chroot_directory conflicts with stdin/out/err options

[Bud P. Bruegger]

Binary package hint: python-daemon

When combining chrooting with redirection of stdin/out/err to a file, an exception occurs.

The cause is that in DaemonContext.open, "change_root_directory" is called at line 320 before "redirect_stream" is called at line 719. Redirect_stream uses os.devnull. It seems that a chrooting makes /dev/null invisible when redirect_stream is called.

Among the two possible solutions I see is to call chroot after redirect_stream (but note, the test verifies the sequence, so this may not be a good solution), or to have an instance variable reference os.devnull before chrooting and make sure the file (/dev/null) is added to exclude_fds (called at line 336) such that it will not be closed in close_all_open_files at line 337