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 155 Consumer::Connected() const 156 { 157 return (m_devdSockFD != -1); 158 } 159 160 //- Consumer Public Inline Methods --------------------------------------------- 161 inline int 162 Consumer::GetPollFd() 163 { 164 return (m_devdSockFD); 165 } 166 167 inline EventFactory 168 Consumer::GetFactory() 169 { 170 return (m_eventFactory); 171 } 172 173 } // namespace DevdCtl 174 #endif /* _DEVDCTL_CONSUMER_H_ */ 175