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/*
* Soft: Keepalived is a failover program for the LVS project
* <www.linuxvirtualserver.org>. It monitor & manipulate
* a loadbalanced server pool using multi-layer checks.
*
* Part: Timer manipulations.
*
* Author: Alexandre Cassen, <acassen@linux-vs.org>
*
* 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.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Copyright (C) 2001-2017 Alexandre Cassen, <acassen@gmail.com>
*/
#include "config.h"
#include <string.h>
#include <errno.h>
#include <sys/time.h>
#include <time.h>
#include <stdbool.h>
#include "timer.h"
#ifdef _TIMER_CHECK_
#include "logger.h"
#endif
/* time_now holds current time */
timeval_t time_now;
#ifdef _TIMER_CHECK_
static timeval_t last_time;
bool do_timer_check;
#endif
timeval_t
timer_add_long(timeval_t a, unsigned long b)
{
if (b == TIMER_NEVER)
{
a.tv_usec = TIMER_HZ - 1;
a.tv_sec = TIMER_DISABLED;
return a;
}
a.tv_usec += b % TIMER_HZ;
a.tv_sec += b / TIMER_HZ;
if (a.tv_usec >= TIMER_HZ) {
a.tv_sec++;
a.tv_usec -= TIMER_HZ;
}
return a;
}
timeval_t
timer_sub_long(timeval_t a, unsigned long b)
{
if (a.tv_usec < (suseconds_t)(b % TIMER_HZ)) {
a.tv_usec += TIMER_HZ;
a.tv_sec--;
}
a.tv_usec -= b % TIMER_HZ;
a.tv_sec -= b / TIMER_HZ;
return a;
}
static void
set_mono_offset(struct timespec *ts)
{
struct timespec realtime, realtime_1, mono_offset;
/* Calculate the offset of the realtime clock from the monotonic
* clock. We read the realtime clock twice and take the mean,
* which should then make it very close to the time the monotonic
* clock was read. */
clock_gettime(CLOCK_REALTIME, &realtime);
clock_gettime(CLOCK_MONOTONIC, &mono_offset);
clock_gettime(CLOCK_REALTIME, &realtime_1);
/* Calculate the mean realtime. If tv_sec is 4 bytes, then
* adding two times after Sat 10 Jan 13:37:04 GMT 2004 results
* in overflow. If tv_sec is only 6 bytes (unlikely) then
* overflow doesn't occur until the two dates average
* Tue 25 Sep 15:41:04 BST 2231866, */
realtime.tv_nsec = (realtime.tv_nsec + realtime_1.tv_nsec) / 2;
#ifndef TIME_T_ADD_OVERFLOWS
realtime.tv_sec = (realtime.tv_sec + realtime_1.tv_sec) / 2;
#else
realtime.tv_sec = realtime.tv_sec / 2 + realtime_1.tv_sec / 2;
if ((realtime.tv_sec & 1) && (realtime_1.tv_sec & 1))
realtime.tv_sec++;
#endif
/* If the sum would be odd, we need to add * 1/2 second. */
if ((realtime.tv_sec ^ realtime_1.tv_sec) & 1)
realtime.tv_nsec += NSEC_PER_SEC / 2;
if (realtime.tv_nsec < mono_offset.tv_nsec) {
realtime.tv_nsec += NSEC_PER_SEC;
realtime.tv_sec--;
}
realtime.tv_sec -= mono_offset.tv_sec;
realtime.tv_nsec -= mono_offset.tv_nsec;
*ts = realtime;
}
/* This function is a wrapper for gettimeofday(). It uses the monotonic clock to
* guarantee that the returned time will always be monotonicly increasing.
* When called for the first time it calculates the difference between the
* monotonic clock and the realtime clock, and this difference is then subsequently
* added to the monotonic clock to return a monotonic approximation to realtime.
*
* It is designed to be used as a drop-in replacement of gettimeofday(&now, NULL).
* It will normally return 0, unless <now> is NULL, in which case it will
* return -1 and set errno to EFAULT.
*/
static int
monotonic_gettimeofday(timeval_t *now)
{
static struct timespec mono_offset;
static bool initialised = false;
struct timespec cur_time;
if (!now) {
errno = EFAULT;
return -1;
}
if (!initialised) {
set_mono_offset(&mono_offset);
initialised = true;
}
/* Read the monotonic clock and add the offset we initially
* calculated of the realtime clock */
clock_gettime(CLOCK_MONOTONIC, &cur_time);
cur_time.tv_sec += mono_offset.tv_sec;
cur_time.tv_nsec += mono_offset.tv_nsec;
if (cur_time.tv_nsec > NSEC_PER_SEC) {
cur_time.tv_nsec -= NSEC_PER_SEC;
cur_time.tv_sec++;
}
TIMESPEC_TO_TIMEVAL(now, &cur_time);
return 0;
}
/* current time */
timeval_t
#ifdef _TIMER_CHECK_
timer_now_r(const char *file, const char *function, int line_no)
#else
timer_now(void)
#endif
{
timeval_t curr_time;
/* init timer */
monotonic_gettimeofday(&curr_time);
#ifdef _TIMER_CHECK_
if (do_timer_check) {
unsigned long timediff = (curr_time.tv_sec - last_time.tv_sec) * 1000000 + curr_time.tv_usec - last_time.tv_usec;
log_message(LOG_INFO, "timer_now called from %s %s:%d - difference %lu usec", file, function, line_no, timediff);
last_time = curr_time;
}
#endif
return curr_time;
}
/* sets and returns current time from system time */
timeval_t
#ifdef _TIMER_CHECK_
set_time_now_r(const char *file, const char *function, int line_no)
#else
set_time_now(void)
#endif
{
/* init timer */
monotonic_gettimeofday(&time_now);
#ifdef _TIMER_CHECK_
if (do_timer_check) {
unsigned long timediff = (time_now.tv_sec - last_time.tv_sec) * 1000000 + time_now.tv_usec - last_time.tv_usec;
log_message(LOG_INFO, "set_time_now called from %s %s:%d, time %" PRI_tv_sec ".%6.6" PRI_tv_usec " difference %lu usec", file, function, line_no, time_now.tv_sec, time_now.tv_usec, timediff);
last_time = time_now;
}
#endif
return time_now;
}
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