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 * $FreeBSD$
33 */
34
35/**
36 * \file devdctl_consumer.h
37 */
38#ifndef	_DEVDCTL_CONSUMER_H_
39#define	_DEVDCTL_CONSUMER_H_
40
41/*============================ Namespace Control =============================*/
42namespace DevdCtl
43{
44
45/*=========================== Forward Declarations ===========================*/
46class Event;
47
48/*============================ Class Declarations ============================*/
49/*----------------------------- DevdCtl::Consumer ----------------------------*/
50
51/**
52 */
53class Consumer
54{
55public:
56	Consumer(Event::BuildMethod *defBuilder = NULL,
57		 EventFactory::Record *regEntries = NULL,
58		 size_t numEntries = 0);
59	virtual ~Consumer();
60
61	bool Connected() const;
62
63	/**
64	 * Return file descriptor useful for client's wishing to poll(2)
65	 * for new events.
66	 */
67	int GetPollFd();
68
69	/**
70         * Queue an event for deferred processing or replay.
71         */
72	bool SaveEvent(const Event &event);
73
74	/**
75	 * Reprocess any events saved via the SaveEvent() facility.
76	 *
77	 * \param discardUnconsumed  If true, events that are not consumed
78	 *                           during replay are discarded.
79	 */
80	void ReplayUnconsumedEvents(bool discardUnconsumed);
81
82	/** Return an event, if one is available.  */
83	Event *NextEvent();
84
85	/**
86	 * Extract events and invoke each event's Process method.
87	 */
88	void ProcessEvents();
89
90	/** Discard all data pending in m_devdSockFD. */
91	void FlushEvents();
92
93	/**
94	 * Test for data pending in m_devdSockFD
95	 *
96	 * \return  True if data is pending.  Otherwise false.
97	 */
98	bool EventsPending();
99
100	/**
101	 * Open a connection to devd's unix domain socket.
102	 *
103	 * \return  True if the connection attempt is successsful.  Otherwise
104	 *          false.
105	 */
106	bool ConnectToDevd();
107
108	/**
109	 * Close a connection (if any) to devd's unix domain socket.
110	 */
111	void DisconnectFromDevd();
112
113	EventFactory GetFactory();
114
115protected:
116	/**
117	 * \brief Reads the most recent record
118	 *
119	 * On error, "" is returned, and errno will be set by the OS
120	 *
121	 * \returns      A string containing the record
122	 */
123	std::string ReadEvent();
124
125	enum {
126		/*
127		 * The maximum event size supported by libdevdctl.
128		 */
129		MAX_EVENT_SIZE = 8192,
130	};
131
132	static const char  s_devdSockPath[];
133
134	/**
135	 * File descriptor representing the unix domain socket
136	 * connection with devd.
137	 */
138	int                m_devdSockFD;
139
140	EventFactory	   m_eventFactory;
141
142	/** Queued events for replay. */
143	EventList	   m_unconsumedEvents;
144
145	/**
146	 * Flag controlling whether events can be queued.  This boolean
147	 * is set during event replay to ensure that previosuly deferred
148	 * events are not requeued and thus retained forever.
149	 */
150	bool		   m_replayingEvents;
151};
152
153//- Consumer Const Public Inline Methods ---------------------------------------
154inline bool
155Consumer::Connected() const
156{
157	return (m_devdSockFD != -1);
158}
159
160//- Consumer Public Inline Methods ---------------------------------------------
161inline int
162Consumer::GetPollFd()
163{
164	return (m_devdSockFD);
165}
166
167inline EventFactory
168Consumer::GetFactory()
169{
170	return (m_eventFactory);
171}
172
173} // namespace DevdCtl
174#endif	/* _DEVDCTL_CONSUMER_H_ */
175