uninative: Add uninative - a way of reusing native/cross over multiple distros

These patches are the start of a new idea, a way of allowing a single set of
cross/native sstate to work over mutliple distros, even old ones.

The assumption is that our own C library is basically up to date. We build
and share a small tarball (~2MB) of a prebuilt copy of this along with a
patchelf binary (which sadly is C++ based so libstdc++ is in there). This
tarball can be generated from our usual SDK generation process through
the supplied recipe, uninative-tarball.

At the start of the build, if its not been extracted into the sysroot, this
tarball is extracted there and configured for the specified path.

When we install binaries from a "uninative" sstate feed, we change the
dynamic loader to point at this dynamic loader and C librbary. This works
exactly the same way as our relocatable SDK does. The only real difference
is a switch to use patchelf, so even if the interpreter section is too small,
it can still adjust the binary.

Right now this implements a working proof of concept. If you build the tarball
and place it at the head of the tree (in COREBASE), you can run a build from
sstate and successfully build packages and construct images.

There is some improvement needed, its hardcoded for x86_64 right now, its trivial
to add 32 bit support too. The tarball isn't fetched right now, there is just a
harcoded path assumption and there is no error handling. I haven't figured
out the best delivery mechanism for that yet. BuildStarted is probably not
the right event to hook on either.

I've merged this to illustrate how with a small change, we might make the
native/cross sstate much more reusable and hence improve the accessibility
of lower overhead builds. With this change, its possible the Yocto Project may
be able to support a configured sstate mirror out the box. This also has
positive implications for our developer workflow/SDK improvements.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/meta/recipes-core/meta/uninative-tarball.bb b/meta/recipes-core/meta/uninative-tarball.bb
new file mode 100644
index 0000000000..ed1279f09b
--- /dev/null
+++ b/meta/recipes-core/meta/uninative-tarball.bb
@@ -0,0 +1,48 @@
+SUMMARY = "libc and patchelf tarball for use with uninative.bbclass"
+LICENSE = "MIT"
+LIC_FILES_CHKSUM = "file://${COREBASE}/LICENSE;md5=4d92cd373abda3937c2bc47fbc49d690 \
+                    file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
+
+TOOLCHAIN_TARGET_TASK = ""
+
+TOOLCHAIN_HOST_TASK = "\
+    nativesdk-eglibc \
+    nativesdk-patchelf \
+    "
+
+INHIBIT_DEFAULT_DEPS = "1"
+DEPENDS += "patchelf-native"
+
+TOOLCHAIN_OUTPUTNAME ?= "${BUILD_ARCH}-nativesdk-libc"
+
+RDEPENDS = "${TOOLCHAIN_HOST_TASK}"
+
+EXCLUDE_FROM_WORLD = "1"
+
+inherit meta
+inherit populate_sdk
+
+deltask install
+deltask package
+
+SDK_PACKAGING_FUNC = ""
+
+fakeroot create_sdk_files() {
+	cp ${COREBASE}/scripts/relocate_sdk.py ${SDK_OUTPUT}/${SDKPATH}/
+
+	# Replace the ##DEFAULT_INSTALL_DIR## with the correct pattern.
+	# Escape special characters like '+' and '.' in the SDKPATH
+	escaped_sdkpath=$(echo ${SDKPATH}/sysroots/${SDK_SYS} |sed -e "s:[\+\.]:\\\\\\\\\0:g")
+	sed -i -e "s:##DEFAULT_INSTALL_DIR##:$escaped_sdkpath:" ${SDK_OUTPUT}/${SDKPATH}/relocate_sdk.py
+}
+
+
+fakeroot tar_sdk() {
+	mkdir -p ${SDK_DEPLOY}
+	cd ${SDK_OUTPUT}/${SDKPATH}
+	mv sysroots/${SDK_SYS} ./${BUILD_SYS}
+	rm sysroots -rf
+	patchelf --set-interpreter ${@''.join('a' for n in xrange(1024))} ./${BUILD_SYS}/usr/bin/patchelf
+	mv ./${BUILD_SYS}/usr/bin/patchelf ./${BUILD_SYS}/usr/bin/patchelf-uninative
+	tar ${SDKTAROPTS} -c --file=${SDK_DEPLOY}/${TOOLCHAIN_OUTPUTNAME}.tar.bz2 .
+}