/* Simple button demon
 *
 * Petr Malat (c) 2008 
 * mail: petris at penguin dot cz
 *
 * Distributed under the terms of GNU GPL version 3 
 * */

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <fcntl.h>
#include <linux/input.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdarg.h>
#include <errno.h>
#include <getopt.h>
#include <signal.h>

/****************** Edit this to configure *****************************/
/* If button is pressed for (min, max) intervall, the cmd is executed via system() call */
struct action_s { float min; float max; char *cmd; };

const struct action_s actions[] = {
	{0., 1.5, "shutdown -h now"},
	{4., 8.,  "ifconfig eth0 192.168.1.1 netmask 255.255.255.0"}
};
/***********************************************************************/


struct settings_s {
	FILE *log_file;
	int dev_fd;
} settings;

void logerror(char *cmd, ...){
	if( settings.log_file != NULL ){
		va_list list;
		va_start(list, cmd);
		vfprintf(settings.log_file, cmd, list);
		va_end(list);
	}
}

void system_exec(const char* cmd){
	pid_t pid;

	pid = fork();
	if( pid == 0 ){ /* child */
		if( system(cmd) == -1)
			logerror("Couldn't execute system(\"%s\"): %d\n", cmd, errno);
		exit(0);
	} else if (pid == -1){ 
		logerror("Couldn't fork new process: %d\n", errno);
	}
}

int process_events(int fd){
	struct input_event event;
	time_t KEY_POWER_sec = 0;
	suseconds_t KEY_POWER_usec = 0;
	float sec;
	int i;

	while(1){
		read(fd, &event, sizeof(event));
		if( event.type == EV_KEY ){
			switch(event.code){
				case KEY_POWER:
					if(event.value == 1){
						KEY_POWER_sec = event.time.tv_sec;
						KEY_POWER_usec = event.time.tv_usec;
					} else {
						sec = ((event.time.tv_sec - KEY_POWER_sec)*1000000 + event.time.tv_usec - KEY_POWER_usec)/1000000.;
						for(i = 0; i < sizeof(actions)/sizeof(struct action_s); i++){
							if( sec > actions[i].min && sec < actions[i].max )
								system_exec(actions[i].cmd);
						}
					}
			}
		}
	}
	return 0;
}

void parse_cmd (int argc, char *argv[])
{
	char *dev_file = NULL;
	char *log_file = NULL;
	int opt;

	while( (opt = getopt(argc, argv, "l:d:h")) != -1 ){
		switch(opt){
			case 'd':
				dev_file = optarg;
				break;
			case 'l':
				log_file = optarg;
				break;
			case ':': 
			case '?': 
				fprintf(stderr, "Bad commandline syntax\n");
			case 'h':
			default:
				fprintf(stderr, "Usage: buttond -d device_filename [-l log_filename] [-h]\n");
				exit(0);
		}
	}

	if( log_file == NULL ){
		settings.log_file = NULL;
	} else {
		if( (settings.log_file = fopen(log_file, "a")) == NULL){
			fprintf(stderr, "Couldn't open file '%s'. Errno %d\n", log_file, errno);
			exit(1);
		} 
	}

	if( dev_file == NULL ){
		fprintf(stderr, "Usage: buttond -d device_filename [-l log_filename] [-h]\n");
		exit(0);
	} else if( (settings.dev_fd = open(dev_file, O_RDONLY)) == -1){
		logerror("Couldn't open device '%s'. Errno %d\n", dev_file, errno);
		fprintf(stderr, "Couldn't open device '%s'. Errno %d\n", dev_file, errno);
		exit(1);
	}
}

int main(int argc, char *argv[]){
	struct sigaction sa;
	pid_t pid;

	parse_cmd(argc, argv);

	pid = fork();
	if( pid == 0 ){
		close(0); close(1); close(2);
		sa.sa_handler = SIG_IGN;
		sigaction(SIGCHLD, &sa, NULL);
		sigaction(SIGTSTP, &sa, NULL);
		sigaction(SIGTTOU, &sa, NULL);
		sigaction(SIGTTIN, &sa, NULL);
		setsid();
		return process_events(settings.dev_fd);
	} else if (pid == -1){
		logerror("Couldn't fork demon process. Errno %d\n", errno);
		fprintf(stderr, "Couldn't fork demon process. Errno %d\n", errno);
		return 1;
	}
	return 0;
}