Create a mount helper program that can start a fuse server that runs as
a socket-based systemd service, and a new libfuse module to wrap all the
details of communicating between the mount helper and the containerized
fuse server.
This enables untrusted ext4 mounts via systemd service containers, which
avoids the problem of malicious filesystems compromising the integrity
of the running kernel through memory corruption.
In theory this could also be supported via inetd and clones, though the
author hasn't found one that supports AF_UNIX sockets.
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Bernd Schubert <bernd@bsbernd.com>
In fact only gnu-libc fully supports symbol versioning, so it is
better to have a generic macro for it. This also allows to manually
disable symbol version and allows to run tests with that
configuration on gnu-libc. That testing will still not catch compat
issues, but least ensures the code can compile.
Testing for __APPLE__ and __ULIBC__ is now done by meson. More of such
checks can be added by people using other libcs.
Allow skipping utils build & installation (-Dutils=false) and examples
build (-Dexamples=false). By default behaviour is unchanged (both are
true: utils and examples get build).
Darrick J. Wong