Initial commit

[people/ms/rstp.git] / epoll_loop.c

/*****************************************************************************
  Copyright (c) 2006 EMC Corporation.

  This program is free software; you can redistribute it and/or modify it 
  under the terms of the GNU General Public License as published by the Free 
  Software Foundation; either version 2 of the License, or (at your option) 
  any later version.
  
  This program is distributed in the hope that it will be useful, but WITHOUT 
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 
  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for 
  more details.
  
  You should have received a copy of the GNU General Public License along with
  this program; if not, write to the Free Software Foundation, Inc., 59 
  Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  
  The full GNU General Public License is included in this distribution in the
  file called LICENSE.

  Authors: Srinivas Aji <Aji_Srinivas@emc.com>

******************************************************************************/

#include "epoll_loop.h"

#include <sys/epoll.h>
#include <errno.h>
#include <sys/time.h>
#include <time.h>
#include <stdio.h>
#include <unistd.h>

#include "bridge_ctl.h"

// globals
int epoll_fd = -1;
struct timeval nexttimeout;

int init_epoll(void)
{
  int r = epoll_create(128);
  if (r < 0) {
    fprintf(stderr, "epoll_create failed: %m\n");
    return -1;
  }
  epoll_fd = r;
  return 0;
}

int add_epoll(struct epoll_event_handler *h)
{
  struct epoll_event ev = 
    {
      .events = EPOLLIN,
      .data.ptr = h,
    };
  h->ref_ev = NULL;
  int r =  epoll_ctl(epoll_fd, EPOLL_CTL_ADD, h->fd, &ev);
  if (r < 0) {
    fprintf(stderr, "epoll_ctl_add: %m\n");
    return -1;
  }
  return 0;
}

int remove_epoll(struct epoll_event_handler *h)
{
  int r =  epoll_ctl(epoll_fd, EPOLL_CTL_DEL, h->fd, NULL);
  if (r < 0) {
    fprintf(stderr, "epoll_ctl_del: %m\n");
    return -1;
  }
  if (h->ref_ev && h->ref_ev->data.ptr == h) {
    h->ref_ev->data.ptr = NULL;
    h->ref_ev = NULL;
  }
  return 0;
}

void clear_epoll(void)
{
  if (epoll_fd >= 0)
    close(epoll_fd);
}

int time_diff(struct timeval *second, struct timeval *first)
{
  return (second->tv_sec - first->tv_sec)*1000
    + (second->tv_usec - first->tv_usec)/1000;
}

void run_timeouts(void)
{
  bridge_one_second();
  nexttimeout.tv_sec++;
}

int epoll_main_loop(void)
{
  gettimeofday(&nexttimeout, NULL);
  nexttimeout.tv_sec++;
#define EV_SIZE 8
  struct epoll_event ev[EV_SIZE];
  
  while (1) {
    int r, i;
    int timeout;

    struct timeval tv;
    gettimeofday(&tv, NULL);
    timeout = time_diff(&nexttimeout, &tv);
    if (timeout < 0) {
      run_timeouts();
      timeout = 0;
    }
      
    r = epoll_wait(epoll_fd, ev, EV_SIZE, timeout);
    if (r < 0 && errno != EINTR) {
      fprintf(stderr, "epoll_wait: %m\n");
      return -1;
    }
    for (i = 0; i < r; i++) {
      struct epoll_event_handler *p = ev[i].data.ptr;
      if (p != NULL)
        p->ref_ev = &ev[i];
    }
    for (i = 0; i < r; i++) {
      struct epoll_event_handler *p = ev[i].data.ptr;
      if (p && p->handler)
        p->handler(ev[i].events, p);
    }
    for (i = 0; i < r; i++) {
      struct epoll_event_handler *p = ev[i].data.ptr;
      if (p != NULL)
        p->ref_ev = NULL;
    }
  }

  return 0;
}