97 lines
2.5 KiB
C
97 lines
2.5 KiB
C
/**
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* @file clockadj.c
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* @note Copyright (C) 2013 Richard Cochran <richardcochran@gmail.com>
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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 the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU 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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#include <string.h>
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#include "clockadj.h"
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#include "missing.h"
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#include "print.h"
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#define NS_PER_SEC 1000000000LL
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void clockadj_set_freq(clockid_t clkid, double freq)
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{
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struct timex tx;
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memset(&tx, 0, sizeof(tx));
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tx.modes = ADJ_FREQUENCY;
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tx.freq = (long) (freq * 65.536);
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if (clock_adjtime(clkid, &tx) < 0)
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pr_err("failed to adjust the clock: %m");
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}
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double clockadj_get_freq(clockid_t clkid)
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{
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double f = 0.0;
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struct timex tx;
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memset(&tx, 0, sizeof(tx));
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if (clock_adjtime(clkid, &tx) < 0)
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pr_err("failed to read out the clock frequency adjustment: %m");
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else
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f = tx.freq / 65.536;
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return f;
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}
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void clockadj_step(clockid_t clkid, int64_t step)
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{
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struct timex tx;
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int sign = 1;
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if (step < 0) {
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sign = -1;
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step *= -1;
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}
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memset(&tx, 0, sizeof(tx));
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tx.modes = ADJ_SETOFFSET | ADJ_NANO;
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tx.time.tv_sec = sign * (step / NS_PER_SEC);
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tx.time.tv_usec = sign * (step % NS_PER_SEC);
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/*
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* The value of a timeval is the sum of its fields, but the
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* field tv_usec must always be non-negative.
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*/
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if (tx.time.tv_usec < 0) {
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tx.time.tv_sec -= 1;
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tx.time.tv_usec += 1000000000;
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}
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if (clock_adjtime(clkid, &tx) < 0)
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pr_err("failed to step clock: %m");
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}
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void clockadj_set_leap(clockid_t clkid, int leap)
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{
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struct timex tx;
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const char *m = NULL;
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memset(&tx, 0, sizeof(tx));
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tx.modes = ADJ_STATUS;
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switch (leap) {
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case -1:
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tx.status = STA_DEL;
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m = "clock set to delete leap second at midnight (UTC)";
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break;
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case 1:
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tx.status = STA_INS;
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m = "clock set to insert leap second at midnight (UTC)";
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break;
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default:
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tx.status = 0;
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}
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if (clock_adjtime(clkid, &tx) < 0)
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pr_err("failed to set the clock status: %m");
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else if (m)
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pr_notice(m);
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}
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