#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <time.h>
#include <sys/signal.h>
#include <fcntl.h>
#include <paths.h>

#define NOLOGINMSG "The system is shutting down.\n"
#define SHUTPID "/var/run/shutdown.pid"


#include "init.h"

void usage(){
	printf("Usage: shutdown {-h,-r.-c} [-t time] [-m message]\n");
	exit(EXIT_FAILURE);
}

void sigint(int n){
	unlink(SHUTPID);
	unlink(_PATH_NOLOGIN);
	exit(EXIT_SUCCESS);
}

int main(int argc,char * argv[]){
	int sock;
	struct sockaddr_un name;
	int c;
	int doreboot=0,dohalt=0,docancel=0;
	int delay=0;
	int newlevel;
	int fd;
	struct initcmd cmd;
	time_t now;
	pid_t pid;

	if(getuid() != 0){
		fprintf(stderr,"%s: Must be root.\n",argv[0]);
		exit(EXIT_FAILURE);
	}

	time(&now);

	while((c = getopt(argc,argv,"hrct:")) != -1){
		switch(c){
			case 'r':
				doreboot = 1;
				break;
			case 'h':
				dohalt = 1;
				break;
			case 'c':
				docancel = 1;
				break;
			case 't':
				if(strchr(optarg,':')){
					int h,m;
					struct tm *lt;
					if(sscanf(optarg,"%d:%2d",&h,&m) != 2) usage();
					if(h > 23 || m > 59) usage();
					lt = localtime(&now);
					delay = ((60*h + m) - (60*lt->tm_hour + lt->tm_min))*60;
					if(delay < 0) delay += 60*60*24;
				} else {
					char *p;
					delay = strtol(optarg,&p,0)*60;
					if(p==optarg || delay < 0) usage();
				}
				break;
			default:
				usage();
				break;
		}
	}

	if(dohalt + doreboot + docancel != 1) usage();

	if(!docancel && (fd = open(SHUTPID,O_RDONLY)) >= 0){
		close(fd);
		fprintf(stderr,"Shutdown already running.\n");
		exit(EXIT_FAILURE);
	}

	if(dohalt){
		newlevel = HALTRL;
	} else if(doreboot) {
		newlevel = REBOOTRL;
	} else {
		if( (fd = open(SHUTPID,O_RDONLY)) < 0){
			fprintf(stderr,"Shutdown not running.\n");
			exit(EXIT_FAILURE);
		}
		if(read(fd,&pid,sizeof(pid)) != sizeof(pid)){
			perror("read");
			exit(EXIT_FAILURE);
		}
		close(fd);
		kill(pid,SIGINT);
		exit(EXIT_SUCCESS);
	}

	fd = open(_PATH_NOLOGIN,O_CREAT|O_WRONLY,0644);
	if(fd >= 0){
		write(fd,NOLOGINMSG,strlen(NOLOGINMSG));
		close(fd);
	}

	if(delay > 0){
		pid = fork();
		if(pid == -1){
			perror("fork");
			exit(EXIT_FAILURE);
		}
		if(pid > 0){
			if( (fd = open(SHUTPID,O_CREAT|O_WRONLY,0644)) < 0){
				perror("open");
				exit(EXIT_FAILURE);
			}
			if(write(fd,&pid,sizeof(pid)) != sizeof(pid)){
				perror("write");
				exit(EXIT_FAILURE);
			}
			close(fd);
			exit(EXIT_SUCCESS);
		}
		signal(SIGINT,sigint);
		while(delay) delay = sleep(delay);
	} else {
		signal(SIGINT,SIG_IGN);
		pid = getpid();
		if( (fd = open(SHUTPID,O_CREAT|O_WRONLY,0644)) >= 0){
			write(fd,&pid,sizeof(pid));
			close(fd);
		}
	}
	
	cmd.command = NEWLEVEL;
	cmd.data = newlevel;

	sock = socket(PF_LOCAL,SOCK_DGRAM,0);
	if(sock < 0){
		perror("socket");
		exit(EXIT_FAILURE);
	}
	name.sun_family = AF_LOCAL;
	strncpy(name.sun_path,SOCK_PATH,sizeof(name.sun_path));
	if(connect(sock,(struct sockaddr*)&name,SUN_LEN(&name))<0){
		perror("connect");
		exit(EXIT_FAILURE);
	}
	if(write(sock,&cmd,sizeof(cmd)) < sizeof(cmd) ){
		perror("write");
		exit(EXIT_FAILURE);
	}
	close(sock);

	signal(SIGTERM,sigint);
	for(;;) sleep(1<<30);

	return(EXIT_SUCCESS);
}