From 8877d7adcdd58ae505fa09450e4a42f63270069c Mon Sep 17 00:00:00 2001
From: Thilo Fromm <thilo@kinvolk.io>
Date: Thu, 22 Apr 2021 15:39:20 +0200
Subject: [PATCH] bootstrap_sdk: use local SDK ebuilds for stage1

This change uses portage-stable and coreos-overlay from the local SDK
chroot (from /var/lib/gentoo/repos) in the stage 1 SDK bootstrap build.
This is part 2 of the SDK bootstrap stage 1 fix (part 1 is covered in
64d8a73ac09853a4b9b813b53299d37569c35071), which ensures stage 1 does
not introduce any changes in its ebuilds over the seed SDK.

The change also introduces an option to consciously divert from the
above enforcement by use of command line parameters:

--stage1_overlay_ref <gitref> will check out coreos-overlay and use
                                <gitref> for stage 1 instead of the
                                local SDK's
                                /var/lib/gentoo/repos/coreos-overlay

--stage1_portage_ref <gitref> will check out portage-stable and use
                                <gitref> for stage 1 instead of the
                                local SDK's
                                /var/lib/gentoo/repos/gentoo

Signed-off-by: Thilo Fromm <thilo@kinvolk.io>
---
 bootstrap_sdk | 132 +++++++++++++++++++++++++++++---------------------
 1 file changed, 78 insertions(+), 54 deletions(-)

diff --git a/bootstrap_sdk b/bootstrap_sdk
index ccfba3720e..f3fb419e12 100755
--- a/bootstrap_sdk
+++ b/bootstrap_sdk
@@ -11,33 +11,36 @@
 # For reference the procedure it performs is this:
 # 
 # 1. snapshot: Grab a snapshot of the portage-stable repo from
-#    third_party/... . coreoy-overlay is used as-is from the same source.
+#     the current SDK's /var/lib/gentoo/repos/gentoo.
+#     Alternatively, check out a git ref specified via --portage-ref.
 #
 # 2. stage1: Using a "seed" tarball as a build environment, build a
-#    minimal root file system into a clean directory using ROOT=...
-#    and USE=-* The restricted USE flags are key be small and avoid
-#    circular dependencies. Tarball is built from the current SDK's
-#    portage-stable and coreos-overlay instead of the ones from stage1
-#    since stage1 must not contain updated ebuilds (see build_stage1 below).
-#    This stage uses:
-#    - portage-stable from the SDK's /var/lib/gentoo/repos/gentoo
-#    - a fresh check-out of coreos-overlay at the revision used to build the SDK
+#     minimal root file system into a clean directory using ROOT=...
+#     and USE=-* The restricted USE flags are key be small and avoid
+#     circular dependencies.
+#     This stage uses:
+#     - portage-stable from the SDK's /var/lib/gentoo/repos/gentoo
+#        or a git ref via --stage1_portage_ref command line option
+#     - coreos-overlay  from the SDK's /var/lib/gentoo/repos/coreos-overlay
+#        or a git ref via --stage1_overlay_ref command line option
+#     Command line option refs need caution though, since
+#     stage1 must not contain updated ebuilds (see build_stage1 below).
 #
 # 3. stage2: Run portage-stable/scripts/bootstrap.sh
-#    This rebuilds the toolchain using Gentoo bootstrapping, ensuring it's not linked
-#    to or otherwise influenced by whatever was in the "seed" tarball.
-#    The toolchain rebuild may contain updated package ebuilds from
-#    third_party/(portage-stable|coreos-overlay).
-#    This and all following stages use portage-stable and coreos-overlay
-#    from third_party/... (see 1.)
+#     This rebuilds the toolchain using Gentoo bootstrapping, ensuring it's not linked
+#     to or otherwise influenced by whatever was in the "seed" tarball.
+#     The toolchain rebuild may contain updated package ebuilds from
+#     third_party/(portage-stable|coreos-overlay).
+#     This and all following stages use portage-stable and coreos-overlay
+#     from third_party/... (see 1.)
 #
 # 4. stage3: Run emerge -e system to rebuild everything using the fresh updated
-#    toolchain from 3., using the normal USE flags provided by the profile. This
-#    will also pull in assorted base system packages that weren't included
-#    in the minimal environment stage1 created.
+#     toolchain from 3., using the normal USE flags provided by the profile. This
+#     will also pull in assorted base system packages that weren't included
+#     in the minimal environment stage1 created.
 #
 # 5. stage4: Install any extra packages or other desired tweaks. For the
-#    sdk we just install all the packages normally make_chroot.sh does.
+#     sdk we just install all the packages normally make_chroot.sh does.
 #
 # Usage: bootstrap_sdk [stage1 stage2 etc]
 # By default all four stages will be built using the latest stage4 as a seed.
@@ -52,6 +55,13 @@ TYPE="flatcar-sdk"
 # include upload options
 . "${BUILD_LIBRARY_DIR}/release_util.sh" || exit 1
 
