src/socketengines/socketengine_select.cpp

   1 /*       +------------------------------------+
   2  *       | Inspire Internet Relay Chat Daemon |
   3  *       +------------------------------------+
   4  *
   5  *  InspIRCd: (C) 2002-2008 InspIRCd Development Team
   6  * See: http://www.inspircd.org/wiki/index.php/Credits
   7  *
   8  * This program is free but copyrighted software; see
   9  *          the file COPYING for details.
  10  *
  11  * ---------------------------------------------------
  12  */
  13
  14 #include "inspircd.h"
  15 #ifndef WINDOWS
  16 #include <sys/select.h>
  17 #endif // WINDOWS
  18 #include "socketengines/socketengine_select.h"
  19
  20
  21 SelectEngine::SelectEngine(InspIRCd* Instance) : SocketEngine(Instance)
  22 {
  23         MAX_DESCRIPTORS = FD_SETSIZE;
  24         EngineHandle = 0;
  25         CurrentSetSize = 0;
  26
  27         writeable = new bool [GetMaxFds()];
  28         memset(writeable, 0, sizeof(writeable));
  29         ref = new EventHandler* [GetMaxFds()];
  30         memset(ref, 0, GetMaxFds() * sizeof(EventHandler*));
  31         ev = new EventHandler* [GetMaxFds()];
  32 }
  33
  34 SelectEngine::~SelectEngine()
  35 {
  36         delete[] ref;
  37         delete[] ev;
  38 }
  39
  40 bool SelectEngine::AddFd(EventHandler* eh)
  41 {
  42         int fd = eh->GetFd();
  43         if ((fd < 0) || (fd > GetMaxFds() - 1))
  44                 return false;
  45
  46         if (GetRemainingFds() <= 1)
  47                 return false;
  48
  49         if (ref[fd])
  50                 return false;
  51
  52         fds[fd] = fd;
  53         ref[fd] = eh;
  54         CurrentSetSize++;
  55
  56         ServerInstance->Logs->Log("SOCKET",DEBUG,"New file descriptor: %d", fd);
  57         return true;
  58 }
  59
  60 void SelectEngine::WantWrite(EventHandler* eh)
  61 {
  62         writeable[eh->GetFd()] = true;
  63 }
  64
  65 bool SelectEngine::DelFd(EventHandler* eh, bool force)
  66 {
  67         int fd = eh->GetFd();
  68
  69         if ((fd < 0) || (fd > GetMaxFds() - 1))
  70                 return false;
  71
  72         std::map<int,int>::iterator t = fds.find(fd);
  73         if (t != fds.end())
  74                 fds.erase(t);
  75
  76         CurrentSetSize--;
  77         ref[fd] = NULL;
  78
  79         ServerInstance->Logs->Log("SOCKET",DEBUG,"Remove file descriptor: %d", fd);
  80         return true;
  81 }
  82
  83 int SelectEngine::GetMaxFds()
  84 {
  85         return FD_SETSIZE;
  86 }
  87
  88 int SelectEngine::GetRemainingFds()
  89 {
  90         return GetMaxFds() - CurrentSetSize;
  91 }
  92
  93 int SelectEngine::DispatchEvents()
  94 {
  95         timeval tval;
  96         int sresult = 0;
  97         socklen_t codesize;
  98         int errcode = 0;
  99
 100         FD_ZERO(&wfdset);
 101         FD_ZERO(&rfdset);
 102         FD_ZERO(&errfdset);
 103
 104         /* Populate the select FD set (this is why select sucks compared to epoll, kqueue, IOCP) */
 105         for (std::map<int,int>::iterator a = fds.begin(); a != fds.end(); a++)
 106         {
 107                 if (ref[a->second]->Readable())
 108                         /* Read notifications */
 109                         FD_SET (a->second, &rfdset);
 110                 else
 111                         /* Write notifications */
 112                         FD_SET (a->second, &wfdset);
 113
 114                 /* Explicitly one-time writeable */
 115                 if (writeable[a->second])
 116                         FD_SET (a->second, &wfdset);
 117
 118                 /* All sockets must receive error notifications regardless */
 119                 FD_SET (a->second, &errfdset);
 120         }
 121
 122         /* One second waits */
 123         tval.tv_sec = 1;
 124         tval.tv_usec = 0;
 125
 126         sresult = select(FD_SETSIZE, &rfdset, &wfdset, &errfdset, &tval);
 127
 128         /* Nothing to process this time around */
 129         if (sresult < 1)
 130                 return 0;
 131
 132         /* Safe assumption (as of 1.1 anyway) that a socket can't remove itself from the list in the middle of the loop */
 133         for (std::map<int,int>::iterator a = fds.begin(); a != fds.end(); a++)
 134         {
 135                 EventHandler* ev = ref[a->second];
 136                 if (ev)
 137                 {
 138                         if (FD_ISSET (ev->GetFd(), &errfdset))
 139                         {
 140                                 ErrorEvents++;
 141                                 if (getsockopt(ev->GetFd(), SOL_SOCKET, SO_ERROR, (char*)&errcode, &codesize) < 0)
 142                                         errcode = errno;
 143
 144                                 ev->HandleEvent(EVENT_ERROR, errcode);
 145                                 continue;
 146                         }
 147                         else
 148                         {
 149                                 /* NOTE: This is a pair of seperate if statements as the socket
 150                                  * may be in both read and writeable state at the same time.
 151                                  * If an error event occurs above it is not worth processing the
 152                                  * read and write states even if set.
 153                                  */
 154                                 if (FD_ISSET (ev->GetFd(), &wfdset))
 155                                 {
 156                                         WriteEvents++;
 157                                         writeable[ev->GetFd()] = false;
 158                                         ev->HandleEvent(EVENT_WRITE);
 159                                 }
 160                                 if (FD_ISSET (ev->GetFd(), &rfdset))
 161                                 {
 162                                                 ReadEvents++;
 163                                                 ev->HandleEvent(EVENT_READ);
 164                                 }
 165                         }
 166                 }
 167         }
 168
 169         return sresult;
 170 }
 171
 172 std::string SelectEngine::GetName()
 173 {
 174         return "select";
 175 }