path: root/src/sigs.c

/*
 * Calcurse - text-based organizer
 *
 * Copyright (c) 2004-2020 calcurse Development Team <misc@calcurse.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the
 *        following disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the
 *        following disclaimer in the documentation and/or other
 *        materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Send your feedback or comments to : misc@calcurse.org
 * Calcurse home page : http://calcurse.org
 *
 */

#ifndef _BSD_SOURCE
/* Needed for SIGWINCH on OpenBSD. */
#define _BSD_SOURCE
/* Silence compiler warning about _BSD_SOURCE being deprecated. */
#ifndef _DEFAULT_SOURCE
#define _DEFAULT_SOURCE
#endif
#endif

#ifndef __BSD_VISIBLE
/* Needed for SIGWINCH on FreeBSD. */
#define __BSD_VISIBLE 1
#endif

#ifndef _DARWIN_C_SOURCE
/* Needed for SIGWINCH on Darwin. */
#define _DARWIN_C_SOURCE 1
#endif

#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <signal.h>

#include "calcurse.h"

#ifndef WAIT_MYPGRP
#define WAIT_MYPGRP 0
#endif

/*
 * General signal handling routine.
 * Catch return values from children (user-defined notification commands).
 * This is needed to avoid zombie processes running on system.
 * Also catch CTRL-C (SIGINT), and SIGWINCH to resize screen automatically.
 */
static void generic_hdlr(int sig)
{
	switch (sig) {
	case SIGCHLD:
		while (waitpid(WAIT_MYPGRP, NULL, WNOHANG) > 0) ;
		break;
	case SIGWINCH:
		resize = 1;
		clearok(curscr, TRUE);
		ungetch(KEY_RESIZE);
		break;
	case SIGTERM:
		if (unlink(path_cpid) != 0) {
			EXIT(_("Could not remove calcurse lock file: %s\n"),
			     strerror(errno));
		}
		exit(EXIT_SUCCESS);
		break;
	case SIGUSR1:
		want_reload = 1;
		ungetch(KEY_RESIZE);
		break;
	}
}

unsigned sigs_set_hdlr(int sig, void (*handler) (int))
{
	struct sigaction sa;

	memset(&sa, 0, sizeof sa);
	sigemptyset(&sa.sa_mask);
	sa.sa_handler = handler;
	sa.sa_flags = 0;
	if (sigaction(sig, &sa, NULL) == -1) {
		ERROR_MSG(_("Error setting signal #%d : %s\n"), sig,
			  strerror(errno));
		return 0;
	}

	return 1;
}

/* Signal handling init. */
void sigs_init()
{
	if (!sigs_set_hdlr(SIGCHLD, generic_hdlr)
	    || !sigs_set_hdlr(SIGWINCH, generic_hdlr)
	    || !sigs_set_hdlr(SIGTERM, generic_hdlr)
	    || !sigs_set_hdlr(SIGUSR1, generic_hdlr)
	    || !sigs_set_hdlr(SIGINT, SIG_IGN))
		exit_calcurse(1);
}

/* Ignore SIGWINCH and SIGTERM signals. */
void sigs_ignore(void)
{
	sigs_set_hdlr(SIGWINCH, SIG_IGN);
	sigs_set_hdlr(SIGTERM, SIG_IGN);
}

/* No longer ignore SIGWINCH and SIGTERM signals. */
void sigs_unignore(void)
{
	sigs_set_hdlr(SIGWINCH, generic_hdlr);
	sigs_set_hdlr(SIGTERM, generic_hdlr);
}