? "reset after" : "set to not insert/delete"));
+ }
+}
+
+/* ================================================== */
+
+static void
+set_sync_status(int synchronised, double est_error, double max_error)
+{
+ struct timex txc;
+
+ if (synchronised) {
+ if (est_error > MAX_SYNC_ERROR)
+ est_error = MAX_SYNC_ERROR;
+ if (max_error >= MAX_SYNC_ERROR) {
+ max_error = MAX_SYNC_ERROR;
+ synchronised = 0;
+ }
+ } else {
+ est_error = max_error = MAX_SYNC_ERROR;
+ }
+
+#ifdef LINUX
+ /* On Linux clear the UNSYNC flag only if rtcsync is enabled */
+ if (!CNF_GetRtcSync())
+ synchronised = 0;
+#endif
+
+ if (synchronised)
+ sys_status &= ~STA_UNSYNC;
+ else
+ sys_status |= STA_UNSYNC;
+
+ txc.modes = MOD_STATUS | MOD_ESTERROR | MOD_MAXERROR;
+ txc.status = sys_status;
+ txc.esterror = est_error * 1.0e6;
+ txc.maxerror = max_error * 1.0e6;
+
+ if (SYS_Timex_Adjust(&txc, 1) < 0)
+ ;
+}
+
+/* ================================================== */
+
+static void
+initialise_timex(void)
+{
+ struct timex txc;
+
+ sys_status = STA_UNSYNC;
+ sys_tai_offset = 0;
+
+ /* Reset PLL offset */
+ txc.modes = MOD_OFFSET | MOD_STATUS;
+ txc.status = STA_PLL | sys_status;
+ txc.offset = 0;
+ SYS_Timex_Adjust(&txc, 0);
+
+ /* Turn PLL off */
+ txc.modes = MOD_STATUS;
+ txc.status = sys_status;
+ SYS_Timex_Adjust(&txc, 0);
+}
+
+/* ================================================== */
+
+void
+SYS_Timex_Initialise(void)
+{
+ SYS_Timex_InitialiseWithFunctions(MAX_FREQ, 1.0 / MIN_TICK_RATE, NULL, NULL, NULL,
+ 0.0, 0.0, NULL, NULL);
+}
+
+/* ================================================== */
+
+void
+SYS_Timex_InitialiseWithFunctions(double max_set_freq_ppm, double max_set_freq_delay,
+ lcl_ReadFrequencyDriver sys_read_freq,
+ lcl_SetFrequencyDriver sys_set_freq,
+ lcl_ApplyStepOffsetDriver sys_apply_step_offset,
+ double min_fastslew_offset, double max_fastslew_rate,
+ lcl_AccrueOffsetDriver sys_accrue_offset,
+ lcl_OffsetCorrectionDriver sys_get_offset_correction)
+{
+ initialise_timex();
+
+ SYS_Generic_CompleteFreqDriver(max_set_freq_ppm, max_set_freq_delay,
+ sys_read_freq ? sys_read_freq : read_frequency,
+ sys_set_freq ? sys_set_freq : set_frequency,
+ sys_apply_step_offset,
+ min_fastslew_offset, max_fastslew_rate,
+ sys_accrue_offset, sys_get_offset_correction,
+ set_leap, set_sync_status);
+}
+
+/* ================================================== */
+
+void
+SYS_Timex_Finalise(void)
+{
+ SYS_Generic_Finalise();
+}
+
+/* ================================================== */
+
+int
+SYS_Timex_Adjust(struct timex *txc, int ignore_error)
+{
+ int state;
+
+#ifdef SOLARIS
+ /* The kernel seems to check the constant even when it's not being set */
+ if (!(txc->modes & MOD_TIMECONST))
+ txc->constant = 10;
+#endif
+
+ state = NTP_ADJTIME(txc);
+
+ if (state < 0) {
+ LOG(ignore_error ? LOGS_DEBUG : LOGS_FATAL,
+ NTP_ADJTIME_NAME"(0x%x) failed : %s", txc->modes, strerror(errno));
+ }
+
+ return state;
+}
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