Need some help with my chat room code !!

This is my project in college. This is a 1 to 1 chatroom code which i have implemented. i need a smalll alteration in this. when a client types ""exit"" in the dialog box, the session should close automatically.

This is the SERVER side code

Code:

---

/* ECE 545 Project - 1*/
/* One to one chat room (server) using TCP */
/* Group No. - 16 */


#include        <stdio.h>
#include        <sys/types.h>
#include        <sys/socket.h>
#include        <netinet/in.h>
#include        <netdb.h>

#define        SERVER_PORT        6667
                        /* Server Port Defined */
#define        MAX_PENDING        5
                        /* Maximum number of clients */
#define        MAX_LINE        256
                        /* Maximum String Length Defined */

int
main ()
{
        struct sockaddr_in sin;
        char buf[MAX_LINE];
        int len,pid,ptr;
        int s, new_s;
       
/* Build address data structure        */

        bzero ((char *)&sin, sizeof(sin));
        sin.sin_family = AF_INET;
        sin.sin_addr.s_addr = INADDR_ANY;
        sin.sin_port = htons(SERVER_PORT);

/* Setup passive open socket */

        if ((s = socket(PF_INET, SOCK_STREAM, 0)) < 0)
        {
                perror("simplex-talk:socket");
                exit(1);
        }
        if ((bind(s,(struct sockaddr *)&sin,sizeof(sin))) < 0)
        {
                perror("simplex-talk:bind");
                exit(1);
        }
        listen (s, MAX_PENDING);
       
/* Wait for a connection, then receive and print text        */

        while(1)
        {
        ptr=sizeof(sin);
       
                if ((new_s = accept(s, (struct sockaddr *)&sin, &ptr)) < 0)
                {
                        perror("simplex-talk: accept");
                        exit(1);
                }
               
/* Process is forked to recieve and send text */
               
                if((pid=fork())>0)
                {
                        while(len=recv (new_s, buf, sizeof(buf), 0))
                        fputs(buf, stdout);
                        close(new_s);
                }
               
                else
                {       
                    while(fgets(buf,sizeof(buf),stdin))
                    {
                        buf[MAX_LINE-1]='\0';
                        len=strlen(buf)+1;
                        send(new_s,buf,len,0);
                    }
                }       
        }
       
                }

---

This is the CLIENT CODE

Code:

---




/* ECE 545 Project - 1*/
/* One to one chat room (client) using TCP */



#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#define SERVER_PORT 6667
                        /* Server Port Defined */
#define MAX_LINE 256
                                /* Maximum String Length Defined */       

int
                                               
main (int argc, char *argv[])
{
        FILE *fp;
        struct hostent        *hp;
        struct        sockaddr_in sin;
        char *host;
        char buf[MAX_LINE];
        int s,new_s;
        int len,pid;
       
/* Checking the presence of host name */

        if (argc == 2)
        {
                host = argv[1];
        }
        else
        {
                fprintf(stderr,"usage:simplex-talk host\n");                exit (1);
        }

/* Translate host name into peer’s IP address*/

        hp = gethostbyname(host);
        if (!hp)
        {
                fprintf(stderr,"simplex-talk:unknown host:%s\n",host);
                exit (1);
        }

/* Build address data structure        */

        bzero((char *)&sin, sizeof(sin));
        sin.sin_family = AF_INET;
        bcopy (hp->h_addr, (char *)&sin.sin_addr, hp->h_length);
        sin.sin_addr.s_addr = INADDR_ANY;
        sin.sin_port = htons (SERVER_PORT);
       
/* Active opening of Socket */
       
        if ((s = socket(PF_INET, SOCK_STREAM, 0)) < 0)
        {
                perror("simplex-talk:socket");
                exit (1);
        }
       
        if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) < 0)
        {
                perror("simplex-talk:connect");
                close(s);
                exit(1);
        }

/* Main loop : Get and send lines of text */
/* Forking the process : To send and recieve the lines of text */
       
        if((pid=fork())>0)
        {
                while(fgets(buf,sizeof(buf), stdin))
                {
                        buf[MAX_LINE-1]='\0';
                        len=strlen(buf)+1;
                        send (s, buf, len, 0) ;
                }
        }
        else
        {               
                while(len=recv(s,buf,sizeof(buf),0))
                fputs(buf,stdout);
                close(s);
        }               
               
               
               
}

---

Thanx for the help

Use strcmp() to compare the string that you receive from the user with the text "exit", if it matches, close(socket);.

Well there's a number of bugs to be fixed.

> while(len=recv (new_s, buf, sizeof(buf), 0))
1. What if recv() returns -1 (like it does on error). Since you do nothing to clear the error, most likely this code would loop forever.
2. recv() does NOT add a \0 to the end of whatever it receives, so your fputs() just wanders off into la-la land. I see your send() sends a \0, but you take no account of the fact that messages can be fragmented.

> buf[MAX_LINE-1]='\0';
Even if fgets() fills the buffer, the last character in the buffer will be \0. It is an unnecessary line of code.

> send (s, buf, len, 0) ;
Same as recv(), send calls can fragment (do not assume that all of your data is sent on the first call). Also, pay attention to it's return result.

> if((pid=fork())>0)
If it returns -1, then you really shouldn't just run one half of the protocol.