+
+DEFINE_string stage1_portage_ref "" \
+  "Custom portage repo git ref to use in stage 1 (USE WITH CAUTION)"
+DEFINE_string stage1_overlay_ref "" \
+  "Custom overlay repo git ref to use in stage 1 (USE WITH CAUTION)"
+
+
 ## Define the stage4 config template
 catalyst_stage4() {
 cat <<EOF
@@ -99,41 +109,65 @@ cp "${BUILD_LIBRARY_DIR}/toolchain_util.sh" "${ROOT_OVERLAY}/tmp"
 # Stage 1 uses "known-good" ebuild repos (both coreos-overlay and portage-stable)
 #  to build a minimal toolchain (USE="-*") for stage 2.
 #
-# No package updates must happen in stage 1, so we use
-# - the portage-stable repo included with the current SDK (from the SDK chroot's
-#    /var/lib/gentoo/repos/gentoo), and
-# - the coreos-overlay repo version listed in the current SDK's manifest.
-#    Unfortunately coreos-overlay is not included in the SDK chroot at all; this
-#    will be addressed in the future.
-#
-# "Current SDK" refers to the SDK we entered with 'cork enter', i.e. the SDK
-#   we run ./bootstrap_sdk in.
+# No package updates must happen in stage 1, so we use the portage-stable and
+#  coreos-overlay repos included with the current SDK (from the SDK chroot's
+#  /var/lib/gentoo/repos/). "Current SDK" refers to the SDK we entered with
+#  'cork enter', i.e. the SDK we run ./bootstrap_sdk in.
 #
 # Using ebuilds from the above mentioned sources will ensure that stage 1 builds
 #  a minimal stage 2 from known-good ebuild versions - the same ebuild versions
 #  that were used to build the very SDK we run ./bootstrap_sdk in.
 #
-# NOTE that stage 1 lacks proper isolation and will link all packages built for stage 2
-#  against its own seed libraries ("/" in the catalyst chroot) instead of against libraries
+# This is needed because stage 1 lacks proper isolation and will link all packages built for
+#  stage 2 against its own seed libraries ("/" in the catalyst chroot) instead of against libraries
 #  installed into the FS root of the stage 2 seed ("/tmp/stage1root" in the catalyst chroot).
 #  This is why we must prevent any updated package ebuilds to "leak" into stage 1, hence we use
 #  "known good" ebuild repo versions outlined above.
+#
+# In special circumstances it may be required to circumvent this and use git
+#  refs of either (or both) portage and overlay. The command line options
+#  --stage1-portage-ref and --stage1-overlay-ref may be used to specify
+#  a git ref known to work for stage1. In that case the stage1 seed (i.e. the seed SDK)
+#  will be updated prior to starting to build stage 2.
+
+stage_repo() {
+    local repo="$1"
+    local gitref="$2"
+    local dest="$3"
+    local gitname="$repo"
+
+    if [ "$gitname" = "gentoo" ] ; then
+        gitname="portage-stable"
+    fi
+
+    if [ -z "$gitref" ]; then
+        cp -R "/var/gentoo/repos/${repo}" "$dest"
+        info "Using local SDK's ebuild repo '$repo' ('$gitname') in stage 1."
+    else
+        info "Using git ref '$gitref' for ebuild repo '$repo' ('$gitname') in stage 1."
+        mkdir "$dest/$repo"
+        (   cd "$dest/$repo" \
+            && git clone "https://github.com/kinvolk/$gitname.git" . \
+            && git fetch --all \
+            && git checkout "$gitref" )
+    fi
+}
 
 build_stage1() {
-
     # First, write out the default 4-stage catalyst configuration files
     write_configs
 
