Programming

#include <sys/socket.h>
#include <sys/types.h>
#include <iostream>
#include <string>
#include <resolv.h>
#include <pthread.h>
#include <fcntl.h>
#include <netdb.h>

using namespace std;

void panic(char *msg);
#define panic(m)        {perror(m); abort();}


/*****************************************************************************
        *** This function makes the socket non-blocking!
*****************************************************************************/
void nonblock(int &sockfd)
{
        int opts;
        opts = fcntl(sockfd, F_GETFL);
        cout<<"in opt"<<endl;
        if(opts < 0)
                panic("fcntl(F_GETFL)\n")

        opts = (opts | O_NONBLOCK);
        if(fcntl(sockfd, F_SETFL, opts) < 0)
                panic("fcntl(F_SETFL)\n")

        cout<<"after opt"<<endl;
}

/*****************************************************************************/
/*** This program creates a simple echo server: whatever you send it, it   ***/
/*** echoes the message back.                                              ***/
/*****************************************************************************/
void *servlet(void *arg)                    /* servlet thread */
{       /* get & convert the data */
        int *client = (int*)arg;
        int n;
        char s[100];
        
        pthread_detach(pthread_self());

           /* proc client's requests */
        memset(s, '\0', 100);
        while( (n = (read(*client,s,100)) ) > 0 )
        {
                if (s[0] == 'Q')
                        break;
                printf("msg: %s", s);
                write(*client,s,n);
                memset(s, '\0', n);
        }

        close(*client);
        return 0;                           /* terminate the thread */
}

int main(int count, char *args[])
{       struct sockaddr_in addr;
        int sd, port;

        if ( count != 2 )
        {
                printf("usage: %s <protocol or portnum>\n", args[0]);
                exit(0);
        }

        /*---Get server's IP and standard service connection--*/
        if ( !isdigit(args[1][0]) )
        {
                struct servent *srv = getservbyname(args[1], "tcp");
                if ( srv == NULL )
                        panic(args[1]);
                printf("%s: port=%d\n", srv->s_name, ntohs(srv->s_port));
                port = srv->s_port;
        }
        else
                port = htons(atoi(args[1]));

        /*--- create socket ---*/
        sd = socket(PF_INET, SOCK_STREAM, 0);
        if ( sd < 0 )
                panic("socket");

        int on = 1;
        if ( (setsockopt(sd, SOL_SOCKET,  SO_REUSEADDR, (char *)&on, sizeof(on)) ) < 0 )
                panic("setsockoptions");

        /*--- bind port/address to socket ---*/
        memset(&addr, 0, sizeof(addr));
        addr.sin_family = AF_INET;
        addr.sin_port = port;
        addr.sin_addr.s_addr = INADDR_ANY;                   /* any interface */
        if ( bind(sd, (struct sockaddr*)&addr, sizeof(addr)) != 0 )
                panic("bind");

        /*--- make into listener with 10 slots ---*/
        if ( listen(sd, 10) != 0 )
                panic("listen")
        /*--- begin waiting for connections ---*/
        else
        {       int csd;
                pthread_t child;
                FILE *fp;
                cout<<"Here: "<<endl;

                while (1)                         /* process all incoming clients */
                {
                        csd = accept(sd, NULL, NULL);     /* accept connection */
                         if (csd > 0 )
                        {
                                cout<<"New connection accepted on socket : "<<csd<<endl;
        //                      nonblock(csd);
                                pthread_create(&child, 0, &servlet, &csd);       /* start thread */
                        }
                }
        }
        close(sd);
        pthread_exit(NULL);
}

#include <sys/socket.h>
#include <sys/types.h>
#include <iostream>
#include <string>
#include <resolv.h>
#include <pthread.h>
#include <fcntl.h>
#include <netdb.h>

using namespace std;

void panic(char *msg);
#define panic(m)        {perror(m); abort();}

/* servlet thread - get & convert the data */
void *servlet(void *arg)
{
   int client = (int)arg;
   int n;
   char s[100];

   /* process client's requests */
   memset(s, '\0', 100);
   while( (n = (read(client,s,100)) ) > 0 ) {
      if (s[0] == 'Q')
              break;
      printf("msg: %s", s);
      write(client,s,n);
      memset(s,'\0', n);
   }

   close(client);
   pthread_exit(0);          /* terminate the thread */
}

int main(int argv, char *args[])
{
   struct sockaddr_in addr;
   int sd, port;
   int csd;
   pthread_t child;
   int on = 1;
   pthread_attr_t pattr;

   if ( argv != 2 ) {
       printf("usage: %s <protocol or portnum>\n", args[0]);
       exit(0);
   }

   /* Get server's IP and standard service connection */
   if ( !isdigit(args[1][0]) ) {
       struct servent *srv = getservbyname(args[1], "tcp");
       if ( srv == NULL )
           panic(args[1]);
       printf("%s: port=%d\n", srv->s_name, ntohs(srv->s_port));
       port = srv->s_port;
   } else
       port = htons(atoi(args[1]));

   /* create socket */
   sd = socket(PF_INET, SOCK_STREAM, 0);
   if ( sd < 0 )
       panic("socket");

   if ((setsockopt(sd, SOL_SOCKET,  SO_REUSEADDR, (char *)&on, sizeof(on)) ) < 0 )
      panic("setsockoptions");

   /* bind port/address to socket */
   memset(&addr, 0, sizeof(addr));
   addr.sin_family = AF_INET;
   addr.sin_port = port;
   addr.sin_addr.s_addr = INADDR_ANY;
   if (bind(sd,(struct sockaddr*)&addr, sizeof(addr)) != 0)
      panic("bind");

   /* set size of request queue to 10 */
   if (listen(sd, 10) < 0)
      panic("listen");

   /* set thread create attributes */
   pthread_attr_init(&pattr);
   pthread_attr_setdetachstate(&pattr, PTHREAD_CREATE_DETACHED);

   while (1) {
      cout << "Waiting for a new connection ...." << endl;
      csd = accept(sd, NULL, NULL);
      if (csd < 0)
         panic("accept");
      cout << "New connection accepted on socket: " << csd << endl;
      pthread_create(&child, &pattr, servlet, (void *)csd);
   }

   close(sd);
   exit(0);
}