Bad File Descriptor. This should be returned when you try to use a syscall that takes a FD, and you have passed it a FD that is not open.

This could happen with open(2), read(2), write(2), select(2), etc ...

cat: /dev/net/tun: File descriptor in bad state

lib/main.php:944: Notice: PageInfo: Cannot find action page

lib/main.php:839: Notice: PageInfo: Unknown action