#define _GNU_SOURCE

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/signal.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/wait.h>

#ifdef __linux__
#include <sys/reboot.h>
#include <sys/ioctl.h>
#include <linux/vt.h>
#endif

#include "init.h"
#include <briconf.h>


int runlevel = BOOTRL;

int changerl(const int newlevel);

#define donothing() select(0,NULL,NULL,NULL,NULL)

char *conlogind;
char *rc;
char *rcS;
char *rcH;
char *cad;
int defrl;

void sigchld(int n){
	int serrno, pid, status;
	serrno = errno;
	for(;;){
		pid = waitpid(WAIT_ANY,&status,WNOHANG);
		if(pid <= 0) break;
	}
	errno = serrno;
}

void sigterm(int n){
	unlink(SOCK_PATH);
	signal (n, SIG_DFL);
	raise (n);
}

void sigint(int n){
	int serrno = errno;
	system(cad);
	errno = serrno;
}

int chvt(int n){
	if(ioctl(1,VT_ACTIVATE,n)   < 0) return(0);
	if(ioctl(1,VT_WAITACTIVE,n) < 0) return(0);
	return(1);
}

void waitforevents(){
	int sock;
	struct sockaddr_un name;
	fd_set set;
	int n;
	struct initcmd cmd;

	sock = socket(PF_LOCAL,SOCK_DGRAM,0);
	if(sock < 0){
		perror("socket");
		donothing();
	}
	name.sun_family = AF_LOCAL;
	strncpy(name.sun_path,SOCK_PATH,sizeof(name.sun_path));
	unlink(SOCK_PATH);
	if(bind(sock,(struct sockaddr*)&name,SUN_LEN(&name))<0){
		perror("bind");
		donothing();
	}
	if(chmod(SOCK_PATH,0600) < 0){
		perror("chmod");
		unlink(SOCK_PATH);
		donothing();
	}

	FD_ZERO(&set);

	for(;;){	
		FD_SET(sock,&set);
		n = select(FD_SETSIZE,&set,NULL,NULL,NULL);

		if(n > 0){
			read(sock,&cmd,sizeof(cmd));
			if(cmd.command == NEWLEVEL){
				chvt(1);
				changerl(cmd.data);
			} else if(cmd.command == ASKLEVEL){
				fprintf(stdout,"Current Runlevel: %i\n",runlevel);
			}
		} else if(n < 0 && errno != EINTR){
			perror("select");
			exit(EXIT_FAILURE);
		}
	}
}

int changerl(const int newlevel){
	char *params[4];
	pid_t pid;
	int status;
	char buf1[sizeof(int)*3], buf2[sizeof(int)*3];

	if(runlevel == BOOTRL && newlevel == 0){
		params[0] = rcS;
		params[1] = NULL;
	} else if( (newlevel == HALTRL || newlevel == REBOOTRL) ){
		if(!changerl(0)) return(0);
		buf1[0] = newlevel == HALTRL ? 'H' : 'R';
		buf1[1] = '\0';
		params[0] = rcH;
		params[1] = buf1;
		params[2] = NULL;
	} else if(newlevel == runlevel){
		return(1);
	} else if(newlevel >= 0 && runlevel >= 0){
		snprintf(buf1,sizeof(buf1),"%i",runlevel);
		snprintf(buf2,sizeof(buf2),"%i",newlevel);
		params[0] = rc;
		params[1] = buf1;
		params[2] = buf2;
		params[3] = NULL;
	} else {
		fprintf(stderr,"init: Unsupported runlevel change\n");
		return(0);
	}
	
	pid = fork();
	if(pid < 0)
		return(0);
	if(pid==0){
		execv(params[0],params);
		perror(params[0]);
		_exit(127);
	}
	waitpid(pid,&status,0);
	if(WEXITSTATUS(status)==EXIT_SUCCESS){
		runlevel = newlevel;
		return(1);
	} else {
		fprintf(stderr, "init: Script: %s failed with exit code: %i\n",params[0],WEXITSTATUS(status));
		return(0);
	}
}

void startconlogind(){
	pid_t pid;
	int status;
	pid = fork();
	if(pid < 0){
		perror("fork");
		return;
	}
	if(pid==0){
		execl(conlogind,conlogind,NULL);
		perror(conlogind);
		pid = fork();
		if(pid == 0){
			execl("/bin/sh","/bin/sh",NULL);
			perror("/bin/sh");
			_exit(127);
		}
		_exit(0);
	}
	waitpid(pid,&status,0);
}

int main(int argc, char* argv[]){
	struct briconf c;
	int i;
	char *s;
	char *p;

	if(getpid() > 1){
		argv[0] = "telinit";
		execv("/sbin/telinit",argv);
		exit(1);
	}
	
	if(!parse_conf("/etc/init.conf",&c))
		fprintf(stderr,"Cannot open init.conf\n");
	
	rc = getval(&c,"rc","/etc/init.d/rc");
	rcS = getval(&c,"rc","/etc/init.d/rc");
	rcH = getval(&c,"rc","/etc/init.d/rc");
	conlogind = getval(&c,"conlogind","/sbin/conlogind");
	cad = getval(&c,"ctrlaltdel","shutdown -r now");
	s = getval(&c,"default","0");
	defrl = strtol(s,NULL,10);
	free(s);
	free_conf(&c);
	
	if(argc > 2){
		if(strcasecmp(argv[2],"single")==0) {
			defrl = 0;
		} else {
			i = strtol(argv[2],&p,0);
			if(*p == '\0')
				defrl = i;
		}
	}

	for(i=1;i<NSIG;i++)
		signal(i,SIG_IGN);
	
	signal(SIGCHLD,sigchld);
	
	if(!changerl(0)){
		fprintf(stderr,"Init script failure. Dropping to shell.\n");
		execl("/bin/sh","-sh",NULL);
		exit(EXIT_FAILURE);
	}

	/* We don't care if this fails. we should have a working system by now */
	if(defrl > 0)
		changerl(defrl);

	startconlogind();

#ifdef __linux__
	/* Enable CTRL+ALT+DEL */
	signal(SIGINT,sigint);
	/* This means disable actually rebooting on CAD */
	reboot(RB_DISABLE_CAD);
#endif

	waitforevents();

	return(EXIT_SUCCESS); /* Not Reached */
}