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+/*
+ chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Richard P. Curnow 1997-2002
+ *
+ * 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.
+ *
+ **********************************************************************
+
+ =======================================================================
+
+ This module provides an interface to the system time, and
+ insulates the rest of the program from the different way
+ that interface has to be done on various operating systems.
+ */
+
+#ifndef GOT_LOCAL_H
+#define GOT_LOCAL_H
+
+#include "sysincl.h"
+
+/* Read the system clock */
+extern void LCL_ReadRawTime(struct timespec *ts);
+
+/* Read the system clock, corrected according to all accumulated
+ drifts and uncompensated offsets.
+
+ In a kernel implementation with vernier frequency control (like
+ Linux), and if we were to apply offsets by stepping the clock, this
+ would be identical to raw time. In any other case (use of
+ adjtime()-like interface to correct offsets, and to adjust the
+ frequency), we must correct the raw time to get this value */
+
+extern void LCL_ReadCookedTime(struct timespec *ts, double *err);
+
+/* Convert raw time to cooked. */
+extern void LCL_CookTime(struct timespec *raw, struct timespec *cooked, double *err);
+
+/* Read the current offset between the system clock and true time
+ (i.e. 'cooked' - 'raw') (in seconds). */
+
+extern void LCL_GetOffsetCorrection(struct timespec *raw, double *correction, double *err);
+
+/* Type of routines that may be invoked as callbacks when there is a
+ change to the frequency or offset.
+
+ raw : raw local clock time at which change occurred
+
+ cooked : cooked local time at which change occurred
+
+ dfreq : delta frequency relative to previous value (in terms of
+ seconds gained by system clock per unit system clock time)
+
+ doffset : delta offset applied (positive => make local system fast
+ by that amount, negative => make it slow by that amount)
+
+ change_type : what type of change is being applied
+
+ anything : Passthrough argument from call to registration routine */
+
+
+typedef enum {
+ LCL_ChangeAdjust,
+ LCL_ChangeStep,
+ LCL_ChangeUnknownStep
+} LCL_ChangeType;
+
+typedef void (*LCL_ParameterChangeHandler)
+ (struct timespec *raw, struct timespec *cooked,
+ double dfreq,
+ double doffset,
+ LCL_ChangeType change_type,
+ void *anything
+ );
+
+/* Add a handler. Then handler MUST NOT deregister itself!!! */
+extern void LCL_AddParameterChangeHandler(LCL_ParameterChangeHandler handler, void *anything);
+
+/* Remove a handler */
+extern void LCL_RemoveParameterChangeHandler(LCL_ParameterChangeHandler, void *anything);
+
+/* Check if a handler is invoked first when dispatching */
+extern int LCL_IsFirstParameterChangeHandler(LCL_ParameterChangeHandler handler);
+
+/* Function type for handlers to be called back when an indeterminate
+ offset is introduced into the local time. This situation occurs
+ when the frequency must be adjusted to effect a clock slew and
+ there is doubt about one of the endpoints of the interval over
+ which the frequency change was applied.It is expected that such
+ handlers will add extra dispersion to any existing samples stored
+ in their registers.
+
+ dispersion : The bound on how much error has been introduced in the
+ local clock, in seconds.
