/*
 * Copyright © 2005-2007  Red Hat, Inc. All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions of the
 * GNU General Public License v.2.  This program is distributed in the hope
 * that it will be useful, but WITHOUT ANY WARRANTY expressed or implied,
 * including the implied warranties 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., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. Any Red Hat
 * trademarks that are incorporated in the source code or documentation are not
 * subject to the GNU General Public License and may only be used or replicated
 * with the express permission of Red Hat, Inc.
 *
 * Red Hat Author(s): Nathan Straz <nstraz@redhat.com>
 *                    Dean Jansa <djansa@redhat.com>
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <syslog.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <time.h>
#include <sys/times.h>

#include "btime_int.h"

static unsigned int get_btime(void);

int
main(int argc, char **argv)
{
	int sd;
	char inmsg[BTIME_MSGLEN];
	char btimeonly[BTIME_MSGLEN];
	char cookiemsg[BTIME_MSGLEN];
	char *outmsg;
	struct sockaddr_storage cli_addr;
	socklen_t cli_addr_len;
	ssize_t nbytes;
	unsigned int local_btime;

	openlog("btimed", LOG_PID, LOG_USER);

	/* Running out of (x)inetd the socket was duped onto stdin. */
	sd = fileno(stdin);

	/* Generate the standard btime message */
	memset(btimeonly, 0, BTIME_MSGLEN);
	local_btime = get_btime();
	sprintf(btimeonly, "%u\n", local_btime);

	syslog(LOG_INFO, "started with btime = %u", local_btime);
	for (;;) {
		memset(&cli_addr, 0, sizeof cli_addr);
		memset(inmsg, 0, BTIME_MSGLEN);
		cli_addr_len = sizeof cli_addr;
		nbytes = recvfrom(sd, &inmsg, BTIME_MSGLEN, MSG_WAITALL, 
		         (struct sockaddr *)&cli_addr, &cli_addr_len);

		if (nbytes < 0) {		
			/* Bail if we get an error.  client side resends
			 * request, no need to retry here.
			 */
			syslog(LOG_INFO, "exitting");
			exit(0);
		}
		if (inmsg[0] == 'B' && inmsg[1] == 'T' ) {
			/* New style heartbeat with cookie */
			/* Copy cookie to message and append timestamp */
			memset(cookiemsg, 0, BTIME_MSGLEN);
			memcpy(cookiemsg, inmsg, COOKIE_LEN);
			strcpy(cookiemsg + COOKIE_LEN, btimeonly);
			outmsg = cookiemsg;
		} else {
			outmsg = btimeonly;
		}

		sendto(sd, outmsg, BTIME_MSGLEN, MSG_DONTWAIT, 
		       (struct sockaddr *)&cli_addr, cli_addr_len);
	}

	return 0;
}


/*
 *---------------------------------------------------------------------------
 *
 * get_btime --
 *
 *	Return machine's boot time rounded up to the nearest five seconds.
 *
 * Returns:
 *	0 on failure
 * 	non-zero on success.
 *
 *---------------------------------------------------------------------------
 */

static unsigned int 
get_btime(void)
{
	unsigned int btime = 0;
	long hertz = sysconf(_SC_CLK_TCK);

	btime = time(0);

	if (access("/proc/uptime", F_OK | R_OK) == 0) {
		FILE *proc_uptime;
		unsigned long upsec = 0;
	       	proc_uptime = fopen("/proc/uptime", "r");
		fscanf(proc_uptime, "%lu.%*u %*u.%*u\n", &upsec);
		fclose(proc_uptime);

		btime -= upsec;
	} else {
		struct tms tms;

		btime -= (times(&tms) / hertz);
	}
	return btime;
}