Currently, vmtest runs a custom program as init in the guest that
communicates with the host via virtio-serial. This is a lot of C code
that turns out can be replaced with a shell script. In order to keep the
dependencies minimal, we use BusyBox.
The current implementation of vmtest has a few issues:
1. Building drgn for each kernel version on Travis is slow, mostly
because they don't all run in parallel.
2. For local, incremental testing, recreating the filesystem image and
rebuilding drgn is slow, and syncing the code to the filesystem image
is brittle.
3. The filesystem image is the only communication channel, and reading
the exit status from the filesystem image is awkward and fragile.
4. Creating and accessing the filesystem image requires root.
This reworks vmtest to use the build on the host via VirtFS with a
simple agent on the guest that can execute arbitrary commands and return
the exit status. This has a few more moving parts but is faster and
saner overall.
v5.6-rc1 was released today, and 5.3 was recently EOL'd. (It might be
worthwhile to continue testing EOL kernels, but for now I don't want
Travis runs to take forever).
The next change will make non-git builds depend on a fully-formed source
distribution. So, let's copy in everything from SOURCES.txt, which
should include the egg metadata and anything else setuptools decides is
important.
Now that we have tests for kernel-specific functionality, we should run
them on various kernel versions. This adds a script for doing so using
QEMU with a pre-built root filesystem image and kernels that I'm hosting
on my Dropbox. The script can be run locally, but this also sets it up
to be run on Travis. For now, we're testing the mainline, stable, and
longterm releases from kernel.org (not including v3.16, which doesn't
even boot for me).
Python 3.8 replaced the unused void *tp_print field with Py_ssize_t
tp_vectorcall_offset, so with -Werror we get "error: initialization of
‘long int’ from ‘void *’ makes integer from pointer without a cast".
Let's just use designated initializers.
Now that we have the bundled version of elfutils, build it from libdrgn
and link to it. We can also get rid of the elfutils version checks from
the libdrgn code.
