Simple FTP Server - Socket programming in C

server.c

/*
 *  server.c
 *
 *  Simple FTP Server
 *  ====================
 *  If the client connects to the server and wants to retrieve a file
 *  with command "Get FILENAME", server retrieves iff the file exists
 *  on the server o/w notifies the client with an error message.
 *
 *  Compile & link  :   gcc server.c -lpthread -o server
 *  Execute         :   ./server
 *
 *  Ozcan Ovunc <[email protected]>
 */

#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/sendfile.h>
#include <fcntl.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdbool.h>
#include <pthread.h>

#define SERVER_PORT 8080

void* ConnectionHandler(void* socket_desc);
char* GetFilenameFromRequest(char* request);
bool SendFileOverSocket(int socket_desc, char* file_name);

int main(int argc, char **argv)
{
	int     socket_desc, 
		socket_client, 
		*new_sock, 
		c = sizeof(struct sockaddr_in);

	struct  sockaddr_i	server, 
				client;

	// Create socket
	socket_desc = socket(AF_INET, SOCK_STREAM, 0);
	if (socket_desc == -1)
	{
		perror("Could not create socket");
		return 1;
	}

	server.sin_family = AF_INET;
	server.sin_addr.s_addr = INADDR_ANY;
	server.sin_port = htons(SERVER_PORT);

	if (bind(socket_desc, (struct sockaddr *)&server, sizeof(server)) < 0)
	{
		perror("Bind failed");
		return 1;
	}

	listen(socket_desc , 3);
	
	while (socket_client = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c))
	{
		pthread_t sniffer_thread;
		new_sock = malloc(1);
		*new_sock = socket_client;        
		pthread_create(&sniffer_thread, NULL,  ConnectionHandler, (void*) new_sock);
		pthread_join(sniffer_thread, NULL);
	}
	 
	if (socket_client<0)
	{
		perror("Accept failed");
		return 1;
	}

	return 0;
}

void *ConnectionHandler(void *socket_desc)
{
	int	socket = *(int*)socket_desc;   
	char	server_response[BUFSIZ],
		client_request[BUFSIZ],
		file_name[BUFSIZ];
	
	recv(socket, client_request, BUFSIZ, 0);
	strcpy(file_name, GetFilenameFromRequest(client_request));

	// If requested file exists, notify the client and send it
	if (access(file_name, F_OK) != -1){

		strcpy(server_response, "OK");
		write(socket, server_response, strlen(server_response));
		SendFileOverSocket(socket, file_name);
	}
	else {
		// Requested file does not exist, notify the client
		strcpy(server_response, "NO");
		write(socket, server_response, strlen(server_response)); 
	}

	free(socket_desc);   
	return 0;
}

char* GetFilenameFromRequest(char* request){

	char *file_name = strchr(request, ' ');
	return file_name + 1;
}

bool SendFileOverSocket(int socket_desc, char* file_name){

	struct stat	obj;
	int		file_desc,
			file_size;

	stat(file_name, &obj);
	file_desc = open(file_name, O_RDONLY);
	file_size = obj.st_size;
	send(socket_desc, &file_size, sizeof(int), 0);
	sendfile(socket_desc, file_desc, NULL, file_size);

	return true;
}