src/IOHandler/IOEngine_select.c

   1 /* IOEngine_select.c - IOMultiplexer
   2  * Copyright (C) 2014  Philipp Kreil (pk910)
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  16  */
  17 #define _IOHandler_internals
  18 #include "IOInternal.h"
  19 #include "IOHandler.h"
  20 #include "IOLog.h"
  21 #include "IOSockets.h"
  22 #include "IOTimer.h"
  23
  24 #include <errno.h>
  25 #include <time.h>
  26 #include <string.h>
  27 #include <stdio.h>
  28 #ifdef WIN32
  29 #define _WIN32_WINNT 0x501
  30 #include <windows.h>
  31 #include <winsock2.h>
  32 #elif defined HAVE_SYS_SELECT_H
  33 #include <sys/select.h>
  34 #endif
  35
  36 /* compat */
  37 #include "compat/utime.h"
  38
  39 static int engine_select_init() {
  40         return 1;
  41 }
  42
  43 static void engine_select_add(struct _IOSocket *iosock) {
  44         /* empty */
  45 }
  46
  47 static void engine_select_remove(struct _IOSocket *iosock) {
  48         /* empty */
  49 }
  50
  51 static void engine_select_update(struct _IOSocket *iosock) {
  52         /* empty */
  53 }
  54
  55 static void engine_select_loop(struct timeval *timeout) {
  56         fd_set read_fds;
  57         fd_set write_fds;
  58         unsigned int fds_size = 0;
  59         struct _IOSocket *iosock, *next_iosock;
  60         struct timeval now, tout;
  61         int select_result;
  62
  63         //clear fds
  64         FD_ZERO(&read_fds);
  65         FD_ZERO(&write_fds);
  66
  67         //check timers
  68         gettimeofday(&now, NULL);
  69         if(iotimer_sorted_descriptors && timeval_is_bigger(now, iotimer_sorted_descriptors->timeout))
  70                 _trigger_timer();
  71
  72         //get timeout (timer or given timeout)
  73         if(iotimer_sorted_descriptors) {
  74                 tout = iotimer_sorted_descriptors->timeout;
  75                 tout.tv_sec -= now.tv_sec;
  76                 tout.tv_usec -= now.tv_usec;
  77                 if(tout.tv_usec < 0) {
  78                         tout.tv_sec --;
  79                         tout.tv_usec += 1000000;
  80                 }
  81         }
  82         if(timeout) {
  83                 if(!iotimer_sorted_descriptors || timeval_is_smaler((*timeout), tout)) {
  84                         tout.tv_usec = timeout->tv_usec;
  85                         tout.tv_sec = timeout->tv_sec;
  86                 }
  87                 timeout = &tout;
  88         } else if(iotimer_sorted_descriptors)
  89                 timeout = &tout;
  90
  91         select_result = 0;
  92         for(iosock = iosocket_first; iosock; iosock = iosock->next) {
  93                 if(!(iosock->socket_flags & IOSOCKETFLAG_ACTIVE))
  94                         continue;
  95                 if(iosock->fd > fds_size)
  96                         fds_size = iosock->fd;
  97                 select_result++;
  98                 if(iosocket_wants_reads(iosock))
  99                         FD_SET(iosock->fd, &read_fds);
 100                 if(iosocket_wants_writes(iosock))
 101                         FD_SET(iosock->fd, &write_fds);
 102         }
 103
 104         if(select_result) //select system call
 105                 select_result = select(fds_size + 1, &read_fds, &write_fds, NULL, timeout);
 106         else if(timeout) {
 107                 usleep_tv(*timeout);
 108                 select_result = 0;
 109         } else
 110                 usleep(10000); // 10ms
 111
 112         if (select_result < 0) {
 113                 if (errno != EINTR) {
 114                         iolog_trigger(IOLOG_FATAL, "select() failed with errno %d %d: %s", select_result, errno, strerror(errno));
 115                         return;
 116                 }
 117         }
 118
 119         gettimeofday(&now, NULL);
 120
 121         //check all descriptors
 122         for(iosock = iosocket_first; iosock; iosock = next_iosock) {
 123                 next_iosock = iosock->next;
 124                 if(!(iosock->socket_flags & IOSOCKETFLAG_ACTIVE))
 125                         return;
 126                 if(FD_ISSET(iosock->fd, &read_fds) || FD_ISSET(iosock->fd, &write_fds))
 127                         iosocket_events_callback(iosock, FD_ISSET(iosock->fd, &read_fds), FD_ISSET(iosock->fd, &write_fds));
 128         }
 129
 130         //check timers
 131         if(iotimer_sorted_descriptors && timeval_is_bigger(now, iotimer_sorted_descriptors->timeout))
 132                 _trigger_timer();
 133
 134 }
 135
 136 static void engine_select_cleanup() {
 137         /* empty */
 138 }
 139
 140 struct IOEngine engine_select = {
 141         .name = "select",
 142         .init = engine_select_init,
 143         .add = engine_select_add,
 144         .remove = engine_select_remove,
 145         .update = engine_select_update,
 146         .loop = engine_select_loop,
 147         .cleanup = engine_select_cleanup,
 148 };