Add test coverage environment using uClibc

[kdave]

#843 added/fixed support for uClibc. We should add it to our CI so we don't break it accidentally. I haven't found any docker image that can be used (like what we do for Musl builds). The buildroot seems to be commonly used for that.

[jolivain]

Hi @kdave,

Buildroot is using a Debian-based Docker reference image. See the Dockerfile at:
https://gitlab.com/buildroot.org/buildroot/-/blob/master/support/docker/Dockerfile

The "current" image is referenced here:
https://gitlab.com/buildroot.org/buildroot/-/blob/master/.gitlab-ci.yml?ref_type=heads#L4
So, this docker image can be started with the command:

docker run -ti registry.gitlab.com/buildroot.org/buildroot/base:20230207.1123

Anyways, any modern Linux system should do (Debian, Ubuntu, Fedora, ...) with the mandatory dependencies should do. See: https://nightly.buildroot.org/manual.html#requirement-mandatory

This example script is made to run a Linux system, I did not write it to run as-is in a CI, specifically.

For preparing an environment, you basically need a base OS image, checkout a Buildroot version, and the btrfs-progs source.

Example of a preparation script:

#! /bin/sh
set -exu

# Checkout a Buildroot release, to have a stable environment. Update
# when needed. or use release tarball:
# https://buildroot.org/downloads/buildroot-2024.05.1.tar.xz
if [ ! -d buildroot ] ; then
    git clone -b 2024.05.1 https://gitlab.com/buildroot.org/buildroot.git
    # We instruct Buildroot to use the latest git devel version of
    # btrfs-progs we will checkout just after. See:
    # https://nightly.buildroot.org/manual.html#_using_buildroot_during_development
    echo "BTRFS_PROGS_OVERRIDE_SRCDIR = $PWD/btrfs-progs" > buildroot/local.mk
fi

if [ ! -d btrfs-progs ] ; then
   git clone https://github.com/kdave/btrfs-progs
else
   git -C btrfs-progs pull
   git -C btrfs-progs clean -fdx
fi

# Regenerate autotools scripts, as Buildroot build recipes assumes a
# release tarball.
btrfs-progs/autogen.sh

cd buildroot
# ...append the test commands here (see below)...

Then, depending of what you want to test, the coverage you need, etc, I list here few examples and options. Pick the relevant ones and adjust to your needs.

The following commands are all assuming the working directory is buildroot, so you can append those to the previous preparation script.

Option 1:

Create a Buildroot configuration just for building btrfs-progs for aarch64 with a gcc+uclibc external bootlin toolchain. This config test the uClibc-ng use-case fixed in PR #843. I believe this is what you are looking for...

cat > .config <<EOF
BR2_aarch64=y
BR2_TOOLCHAIN_EXTERNAL=y
BR2_TOOLCHAIN_EXTERNAL_BOOTLIN=y
BR2_TOOLCHAIN_EXTERNAL_BOOTLIN_AARCH64_UCLIBC_STABLE=y
BR2_PACKAGE_BTRFS_PROGS=y
BR2_TARGET_ROOTFS_BTRFS=y
# BR2_TARGET_ROOTFS_TAR is not set
EOF
make olddefconfig
make clean
make

Option 2:

Try to compile the package with 6 representative toolchains. This command can catch the issue fixed in PR #843.

utils/test-pkg -p btrfs-progs

Option 3:

This command try to compile package with 41 arch/libc/toolchains. This is the command which caught the issue fixed in PR #842. There is "older" gcc toolchains in this list. Note that it should be possible to create another configuration as in "Option 1" to test with an older gcc.

utils/test-pkg -a -p btrfs-progs

Option 4:

A custom list of arch/libc/toolchains which can be created, from:
https://gitlab.com/buildroot.org/buildroot/-/blob/master/support/config-fragments/autobuild/toolchain-configs.csv?ref_type=heads&plain=1
When the list is created, the test can be run with:

utils/test-pkg -t my-toolchain-list.csv -a -p btrfs-progs

Option 5:

Buildroot has some runtime testing capabilities, to check the built is running (in qemu) in a known configuration.
This test is using glibc (NOT using uClibc-ng), and create and use btrfs on target (in qemu). This test is not in a Buildroot release yet. It can be used by using the Buildroot "master" branch. See the test sequence at: https://gitlab.com/buildroot.org/buildroot/-/blob/master/support/testing/tests/package/test_btrfs_progs.py?ref_type=heads

support/testing/run-tests -d dl -o output_folder tests.package.test_btrfs_progs

Option 6:

Buildroot has a host/target runtime test. It creates a btrfs rootfs on host, use it to boot on target (in qemu). Again this test is using glibc (NOT using uClibc-ng). Same comment as in "Option 5". See the test sequence at: https://gitlab.com/buildroot.org/buildroot/-/blob/master/support/testing/tests/fs/test_btrfs.py?ref_type=heads

support/testing/run-tests -d dl -o output_folder tests.fs.test_btrfs

I hope this will help you...

[kdave]

This is perfect, thank you very much.