#include<sys/socket.h>
#include<sys/types.h>
#include<sys/wait.h>
#include<netinet/ip.h>
#include<stdio.h>
#include<unistd.h>
#include<signal.h>

void wait_for_child(int signum){
	int exit_status;
	wait(&exit_status);
	printf("Child exited with status %d\n", exit_status);
}

int main(int argc, char ** argv){
	// Install signal handler
	struct sigaction sa;
	sa.sa_handler = wait_for_child;
	sigaction(SIGCHLD, &sa, 0);

	// Network part 
	struct sockaddr_in sad;
	sad.sin_port = htons(5141);
	sad.sin_addr.s_addr = INADDR_ANY;
	sad.sin_family = AF_INET;

	int skt = socket(AF_INET, SOCK_STREAM, 0);
	bind(skt, (struct sockaddr *)(&sad), sizeof(struct sockaddr_in));
	listen(skt, 5);
	int client_fd;
	int usecount = 0;
	for(;;){
		client_fd = accept(skt, 0, 0);
		if(client_fd < 3){
			printf("Accept returned %d\n", client_fd);
			continue;
		}

		pid_t pid = fork(); 
		if(pid){ // parent
			printf("Accepted a connection\n");
		} else { // child inherits file descriptors that are open
			// This will replace our child with the wumpus game
			dup2(client_fd, 1);
			dup2(client_fd, 0);
			execl("/bin/sh", "sh", "-c", "wump", 0);
			// If wumpus runs, this next line will NEVER happen!
			printf("Couldn't start wumpus!\n");
		}
		close(client_fd); // Connection doesn't close until BOTH parent and child have done this!
	}
	return 0;
}