     # Prepare local copies of both the "known-good" portage-stable and the
     #  "known-good" coreos-overlay ebuild repos
-    info "Creating stage 1 ebuild repos and stage 1 snapshot in '$stage1_repos'"
     local stage1_repos="$TEMPDIR/stage1-ebuild-repos"
+    info "Creating stage 1 ebuild repos and stage 1 snapshot in '$stage1_repos'"
     rm -rf "$stage1_repos"
     mkdir "$stage1_repos"
 
-    # PORTAGE-STABLE
-    # copy local SDK's "known-good" portage-stable repo into stage 1 tempdir
-    cp -R /var/gentoo/repos/gentoo "$stage1_repos"
+    # prepare ebuild repos for stage 1, either from the local SDK (default)
+    #  or from git refs specified via command line flags
+    stage_repo "gentoo" "${FLAGS_stage1_portage_ref}" "$stage1_repos"
+    stage_repo "coreos-overlay" "${FLAGS_stage1_overlay_ref}" "$stage1_repos"
 
     # Create a snapshot of "known-good" portage-stable repo copy for use in stage 1
     #  This requires us to create a custom catalyst config to point it to the
@@ -144,29 +178,19 @@ build_stage1() {
     # take the "portage directory" (portage-stable copy) snapshot
     catalyst $DEBUG -c "$TEMPDIR/catalyst-stage1.conf" -s "$FLAGS_version-stage1"
 
-    # COREOS-OVERLAY
-    # get revision of coreos-overlay used by the SDK we're currently in so we can
-    #  check out exactly that version. Unfortunately, coreos-overlay is not available
-    #  in /var/lib/gentoo/repos - we might want to change that in the future, after which
-    #  this step will be a lot simpler.
-    local overlay_revision=$(
-        grep 'name="kinvolk/coreos-overlay"' /mnt/host/source/.repo/manifests/default.xml \
-        | sed 's/.*revision="refs\/\(heads\/\)\{0,1\}\([^"]\+\)".*/\2/' )
-
-    info "Using coreos-overlay revision '$overlay_revision'"
-
-    # Check out local SDK's "known-good" coreos-overlay version for use in stage 1
-    mkdir "$stage1_repos/coreos-overlay"
-    ( cd "$stage1_repos/coreos-overlay" \
-         && git clone https://github.com/kinvolk/coreos-overlay.git . \
-         && git checkout "$overlay_revision" )
-
-    # Wire up stage 1 spec to use the "known-good" portage-stable and coreos-overlay
-    #  repository versions from above.
+    # Update the stage 1 spec to use the "known-good" portage-stable snapshot
+    #  and coreos-overlay copy repository versions from above.
     sed -i -e "s/^snapshot:.*/snapshot: $FLAGS_version-stage1/" \
            -e "s,^portage_overlay:.*,portage_overlay: $stage1_repos/coreos-overlay," \
         "$TEMPDIR/stage1.spec"
 
+    # If we are to use a git ref for either ebuild repo we want to update the stage1 seed SDK
+    if [ -n "${FLAGS_stage1_portage_ref}" -o -n "${FLAGS_stage1_overlay_ref}" ] ; then
+        sed -i 's/^update_seed: no/update_seed: yes/' "$TEMPDIR/stage1.spec"
+        echo "update_seed_command: --update --deep --newuse --complete-graph --rebuild-if-new-ver --rebuild-exclude cross-*-cros-linux-gnu/* sys-devel/gcc " \
+            >>"$TEMPDIR/stage1.spec"
+    fi
+
     # Finally, build stage 1
     build_stage stage1 "$SEED" "$TEMPDIR/catalyst-stage1.conf"
 }