4b511143b8
On some systems, passing NULL as the first argument to adjtime, will result in returning the amount of adjustment outstanding from a previous call to adjtime(). On macOS this is not allowed and the adjtime call will fault. We can simulate the behaviour of the other systems by cancelling the current adjustment then restarting the adjustment using the outstanding time that was returned. On macOS 10.13 and later, the netbsd driver is now used and must use these semantics when making/measuring corrections.
154 lines
4.1 KiB
C
154 lines
4.1 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 1997-2001
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* Copyright (C) J. Hannken-Illjes 2001
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* Copyright (C) Miroslav Lichvar 2015
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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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Driver file for the NetBSD and FreeBSD operating system.
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*/
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#include "config.h"
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#include "sysincl.h"
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#include "sys_netbsd.h"
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#include "sys_timex.h"
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#include "logging.h"
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#include "privops.h"
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#include "util.h"
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/* Maximum frequency offset accepted by the kernel (in ppm) */
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#define MAX_FREQ 500.0
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/* Minimum assumed rate at which the kernel updates the clock frequency */
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#define MIN_TICK_RATE 100
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/* Interval between kernel updates of the adjtime() offset */
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#define ADJTIME_UPDATE_INTERVAL 1.0
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/* Maximum adjtime() slew rate (in ppm) */
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#define MAX_ADJTIME_SLEWRATE 5000.0
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/* Minimum offset adjtime() slews faster than MAX_FREQ */
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#define MIN_FASTSLEW_OFFSET 1.0
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/* ================================================== */
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/* Positive offset means system clock is fast of true time, therefore
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slew backwards */
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static void
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accrue_offset(double offset, double corr_rate)
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{
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struct timeval newadj, oldadj;
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double doldadj;
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UTI_DoubleToTimeval(-offset, &newadj);
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if (PRV_AdjustTime(&newadj, &oldadj) < 0)
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LOG_FATAL("adjtime() failed");
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/* Add the old remaining adjustment if not zero */
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doldadj = UTI_TimevalToDouble(&oldadj);
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if (doldadj != 0.0) {
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UTI_DoubleToTimeval(-offset + doldadj, &newadj);
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if (PRV_AdjustTime(&newadj, NULL) < 0)
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LOG_FATAL("adjtime() failed");
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}
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}
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/* ================================================== */
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static void
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get_offset_correction(struct timespec *raw,
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double *corr, double *err)
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{
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struct timeval remadj;
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double adjustment_remaining;
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#ifdef MACOSX
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struct timeval tv = {0, 0};
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if (PRV_AdjustTime(&tv, &remadj) < 0)
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LOG_FATAL("adjtime() failed");
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if (PRV_AdjustTime(&remadj, NULL) < 0)
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LOG_FATAL("adjtime() failed");
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#else
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if (PRV_AdjustTime(NULL, &remadj) < 0)
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LOG_FATAL("adjtime() failed");
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#endif
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adjustment_remaining = UTI_TimevalToDouble(&remadj);
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*corr = adjustment_remaining;
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if (err) {
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if (*corr != 0.0)
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*err = 1.0e-6 * MAX_ADJTIME_SLEWRATE / ADJTIME_UPDATE_INTERVAL;
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else
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*err = 0.0;
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}
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}
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/* ================================================== */
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void
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SYS_NetBSD_Initialise(void)
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{
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SYS_Timex_InitialiseWithFunctions(MAX_FREQ, 1.0 / MIN_TICK_RATE,
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NULL, NULL, NULL,
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MIN_FASTSLEW_OFFSET, MAX_ADJTIME_SLEWRATE,
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accrue_offset, get_offset_correction);
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}
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/* ================================================== */
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void
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SYS_NetBSD_Finalise(void)
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{
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SYS_Timex_Finalise();
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}
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/* ================================================== */
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#ifdef FEAT_PRIVDROP
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void
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SYS_NetBSD_DropRoot(uid_t uid, gid_t gid)
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{
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#ifdef NETBSD
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int fd;
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#endif
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/* On NetBSD the helper is used only for socket binding, but on FreeBSD
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it's used also for setting and adjusting the system clock */
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PRV_StartHelper();
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UTI_DropRoot(uid, gid);
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#ifdef NETBSD
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/* Check if we have write access to /dev/clockctl */
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fd = open("/dev/clockctl", O_WRONLY);
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if (fd < 0)
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LOG_FATAL("Can't write to /dev/clockctl");
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close(fd);
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#endif
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}
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#endif
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