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It's possible to add user-defined fields in the debian/control file using the XBS- method, as defined in the Debian Policy Manual, and those will be injected into the binary .deb and source packages.

Something like this before calling dpkg-buildpackage will work to inject a new field into both the Source and Binary packages. But some packages don't contain debian/control as they generate it (kernel etc) so this is not always reliable.

sed -i "0,/^\s*$/s//XBS-Git-Branch: ${CI_COMMIT_BRANCH}\n/" debian/control
dpkg-buildpackage

It's also possible to inject the user-defined field into the generated source package using options passed to dpkg-source while building the package:

dpkg-buildpackage --source-option=-DGit-Branch=${CI_COMMIT_BRANCH}

However, that will only inject the field into the generated source package, not the generated binary packages. Is there a method to reliably inject fields into the binary packages?

2 Answers 2

Reset to default
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It seems your underlying problem is not having debian/control in all cases. The fix for that is always to start from source packages, since they have to provide a debian/control file. Any other approach is going to involve running part of the build directly, since dpkg-buildpackage requires debian/control; for example, you could run debian/rules build, and then patch debian/control (which must exist at this point) before running debian/rules binary (which produces the binary packages).

To control what goes into the binary packages’ control file, you can also add options for dpkg-gencontrol, e.g. using dh_gencontrol:

override_dh_gencontrol:
        dh_gencontrol -- -Dfoo=bar

will add a Foo: bar entry to your binary packages’ control files. This is probably more useful in your scenario.

You’ll need to change debian/rules to do this; you can use dh_gencontrol as above, or dpkg-gencontrol directly if the package doesn’t use dh.

3
  • Thanks, that's a useful bit of information. I'm not sure it helps me, as making that change to debian/rules using sed, for an arbitrary package, is even less reliable than my original sed modification of debian/control. I'm looking for method to inject fields into both the generated source/binary packages when building an arbitrary package with dpkg-buildpackage (or gbp).
    – NickBroon
    May 25, 2021 at 9:53
  • Ah right, I hadn’t understood that this is for arbitrary packages that you don’t necessarily want to modify.
    – Stephen Kitt
    May 25, 2021 at 10:42
  • See the updated answer.
    – Stephen Kitt
    May 25, 2021 at 10:53
0

It is possible to modify the binary packages control files from the --hook-buildinfo hook that's called immediately after debian/rules build is called, using dpkg-deb to unpack/repack them.

#!/bin/bash
#
# deb_insert_meta.sh
#
# Inserts CI metadata into all deb files in parent directory
# Intended for use with:
# `dpkg-buildpackage --hook-buildinfo='fakeroot deb_insert_meta.sh'`
# which is the first hook after the binary deb files are generated
# but before checksums for .changes are calculated
# Should be called with 'fakeroot' so that the repacked binaries
# have their content/control ownership/permissions preserved.

pushd .. > /dev/null || exit 1

    for deb_file in *.deb; do
        [ -e "$deb_file" ] || continue

        DEB_TMPDIR=$(mktemp -d)
        if [ -z "${DEB_TMPDIR}" ]; then
            echo "Failed to create a temporary work directory"
            exit 1
        fi

        dpkg-deb -R "${deb_file}" "${DEB_TMPDIR}"

        if [ -e "${DEB_TMPDIR}/DEBIAN/control" ]; then
            if [ -n "${CI_PROJECT_PATH}" ]; then
                echo "Git-Repo: ${CI_PROJECT_PATH}" >> "${DEB_TMPDIR}/DEBIAN/control"
            fi
            if [ -n "${CI_COMMIT_SHA}" ]; then
                echo "Git-Hash: ${CI_COMMIT_SHA}" >> "${DEB_TMPDIR}/DEBIAN/control"
            fi
            if [ -n "${CI_COMMIT_BRANCH}" ]; then
                echo "Git-Branch: ${CI_COMMIT_BRANCH}" >> "${DEB_TMPDIR}/DEBIAN/control"
            fi

            dpkg-deb -b "${DEB_TMPDIR}" "${deb_file}"

        fi

        rm -rf "${DEB_TMPDIR}"

    done

popd > /dev/null || exit 1

exit 0

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