LightDM with VNC (NOT INETD)

lightdm.conf

[Seat:*]
xserver-command=/etc/vlab/vncserver-lightdm
greeter-hide-users=false
greeter-setup-script=/etc/vlab/setup.sh
#allow-user-switching=true

setup.sh

#!/bin/sh
vncconfig -nowin &

vncserver-lightdm.c

#include <time.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>

pid_t xvnc_pid;

volatile sig_atomic_t done = 0;

void term(int signum) {
    kill(xvnc_pid, SIGTERM);
    wait(NULL);
    done = 1;
}

int main(int argc, char **argv) {
    const char *display = ":0";
    if (argc >= 2) {
        display = argv[1];
    }
    pid_t lightdm_pid = getppid();
    pid_t pid = fork();
    char auth[32] = "/var/run/lightdm/root/";
    strcat(auth, display);
    if (pid == 0) {
        execl(
            "/usr/bin/Xvnc",
            "/usr/bin/Xvnc",
            display,
            "-rfbport",
            "5900",
            "-seat",
            "seat0",
            "-SecurityTypes",
            "None",
            "-auth",
            auth,
            NULL
        );
    }
    xvnc_pid = pid;
    struct sigaction action;
    memset(&action, 0, sizeof(struct sigaction));
    action.sa_handler = term;
    sigaction(SIGTERM, &action, NULL);
    sleep(2);
    kill(lightdm_pid, SIGUSR1);
    wait(NULL);
    return 0;
}