1/*-
2 * Copyright (c) 2011, 2012, 2013, 2014 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 devdctl_consumer.h
35 */
36#ifndef	_DEVDCTL_CONSUMER_H_
37#define	_DEVDCTL_CONSUMER_H_
38
39/*============================ Namespace Control =============================*/
40namespace DevdCtl
41{
42
43/*=========================== Forward Declarations ===========================*/
44class Event;
45
46/*============================ Class Declarations ============================*/
47/*----------------------------- DevdCtl::Consumer ----------------------------*/
48
49/**
50 */
51class Consumer
52{
53public:
54	Consumer(Event::BuildMethod *defBuilder = NULL,
55		 EventFactory::Record *regEntries = NULL,
56		 size_t numEntries = 0);
57	virtual ~Consumer();
58
59	bool Connected() const;
60
61	/**
62	 * Return file descriptor useful for client's wishing to poll(2)
63	 * for new events.
64	 */
65	int GetPollFd();
66
67	/**
68         * Queue an event for deferred processing or replay.
69         */
70	bool SaveEvent(const Event &event);
71
72	/**
73	 * Reprocess any events saved via the SaveEvent() facility.
74	 *
75	 * \param discardUnconsumed  If true, events that are not consumed
76	 *                           during replay are discarded.
77	 */
78	void ReplayUnconsumedEvents(bool discardUnconsumed);
79
80	/** Return an event, if one is available.  */
81	Event *NextEvent();
82
83	/**
84	 * Extract events and invoke each event's Process method.
85	 */
86	void ProcessEvents();
87
88	/** Discard all data pending in m_devdSockFD. */
89	void FlushEvents();
90
91	/**
92	 * Test for data pending in m_devdSockFD
93	 *
94	 * \return  True if data is pending.  Otherwise false.
95	 */
96	bool EventsPending();
97
98	/**
99	 * Open a connection to devd's unix domain socket.
100	 *
101	 * \return  True if the connection attempt is successful.  Otherwise
102	 *          false.
103	 */
104	bool ConnectToDevd();
105
106	/**
107	 * Close a connection (if any) to devd's unix domain socket.
108	 */
109	void DisconnectFromDevd();
110
111	EventFactory GetFactory();
112
113protected:
114	/**
115	 * \brief Reads the most recent record
116	 *
117	 * On error, "" is returned, and errno will be set by the OS
118	 *
119	 * \returns      A string containing the record
120	 */
121	std::string ReadEvent();
122
123	enum {
124		/*
125		 * The maximum event size supported by libdevdctl.
126		 */
127		MAX_EVENT_SIZE = 8192,
128	};
129
130	static const char  s_devdSockPath[];
131
132	/**
133	 * File descriptor representing the unix domain socket
134	 * connection with devd.
135	 */
136	int                m_devdSockFD;
137
138	EventFactory	   m_eventFactory;
139
140	/** Queued events for replay. */
141	EventList	   m_unconsumedEvents;
142
143	/**
144	 * Flag controlling whether events can be queued.  This boolean
145	 * is set during event replay to ensure that previosuly deferred
146	 * events are not requeued and thus retained forever.
147	 */
148	bool		   m_replayingEvents;
149};
150
151//- Consumer Const Public Inline Methods ---------------------------------------
152inline bool
153Consumer::Connected() const
154{
155	return (m_devdSockFD != -1);
156}
157
158//- Consumer Public Inline Methods ---------------------------------------------
159inline int
160Consumer::GetPollFd()
161{
162	return (m_devdSockFD);
163}
164
165inline EventFactory
166Consumer::GetFactory()
167{
168	return (m_eventFactory);
169}
170
171} // namespace DevdCtl
172#endif	/* _DEVDCTL_CONSUMER_H_ */
173