+
+ anything : passthrough from the registration routine
+
+ */
+
+typedef void (*LCL_DispersionNotifyHandler)(double dispersion, void *anything);
+
+/* Register a handler for being notified of dispersion being added to
+ the local clock. The handler MUST NOT unregister itself!!! */
+
+extern void LCL_AddDispersionNotifyHandler(LCL_DispersionNotifyHandler handler, void *anything);
+
+/* Delete a handler */
+
+extern void LCL_RemoveDispersionNotifyHandler(LCL_DispersionNotifyHandler handler, void *anything);
+
+
+/* Read the absolute system frequency, relative to the uncompensated
+ system. Returned in units of parts per million. Thus the result of
+ this is how many seconds fast the uncompensated system would be after
+ its own time has reached 1 million seconds from the start of the
+ measurement. */
+extern double LCL_ReadAbsoluteFrequency(void);
+
+/* Routine to set the absolute frequency. Only expected to be used
+ when either (i) reading the drift from a file at the start of a
+ run, or (ii) responsing to a user parameter 'poke'. This is
+ defined in ppm, as for the absolute frequency reading routine. */
+
+extern void LCL_SetAbsoluteFrequency(double afreq);
+
+/* Routine to apply a change of frequency to the local clock. The
+ argument is the estimated gain (positive) or loss (negative) of the
+ local clock relative to true time, per unit time of the PREVIOUS
+ frequency setting of the local clock. This is assumed to be based
+ on a regression of y=offset v x=cooked local time. */
+
+extern void LCL_AccumulateDeltaFrequency(double dfreq);
+
+/* Routine to apply an offset (in seconds) to the local clock. The
+ argument should be positive to move the clock backwards (i.e. the
+ local clock is currently fast of true time), or negative to move it
+ forwards (i.e. it is currently slow of true time). Provided is also
+ a suggested correction rate (correction time * offset). */
+
+extern int LCL_AccumulateOffset(double offset, double corr_rate);
+
+/* Routine to apply an immediate offset by doing a sudden step if
+ possible. (Intended for use after an initial estimate of offset has
+ been obtained, so that we don't end up using adjtime to achieve a
+ slew of an hour or something like that). A positive argument means
+ the system clock is fast on true time, i.e. it needs to be stepped
+ backwards. (Same convention as for AccumulateOffset routine). */
+
+extern int LCL_ApplyStepOffset(double offset);
+
+/* Routine to invoke notify handlers on an unexpected time jump
+ in system clock */
+extern void LCL_NotifyExternalTimeStep(struct timespec *raw, struct timespec *cooked,
+ double offset, double dispersion);
+
+/* Routine to invoke notify handlers on leap second when the system clock
+ doesn't correct itself */
+extern void LCL_NotifyLeap(int leap);
+
+/* Perform the combination of modifying the frequency and applying
+ a slew, in one easy step */
+extern int LCL_AccumulateFrequencyAndOffset(double dfreq, double doffset, double corr_rate);
+
+/* Same as the routine above, except it does not call the registered
+ parameter change handlers */
+extern int LCL_AccumulateFrequencyAndOffsetNoHandlers(double dfreq, double doffset,
+ double corr_rate);
+
+/* Routine to read the system precision as a log to base 2 value. */
+extern int LCL_GetSysPrecisionAsLog(void);
+
+/* Routine to read the system precision in terms of the actual time step */
+extern double LCL_GetSysPrecisionAsQuantum(void);
+
+/* Routine to read the maximum frequency error of the local clock. This
+ is a frequency stability, not an absolute error. */
+extern double LCL_GetMaxClockError(void);
+
+/* Routine to initialise the module (to be called once at program
+ start-up) */
+
+extern void LCL_Initialise(void);
+
+/* Routine to finalise the module (to be called once at end of
+ run). */
+extern void LCL_Finalise(void);
+
+/* Routine to convert the outstanding system clock error to a step and
+ apply it, e.g. if the system clock has ended up an hour wrong due
+ to a timezone problem. */
+extern int LCL_MakeStep(void);
+
+/* Routine to cancel the outstanding system clock correction */
+extern void LCL_CancelOffsetCorrection(void);
+
+/* Check if the system driver supports leap seconds, i.e. LCL_SetSystemLeap
+ does something */
+extern int LCL_CanSystemLeap(void);
+
+/* Routine to set the system clock to correct itself for a leap second and also
+ set its TAI-UTC offset. If supported, leap second will be inserted at the
+ end of the day if the argument is positive, deleted if negative, and zero
+ resets the setting. */
+extern void LCL_SetSystemLeap(int leap, int tai_offset);
+
+/* Routine to set a frequency correction (in ppm) that should be applied
+ to local clock to compensate for temperature changes. A positive
+ argument means that the clock frequency should be increased. Return the
+ actual compensation (may be different from the requested compensation
+ due to clamping or rounding). */
+extern double LCL_SetTempComp(double comp);
+
+/* Routine to update the synchronisation status in the kernel to allow other
+ applications to know if the system clock is synchronised and error bounds */
+extern void LCL_SetSyncStatus(int synchronised, double est_error, double max_error);
+
+#endif /* GOT_LOCAL_H */