/* $Id: daemon.c,v 1.4 2005-07-12 17:39:43 rjkaes Exp $
 *
 * This file contains functions which are useful when writing a
 * daemon process.  The functions include a "makedaemon" function and
 * a function to portably set a signal handler.
 *
 * Copyright (C) 2002  Robert James Kaes (rjkaes@users.sourceforge.net)
 *
 * 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, 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.
 */

#include "tinyproxy.h"

#include "daemon.h"

/*
 * Fork a child process and then kill the parent so make the calling
 * program a daemon process.
 */
void
makedaemon(void)
{
	if (fork() != 0)
		exit(0);

	setsid();
	set_signal_handler(SIGHUP, SIG_IGN);

	if (fork() != 0)
		exit(0);

	chdir("/");
	umask(077);

#if NDEBUG
        /*
         * When not in debugging mode, close the standard file
         * descriptors.
         */
	close(0);
	close(1);
	close(2);
#endif
}

/*
 * Pass a signal number and a signal handling function into this function
 * to handle signals sent to the process.
 */
signal_func *
set_signal_handler(int signo, signal_func *func)
{
	struct sigaction act, oact;

	act.sa_handler = func;
	sigemptyset(&act.sa_mask);
	act.sa_flags = 0;
	if (signo == SIGALRM) {
#ifdef SA_INTERRUPT
		act.sa_flags |= SA_INTERRUPT;	/* SunOS 4.x */
#endif
	} else {
#ifdef SA_RESTART
		act.sa_flags |= SA_RESTART;	/* SVR4, 4.4BSD */
#endif
	}

	if (sigaction(signo, &act, &oact) < 0)
		return SIG_ERR;

	return oact.sa_handler;
}