/* 
 * Copyright (c) 2009 Peter J. Philipp
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 * 
 */


#include <sys/types.h>
#include <sys/time.h>

#include <netinet/in.h>
#include <netdb.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <syslog.h>
#include <time.h>
#include <signal.h>

#define DEFAULT_IP		"62.75.160.180"
#define DEFAULT_POPSERVER 	"pop3.solarscale.de"
#define DEFAULT_TIMEOUT		60

void onalrm(int);

int
main(void)
{
	struct sockaddr_in sin;
	struct hostent *hp;
	
	if (geteuid() != 0) {
		perror("must be root");
		exit(1);
	}	
	if (chdir("/var/googlewatch/") < 0) {
		perror("chdir");
		exit(1);
	}
	if (chroot("/var/googlewatch/") < 0) {
		perror("chroot");
		exit(1);
	}
	if (chdir("/") < 0) {
		perror("chdir 2");
		exit(1);
	}

	sin.sin_addr.s_addr = inet_addr(DEFAULT_IP);

	openlog("googlewatch", LOG_PID | LOG_NDELAY, LOG_DAEMON);
		
	daemon(0, 0);

	syslog(LOG_INFO, "googlewatch starting");
	
	signal(SIGALRM, onalrm);

	for (;;) {
		alarm(DEFAULT_TIMEOUT);
		hp = gethostbyname(DEFAULT_POPSERVER);

		if (hp == NULL) {
			syslog(LOG_INFO, "google nameservers down: %s",  hstrerror(h_errno));
			goto out;
		}

		if (memcmp(hp->h_addr, (char*)&sin.sin_addr.s_addr, sizeof(struct in_addr)) != 0) {
			syslog(LOG_INFO, "google gave wrong pop3 server: %s\n", inet_ntop(hp->h_addr));
		}
		
out:
		sleep(300);
	}

	/* NOTREACHED */
}


void 
onalrm(int sig)
{
#if 0
	syslog(LOG_INFO, "itimer debug");
#endif
	return;
}