non-blocking code with while loops - c

Question

I'm trying to write some code that will spawn off two separate chunks of code listening for connections.
int runsocket()
{
int socket_desc , client_sock , c;
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( 8888 );
//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);
pthread_t thread_id;
while( (client_sock = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)) )
{
puts("Connection accepted");
if( pthread_create( &thread_id , NULL , connection_handler , (void*) &client_sock) < 0)
{
perror("could not create thread");
return 1;
}
//Now join the thread , so that we dont terminate before the thread
//pthread_join( thread_id , NULL);
puts("Handler assigned");
}
if (client_sock < 0)
{
perror("accept failed");
return 1;
}
return 0;
}
/*
* 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];
//Send some messages to the client
message = "Greetings! I am your connection handler\n";
write(sock , message , strlen(message));
message = "Now type something and i shall repeat what you type \n";
write(sock , message , strlen(message));
//Receive a message from client
while( (read_size = recv(sock , client_message , 2000 , 0)) > 0 )
{
//end of string marker
client_message[read_size] = '\0';
//Send the message back to client
write(sock , client_message , strlen(client_message));
//clear the message buffer
memset(client_message, 0, 2000);
}
if(read_size == 0)
{
puts("Client disconnected");
fflush(stdout);
}
else if(read_size == -1)
{
perror("recv failed");
}
return 0;
}
Now, say theoretically, I have a runsocket2() that also opens a socket on a separate port, using a separate connection_handler function. In my main, I call runsocket(); and runsocket2() . Only run socket(); gets executed and it freezes from that point forward, with runsocket2(); never being called. How can I get around this and effectively execute both of them?
The real issue I'm encountering is using a websocket library, that has a call: libwebsock_wait(ctx);
Once this is called, that's it - all code below it no longer gets executed, as it essentially creates a loop. I'd like to be able to force a separate socket to listen on a separate port and process data through it outside of the websocket. If I call runsocket(); prior to libwebsock_wait(ctx); then the program successfully begins listening on the socket 8888, but does not fire up the websocket. Any ideas on how I can counteract this behavior?

Answer 1

The point of the accept call is to block and wait for incoming connections. So runsocket2() is never called and runsocket() "freezes" as it should. You could set the socket to non-blocking using socket(AF_INET|SOCK_NONBLOCK, SOCK_STREAM, 0) but you'd still have to continuously check for an incoming connection. You could create the socket and use the select statement. (See the man pages). Or the best way to go is thread runsocket()