/*
 * Copyright (c) 2002 by Louis Zechtzer
 *
 * Permission to use, copy and distribute this software is hereby granted
 * under the terms of version 2 or any later version of the GNU General Public
 * License, as published by the Free Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED IN ITS "AS IS" CONDITION, WITH NO WARRANTY
 * WHATSOEVER. NO LIABILITY OF ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING
 * FROM THE USE OF THIS SOFTWARE WILL BE ACCEPTED.
 */
/* 
 * Authors: Louis Zechtzer (lou@clarity.net)
 */
#include "sys.h"

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>
#include <unistd.h>

static int sys_daemon;
static void sys_make_daemon();
static void signal_handler(int);

int sys_sighandled = 0;

/*
 * sys_initialize: called to initialize the system module.  The system
 * module handles os specific things like daemons and signal handling.
 */
void 
sys_initialize(int flags)
{
	/* initialize signal handlers */
	struct sigaction sa;
	
	sa.sa_handler = signal_handler;
	sa.sa_flags = 0; /* XXX */
	sigemptyset(&sa.sa_mask);

	sigaction(SIGHUP, &sa, NULL);
	sigaction(SIGTERM, &sa, NULL);
	sigaction(SIGINT, &sa, NULL);
	sigaction(SIGUSR1, &sa, NULL);
	sigaction(SIGUSR2, &sa, NULL);

	/* convert process to daemon if requested */
	if (flags & SYS_DAEMON) {
		sys_daemon = 1;
		sys_make_daemon();
	} else {
		sys_daemon = 0;
	}
}

/*
 * is_daemon: primitive for other modules to know if running as a daemon.
 */
int
is_daemon()
{
	return sys_daemon;
}
 
/*
 * sys_make_daemon: convert process to a daemon.  See Steven's UNPv1 pp. 
 * 335-336.
 *
 * XXX - error handling for fork and retry on failure.
 */
static void 
sys_make_daemon()
{
	pid_t pid;
	
	if ((pid = fork()) == -1) {
		perror("fork");
		exit(1);
	} else if (pid != 0) {
		exit(0);
	}
		
	setsid();
	if ((pid = fork()) == -1) {
		perror("fork");
		exit(1);
	} else if (pid != 0) {
		exit(0);
	}

	chdir("/");
	umask(0);
	
	close(STDIN_FILENO);
	close(STDOUT_FILENO);
	close(STDERR_FILENO);	
}

static void
signal_handler(int s)
{
	switch (s) {
	case SIGINT:
	case SIGTERM:
		sys_sighandled |= SYS_GOT_SIGINT;
		break;

	case SIGHUP:
		sys_sighandled |= SYS_GOT_SIGHUP;
		break;

	case SIGUSR1:
		sys_sighandled |= SYS_GOT_SIGUSR1;	
		break;

	case SIGUSR2:
		sys_sighandled |= SYS_GOT_SIGUSR2;
		break;
	}
}