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
33/**
34 * \file callout.cc
35 *
36 * \brief Implementation of the Callout class - multi-client
37 *        timer services built on top of the POSIX interval timer.
38 */
39
40#include <sys/byteorder.h>
41#include <sys/time.h>
42
43#include <signal.h>
44#include <syslog.h>
45
46#include <climits>
47#include <list>
48#include <map>
49#include <string>
50
51#include <devdctl/guid.h>
52#include <devdctl/event.h>
53#include <devdctl/event_factory.h>
54#include <devdctl/consumer.h>
55#include <devdctl/exception.h>
56
57#include "callout.h"
58#include "vdev_iterator.h"
59#include "zfsd.h"
60#include "zfsd_exception.h"
61
62std::list<Callout *> Callout::s_activeCallouts;
63bool		     Callout::s_alarmFired(false);
64
65void
66Callout::Init()
67{
68	signal(SIGALRM,  Callout::AlarmSignalHandler);
69}
70
71bool
72Callout::Stop()
73{
74	if (!IsPending())
75		return (false);
76
77	for (std::list<Callout *>::iterator it(s_activeCallouts.begin());
78	     it != s_activeCallouts.end(); it++) {
79		if (*it != this)
80			continue;
81
82		it = s_activeCallouts.erase(it);
83		if (it != s_activeCallouts.end()) {
84
85			/*
86			 * Maintain correct interval for the
87			 * callouts that follow the just removed
88			 * entry.
89			 */
90			timeradd(&(*it)->m_interval, &m_interval,
91				 &(*it)->m_interval);
92		}
93		break;
94	}
95	m_pending = false;
96	return (true);
97}
98
99bool
100Callout::Reset(const timeval &interval, CalloutFunc_t *func, void *arg)
101{
102	bool cancelled(false);
103
104	if (!timerisset(&interval))
105		throw ZfsdException("Callout::Reset: interval of 0");
106
107	cancelled = Stop();
108
109	m_interval = interval;
110	m_func     = func;
111	m_arg      = arg;
112	m_pending  = true;
113
114	std::list<Callout *>::iterator it(s_activeCallouts.begin());
115	for (; it != s_activeCallouts.end(); it++) {
116
117		if (timercmp(&(*it)->m_interval, &m_interval, <=)) {
118			/*
119			 * Decrease our interval by those that come
120			 * before us.
121			 */
122			timersub(&m_interval, &(*it)->m_interval, &m_interval);
123		} else {
124			/*
125			 * Account for the time between the newly
126			 * inserted event and those that follow.
127			 */
128			timersub(&(*it)->m_interval, &m_interval,
129				 &(*it)->m_interval);
130			break;
131		}
132	}
133	s_activeCallouts.insert(it, this);
134
135
136	if (s_activeCallouts.front() == this) {
137		itimerval timerval = { {0, 0}, m_interval };
138
139		setitimer(ITIMER_REAL, &timerval, NULL);
140	}
141
142	return (cancelled);
143}
144
145void
146Callout::AlarmSignalHandler(int)
147{
148	s_alarmFired = true;
149	ZfsDaemon::WakeEventLoop();
150}
151
152void
153Callout::ExpireCallouts()
154{
155	if (!s_alarmFired)
156		return;
157
158	s_alarmFired = false;
159	if (s_activeCallouts.empty()) {
160		/* Callout removal/SIGALRM race was lost. */
161		return;
162	}
163
164	/*
165	 * Expire the first callout (the one we used to set the
166	 * interval timer) as well as any callouts following that
167	 * expire at the same time (have a zero interval from
168	 * the callout before it).
169	 */
170	do {
171		Callout *cur(s_activeCallouts.front());
172		s_activeCallouts.pop_front();
173		cur->m_pending = false;
174		cur->m_func(cur->m_arg);
175	} while (!s_activeCallouts.empty()
176	      && timerisset(&s_activeCallouts.front()->m_interval) == 0);
177
178	if (!s_activeCallouts.empty()) {
179		Callout *next(s_activeCallouts.front());
180		itimerval timerval = { { 0, 0 }, next->m_interval };
181
182		setitimer(ITIMER_REAL, &timerval, NULL);
183	}
184}
185
186timeval
187Callout::TimeRemaining() const
188{
189	/*
190	 * Outline: Add the m_interval for each callout in s_activeCallouts
191	 * ahead of this, except for the first callout.  Add to that the result
192	 * of getitimer (That's because the first callout stores its original
193	 * interval setting while the timer is ticking).
194	 */
195	itimerval timervalToAlarm;
196	timeval timeToExpiry;
197	std::list<Callout *>::iterator it;
198
199	if (!IsPending()) {
200		timeToExpiry.tv_sec = INT_MAX;
201		timeToExpiry.tv_usec = 999999;	/*maximum normalized value*/
202		return (timeToExpiry);
203	}
204
205	timerclear(&timeToExpiry);
206	getitimer(ITIMER_REAL, &timervalToAlarm);
207	timeval& timeToAlarm = timervalToAlarm.it_value;
208	timeradd(&timeToExpiry, &timeToAlarm, &timeToExpiry);
209
210	it =s_activeCallouts.begin();
211	it++;	/*skip the first callout in the list*/
212	for (; it != s_activeCallouts.end(); it++) {
213		timeradd(&timeToExpiry, &(*it)->m_interval, &timeToExpiry);
214		if ((*it) == this)
215			break;
216	}
217	return (timeToExpiry);
218}
219