Bug#504721: Possible reason for serial console misdetection

[Frans Pop <elendil@planet.nl>]

On Tuesday 02 December 2008, Frans Pop wrote:
> Someone who can actually write in C please check the code and let me
> know if anything can be removed or is missing. I may well have added
> unneeded includes for example and I have no idea what the original
> sprintf statements were supposed to do.

main can probably be safely reduced to:
+int main(int argc, char ** argv)
+{
+       union {
+               struct vt_stat vt;
+               struct serial_struct sr;
+               char paranoia[sizeof(struct serial_struct) * 3];
+       } u;
+
+       if (ioctl(0, TIOCGSERIAL, &u.sr) == 0) {
+               /* this is a serial console */
+               printf("serial\n");
+       } else if (ioctl(0, VT_GETSTATE, &u.vt) == 0) {
+               /* this is linux virtual tty */
+               printf("virtual\n");
+       }
+
+       return 0;
+}