#include <stdbool.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/select.h>
#include <signal.h>
#include <errno.h>
#include <stdio.h>
#include <xcb/xcb.h>

void handle_signal(int s)
{
	static sig_atomic_t dead = 0;
	if(!dead) {
		pid_t pgid = getpgid(0);
		dead = 1;
		killpg(pgid, s);
	}
}

int main(int argc, char **argv)
{
	setsid();

	struct sigaction act = { 0 };
	act.sa_handler = handle_signal;

	sigaction(SIGHUP, &act, NULL);
	sigaction(SIGTERM, &act, NULL);
	sigaction(SIGINT, &act, NULL);

	if(argc == 2 && fork() == 0) {
		char *cmd[] = {"/bin/bash", "-c", argv[1], NULL};
		execvp(cmd[0], cmd);
	}

	xcb_connection_t *c = xcb_connect(NULL, NULL);
	if(xcb_connection_has_error(c))
		return 1;

	int xfd = xcb_get_file_descriptor(c);

	fd_set dsc;

	bool running = true;
	while(running) {
		FD_ZERO(&dsc);
		FD_SET(xfd, &dsc);
		int rc = select(xfd + 1, &dsc, NULL, NULL, NULL);
		if((rc == -1 && errno == EINTR))
			running = false;
		else if(rc > 0) {
			xcb_generic_event_t *e;
			while((e = xcb_poll_for_event(c))) {
				free(e);
			}
		}

		if(xcb_connection_has_error(c))
			running = false;
	}
	xcb_disconnect(c);

	handle_signal(SIGTERM);

	return 0;
}