#define BACKLOG 10

#include <netinet/in.h>
#include <sys/wait.h>

int main(int argc, char ** argv)
{
		int	sockfd, new_fd;
		struct sockaddr_in	my_addr;
		struct sockaddr_in	their_addr;
		int sin_size;

		if((sockfd = socket(AF_INET,SOCK_STREAM,0)) == -1)
		{
				perror("socket");
				exit(1);
		}
		if(argc !=2)
				return 1;
		my_addr.sin_family = AF_INET;					/*host byte order*/
		my_addr.sin_port = htons(atoi(argv[1]));		/*short, network byte order*/
		my_addr.sin_addr.s_addr = INADDR_ANY;			/*auto-fill with my IP*/
		bzero(&(my_addr.sin_zero),8);					/*zero the rest of the struct*/

		if(bind(sockfd,(struct sockaddr*)&my_addr, sizeof(struct sockaddr)) == -1)
		{
				perror("bind");
				exit(1);
		}
		if(listen(sockfd, BACKLOG) == -1)
		{
				perror("listen");
				exit(1);
		}

		while(1)
		{		
				/*main accept() loop*/
				sin_size = sizeof(struct sockaddr_in);
				if((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size)) == -1)
				{
						perror("accept");
						exit(1);
				}
				printf("server: connection from %s\n", inet_ntoa(their_addr.sin_addr));
				if(!fork())
				{	
						/*this is the child process*/
						if(send(new_fd, "Hello World!\n",14,0) == -1)
								perror("send");
						close(new_fd);
						exit(0);
				}
				close(new_fd);							/*parent doesn't need this*/
				
				while(waitpid(-1, NULL, WNOHANG) > 0);	/*clean up child process*/
		}
		return 0;
}