[PATCH v2 5/7] meta/class/image: Add populate_sdk task to trigger SDK rootfs creation

["Maxim Yu. Osipov" <mosipov@ilbers.de>]

User manually triggers creation of SDK root filesystem for target platform by
launching the task `do_populate_sdk` for target image, f.e.
`bitbake -c do_populate_sdk multiconfig:${MACHINE}-${DISTRO}:isar-image-base`.

Adding such dependency to image class is to make sure that
target packages listed in IMAGE_INSTALL are already built.

The resulting SDK rootfs is located under
`tmp/work/${DISTRO}-${DISTRO_ARCH}/sdkchroot-${HOST_DISTRO}-${HOST_ARCH}/rootfs`.
SDK rootfs directory `/isar-apt` contains the copy of isar-apt repo with locally
prebuilt target debian packages for <HOST_DISTRO>.

One may chroot to SDK and install required target packages with the help of
`apt-get install <package_name>:<DISTRO_ARCH>` command.

Signed-off-by: Maxim Yu. Osipov <mosipov@ilbers.de>
---
 meta/classes/image.bbclass | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/meta/classes/image.bbclass b/meta/classes/image.bbclass
index 4738cb8..1cb6ea8 100644
--- a/meta/classes/image.bbclass
+++ b/meta/classes/image.bbclass
@@ -71,3 +71,18 @@ do_copy_boot_files() {
 addtask copy_boot_files before do_build after do_rootfs
 do_copy_boot_files[dirs] = "${DEPLOY_DIR_IMAGE}"
 do_copy_boot_files[stamp-extra-info] = "${DISTRO}-${MACHINE}"
+
+
+SDKCHROOT_DIR = "${TMPDIR}/work/${DISTRO}-${DISTRO_ARCH}/sdkchroot-${HOST_DISTRO}-${HOST_ARCH}/rootfs"
+
+do_populate_sdk() {
+    if [ ${HOST_DISTRO} != "debian-stretch" ]; then
+         bbfatal "SDK doesn't support ${HOST_DISTRO}"
+    fi
+    sudo cp -Trpfx ${DEPLOY_DIR_APT}/${HOST_DISTRO}  ${SDKCHROOT_DIR}/isar-apt
+}
+
+do_populate_sdk[stamp-extra-info] = "${MACHINE}-${DISTRO}"
+do_populate_sdk[depends] = "sdkchroot:do_build"
+
+addtask populate_sdk after do_rootfs
-- 
2.11.0