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 =============================*/ 40 namespace DevdCtl 41 { 42 43 /*=========================== Forward Declarations ===========================*/ 44 class Event; 45 46 /*============================ Class Declarations ============================*/ 47 /*----------------------------- DevdCtl::Consumer ----------------------------*/ 48 49 /** 50 */ 51 class Consumer 52 { 53 public: 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(); 112 113 protected: 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 --------------------------------------- 152 inline bool 153 Consumer::Connected() const 154 { 155 return (m_devdSockFD != -1); 156 } 157 158 //- Consumer Public Inline Methods --------------------------------------------- 159 inline int 160 Consumer::GetPollFd() 161 { 162 return (m_devdSockFD); 163 } 164 165 inline EventFactory 166 Consumer::GetFactory() 167 { 168 return (m_eventFactory); 169 } 170 171 } // namespace DevdCtl 172 #endif /* _DEVDCTL_CONSUMER_H_ */ 173