Re: kernel api testing with atf and rump ?

[Mindaugas Rasiukevicius <rmind%netbsd.org@localhost>]

"Cherry G. Mathew" <cherry.g.mathew%gmail.com@localhost> wrote:
> Hi Antti, tech-kern,
> 
> I'm trying to understand how/if it's possible to unit test a
> self-contained api implementation within kernel source via rump.
> 
> For eg: let's say I'm going to write an api with a single function:
> 
> int add(int a, int b);
> 
> ...
> 
> Any pointers would be great.

It seems to me that there are two ways one can use RUMP: a client-server
model (where system calls are passed to the RUMP hypervisor kernel) or raw
calls to the kernel-space functions.  I cannot tell much about the former.
The latter is better (at least for me) for unit tests.  Here is an example
of NPF unit tests:

http://nxr.netbsd.org/xref/src/usr.sbin/npf/npftest/

Kernel namespace code has to be in a separate object file (we do it via
private library, see the Makefile magic):

http://nxr.netbsd.org/xref/src/usr.sbin/npf/npftest/libnpftest/

Kernel namespace is prefixed with rumpns_.  Symbols in the object/library
are renamed by the RUMP framework.  In your example, the call from the
frontend of application (user namespace part) would be to rumpns_add().

Note that we already have shared libraries for kernel subsystems, which
can be just linked (e.g. librumpnet, librumpvfs, etc):

http://nxr.netbsd.org/xref/src/sys/rump/

For example, NPF itself is provided by librumpdev_npf:

http://nxr.netbsd.org/xref/src/sys/rump/dev/lib/libnpf/

So, you have the following (kernel namespace is in curly brackets and
already built and provided kernel components in square brackets):

npftest -> { libnpftest -> [ librumpdev_npf + librumpnet_net + ... ] }

It is something what "works for me".  If intended way of RUMP framework
use was different, I hope Antti will point that out.

-- 
Mindaugas