/* Socket server demo
 *	by OrangeTide (jmayo@mail.alliance.net) Dec 1996
 */
#include <stdio.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/time.h>		       /* needed for select() */
#include <netinet/in.h>		       /* internet socket stuff */
#include <netdb.h>		       /* network database stuff.
				          (gethostbyname, etc) */

#define MAXHOSTNAME 80		       /* I don't know what the posix keyword
				          is for this */
#define PORT 50000		       /* default port to use */

#undef DEBUGGING_INFO			/* handy if you want to know what is 
					 * going on with the sockets. Just
					 * provides a few extra tidbits that
					 * aren't even that useful. I suppose 
					 * I should make this a cmdline option
					 */
char *inet_ntoa(struct in_addr in);
int atoi(const char *nptr);


void print_hostent(const struct hostent *hp)
{
 /* protos */
/*   char *inet_ntoa(struct in_addr in); */

   printf("%s (%s)\n", hp->h_name, inet_ntoa(*((struct in_addr *) (hp->h_addr))));
}

int grab_port(unsigned short int portnum)
{
 /* protos */
   void print_hostent(const struct hostent *hp);
   unsigned short int htons(unsigned short int hostshort);
   void bzero(void *s, int n);

 /* vars */
   struct hostent *hp;
   char myhost[MAXHOSTNAME + 1];
   struct sockaddr_in sa;
   int s;			       /* the socket */

   bzero(&sa, sizeof(struct sockaddr_in));

   gethostname(myhost, MAXHOSTNAME);
   hp = gethostbyname(myhost);
   if (hp == NULL)
   {
      perror("socket build error: No Hostname");
      return -1;
   }
   sa.sin_family = hp->h_addrtype;     /* host address */
   sa.sin_port = htons(portnum);       /* port number */
   if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0)	/* build socket */
   {
      perror("socket build error: Allocating socket");
      return -1;		       /* error building socket */
   }
   if (bind(s, (struct sockaddr*)&sa, sizeof sa) < 0)
   {
      perror("socket build error: Binding");
      close(s);
      return -1;
   }
   listen(s, 3);		       /* max # in queue */
   printf("Taking port %d on ", portnum);	/* prints the local host */
   print_hostent(hp);
   return s;			       /* return socket */
}

int main(int argc, char *argv[])
{
 /* protos */
   int grab_port(u_short portnum);

 /* vars */
   int mysock[20 + 1];		       /* max of twenty connection 0=bound
				          socket, 1-20=normal */
   fd_set sockrd;
   fd_set sockex;
/*    fd_set sockwr; */
   fd_set completefd;
/*   struct timeval tv; */
   int topfd;			       /* value of the top file descriptor */
   int topsock = 0;		       /* top socket */
   int portnum;
   int stay_connected = 1;		/* keeps the while loop going */   
 /* code */
   if (argc>1)
     portnum=atoi(argv[1]);
   else
     portnum=PORT;
   
   if ((mysock[0] = grab_port(portnum)) < 0)
   {
      perror("Cannot connect socket");
      return -1;
   }
   topfd = mysock[0];
   FD_ZERO(&completefd);
   FD_SET(mysock[0], &completefd);

   while (stay_connected)
   {
      sockrd = completefd;
      sockex = completefd;
/* tv.tv_sec=1; tv.tv_usec=0; */
#     ifdef DEBUGGING_INFO      
      printf("select() start\n");
      printf("topsock: %d\ntopfd: %d\n",topsock,topfd);
#     endif      
      if (select(256/* topfd + 1 */, &sockrd, NULL, &sockex, NULL) > 0)
      {
	 struct sockaddr_in myaddr;
	 int myaddr_len;
	 int i; /* index */

	 myaddr_len = sizeof(struct sockaddr_in);
#        ifdef DEBUGGING_INFO	 
	 printf("select() done\n");
#        endif	 
/* some sort of code needs to be implementated to handle "exceptions" and
* actually use &sockex, because I think that it has something to do with the
* disconnection of a socket */
	 
	 if (FD_ISSET(mysock[0], &sockrd))
	 {
	    if ((mysock[++topsock] = accept(mysock[0], (struct sockaddr*)&myaddr, &myaddr_len)) < 0)
	      perror("accept");
	    printf("%d!connection (%s)\n", topsock, inet_ntoa(myaddr.sin_addr));
	    FD_SET(mysock[topsock], &completefd);	  
	    if (mysock[topsock]>topfd) 
	      topfd=mysock[topsock];
	 } 
/* else */ /* I have no idea why I even put this here! kludging working code, I guess */
	 
	   for (i=1;i<=topsock;i++)
	   {
	      printf("%d!checking\n",i);
	      if(FD_ISSET(mysock[i], &sockrd))
		{
		   char s[80];
		   int dataread;
		   printf("%d!reading.\n",i);
		   dataread=read(mysock[i],s,sizeof s);
		   if (0==dataread)
		     {
			printf("#%d!closed.\n",i);
			FD_CLR(mysock[i],&completefd);
			close(mysock[i]);
			mysock[i]=mysock[topsock--]; /* this hopefully swaps
						      * top FD to the closed
						      * fd and lowers the the
						      * socket count */
	     	
			 
		     }
		   s[dataread]='\0';
		   printf("#%d:%s",i,s);
		}
	      printf("*\n");
	   }

      }
   }
   
   /* we're done, let's close all the sockets */
   while (topsock >= 0)
     if (close(mysock[topsock--]) != 0)
     perror("close");
   return 0;
}

/* 
   unsigned long ipaddr; if((ipaddr=inet_addr(myhost))==-1)
   hp=gethostbyname(myhost); else hp=gethostbyaddr((char *)&ipaddr,
   sizeof(struct in_addr), AF_INET);

 */