1/*-
2 * Copyright (c) 2011, 2012, 2013 Spectra Logic Corporation
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions, and the following disclaimer,
10 *    without modification.
11 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
12 *    substantially similar to the "NO WARRANTY" disclaimer below
13 *    ("Disclaimer") and any redistribution must be conditioned upon
14 *    including a substantially similar Disclaimer requirement for further
15 *    binary redistribution.
16 *
17 * NO WARRANTY
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
26 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
27 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGES.
29 *
30 * Authors: Justin T. Gibbs     (Spectra Logic Corporation)
31 *
32 * $FreeBSD$
33 */
34
35/**
36 * \file callout.cc
37 *
38 * \brief Implementation of the Callout class - multi-client
39 *        timer services built on top of the POSIX interval timer.
40 */
41
42#include <sys/byteorder.h>
43#include <sys/time.h>
44
45#include <signal.h>
46#include <syslog.h>
47
48#include <climits>
49#include <list>
50#include <map>
51#include <string>
52
53#include <devdctl/guid.h>
54#include <devdctl/event.h>
55#include <devdctl/event_factory.h>
56#include <devdctl/consumer.h>
57#include <devdctl/exception.h>
58
59#include "callout.h"
60#include "vdev_iterator.h"
61#include "zfsd.h"
62#include "zfsd_exception.h"
63
64std::list<Callout *> Callout::s_activeCallouts;
65bool		     Callout::s_alarmFired(false);
66
67void
68Callout::Init()
69{
70	signal(SIGALRM,  Callout::AlarmSignalHandler);
71}
72
73bool
74Callout::Stop()
75{
76	if (!IsPending())
77		return (false);
78
79	for (std::list<Callout *>::iterator it(s_activeCallouts.begin());
80	     it != s_activeCallouts.end(); it++) {
81		if (*it != this)
82			continue;
83
84		it = s_activeCallouts.erase(it);
85		if (it != s_activeCallouts.end()) {
86
87			/*
88			 * Maintain correct interval for the
89			 * callouts that follow the just removed
90			 * entry.
91			 */
92			timeradd(&(*it)->m_interval, &m_interval,
93				 &(*it)->m_interval);
94		}
95		break;
96	}
97	m_pending = false;
98	return (true);
99}
100
101bool
102Callout::Reset(const timeval &interval, CalloutFunc_t *func, void *arg)
103{
104	bool cancelled(false);
105
106	if (!timerisset(&interval))
107		throw ZfsdException("Callout::Reset: interval of 0");
108
109	cancelled = Stop();
110
111	m_interval = interval;
112	m_func     = func;
113	m_arg      = arg;
114	m_pending  = true;
115
116	std::list<Callout *>::iterator it(s_activeCallouts.begin());
117	for (; it != s_activeCallouts.end(); it++) {
118
119		if (timercmp(&(*it)->m_interval, &m_interval, <=)) {
120			/*
121			 * Decrease our interval by those that come
122			 * before us.
123			 */
124			timersub(&m_interval, &(*it)->m_interval, &m_interval);
125		} else {
126			/*
127			 * Account for the time between the newly
128			 * inserted event and those that follow.
129			 */
130			timersub(&(*it)->m_interval, &m_interval,
131				 &(*it)->m_interval);
132			break;
133		}
134	}
135	s_activeCallouts.insert(it, this);
136
137
138	if (s_activeCallouts.front() == this) {
139		itimerval timerval = { {0, 0}, m_interval };
140
141		setitimer(ITIMER_REAL, &timerval, NULL);
142	}
143
144	return (cancelled);
145}
146
147void
148Callout::AlarmSignalHandler(int)
149{
150	s_alarmFired = true;
151	ZfsDaemon::WakeEventLoop();
152}
153
154void
155Callout::ExpireCallouts()
156{
157	if (!s_alarmFired)
158		return;
159
160	s_alarmFired = false;
161	if (s_activeCallouts.empty()) {
162		/* Callout removal/SIGALRM race was lost. */
163		return;
164	}
165
166	/*
167	 * Expire the first callout (the one we used to set the
168	 * interval timer) as well as any callouts following that
169	 * expire at the same time (have a zero interval from
170	 * the callout before it).
171	 */
172	do {
173		Callout *cur(s_activeCallouts.front());
174		s_activeCallouts.pop_front();
175		cur->m_pending = false;
176		cur->m_func(cur->m_arg);
177	} while (!s_activeCallouts.empty()
178	      && timerisset(&s_activeCallouts.front()->m_interval) == 0);
179
180	if (!s_activeCallouts.empty()) {
181		Callout *next(s_activeCallouts.front());
182		itimerval timerval = { { 0, 0 }, next->m_interval };
183
184		setitimer(ITIMER_REAL, &timerval, NULL);
185	}
186}
187
188timeval
189Callout::TimeRemaining() const
190{
191	/*
192	 * Outline: Add the m_interval for each callout in s_activeCallouts
193	 * ahead of this, except for the first callout.  Add to that the result
194	 * of getitimer (That's because the first callout stores its original
195	 * interval setting while the timer is ticking).
196	 */
197	itimerval timervalToAlarm;
198	timeval timeToExpiry;
199	std::list<Callout *>::iterator it;
200
201	if (!IsPending()) {
202		timeToExpiry.tv_sec = INT_MAX;
203		timeToExpiry.tv_usec = 999999;	/*maximum normalized value*/
204		return (timeToExpiry);
205	}
206
207	timerclear(&timeToExpiry);
208	getitimer(ITIMER_REAL, &timervalToAlarm);
209	timeval& timeToAlarm = timervalToAlarm.it_value;
210	timeradd(&timeToExpiry, &timeToAlarm, &timeToExpiry);
211
212	it =s_activeCallouts.begin();
213	it++;	/*skip the first callout in the list*/
214	for (; it != s_activeCallouts.end(); it++) {
215		timeradd(&timeToExpiry, &(*it)->m_interval, &timeToExpiry);
216		if ((*it) == this)
217			break;
218	}
219	return (timeToExpiry);
220}
221