/* vim: set sw=8 ts=8 si : *//* * Serial line daemon program for shutdown of your server. * A blinking LED indicates the server is running. * The program uses the serial interface lines * DTR (output: data terminal ready), RTS (output:request to send)   * and CD (input: carrier detect) * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License. * See http://www.gnu.org/copyleft/ for details. * * Written by Guido Socher <guido@linuxfocus.org>  * * Some ideas were taken from an earlier progam called  * cpanel written by Mirko D鰈le <dg2fer@qsl.net> */#define VERINFO "version 0.1"#include <stdio.h>#include <stdlib.h>#include <sys/ioctl.h>#include <sys/types.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h>#include <signal.h>static int fd = 0;enum led {rts_yellow,dtr_green,all};/* Signal handler: all led off then exit */void offandexit(int code){	int state = 0;	ioctl(fd, TIOCMSET, &state);	exit(0);}/* Switch the LEDs on or off */int setled( enum led whichled, int fd, int onoff, int *ledstate){	int bitpat;	/* the blinking LED first */	if (whichled == rts_yellow){		bitpat=TIOCM_RTS;	}else if (whichled == dtr_green){		bitpat=TIOCM_DTR;	}else if (whichled == all){		bitpat=(TIOCM_RTS | TIOCM_DTR);	}	if (onoff){		/* on */		*ledstate |= bitpat;	}else{		*ledstate &= ~bitpat;	}	ioctl(fd, TIOCMSET, ledstate);	return *ledstate;}/* switch off green led and run shutdown  * the init scripts will finally kill us. We do not * terminate here  */int runshutdown(int fd,int *ledstate){	setled( dtr_green, fd, 0, ledstate);	system("/sbin/shutdown -t2 -h now");	return (0);}/* get the current state of the push button  * and return it. */int getpushbutton(int fd){	int state;	ioctl(fd, TIOCMGET, &state);	/* read interface */	if (state & TIOCM_CAR) {		return (1);	}	return (0);}void help(){	printf("sled -- serial line pushbutton and LED control daemon\n\USAGE: sled serial-device\n\\n\EXAMPLE:\n\         sled /dev/ttyS0\n\\n\Use command setserial -g /dev/ttyS* to see available ttyS devices.\n\This program forks it self to background. It must have permissions\n\to execute /sbin/shutdown\n\");#ifdef VERINFO	puts(VERINFO);#endif	 exit(0); }int main(int argc, char **argv){	int lstate = 0;	int i = 0;	pid_t pid;	/* exactly one argument must be given */	if (argc != 2)		help();	/* open device */	fd = open(argv[1], O_RDWR | O_NDELAY);	if (fd < 0) {		fprintf(stderr, "ERROR: can not open \"%s\"\n", argv[1]);		exit(2);	}	/* catch signals INT and TERM and switch of LEDs before 	 * terminating */	signal(SIGINT, offandexit);	signal(SIGTERM, offandexit);	/* first set a defined state, all off */	ioctl(fd, TIOCMSET, &lstate);	/* switch on the green LED to indicate that the 	 * shutdown pushbutton is active */        setled( dtr_green, fd, 1, &lstate);	/* now we fork to background */	if ((pid = fork())<0){		perror("sled server fork");		exit(1);	}else if (pid > 0){		/* parent dies */		exit(0);	}	/* we are the child and run as a daemon */	while(1){		/* blink led on */		setled( rts_yellow, fd, 1, &lstate);		if (getpushbutton(fd)){			runshutdown(fd,&lstate);		}		sleep(2);		/* blink led off */		setled( rts_yellow, fd,0, &lstate);		if (getpushbutton(fd)){			runshutdown(fd,&lstate);		}		sleep(1);	}	/* we never get here */	return (2);}