In some cases we cannot do a fast bind-mount of the files we want
in our jail since we don't have cap_sys_admin for loolmount inside
eg. docker.
Thus we need to fallback to hard-linking, however various security
systems namespace parts of our tree, such that link() fails with
EXDEV even across the (apparently) same file-system.
As such we need to assemble a copy of what we want to hard-link
close to our jails. However, this needs to be owned by root / the
system to avoid having writable files shared between jails. Hence
we need cap_chown in addition to cap_fowner, to get ownership right
and then hard-link.
Change-Id: Iba0ef46ddbc1c03f3dc7177bc1ec1755624135db
Signed-off-by: Michael Meeks <michael.meeks@collabora.com>
317dffb817