/******************************** -*- C -*- ****************************
 *
 *	Emulation for poll
 *
 *
 ***********************************************************************/

/***********************************************************************
 *
 * Copyright 2001, 2002 Free Software Foundation, Inc.
 * Written by Paolo Bonzini.
 *
 * This file is part of GNU Smalltalk.
 *
 * GNU Smalltalk 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, or (at your option) any later 
 * version.
 * 
 * GNU Smalltalk 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
 * GNU Smalltalk; see the file COPYING.  If not, write to the Free Software
 * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  
 *
 ***********************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "poll.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <errno.h>

#include <sys/time.h>

#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif

int poll(struct pollfd *pfd, int nfd, int timeout)
{
  fd_set rfds, wfds, efds;
  struct timeval tv, *ptv;
  int maxfd, rc, ok;
  unsigned int i;
  char data[64];

  /* poll(2) semantics */
  if (pfd == NULL) {
    errno = EFAULT;
    return -1;
  }

  /* convert timeout number into a timeval structure */
  ptv = &tv;
  if (timeout == 0) {
    /* return immediately */
    ptv->tv_sec  = 0;
    ptv->tv_usec = 0;
  }
  else if (timeout == INFTIM /* (-1) */) {
    /* wait forever */
    ptv = NULL;
  }
  else if (timeout > 0) {
    /* return after timeout */
    ptv->tv_sec  = timeout / 1000;
    ptv->tv_usec = (timeout % 1000) * 1000;
  }
  else {
    errno = EINVAL;
    return -1;
  }

  /* create fd sets and determine max fd */
  maxfd = -1;
  FD_ZERO(&rfds);
  FD_ZERO(&wfds);
  FD_ZERO(&efds);
  for(i = 0; i < nfd; i++) {
    if (pfd[i].fd < 0)
      continue;

    if (pfd[i].events & (POLLIN|POLLRDNORM))
      FD_SET(pfd[i].fd, &rfds);

    /* see select(2): "the only exceptional condition detectable
       is out-of-band data received on a socket", hence we push
       POLLWRBAND events onto wfds instead of efds. */
    if (pfd[i].events & (POLLOUT|POLLWRNORM|POLLWRBAND))
      FD_SET(pfd[i].fd, &wfds);
    if (pfd[i].events & (POLLPRI|POLLRDBAND))
      FD_SET(pfd[i].fd, &efds);
    if (pfd[i].fd >= maxfd &&
	(pfd[i].events & (POLLIN|POLLOUT|POLLPRI|
			  POLLRDNORM|POLLRDBAND|
                          POLLWRNORM|POLLWRBAND)))
      maxfd = pfd[i].fd;
  }
  if (maxfd == -1) {
    errno = EINVAL;
    return -1;
  }

  /* examine fd sets */
  rc = select(maxfd+1, &rfds, &wfds, &efds, ptv);

  /* establish results */
  if (rc > 0) {
    rc = 0;
    for (i = 0; i < nfd; i++) {
      ok = 0;
      pfd[i].revents = 0;
      if (pfd[i].fd < 0) {
	pfd[i].revents |= POLLNVAL;
	continue;
      }
      if (FD_ISSET(pfd[i].fd, &rfds)) {
	/* support for POLLHUP */
	if (recv(pfd[i].fd, data, 64, MSG_PEEK) == -1) {
	  if (errno == ESHUTDOWN || errno == ECONNRESET ||
	      errno == ECONNABORTED || errno == ENETRESET)
	    pfd[i].revents |= POLLHUP;
	}
	else {
	  pfd[i].revents |= pfd[i].events & (POLLIN|POLLRDNORM);
	  ok++;
	}
      }
      if (FD_ISSET(pfd[i].fd, &wfds)) {
	pfd[i].revents |= pfd[i].events & (POLLOUT|POLLWRNORM|POLLWRBAND);
	ok++;
      }
      if (FD_ISSET(pfd[i].fd, &efds)) {
	pfd[i].revents |= pfd[i].events & (POLLPRI|POLLRDBAND);
	ok++;
      }
      if (ok)
	rc++;
    }
  }

  return rc;
}