/*
 * Copyright (c) 1995, 1996 Gunther Schadow.  All rights reserved.
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "pg_config.h"
#include "trip.h"
#include "trap.h"
#include <syslog.h>

result
claim_line(pid_t pid, int pri)
{
  sigset_t mask;
  struct sigsave ss_CLAIM, ss_YIELD;

  svsignal(SIGYIELD, &ss_YIELD);
  svsignal(SIGCLAIM, &ss_CLAIM);

  if(pri == PRI_HIGH)
    ssignal(SIGCLAIM, SIG_IGN, 0);
  else
    atsignal(SIGCLAIM, 0)
      {
	sigaddset(&mask, SIGYIELD);
	sigprocmask(SIG_BLOCK, &mask, NULL);
	syslog(LOG_WARNING, "concurrent claim has piority");
	ss_CLAIM.ss_blk = FALSE;
	rssignal(SIGCLAIM, &ss_CLAIM);
	rssignal(SIGYIELD, &ss_YIELD);  
	kill(getpid(), SIGCLAIM);
      }

  atsignal(SIGYIELD, 0)
    {
      DBG(syslog(LOG_DEBUG, "the line is free"));
      dsignal(SIGCLAIM);
      rssignal(SIGCLAIM, &ss_CLAIM);
      rssignal(SIGYIELD, &ss_YIELD);  
      return SUCCESS;
    }

  while(TRUE)
    {
      if(kill(pid, SIGCLAIM) == FAIL)
	{
	  syslog(LOG_WARNING, "no concurrent process %d", pid);
	  dsignal(SIGCLAIM);
	  rssignal(SIGCLAIM, &ss_CLAIM);
	  rssignal(SIGYIELD, &ss_YIELD);  
	  return FAIL;
	}
      usleep(CLAIM_SLEEP_TIMER);
    }
}

void
wait_line()
{
  sigset_t mask;
  sigprocmask(SIG_SETMASK, NULL, &mask);
  sigdelset(&mask, SIGYIELD);
  while(TRUE) sigsuspend(&mask);
}