main.c

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#define PORT    5000
#define MAXMSG  1025

typedef struct client {
	int sockid;
	char path[1024];
	char inbuffer[1024];

	struct client * next;
	struct client * prev;
} client_t;

client_t * listHead = NULL;
client_t * listTail = NULL;


client_t * new_client( _sock )
{
	client_t * p = malloc( sizeof( client_t ) );
	p->sockid = _sock;
	p->path[0] = '\0';
	p->next = NULL;
	p->prev = NULL;
	return p;
}

void list_addClient( client_t * _client, int add_to_head )
{
	if ( listHead == NULL ) {
		listHead = listTail = _client;
		return;
	}

	if ( add_to_head != 0 ) {
		_client->next = listHead;
		listHead->prev = _client;
		listHead = _client;
	} else {
		_client->prev = listTail;
		listTail->next = _client;
		listTail = _client;
	}
}

void list_remClient( client_t * _client )
{

	if ( listHead == _client ) {
		listHead = _client->next;
	}

	if ( listTail == _client ) {
		listTail = _client->prev;
	}

	if ( _client->prev != NULL ) {
		_client->prev->next = _client->next;
	}

	if ( _client->next != NULL ) {
		_client->next->prev = _client->prev;
	}

}

int read_from_client( client_t * _client )
{
	int nbytes;
	nbytes = read( _client->sockid, _client->inbuffer, 512 );

	if ( nbytes > 0 ) {

		_client->inbuffer[nbytes] = '\0';
		return 1;

	} else if ( nbytes == 0 ) {
		return 0;
	} else if ( errno == EAGAIN ) {
		return 1;
	} else {
		return 0;
	}
}


int     main( void )
{
	//extern int make_socket (uint16_t port);
	int sock;
	fd_set active_fd_set, read_fd_set;
	struct sockaddr_in clientname;
	;
	//size_t size;
	unsigned int size;

	/* Create the socket and set it up to accept connections. */
	//sock = make_socket (PORT);
	if ( ( sock = socket( AF_INET, SOCK_STREAM, 0 ) ) == -1 ) {
		perror( "Server-socket() error lol!" );
		/*just exit lol!*/
		exit( 1 );
	}

	printf( "Server-socket() is OK...\n" );



	/*"address already in use" error message */
	int yes = 1;

	if ( setsockopt( sock, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof( int ) ) == -1 ) {
		perror( "Server-setsockopt() error lol!" );
		exit( 1 );
	}

	printf( "Server-setsockopt() is OK...\n" );


	/* bind */
	clientname.sin_family = AF_INET;
	clientname.sin_addr.s_addr = htonl( INADDR_ANY );
	clientname.sin_port = htons( 5000 );
	//memset(clientname.sin_zero, '\0', 8);

	if ( bind( sock, ( struct sockaddr * )&clientname, sizeof( clientname ) ) == -1 ) {
		perror( "Server-bind() error lol!" );
		exit( 1 );
	}

	printf( "Server-bind() is OK...\n" );


	if ( listen( sock, 1 ) < 0 ) {
		perror( "listen" );
		exit( EXIT_FAILURE );
	}

	/* Initialize the set of active sockets. */
	FD_ZERO( &active_fd_set );
	FD_SET( sock, &active_fd_set );

	while ( 1 ) {
		/* Block until input arrives on one or more active sockets. */
		read_fd_set = active_fd_set;

		if ( select( FD_SETSIZE, &read_fd_set, NULL, NULL, NULL ) < 0 ) {
			perror( "select" );
			exit( EXIT_FAILURE );
		}

		//check for incomming connections
		if ( FD_ISSET( sock, &read_fd_set ) ) {
			int sockid;
			size = sizeof( clientname );
			sockid = accept( sock, ( struct sockaddr * ) &clientname, & size );

			if ( sockid < 0 ) {
				perror( "accept failure: abandoning this client" );
			} else {
				client_t * newSock = new_client( sockid );
				list_addClient( newSock, 1 );

				fprintf( stderr,
						 "Server: new connection from host %s, port %hd.\n",
						 inet_ntoa( clientname.sin_addr ),
						 ntohs( clientname.sin_port ) );
				FD_SET( sockid, &active_fd_set );
			}
		}

		//process all connected clients
		client_t * check = listHead;
		client_t * check_next = listHead;

		while ( check != NULL ) {
			check_next = check->next; //needed because we might delete clients while navigating list;

			if ( FD_ISSET( check->sockid, &read_fd_set ) ) {
				//TODO: read data from client

				if ( read_from_client(check) == 0) {
					list_remClient( check );
					FD_CLR(check->sockid,&active_fd_set);
					free(check);
				} else {
					fprintf( stderr, "Server: got message: `%s'\n", check->inbuffer );
				}
			}

			check = check_next;
		}

	}
}