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 #ifdef WIN32
  27 #define _WIN32_WINNT 0x501
  28 #include <windows.h>
  29 #include <winsock2.h>
  30 #else
  31 #include <string.h>
  32 #include <stdio.h>
  33 #endif
  34
  35 /* compat */
  36 #include "compat/utime.h"
  37
  38 static int engine_select_init() {
  39         return 1;
  40 }
  41
  42 static void engine_select_add(struct _IOSocket *iosock) {
  43         /* empty */
  44 }
  45
  46 static void engine_select_remove(struct _IOSocket *iosock) {
  47         /* empty */
  48 }
  49
  50 static void engine_select_update(struct _IOSocket *iosock) {
  51         /* empty */
  52 }
  53
  54 static void engine_select_loop(struct timeval *timeout) {
  55         fd_set read_fds;
  56         fd_set write_fds;
  57         unsigned int fds_size = 0;
  58         struct _IOSocket *iosock, *next_iosock;
  59         struct timeval now, tout;
  60         int select_result;
  61
  62         //clear fds
  63         FD_ZERO(&read_fds);
  64         FD_ZERO(&write_fds);
  65
  66         //check timers
  67         gettimeofday(&now, NULL);
  68         if(iotimer_sorted_descriptors && timeval_is_bigger(now, iotimer_sorted_descriptors->timeout))
  69                 _trigger_timer();
  70
  71         //get timeout (timer or given timeout)
  72         if(iotimer_sorted_descriptors) {
  73                 tout = iotimer_sorted_descriptors->timeout;
  74                 tout.tv_sec -= now.tv_sec;
  75                 tout.tv_usec -= now.tv_usec;
  76                 if(tout.tv_usec < 0) {
  77                         tout.tv_sec --;
  78                         tout.tv_usec += 1000000;
  79                 }
  80         }
  81         if(timeout) {
  82                 if(!iotimer_sorted_descriptors || timeval_is_smaler((*timeout), tout)) {
  83                         tout.tv_usec = timeout->tv_usec;
  84                         tout.tv_sec = timeout->tv_sec;
  85                 }
  86                 timeout = &tout;
  87         } else if(iotimer_sorted_descriptors)
  88                 timeout = &tout;
  89
  90         select_result = 0;
  91         for(iosock = iosocket_first; iosock; iosock = iosock->next) {
  92                 if(!(iosock->socket_flags & IOSOCKETFLAG_ACTIVE))
  93                         continue;
  94                 if(iosock->fd > fds_size)
  95                         fds_size = iosock->fd;
  96                 select_result++;
  97                 if(iosocket_wants_reads(iosock))
  98                         FD_SET(iosock->fd, &read_fds);
  99                 if(iosocket_wants_writes(iosock))
 100                         FD_SET(iosock->fd, &write_fds);
 101         }
 102
 103         if(select_result) //select system call
 104                 select_result = select(fds_size + 1, &read_fds, &write_fds, NULL, timeout);
 105         else if(timeout) {
 106                 usleep_tv(*timeout);
 107                 select_result = 0;
 108         } else
 109                 usleep(10000); // 10ms
 110
 111         if (select_result < 0) {
 112                 if (errno != EINTR) {
 113                         iolog_trigger(IOLOG_FATAL, "select() failed with errno %d %d: %s", select_result, errno, strerror(errno));
 114                         return;
 115                 }
 116         }
 117
 118         gettimeofday(&now, NULL);
 119
 120         //check all descriptors
 121         for(iosock = iosocket_first; iosock; iosock = next_iosock) {
 122                 next_iosock = iosock->next;
 123                 if(!(iosock->socket_flags & IOSOCKETFLAG_ACTIVE))
 124                         return;
 125                 if(FD_ISSET(iosock->fd, &read_fds) || FD_ISSET(iosock->fd, &write_fds))
 126                         iosocket_events_callback(iosock, FD_ISSET(iosock->fd, &read_fds), FD_ISSET(iosock->fd, &write_fds));
 127         }
 128
 129         //check timers
 130         if(iotimer_sorted_descriptors && timeval_is_bigger(now, iotimer_sorted_descriptors->timeout))
 131                 _trigger_timer();
 132
 133 }
 134
 135 static void engine_select_cleanup() {
 136         /* empty */
 137 }
 138
 139 struct IOEngine engine_select = {
 140         .name = "select",
 141         .init = engine_select_init,
 142         .add = engine_select_add,
 143         .remove = engine_select_remove,
 144         .update = engine_select_update,
 145         .loop = engine_select_loop,
 146         .cleanup = engine_select_cleanup,
 147 };