When the controlling process exits, any existing file descriptors
for that FD will be marked as hung-up and ioctls on them will
file with EIO. To work around this, open a new file descriptor
for the VT we want to clean up.
Thanks to Ray Strode for help in sorting out the problem and
coming up with a fix!
https://github.com/systemd/systemd/issues/989
int vt, kb = K_XLATE;
struct vt_mode mode = { 0 };
+ /* We need to get a fresh handle to the virtual terminal,
+ * since the old file-descriptor is potentially in a hung-up
+ * state after the controlling process exited; we do a
+ * little dance to avoid having the terminal be available
+ * for reuse before we've cleaned it up.
+ */
+ int old_fd = s->vtfd;
+ s->vtfd = -1;
+
vt = session_open_vt(s);
+ safe_close(old_fd);
+
if (vt < 0)
return;