// Turn off USB if we're in danger.
static void
usboff(void) {
#if USBOFF
// Needs sudo privileges - alter your /etc/sudoers file:
// sysctl: [username] [hostname] =NOPASSWD: /sbin/sysctl kernel.grsecurity.deny_new_usb=0
char *args[] = { "sudo", "sysctl", "kernel.grsecurity.deny_new_usb=1", NULL };
#if STRICT_USBOFF
char *argst[] = { "sudo", "sysctl", "kernel.grsecurity.grsec_lock=1", NULL };
execvp(argst[0], argst);
#endif
execvp(args[0], args);
#else
return;
#endif
}

// Turn on USB when the correct password is entered.
static void
usbon(void) {
#if USBOFF
// Needs sudo privileges - alter your /etc/sudoers file:
// sysctl: [username] [hostname] =NOPASSWD: /sbin/sysctl kernel.grsecurity.deny_new_usb=0
char *args[] = { "sudo", "sysctl", "kernel.grsecurity.deny_new_usb=0", NULL };
execvp(args[0], args);
#else
return;
#endif
}