/*
   answer connections to port 1974 --
   if the bot's not running, reload it

   TO COMPILE:
      cc -o autore autore.c
*/

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/time.h>

#define PORT 1974
#define SCRIPT "/your/full/path/here/botchk"

void fatal(s)
char *s;
{
  printf("\n\n* %s\n",s);
  exit(1);
}

/* returns a socket number for a listening socket that will accept any */
/* connection -- port # is returned in port */
int open_listen(port)
int *port;
{
  int sock,addrlen; struct sockaddr_in name;
  sock=socket(AF_INET,SOCK_STREAM,0);
  if (sock<0) fatal("Can't open a socket at all.",0);
  bzero((char *)&name,sizeof(struct sockaddr_in));
  name.sin_family=AF_INET;
  name.sin_port=htons(*port);   /* 0 = just assign us a port */
  name.sin_addr.s_addr=INADDR_ANY;
  if (bind(sock,(struct sockaddr *)&name,sizeof(name))<0) {
    close(sock); return -1;
  }
  /* what port are we on? */
  addrlen=sizeof(name);
  if (getsockname(sock,(struct sockaddr *)&name,&addrlen)<0) {
    close(sock); return -1;
  }
  *port=ntohs(name.sin_port);
  if (listen(sock,1)<0) { close(sock); return -1; }
  return sock;
}

/* given network-style IP address, return hostname */
/* hostname will be "##.##.##.##" format if there was an error */
char *hostnamefromip(ip)
unsigned long ip;
{
  static char name[121]; struct hostent *hp; unsigned long addr=ip;
  unsigned char *p;
  hp=gethostbyaddr((char *)&addr,sizeof(addr),AF_INET);
  if (hp==NULL) {
    p=(unsigned char *)&addr;
    sprintf(name,"%u.%u.%u.%u",p[0],p[1],p[2],p[3]);
  }
  else strcpy(name,hp->h_name);
  return name;
}

/* short routine to answer a connect received on a socket made previously */
/* by open_listen ... returns hostname of the caller & the new socket */
/* does NOT dispose of old "public" socket! */
int answer(sock,caller)
int sock; char *caller;
{
  int new_sock,addrlen; struct sockaddr_in from; unsigned long ip;
  addrlen=sizeof(struct sockaddr);
  new_sock=accept(sock,(struct sockaddr *)&from,&addrlen);
  if (new_sock<0) return -1;
  ip=from.sin_addr.s_addr;
  strcpy(caller,hostnamefromip(ip));
  return new_sock;
}

main()
{
  int i,x,y; fd_set fd; char s[121];
  i=getdtablesize(); x=fork();
  if (x>0) {
    printf("\nBot auto-restart running now.\n");
    exit(0);
  }
  if (x==-1) {
    printf("\nCan't fork.\n"); exit(1);
  }
  y=PORT;
  x=open_listen(&y);
  if (x==-1) {
    fprintf(stderr,"\nAUTORE: Can't open listening socket at %d.\n",PORT);
    exit(1);
  }
  while(1) {
    FD_ZERO(&fd); FD_SET(x,&fd);
    if (select(i,&fd,NULL,NULL,NULL)==-1) {
      fprintf(stderr,"\nAUTORE: select returned error.\n");
      exit(1);
    }
    y=answer(x,s);
    if (y!=-1) if (fork()==0) {
      dup2(y,1); dup2(y,2);
      system(SCRIPT);
      sleep(1); close(y);
      exit(0);
    }
    else close(y);
  }
}