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/*-
* Copyright (c) 2011, 2012, 2013 Spectra Logic Corporation
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* Authors: Justin T. Gibbs (Spectra Logic Corporation)
*/
/**
* \file callout.cc
*
* \brief Implementation of the Callout class - multi-client
* timer services built on top of the POSIX interval timer.
*/
#include <sys/byteorder.h>
#include <sys/time.h>
#include <signal.h>
#include <syslog.h>
#include <climits>
#include <list>
#include <map>
#include <string>
#include <devdctl/guid.h>
#include <devdctl/event.h>
#include <devdctl/event_factory.h>
#include <devdctl/consumer.h>
#include <devdctl/exception.h>
#include "callout.h"
#include "vdev_iterator.h"
#include "zfsd.h"
#include "zfsd_exception.h"
std::list<Callout *> Callout::s_activeCallouts;
bool Callout::s_alarmFired(false);
void
Callout::Init()
{
signal(SIGALRM, Callout::AlarmSignalHandler);
}
bool
Callout::Stop()
{
if (!IsPending())
return (false);
for (std::list<Callout *>::iterator it(s_activeCallouts.begin());
it != s_activeCallouts.end(); it++) {
if (*it != this)
continue;
it = s_activeCallouts.erase(it);
if (it != s_activeCallouts.end()) {
/*
* Maintain correct interval for the
* callouts that follow the just removed
* entry.
*/
timeradd(&(*it)->m_interval, &m_interval,
&(*it)->m_interval);
}
break;
}
m_pending = false;
return (true);
}
bool
Callout::Reset(const timeval &interval, CalloutFunc_t *func, void *arg)
{
bool cancelled(false);
if (!timerisset(&interval))
throw ZfsdException("Callout::Reset: interval of 0");
cancelled = Stop();
m_interval = interval;
m_func = func;
m_arg = arg;
m_pending = true;
std::list<Callout *>::iterator it(s_activeCallouts.begin());
for (; it != s_activeCallouts.end(); it++) {
if (timercmp(&(*it)->m_interval, &m_interval, <=)) {
/*
* Decrease our interval by those that come
* before us.
*/
timersub(&m_interval, &(*it)->m_interval, &m_interval);
} else {
/*
* Account for the time between the newly
* inserted event and those that follow.
*/
timersub(&(*it)->m_interval, &m_interval,
&(*it)->m_interval);
break;
}
}
s_activeCallouts.insert(it, this);
if (s_activeCallouts.front() == this) {
itimerval timerval = { {0, 0}, m_interval };
setitimer(ITIMER_REAL, &timerval, NULL);
}
return (cancelled);
}
void
Callout::AlarmSignalHandler(int)
{
s_alarmFired = true;
ZfsDaemon::WakeEventLoop();
}
void
Callout::ExpireCallouts()
{
if (!s_alarmFired)
return;
s_alarmFired = false;
if (s_activeCallouts.empty()) {
/* Callout removal/SIGALRM race was lost. */
return;
}
/*
* Expire the first callout (the one we used to set the
* interval timer) as well as any callouts following that
* expire at the same time (have a zero interval from
* the callout before it).
*/
do {
Callout *cur(s_activeCallouts.front());
s_activeCallouts.pop_front();
cur->m_pending = false;
cur->m_func(cur->m_arg);
} while (!s_activeCallouts.empty()
&& timerisset(&s_activeCallouts.front()->m_interval) == 0);
if (!s_activeCallouts.empty()) {
Callout *next(s_activeCallouts.front());
itimerval timerval = { { 0, 0 }, next->m_interval };
setitimer(ITIMER_REAL, &timerval, NULL);
}
}
timeval
Callout::TimeRemaining() const
{
/*
* Outline: Add the m_interval for each callout in s_activeCallouts
* ahead of this, except for the first callout. Add to that the result
* of getitimer (That's because the first callout stores its original
* interval setting while the timer is ticking).
*/
itimerval timervalToAlarm;
timeval timeToExpiry;
std::list<Callout *>::iterator it;
if (!IsPending()) {
timeToExpiry.tv_sec = INT_MAX;
timeToExpiry.tv_usec = 999999; /*maximum normalized value*/
return (timeToExpiry);
}
timerclear(&timeToExpiry);
getitimer(ITIMER_REAL, &timervalToAlarm);
timeval& timeToAlarm = timervalToAlarm.it_value;
timeradd(&timeToExpiry, &timeToAlarm, &timeToExpiry);
it =s_activeCallouts.begin();
it++; /*skip the first callout in the list*/
for (; it != s_activeCallouts.end(); it++) {
timeradd(&timeToExpiry, &(*it)->m_interval, &timeToExpiry);
if ((*it) == this)
break;
}
return (timeToExpiry);
}
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