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