/* bkpupsd - Simple UPS daemon for APC Back-UPS pro. series
 * Copyright (c) 1997, Yoshifumi Watanabe<mwatts@edu1.tokyo-med.ac.jp>
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 *	Ver 1.0 A
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <err.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <signal.h>
#include <syslog.h>
#include <stdarg.h>

#define POWER_TIMEOUT		5*60
#define DEFAULT_PORT		"/dev/cuaa1"
#define _BKPUPSD_PID_PATH	"/var/run/bkpupsd.pid"
#define SH_SHUTDOWN		"/usr/local/libexec/bkpupsd/bkpups.shutdown"
#define SH_FAILED		"/usr/local/libexec/bkpupsd/bkpups.failed"
#define SH_RESTORED		"/usr/local/libexec/bkpupsd/bkpups.restored"
#define SH_BATTLOW		"/usr/local/libexec/bkpupsd/bkpups.battlow"

int makepid(char *s);
void execomand();

int main(argc, argv)
int argc;
char  **argv;
{
	int fd;
	int lstatus;
	int rts_bit = TIOCM_RTS;
	int dtr_bit = TIOCM_DTR;
	int pfail = 0;
	int pfcount = 0;
	int prcount = 0;
	int blcount = 0;
	char *sh_shutdown = SH_SHUTDOWN;
	char *sh_failed   = SH_FAILED;
	char *sh_restored = SH_RESTORED;
	char *sh_battlow  = SH_BATTLOW;
	char *ups_port	  = DEFAULT_PORT;

		/* open ups port */
	if(argc > 2) {
		errx(1,"Usage: bkpupsd <port device>: %s\n", strerror(errno));
	}
	if(argc == 2) {
		ups_port = argv[1];
	}
	if((fd = open(ups_port, O_RDWR | O_NDELAY)) < 0) {
		errx(1,"%s: %s", ups_port, strerror(errno));
	}
		/* Initialize UPS */
	ioctl(fd, TIOCMBIC, &rts_bit);
	ioctl(fd, TIOCMBIS, &dtr_bit);
		/* Detach and Become to a daemon process */
	if(daemon(1,1) < 0) {
		syslog(LOG_ERR, "Cannot become a daemon: %m");
		exit(1);
	}
	(void)makepid(_BKPUPSD_PID_PATH);
		/* Get line-status */
	while(1) {
		ioctl(fd, TIOCMBIC, &rts_bit);
		ioctl(fd, TIOCMBIC, &dtr_bit);
		ioctl(fd, TIOCMBIS, &dtr_bit);
		ioctl(fd, TIOCMGET, &lstatus);
		if(lstatus & TIOCM_CAR) {
			++blcount;
			if(blcount == 6) {
			syslog(LOG_ALERT, "Shutdown for Battery-Low.");
			/* Check line-failure */
			ioctl(fd, TIOCMBIC, &dtr_bit);
			ioctl(fd, TIOCMBIS, &dtr_bit);
			ioctl(fd, TIOCMGET, &lstatus);
			if(lstatus & TIOCM_RNG) {
				/* BK-UPS Pro to Sleep. */
				ioctl(fd, TIOCMBIC, &dtr_bit);
				ioctl(fd, TIOCMBIS, &dtr_bit);
				ioctl(fd, TIOCMBIS, &rts_bit);
				/* Emergency Shutdown Sequence */
				execomand(sh_battlow);
				sleep(100);
				}
			}
		}
		else if(lstatus & TIOCM_RNG) {
			++pfcount;
			prcount = 0;
			blcount = 0;
			if(pfcount == 3) {
				/* Powerfail */
				syslog(LOG_WARNING, "Line Power is failing.");
				execomand(sh_failed);
				pfail = 1;
			}
			if(pfcount == POWER_TIMEOUT) {
				syslog(LOG_ALERT, "Shutdown for Powerfail.");
					/* BK-UPS Pro to Sleep */
				ioctl(fd, TIOCMBIC, &dtr_bit);
				ioctl(fd, TIOCMBIS, &dtr_bit);
				ioctl(fd, TIOCMBIS, &rts_bit);
				/* Shutdown sequence */
				execomand(sh_shutdown);
				sleep(100);
			}
		}
		else if(pfail == 1) {
			/* power recovery */
			++prcount;
			pfcount = 0;
			if(prcount == 3) {
				execomand(sh_restored);
				pfail = 0;
				blcount = 0;
				ioctl(fd, TIOCMBIC, &rts_bit);
				ioctl(fd, TIOCMBIC, &dtr_bit);
				ioctl(fd, TIOCMBIS, &dtr_bit);
			}
		/* Battery recovery */
		else blcount = 0;
		}
	sleep(1);
	}
}


/* Subroutine to execute shell script command */

void execomand(shcommand)
char *shcommand;
{
	switch(fork()) {
	case 0:
		system(shcommand);
		exit(0);
	case -1:
		errx(1, "unable to execute shell command: %s", strerror(errno));
		break;
	default:
		break;
	}
}


/* Subroutine to make bkpupsd.pid to /var/run/ directory. */

int makepid(s)
char *s;
{
	FILE *fp;
	pid_t pid;

	pid = getpid();
	if((fp =  fopen(s, "w")) == NULL)
		return -1;
	fprintf(fp, "%lu\n", (u_long)pid);
	fclose(fp);
	return 0;
}