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 =============================*/
42 namespace DevdCtl
43 {
44
45 /*=========================== Forward Declarations ===========================*/
46 class Event;
47
48 /*============================ Class Declarations ============================*/
49 /*----------------------------- DevdCtl::Consumer ----------------------------*/
50
51 /**
52 */
53 class Consumer
54 {
55 public:
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
115 protected:
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 ---------------------------------------
154 inline bool
Connected()155 Consumer::Connected() const
156 {
157 return (m_devdSockFD != -1);
158 }
159
160 //- Consumer Public Inline Methods ---------------------------------------------
161 inline int
GetPollFd()162 Consumer::GetPollFd()
163 {
164 return (m_devdSockFD);
165 }
166
167 inline EventFactory
GetFactory()168 Consumer::GetFactory()
169 {
170 return (m_eventFactory);
171 }
172
173 } // namespace DevdCtl
174 #endif /* _DEVDCTL_CONSUMER_H_ */
175