/* serverwiththread.c - creates a connection oriented (stream)
   socket in the Internet domain for the Unix Operating system
   Each connection is handled in a separate thread
   To compile on solaris gcc ... -lnsl -lsocket -lpthread
   To compile on freebsd gcc ... -pthread 
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <unistd.h> 
#include <stdlib.h>
#include <arpa/inet.h>
#include <pthread.h>

#define BUFSIZE 1024

extern int errno;
void error(char *msg)
{
    perror(msg);
    exit(0);
}

int main(int argc, char *argv[])
{
     int sock, *newsock, len, fromlen, retval;
     unsigned short port;
     struct sockaddr_in server;
     struct sockaddr_in from;
     pthread_t tid;
     void *ConnectionThread(void *); //function prototype

     if (argc < 2) {
         fprintf(stderr,"usage %s portnumber\n",argv[0]);
         exit(0);
     }
     port = (unsigned short) atoi(argv[1]);
     sock=socket(AF_INET, SOCK_STREAM, 0);
     if (sock < 0) error("Opening socket");
     server.sin_family=AF_INET;
     server.sin_addr.s_addr=INADDR_ANY;
     server.sin_port=htons(port);  
     len=sizeof(server);
     if (bind(sock, (struct sockaddr *)&server, len) < 0) 
          error("binding socket");
     fromlen=sizeof(from);
     if (listen(sock,5) < 0) 
          error("listening");;
     while (1) {
         newsock = (int *)malloc(sizeof (int));
         *newsock=accept(sock, (struct sockaddr *)&from, &fromlen);
         if (*newsock < 0) error("Accepting");
         printf("A connection has been accepted from %s\n",
                 inet_ntoa((struct in_addr)from.sin_addr));
         retval = pthread_create(&tid, NULL, ConnectionThread, (void *)newsock);
         if (retval != 0)   {
            error("Error, could not create thread");
         }
     } 
     return 0; // we never get here 
}

/****** ConnectionThread **********/
void *ConnectionThread(void *arg)
{
    int sock, n, len;
    char buffer[BUFSIZE];
    char *msg = "Got your message";
  
    sock = *(int *)arg;
    len  = strlen(msg);
    n = read(sock,buffer,BUFSIZE-1);
    while (n > 0) {
        buffer[n]='\0';
        printf("Message is %s\n",buffer);
        n = write(sock,msg,len);
        if (n < len) error("Error writing");
        n = read(sock,buffer,BUFSIZE-1);
        if (n < 0) error("Error reading");
    }
    if (close(sock) < 0) error("closing");
    pthread_exit(NULL);
    return NULL;
}