1 /* 2 Copyright (c) 2009-2017, Intel Corporation 3 All rights reserved. 4 5 Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 6 7 * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 8 * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 9 * Neither the name of Intel Corporation nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. 10 11 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 12 */ 13 // written by Steven Briscoe 14 15 #include <cstdlib> 16 #include <iostream> 17 #include <unistd.h> 18 #include <sys/types.h> 19 #include <sys/ipc.h> 20 #include <sys/shm.h> 21 #include <errno.h> 22 #include <sstream> 23 #include <exception> 24 #include <stdexcept> 25 #include <grp.h> 26 #include <stdio.h> 27 #include <stdlib.h> 28 29 #include "../daemon/common.h" 30 #include "client.h" 31 32 namespace PCMDaemon { 33 Client()34 Client::Client() 35 : pollIntervalMs_(0), shmIdLocation_(DEFAULT_SHM_ID_LOCATION), shmAttached_(false), lastUpdatedClientTsc_(0) 36 {} 37 setSharedMemoryIdLocation(const std::string & location)38 void Client::setSharedMemoryIdLocation(const std::string& location) 39 { 40 if(shmAttached_) 41 { 42 throw std::runtime_error("Shared memory segment already attached. You must call this method before the .connect() method."); 43 } 44 shmIdLocation_ = location; 45 } 46 setPollInterval(int pollMs)47 void Client::setPollInterval(int pollMs) 48 { 49 pollIntervalMs_ = pollMs; 50 } 51 connect()52 void Client::connect() 53 { 54 setupSharedMemory(); 55 56 //Set last updated timestamp to avoid a detected change 57 //when the client starts 58 lastUpdatedClientTsc_ = sharedPCMState_->lastUpdateTscEnd; 59 } 60 read()61 PCMDaemon::SharedPCMState& Client::read() 62 { 63 if(pollIntervalMs_ <= 0) 64 { 65 throw std::runtime_error("The poll interval is not set or is negative."); 66 } 67 68 if(!shmAttached_) 69 { 70 throw std::runtime_error("Not attached to shared memory segment. Call .connect() method."); 71 } 72 73 while(true) 74 { 75 // Check client version matches daemon version 76 if(strlen(sharedPCMState_->version) > 0 && strcmp(sharedPCMState_->version, VERSION) != 0) 77 { 78 std::cout << sharedPCMState_->lastUpdateTscEnd << " " << lastUpdatedClientTsc_ << "\n"; 79 std::stringstream ss; 80 ss << "Out of date PCM daemon client. Client version: " << VERSION << " Daemon version: " << sharedPCMState_->version; 81 82 throw std::runtime_error(ss.str()); 83 } 84 85 if(countersHaveUpdated()) 86 { 87 //There is new data 88 lastUpdatedClientTsc_ = sharedPCMState_->lastUpdateTscEnd; 89 90 return *sharedPCMState_; 91 } 92 else 93 { 94 //Nothing has changed since we last checked 95 usleep(pollIntervalMs_ * 1000); 96 } 97 } 98 } 99 countersHaveUpdated()100 bool Client::countersHaveUpdated() 101 { 102 return lastUpdatedClientTsc_ != sharedPCMState_->lastUpdateTscEnd; 103 } 104 setupSharedMemory()105 void Client::setupSharedMemory() 106 { 107 int sharedMemoryId; 108 FILE *fp = fopen (shmIdLocation_.c_str(), "r"); 109 if (!fp) 110 { 111 std::cerr << "Failed to open to shared memory key location: " << shmIdLocation_ << "\n"; 112 exit(EXIT_FAILURE); 113 } 114 int maxCharsToRead = 11; 115 char readBuffer[maxCharsToRead]; 116 fread(&readBuffer, maxCharsToRead, 1, fp); 117 fclose (fp); 118 119 sharedMemoryId = atoi(readBuffer); 120 121 sharedPCMState_ = (PCMDaemon::SharedPCMState*)shmat(sharedMemoryId, NULL, 0); 122 if (sharedPCMState_ == (void *)-1) 123 { 124 std::stringstream ss; 125 ss << "Failed to attach shared memory segment (errno=" << errno << ")"; 126 127 throw std::runtime_error(ss.str()); 128 } 129 130 shmAttached_ = true; 131 } 132 133 } 134