This LD_PRELOAD shared library is used to override vsftpd requiring chroot
to be non-writeable, and Debian wheezy missing option
allow_writable_root=YES

So, we fake access(2) check for "/", W_OK to return "false" always.

For example, on Debian system you can edit /etc/init.d/vsftpd and before
starting daemon put

LD_PRELOAD="/usr/local/lib/libfakeaccess.so"
export LD_PRELOAD