epoll_loop.c

   1 /*****************************************************************************
   2   Copyright (c) 2006 EMC Corporation.
   3
   4   This program is free software; you can redistribute it and/or modify it
   5   under the terms of the GNU General Public License as published by the Free
   6   Software Foundation; either version 2 of the License, or (at your option)
   7   any later version.
   8
   9   This program is distributed in the hope that it will be useful, but WITHOUT
  10   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12   more details.
  13
  14   You should have received a copy of the GNU General Public License along with
  15   this program; if not, write to the Free Software Foundation, Inc., 59
  16   Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17
  18   The full GNU General Public License is included in this distribution in the
  19   file called LICENSE.
  20
  21   Authors: Srinivas Aji <Aji_Srinivas@emc.com>
  22
  23 ******************************************************************************/
  24
  25 #include "epoll_loop.h"
  26
  27 #include <sys/epoll.h>
  28 #include <errno.h>
  29 #include <sys/time.h>
  30 #include <time.h>
  31 #include <stdio.h>
  32 #include <unistd.h>
  33
  34 #include "bridge_ctl.h"
  35
  36 // globals
  37 int epoll_fd = -1;
  38 struct timeval nexttimeout;
  39
  40 int init_epoll(void)
  41 {
  42         int r = epoll_create(128);
  43         if (r < 0) {
  44                 fprintf(stderr, "epoll_create failed: %m\n");
  45                 return -1;
  46         }
  47         epoll_fd = r;
  48         return 0;
  49 }
  50
  51 int add_epoll(struct epoll_event_handler *h)
  52 {
  53         struct epoll_event ev = {
  54                 .events = EPOLLIN,
  55                 .data.ptr = h,
  56         };
  57         h->ref_ev = NULL;
  58         int r = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, h->fd, &ev);
  59         if (r < 0) {
  60                 fprintf(stderr, "epoll_ctl_add: %m\n");
  61                 return -1;
  62         }
  63         return 0;
  64 }
  65
  66 int remove_epoll(struct epoll_event_handler *h)
  67 {
  68         int r = epoll_ctl(epoll_fd, EPOLL_CTL_DEL, h->fd, NULL);
  69         if (r < 0) {
  70                 fprintf(stderr, "epoll_ctl_del: %m\n");
  71                 return -1;
  72         }
  73         if (h->ref_ev && h->ref_ev->data.ptr == h) {
  74                 h->ref_ev->data.ptr = NULL;
  75                 h->ref_ev = NULL;
  76         }
  77         return 0;
  78 }
  79
  80 void clear_epoll(void)
  81 {
  82         if (epoll_fd >= 0)
  83                 close(epoll_fd);
  84 }
  85
  86 int time_diff(struct timeval *second, struct timeval *first)
  87 {
  88         return (second->tv_sec - first->tv_sec) * 1000
  89             + (second->tv_usec - first->tv_usec) / 1000;
  90 }
  91
  92 void run_timeouts(void)
  93 {
  94         bridge_one_second();
  95         nexttimeout.tv_sec++;
  96 }
  97
  98 int epoll_main_loop(void)
  99 {
 100         gettimeofday(&nexttimeout, NULL);
 101         nexttimeout.tv_sec++;
 102 #define EV_SIZE 8
 103         struct epoll_event ev[EV_SIZE];
 104
 105         while (1) {
 106                 int r, i;
 107                 int timeout;
 108
 109                 struct timeval tv;
 110                 gettimeofday(&tv, NULL);
 111                 timeout = time_diff(&nexttimeout, &tv);
 112                 if (timeout < 0) {
 113                         run_timeouts();
 114                         timeout = 0;
 115                 }
 116
 117                 r = epoll_wait(epoll_fd, ev, EV_SIZE, timeout);
 118                 if (r < 0 && errno != EINTR) {
 119                         fprintf(stderr, "epoll_wait: %m\n");
 120                         return -1;
 121                 }
 122                 for (i = 0; i < r; i++) {
 123                         struct epoll_event_handler *p = ev[i].data.ptr;
 124                         if (p != NULL)
 125                                 p->ref_ev = &ev[i];
 126                 }
 127                 for (i = 0; i < r; i++) {
 128                         struct epoll_event_handler *p = ev[i].data.ptr;
 129                         if (p && p->handler)
 130                                 p->handler(ev[i].events, p);
 131                 }
 132                 for (i = 0; i < r; i++) {
 133                         struct epoll_event_handler *p = ev[i].data.ptr;
 134                         if (p != NULL)
 135                                 p->ref_ev = NULL;
 136                 }
 137         }
 138
 139         return 0;
 140 }