/* 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. This is analogous to gettimeofday(), but with the timezone information ignored */ extern void LCL_ReadRawTime(struct timeval *); /* 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 timeval *t, double *err); /* Convert raw time to cooked. */ extern void LCL_CookTime(struct timeval *raw, struct timeval *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 timeval *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) is_step_change : true if change is being applied as a jump (using settimeofday rather than adjtime) anything : Passthrough argument from call to registration routine */ typedef void (*LCL_ParameterChangeHandler) (struct timeval *raw, struct timeval *cooked, double dfreq, double doffset, int is_step_change, 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); /* 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). */ extern void LCL_AccumulateOffset(double offset); /* 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 void LCL_ApplyStepOffset(double offset); /* Perform the combination of modifying the frequency and applying a slew, in one easy step */ extern void LCL_AccumulateFrequencyAndOffset(double dfreq, double doffset); /* 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(double threshold); /* Routine to schedule a leap second. Leap second will be inserted at the end of the day if argument is positive, deleted if negative, and zero cancels scheduled leap second. */ extern void LCL_SetLeap(int leap); /* 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); #endif /* GOT_LOCAL_H */