server accept error

calorie712 · 03-16-2006, 04:11 PM

When I run the below code, I can't figure out why I am getting hung when the server tries to accept the client. I am using Firefox as the client. I just want to read the Firefox header, and write back my HTML to the socket.

Code:


/* Library Section */
#include <stdio.h>        /* Standard Input and Output */
#include <unistd.h>       /* Unix Standard Functions */
#include <string.h>       /* Used for bzero */
#include <math.h>         /* Math Library used for log10 */
#include <sys/types.h>    /* Used for System Data Type Defitions */
#include <sys/socket.h>   /* Used for sockets */
#include <netinet/in.h>   /* sockaddr_in definition */
#include <arpa/inet.h>    /* Internet Sockets */
#include <stdlib.h>



/* Definitions */
#define SERV_TCP_PORT    10617            /* Port Number */
#define SERV_HOST_ADDR   "198.102.147.137" /* IP address for Gimli */
#define BUFFSIZE         2048              /* Buffer Size */


int main() {
  int    sockfd;      /* Initial socket descriptor */
  int    newsockfd;   /* Client/Server socket descriptor */
  socklen_t client_len;  /* Client Socket File Length */
  struct sockaddr_in serv_addr;   /* Server Address Information */
  struct sockaddr_in cli_addr;    /* Client Address Information */
  char    fire_head[2048];     /* header from Firefox */
  char    g_file[2048];     /* HTML to send as response to client */

  /* Open a TCP socket (an Internet stream socket). */

  if ( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)/* creating internet socket */
    fprintf(stderr, "server: can't open stream socket\n");

  /* Bind our local address so that the client can send to us. */
 
  /* First, clear out the structure */
  bzero((char *) &serv_addr, sizeof(serv_addr));
  serv_addr.sin_family      = AF_INET;
  serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
  serv_addr.sin_port        = htons(SERV_TCP_PORT);

  if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
    fprintf(stderr, "server: can't bind local address\n");

  /* Now, listen for incomming connections. */
  listen(sockfd, 5);
  printf("The server is now listening for connections\n");
  bzero(fire_head, BUFFSIZE);
  while (1) {    /* loop forever */

    client_len = sizeof(cli_addr);
    /* Accept the client connection */
    newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &client_len);
    if (newsockfd < 0)
      fprintf(stderr, "server: accept error\n");
    	

  
  /* Read header from Firefox from the socket */

  read(newsockfd, fire_head, BUFFSIZE);   
  printf("%s", fire_head);

  /* Build g_file webpage */

  strcat(g_file, "HTTP/1.1 200 OK\n");
  strcat(g_file, "Content-Type: text/html\n");
  strcat(g_file, "<HTML><HEAD><TITLE>PROGRAMMING EXERCISE #2</TITLE></HEAD><BODY>\n");
  strcat(g_file, "<UL>\n");
  strcat(g_file, "<LI>ITEM NUMBER ONE</LI>\n");
  strcat(g_file, "<LI>TWO IS RIGHT HERE</LI>\n");
  strcat(g_file, "<LI>THREE IS TAKING A BREAK, I AM FOUR</LI>\n");
  strcat(g_file, "<LI>OKAY I AM THE LAST ONE, I AM NUMBER FIVE</LI>\n");
  strcat(g_file, "</UL>\n");
  strcat(g_file, "<A HREF = 'http://morningside.edu'>Morningside College Homepage</A>\n");
  strcat(g_file, "</BODY></HTML>\n");
  

  /* Write webpage socket */
  write(newsockfd, g_file, strlen(g_file));
  
  close(newsockfd);     /* We are finished with the socket */
  close(sockfd);     /* We are finished with the socket */

    bzero(fire_head, BUFFSIZE);
    bzero(g_file, BUFFSIZE);

     
  } /* END WHILE */
   return (0);
   
}

FLLinux · 03-17-2006, 06:41 AM

Well you are closeing you listening socket (sockfd) after you write out the data, and then you are looping back around and trying to accept again on an invalid sock. So i would suggest either remove the while loop or move the close of the sockfd outside the while loop so when you loop back around to the accept again you are trying it on a valid socket.