/* 
 * pf.c - powerfail daemon
 * Copyright 1992-2000 Ronald Florence <ron@18james.com>
 * based on original from rac@sherpa.UUCP (Roger Cornelius), 13 May 1990
 *
 * maf+@osu.edu - fixed bug where pf would get stuck in the last state
 * before the shutdown sequence, then immediately shutdown on the next
 * change to battery.
 * 
 * Toby Creek <creek@aur.alcatel.com> added SUSPEND option for
 * Sparc-4m & 4u architectures.  With SUSPEND defined, pf will freeze
 * the system so it can be brought back with the power button on the
 * keyboard.  This may not be what you want for an unattended machine.
 *
 * To install, you need a serial port with modem-control enabled.  For
 * Sunos-4.1.x put 'off remote' in the status column of /etc/ttytab
 * for the serial port that will be connected to the UPS.  For
 * Solaris, use pmadm -r -p zsmon -s tty[a|b] to remove any monitor
 * on the port.  Make sure you have eeprom ttyX-ignore-cd=false on the
 * port.
 *
 * The cable from the UPS needs only two wires, the signal ground from
 * the UPS should be connected to the signal ground on the serial port
 * [pin 7 on a 25-pin port, pin 5 on a 9-pin port, or pin 4 on the
 * Sun IPC/IPX serial ports]; the powerfail signal from the UPS to
 * CD [pin 8 on a 25-pin port, pin 1 on a 9-pin port, or pin-7 on the
 * Sun IPC/IPX serial ports].  
 *
 * Define DEVICE, the serial port that will monitor the UPS, and
 * IGNORE, the time in seconds before a system shutdown is initiated,
 * to suit your setup.  You can also specify the device, ignoretime,
 * or the shutdown script on the command line when pf is started.  The
 * normal usage is to put pf somewhere in /etc/rc or in one of the
 * late init files in /etc/init.d
 *
 * compile:  [g]cc -O [-DSUSPEND] -o pf pf.c 
 */

#include <stdio.h>
#include <fcntl.h>
#include <signal.h>
#include <setjmp.h>
#include <syslog.h>

#ifdef SUSPEND
#define USAGE	"Usage: pf [-d device] [-i ignoretime] \n"
#else
#define USAGE	"Usage: pf [-d device] [-i ignoretime] [-s script]\n"
#endif

#define DEVICE	"/dev/ttyb" 
#define OPEN_TM	3       
#define IGNORE	600

jmp_buf jbuf;
				/* for Sunos-4.1.x */
/* char	*script[] = {"/usr/etc/shutdown", "-h", "now", "Power Failure", 0}; */
				/* for Solaris */
char *script[] = {"/usr/sbin/shutdown", "-y", "-i0", "-g30", 
		  "Power Failure", 0};

main(argc,argv)
int argc;
char **argv;
{
    void sighand(), myfork();
    int didopen(), opt, ignore;
    char *device;
    extern char *optarg;

    device = DEVICE;
    ignore = IGNORE;

    if (0 != getuid())
      {
	fputs("pf: must be root\n", stderr);
	exit(1);
      }
#ifdef SUSPEND
    while ((opt = getopt(argc, argv, "d:i:?")) != -1) 
#else
    while ((opt = getopt(argc, argv, "d:i:s:?")) != -1) 
#endif
      {
        switch (opt) 
	  {
	  case 'd':   device = optarg; break;
	  case 'i':   ignore = atoi(optarg); break;
#ifndef SUSPEND
	  case 's':   *script = optarg; script[1] = '\0'; break;      
#endif
          default :   fputs(USAGE, stderr); exit(1);
	  }
      }
    if (1 != getppid())		/* if parent not init */
      {
        myfork(); 
        setpgrp();  
        myfork(); 
      }
    close(0);			/* close files and make sure we don't */
    close(1);			/* hold any mounted fs open */
    close(2);
    chdir("/");
				/* set up syslogging, direct to */
				/* console in case logger fails, */
				/* no wait for child process */
    openlog("UPS", LOG_CONS|LOG_NOWAIT, LOG_DAEMON);

/* Here we attempt to open the port attached to the UPS.  The open
 * will block, waiting for CD, until we have a power failure.  When
 * the open succeeds, we close the port, sleep the amount of time
 * specified in `ignore', then try the open again, this time setting
 * an alarm.  If the alarm runs out before the second open succeeds,
 * we only had a temporary outage and the process starts over.  If the
 * second open succeeds, we assume it's an extended failure so we exec
 * /etc/shutdown or the suspend daemon, after a warning and one final
 * try to open the line.  
 */

  restart:
    setjmp(jbuf);
    if (didopen(device))	/* power failure */
      {
	syslog(LOG_CRIT, "Power line Event");
	sleep(ignore);
	signal(SIGALRM, sighand);
	alarm(OPEN_TM);
	if (didopen(device)) 
	  {
	    alarm(0);
	    syslog(LOG_ALERT,
		   "Power line failure - System going down in 60 seconds");
	    sleep(30);
	    alarm(OPEN_TM);
	    if (didopen(device))
	      {
		alarm(0);
                syslog(LOG_ALERT,
		   "Power line failure - System going down now");
	        sleep(5);
#ifdef SUSPEND
		system("/usr/openwin/bin/sys-suspend -fnx");
		sleep(30);
#else
		execvp(script[0], script);
		syslog(LOG_ALERT, "Unable to shutdown system");
#endif
		goto restart;
	      }
	    else 
	      {
		alarm(0);
		syslog(LOG_ALERT, "Shutdown cancelled - Power restored");
		goto restart;
	      }
	  }
	else
	  {
	    syslog(LOG_CRIT, "Power restored - Countdown expired");
	    goto restart;
	  }
      }
}



void myfork()
{
    int stat;

    stat = fork();
    if (stat < 0) 
      syslog(LOG_ALERT,"pf: fork failed");
    else if (stat > 0)  /* parent */
      exit(0);
}


/*
 * Attempt to open the device attached to the UPS
 * Should never succeed except during power failure
 */
int didopen(device)
char *device;
{
  int fd;

  fd = open(device, O_RDONLY);
  if (fd != -1)
    {
      close(fd);
      return(1);
    }
  syslog(LOG_ALERT, "pf: bogus open on UPS line");
  exit(1);
}


void sighand(sig)
int sig;
{
  longjmp(jbuf,1);
}