src/socketengines/socketengine_select.cpp

   1 /*       +------------------------------------+
   2  *       | Inspire Internet Relay Chat Daemon |
   3  *       +------------------------------------+
   4  *
   5  *  InspIRCd: (C) 2002-2009 InspIRCd Development Team
   6  * See: http://wiki.inspircd.org/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()
  22 {
  23         MAX_DESCRIPTORS = FD_SETSIZE;
  24         EngineHandle = 0;
  25         CurrentSetSize = 0;
  26
  27         writeable.assign(GetMaxFds(), false);
  28         ref = new EventHandler* [GetMaxFds()];
  29         memset(ref, 0, GetMaxFds() * sizeof(EventHandler*));
  30 }
  31
  32 SelectEngine::~SelectEngine()
  33 {
  34         delete[] ref;
  35 }
  36
  37 bool SelectEngine::AddFd(EventHandler* eh, bool writeFirst)
  38 {
  39         int fd = eh->GetFd();
  40         if ((fd < 0) || (fd > GetMaxFds() - 1))
  41                 return false;
  42
  43         if (GetRemainingFds() <= 1)
  44                 return false;
  45
  46         if (ref[fd])
  47                 return false;
  48
  49         fds.insert(fd);
  50         ref[fd] = eh;
  51         CurrentSetSize++;
  52
  53         writeable[eh->GetFd()] = writeFirst;
  54
  55         ServerInstance->Logs->Log("SOCKET",DEBUG,"New file descriptor: %d", fd);
  56         return true;
  57 }
  58
  59 void SelectEngine::WantWrite(EventHandler* eh)
  60 {
  61         writeable[eh->GetFd()] = true;
  62 }
  63
  64 bool SelectEngine::DelFd(EventHandler* eh, bool force)
  65 {
  66         int fd = eh->GetFd();
  67
  68         if ((fd < 0) || (fd > GetMaxFds() - 1))
  69                 return false;
  70
  71         std::set<int>::iterator t = fds.find(fd);
  72         if (t != fds.end())
  73                 fds.erase(t);
  74
  75         CurrentSetSize--;
  76         ref[fd] = NULL;
  77
  78         ServerInstance->Logs->Log("SOCKET",DEBUG,"Remove file descriptor: %d", fd);
  79         return true;
  80 }
  81
  82 int SelectEngine::GetMaxFds()
  83 {
  84         return FD_SETSIZE;
  85 }
  86
  87 int SelectEngine::GetRemainingFds()
  88 {
  89         return GetMaxFds() - CurrentSetSize;
  90 }
  91
  92 int SelectEngine::DispatchEvents()
  93 {
  94         timeval tval;
  95         int sresult = 0;
  96         socklen_t codesize = sizeof(int);
  97         int errcode = 0;
  98
  99         FD_ZERO(&wfdset);
 100         FD_ZERO(&rfdset);
 101         FD_ZERO(&errfdset);
 102
 103         /* Populate the select FD set (this is why select sucks compared to epoll, kqueue, IOCP) */
 104         for (std::set<int>::iterator a = fds.begin(); a != fds.end(); a++)
 105         {
 106                 /* Explicitly one-time writeable */
 107                 if (writeable[*a])
 108                         FD_SET (*a, &wfdset);
 109                 else
 110                         FD_SET (*a, &rfdset);
 111
 112                 /* All sockets must receive error notifications regardless */
 113                 FD_SET (*a, &errfdset);
 114         }
 115
 116         /* One second waits */
 117         tval.tv_sec = 1;
 118         tval.tv_usec = 0;
 119
 120         sresult = select(FD_SETSIZE, &rfdset, &wfdset, &errfdset, &tval);
 121
 122         /* Nothing to process this time around */
 123         if (sresult < 1)
 124                 return 0;
 125
 126         std::vector<int> copy(fds.begin(), fds.end());
 127         for (std::vector<int>::iterator a = copy.begin(); a != copy.end(); a++)
 128         {
 129                 EventHandler* ev = ref[*a];
 130                 if (ev)
 131                 {
 132                         if (FD_ISSET (ev->GetFd(), &errfdset))
 133                         {
 134                                 ErrorEvents++;
 135                                 if (getsockopt(ev->GetFd(), SOL_SOCKET, SO_ERROR, (char*)&errcode, &codesize) < 0)
 136                                         errcode = errno;
 137
 138                                 ev->HandleEvent(EVENT_ERROR, errcode);
 139                                 continue;
 140                         }
 141                         else
 142                         {
 143                                 /* NOTE: This is a pair of seperate if statements as the socket
 144                                  * may be in both read and writeable state at the same time.
 145                                  * If an error event occurs above it is not worth processing the
 146                                  * read and write states even if set.
 147                                  */
 148                                 if (FD_ISSET (ev->GetFd(), &wfdset))
 149                                 {
 150                                         WriteEvents++;
 151                                         writeable[ev->GetFd()] = false;
 152                                         ev->HandleEvent(EVENT_WRITE);
 153                                 }
 154                                 if (FD_ISSET (ev->GetFd(), &rfdset))
 155                                 {
 156                                                 ReadEvents++;
 157                                                 ev->HandleEvent(EVENT_READ);
 158                                 }
 159                         }
 160                 }
 161         }
 162
 163         return sresult;
 164 }
 165
 166 std::string SelectEngine::GetName()
 167 {
 168         return "select";
 169 }