only use prepare_build in legacy build path

The new build path being the use of container tools to build CoreOS
and the legacy path being the use of `rpm-ostree` directly where
prepare_build is leveraged.

Let's remove the use of `prepare_build` in all cases that aren't the
legacy `cmd-fetch` and `cmd-build`.

Author: dustymabe

cmd/clean.go

@@ -34,10 +34,6 @@ Delete all build artifacts.  Use --all to also clean the cache/ directory.
 	if err != nil {
 		return err
 	}
-	// XXX: why do we need to prepare_build here?
-	if _, err := sh.PrepareBuild(""); err != nil {
-		return err
-	}
 
 	if all {
 		priv, err := sh.HasPrivileges()

src/cmd-osbuild

@@ -165,21 +165,16 @@ postprocess_qemu_secex() {
 generate_runvm_osbuild_config() {
     local outfile=$1; shift
 
-    # reread these values from the build itself rather than rely on the ones loaded
-    # by prepare_build since the config might've changed since then
     ostree_commit=$(meta_key ostree-commit)
     ostree_ref=$(meta_key ref)
     if [ "${ostree_ref}" = "None" ]; then
         ostree_ref=""
     fi
 
-    ostree_repo=${tmprepo}
+    ostree_repo=${workdir}/tmp/repo
     # Ensure that we have the cached unpacked commit
     import_ostree_commit_for_build "${build}"
-    # Note this overwrote the bits generated in prepare_build
-    # for image_json.  In the future we expect to split prepare_build
-    # into prepare_ostree_build and prepare_diskimage_build; the
-    # latter path would only run this.
+    # Note this extracted the image.json file from the build.
     image_json=${workdir}/tmp/image.json
 
     # Grab a few values from $image_json
@@ -342,7 +337,13 @@ main() {
     # shellcheck disable=SC2031
     export LIBGUESTFS_BACKEND=direct
     export IMAGE_TYPE="${platforms[0]}"
-    prepare_build
+    export workdir="${PWD}"
+    export tmp_builddir="${workdir}/tmp/build${IMAGE_TYPE:+.$IMAGE_TYPE}"
+    rm "${tmp_builddir}" -rf
+    mkdir "${tmp_builddir}"
+
+    # Basic checks for the environment
+    preflight_checks
 
     if [ -z "${build}" ]; then
         build=$(get_latest_build)
@@ -364,8 +365,6 @@ main() {
     touch "${build_semaphore}"
     trap 'rm -f ${build_semaphore}' EXIT
 
-    # reread these values from the build itself rather than rely on the ones loaded
-    # by prepare_build since the config might've changed since then
     name=$(meta_key name)
 
     for platform in "${platforms[@]}"; do

src/cmd-supermin-shell

@@ -5,6 +5,7 @@ dn=$(dirname "$0")
 # shellcheck source=src/cmdlib.sh
 . "${dn}"/cmdlib.sh
 
-prepare_build
+export workdir="${PWD}"
+preflight_checks
 
 RUNVM_SHELL=1 runvm_with_cache "$@" -- bash

src/cmdlib.sh

@@ -121,6 +121,11 @@ preflight_kvm() {
     fi
 }
 
+preflight_checks() {
+    preflight
+    preflight_kvm
+}
+
 # Use this for things like disabling fsync.
 # For more information, see the docs of `cosa init --transient`.
 is_transient() {
@@ -170,6 +175,9 @@ should_build_with_buildah() {
     return 1
 }
 
+# Only used by legacy (not via container tools) path. Delete when we
+# have moved away from legacy building (i.e. delete or overwrite cmd-build
+# and delete cmd-fetch)
 prepare_build() {
     preflight
     preflight_kvm