bootstrap_sdk: no package updates in stage 1

This change updates the stage1 SDK bootstrap build to use local
("known good") package ebuilds only, preventing updated package ebuilds
to apply in stage 1. This fixes SDK build breakage we observed when
upgrading core libraries like readline.

The change also removes the seed update from stage 1 as it should not
be needed anymore now that we postpone any package updates to stage 2.

The following package ebuild repos are used for stage 1:
- for portage-stable, we simply copy /var/gentoo/repos/gentoo
   from the SDK root.
- coreos-overlay is more complicated since ebuilds are missing from
   the SDK. So we grok the version the SDK was built with from
     /mnt/host/source/.repo/manifests/default.xml
   and then we create a local stage 1 clone of
     https://github.com/kinvolk/coreos-overlay.git
   in which we then check out the revision noted in the default mnifest.

Signed-off-by: Thilo Fromm <thilo@kinvolk.io>

bootstrap_sdk

@@ -83,6 +83,54 @@ mkdir -p "${ROOT_OVERLAY}/tmp"
 chmod 1777 "${ROOT_OVERLAY}/tmp"
 cp "${BUILD_LIBRARY_DIR}/toolchain_util.sh" "${ROOT_OVERLAY}/tmp"
 
+
+# Stage 1 uses a different ebuild repo snapshot as well as a different portage_overlay 
+# the ones from the SDK where ./bootstrap_sdk is being executed -
+# to buils a known-good stage 1 (see stages description at top
+# of file). This prevents package upgrades from updated ebuild files in the portage/coreos
+# to apply in stage 1.
+# Stage 1 lacks proper isolation and will link all packages built against its own
+# seed libraries instead of against libraries installed to /tmp/stage1root.
+build_stage1() {
+    local stage1_repos="$TEMPDIR/stage1-ebuild-repos"
+
+    write_configs
+
+    # use known-good gentoo base repo from SDK, coreos-overlay from manifest
+    info "Creating stage 1 ebuild repos and stage 1 snapshot in '$stage1_repos'"
+    rm -rf "$stage1_repos"
+    mkdir "$stage1_repos"
+    cp -R /var/gentoo/repos/gentoo "$stage1_repos"
+
+    local overlay_revision=$(
+        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 '$overlay_revision'"
+
+    mkdir "$stage1_repos/coreos-overlay"
+    ( cd "$stage1_repos/coreos-overlay" \
+         && git clone https://github.com/kinvolk/coreos-overlay.git . \
+         && git checkout "$overlay_revision" )
+
+    catalyst_conf > "$TEMPDIR/catalyst-stage1.conf"
+    sed -i "s:^portdir.*:portdir=\"$stage1_repos/gentoo\":" \
+         "$TEMPDIR/catalyst-stage1.conf"
+
+    catalyst $DEBUG -c "$TEMPDIR/catalyst-stage1.conf" -s "$FLAGS_version-stage1"
+
+    sed -i -e "s/^snapshot:.*/snapshot: $FLAGS_version-stage1/" \
+           -e "s,^portage_overlay:.*,portage_overlay: $stage1_repos/coreos-overlay," \
+        "$TEMPDIR/stage1.spec"
+
+    build_stage stage1 "$SEED" "$TEMPDIR/catalyst-stage1.conf"
+}
+
+if [[ "$STAGES" =~ stage1 ]]; then
+    build_stage1
+    STAGES="${STAGES/stage1/}"
+fi
+
 catalyst_build
 
 if [[ "$STAGES" =~ stage4 ]]; then

build_library/catalyst.sh

@@ -120,16 +120,7 @@ cat <<EOF
 target: stage1
 # stage1 packages aren't published, save in tmp
 pkgcache_path: ${TEMPDIR}/stage1-${ARCH}-packages
-update_seed: yes
-# Install virtual/rust to avoid version conflicts that happen in case of
-# rust versions in the SDK being different from those in the new ebuilds.
-# /usr/share/catalyst/targets/stage1/stage1-chroot.sh installs gcc and
-# its dependencies, including dev-lang/rust, while virtual/rust does not
-# get updated. That results in version conflicts between virtual/rust and
-# dev-lang/rust. To avoid such an issue, we should update virtual/rust
-# before building stage1. Since virtual/rust automatically pulls in
-# dev-lang/rust, we do not need to explicitly specify dev-lang/rust here.
-update_seed_command: --update --deep --newuse --complete-graph --rebuild-if-new-ver --rebuild-exclude cross-*-cros-linux-gnu/* sys-devel/gcc virtual/rust
+update_seed: no
 EOF
 catalyst_stage_default
 }
@@ -259,8 +250,11 @@ write_configs() {
 build_stage() {
     stage="$1"
     srcpath="$2"
+    catalyst_conf="$3"
     target_tarball="${stage}-${ARCH}-${FLAGS_version}.tar.bz2"
 
+    [ -z "$catalyst_conf" ] && catalyst_conf="$TEMPDIR/catalyst.conf"
+
     if [[ -f "$BUILDS/${target_tarball}" && $FLAGS_rebuild == $FLAGS_FALSE ]]
     then
         info "Skipping $stage, $target_tarball already exists."