Subversion Repositories f9daq

/*
    C socket server example, handles multiple clients using threads */
 
#include<stdio.h>
#include<string.h> //strlen
#include<stdlib.h> //strlen
#include<sys/socket.h>
#include<arpa/inet.h> //inet_addr
#include<unistd.h>
#//write
#include<pthread.h>
//for threading , link with lpthread
#define PORT 3210
//the thread function



void *connection_handler(void *);
 
int is_connected = 0;
int ncalls=0;

int writesock(int sock, char *msg, int len ){
    int hdr[2];
    hdr[0]=ncalls++;
    hdr[1]= len + 8;
    write(sock , hdr , 8);
    return write(sock , msg , len);
}


int main(int argc , char *argv[]) {
    int socket_desc , client_sock , c , *new_sock=NULL;
    struct sockaddr_in server , client;
     
    //Create socket
    socket_desc = socket(AF_INET , SOCK_STREAM , 0);
    if (socket_desc == -1)
    {
        printf("Could not create socket");
    }
    puts("Socket created");
     
    //Prepare the sockaddr_in structure
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = INADDR_ANY;
    server.sin_port = htons( PORT );
     
    //Bind
    if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0)
    {
        //print the error message
        perror("bind failed. Error");
        return 1;
    }
    puts("bind done");
     
    //Listen
    listen(socket_desc , 3);
     
    //Accept and incoming connection
    puts("Waiting for incoming connections...");
    c = sizeof(struct sockaddr_in);
     
     
    //Accept and incoming connection
    puts("Waiting for incoming connections...");
    c = sizeof(struct sockaddr_in);
    while( (client_sock = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)) )
    {
        puts("Connection accepted");
         
        pthread_t sniffer_thread;

        if (is_connected){
            char message[0xFF]="Only one client can connect. Disconnect it first!";
            perror(message);
            writesock(client_sock , message , strlen(message));
            close (client_sock);
            continue;
        }
        new_sock = (int *) malloc(1);
        *new_sock = client_sock;
        if( pthread_create( &sniffer_thread , NULL , connection_handler , (void*) new_sock) < 0)
        {
            perror("could not create thread");
            return 1;
        }

         
        //Now join the thread , so that we dont terminate before the thread
        //pthread_join( sniffer_thread , NULL);
        puts("Handler assigned");
       
    }
     
    if (client_sock < 0)
    {
        perror("accept failed");
        return 1;
    }
     
    return 0;
}
 


void *daq_handler(void *data){
 
 int s = pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
 //Get the socket descriptor
 int sock = *(int*)data;
 char msg[0xFF];
 int cnt=0;
 while (1){
    sprintf(msg, "daq_handler %d %d", sock, cnt++);
    int error = 0;
    socklen_t len = sizeof (error);
    int retval = getsockopt (sock, SOL_SOCKET, SO_ERROR, &error, &len);
    if (retval!=0 || error!=0) break;
    writesock(sock , msg , strlen(msg));
    sleep(5);
 }
 printf("Exiting thread %d", sock ) ;

}

/*
 * This will handle connection for each client
 * */

void *connection_handler(void *socket_desc) {
    //Get the socket descriptor
    int sock = *(int*)socket_desc;
    int read_size;
    char *message , client_message[2000];
    is_connected = 1;
    //Send some messages to the client
    message = "Info from connection handler\n";
    writesock(sock , message , strlen(message));
         
    //Receive a message from client
    pthread_t daq_thread = 0;

    while( (read_size = recv(sock , client_message , 2000 , 0)) > 0 )
    {
        //Send the message back to client
        int * hdr = (int *) client_message;
        char *msg = &client_message[8];
        printf("Received %d bytes RECID = %d LEN %d\n",read_size, hdr[0], hdr[1]);
        switch (hdr[0]){
           case 0:
           hdr[0]= sock;
           if( pthread_create( &daq_thread , NULL , daq_handler , (void*) &client_message) < 0)
        {
            perror("could not create daq thread");
            break ;
        }
 
break;
           case 3:
         if (daq_thread) {
            pthread_cancel(daq_thread);
            daq_thread = 0;
         }
break;
           default: break;

        }
        writesock(sock , msg , strlen(msg));
    }
     
    if(read_size == 0)
    {
        puts("Client disconnected");
        fflush(stdout);
    }
    else if(read_size == -1)
    {
        perror("recv failed");
       
    }
    if (daq_thread) {
      pthread_cancel(daq_thread);
      daq_thread = 0;
    }

         
    //Free the socket pointer
    free(socket_desc);
    socket_desc = 0;
    is_connected = 0;
     
    return 0;
}