signals.c

/*
* Disktest
* Copyright (c) International Business Machines Corp., 2005
*
* 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.
*
*  Please send e-mail to yardleyb@us.ibm.com if you have
*  questions or comments.
*
*  Project Website:  TBD
*
* $Id: signals.c,v 1.4 2007/03/16 01:06:05 yardleyb Exp $
*/
#ifdef WINDOWS
#include <windows.h>
#else
#include <pthread.h>
#endif
#include <signal.h>
#include "threading.h"
#include "signals.h"

/*
 * global variable used to indicate what signal
 * (if any) has been caught
 */
int handled_signal = -1;
int signal_action = SIGNAL_NONE;

/*
 * mutex to be used whenever accessing the above
 * global data
 */
#ifdef WINDOWS
HANDLE sig_mutex;
#else
pthread_mutex_t sig_mutex = PTHREAD_MUTEX_INITIALIZER;
#endif

#ifdef WINDOWS
void sig_handler( int sig )
#else
void* sig_handler( void* arg )
#endif
{
#ifndef WINDOWS
	sigset_t signal_set;
	int sig;
	int rv;

	/* wait for any and all signals */
	sigfillset( &signal_set );
#ifdef AIX
	/* except in AIX, can't sigwait on this signals */
	sigdelset( &signal_set, SIGKILL );
	sigdelset( &signal_set, SIGWAITING );
	sigdelset( &signal_set, SIGSTOP );
#endif

	for(;;) {
		rv = sigwait( &signal_set, &sig );
#endif

		switch( sig ) {
			case SIGQUIT:
				LOCK(sig_mutex);
				handled_signal = SIGQUIT;
				signal_action |= SIGNAL_STOP;
				UNLOCK(sig_mutex);
				break;

			case SIGINT:
				LOCK(sig_mutex);
				handled_signal = SIGINT;
				signal_action |= SIGNAL_STOP;
				UNLOCK(sig_mutex);
				break;

			case SIGTERM:
				LOCK(sig_mutex);
				handled_signal = SIGTERM;
				signal_action |= SIGNAL_STOP;
				UNLOCK(sig_mutex);
				break;

			case SIGHUP:
				LOCK(sig_mutex);
				handled_signal = SIGHUP;
				signal_action |= SIGNAL_STOP;
				UNLOCK(sig_mutex);
				break;

			case SIGUSR1:
				LOCK(sig_mutex);
				handled_signal = SIGUSR1;
				signal_action |= SIGNAL_STAT;
				UNLOCK(sig_mutex);
				break;

			/* whatever you need to do for other signals */
			default:
				LOCK(sig_mutex);
				handled_signal = 0;
				UNLOCK(sig_mutex);
				break;
			}
#ifndef WINDOWS
	}
	return (void *)0;
#endif
}

void setup_sig_mask( void )
{
#ifndef WINDOWS
    sigset_t signal_set;
    pthread_t sig_thread;
#endif

#ifdef WINDOWS
	if((sig_mutex = CreateMutex(NULL, FALSE, NULL)) == NULL) {
		return;
	}
#endif

	/* block all signals */
#ifdef WINDOWS
	signal( SIGINT, sig_handler );
	signal( SIGTERM, sig_handler );
	signal( SIGUSR1, sig_handler );
#else
	sigemptyset( &signal_set );
	sigaddset( &signal_set, SIGINT );
	sigaddset( &signal_set, SIGHUP );
	sigaddset( &signal_set, SIGQUIT );
	sigaddset( &signal_set, SIGTERM );
	sigaddset( &signal_set, SIGUSR1 );

#ifdef AIX
	sigthreadmask(SIG_SETMASK, &signal_set, NULL);
#else
	pthread_sigmask( SIG_SETMASK, &signal_set, NULL );
#endif

	/* create the signal handling thread */
	pthread_create( &sig_thread, NULL, sig_handler, NULL );
#endif
}

void clear_stat_signal( void )
{
	if(signal_action & SIGNAL_STAT) {
		LOCK(sig_mutex);
		signal_action &= ~SIGNAL_STAT;
		UNLOCK(sig_mutex);
	}
}