
Simon McVittie
authored
Previously, we assumed that if OS files on the provider are in a
location that is not /usr or a related directory, for example if the OS
has /lib/ld-linux.so.2 -> /some/odd/path/i386/ld.so, then they will
appear below the same path_in_container_ns as /usr, for example
/run/host/some/odd/path/i386/ld.so. However, nothing sets this up for
directories other than /usr, /lib*, /bin, /sbin and /etc, so it's
a bad assumption.
A previous commit handled /etc by redirecting it to /run/host/etc,
/run/parent/etc or /run/gfx/etc as appropriate, so we don't need to
worry about that here.
For the rest, assume that if they appear in the container at all,
they'll appear at a path that matches their location in the provider.
For the common case where provider = host, which is the only one where
we really need to support non-FHS layouts, this means that users can
work around lack of explicit support for a particular non-FHS directory
with something like PRESSURE_VESSEL_FILESYSTEMS_RO=/some/odd/path.
In particular, if we didn't have explicit support for /nix, NixOS users
would have been able to use that workaround to get it mounted.
Signed-off-by:
Simon McVittie <smcv@collabora.com>