# Choose the best mirror to download linux kernel
KERNEL_REPO = http://www.kernel.org

LINUX_SRCDIR ?= linux-$(LINUX_VER)-xen

# Setup pristine search path
PRISTINE_SRC_PATH	?= .:..
vpath pristine-% $(PRISTINE_SRC_PATH)

vpath linux-%.tar.bz2 $(LINUX_SRC_PATH)
vpath patch-%.bz2 $(LINUX_SRC_PATH)

# download a pristine Linux kernel tarball if there isn't one in LINUX_SRC_PATH
linux-%.tar.bz2: override _LINUX_VDIR = $(word 1,$(subst ., ,$*)).$(word 2,$(subst ., ,$*))
linux-%.tar.bz2:
	@echo "Cannot find $@ in path $(LINUX_SRC_PATH)"
	wget $(KERNEL_REPO)/pub/linux/kernel/v$(_LINUX_VDIR)/$@ -O./$@

patch-%.bz2: override _LINUX_VDIR = $(word 1,$(subst ., ,$(*F))).$(word 2,$(subst ., ,$(*F)))
patch-%.bz2: override _LINUX_XDIR = $(if $(word 3,$(subst -, ,$(*F))),snapshots,testing)
patch-%.bz2:
	@echo "Cannot find $(@F) in path $(LINUX_SRC_PATH)"
	wget $(KERNEL_REPO)/pub/linux/kernel/v$(_LINUX_VDIR)/$(_LINUX_XDIR)/$(@F) -O./$@

pristine-%: pristine-%/.valid-pristine
	@true

pristine-%/.valid-pristine: %.tar.bz2
	rm -rf tmp-pristine-$* $(@D)
	mkdir -p tmp-pristine-$*
	tar -C tmp-pristine-$* -jxf $<
	-@rm -f tmp-pristine-$*/pax_global_header
	mv tmp-pristine-$*/* $(@D)
	@rm -rf tmp-pristine-$*
	touch $(@D)/.hgskip
	touch $@ # update timestamp to avoid rebuild

PATCHDIRS := $(wildcard patches/*-*)

ifneq ($(PATCHDIRS),)
-include $(patsubst %,%/.makedep,$(PATCHDIRS))

$(patsubst patches/%,patches/%/.makedep,$(PATCHDIRS)): patches/%/.makedep: 
	@echo 'ref-$*/.valid-ref: $$(wildcard patches/$*/*.patch)' >$@

ref-%/.valid-ref: pristine-%/.valid-pristine
	set -e
	rm -rf $(@D)
	cp -al $(<D) $(@D)
	if [ -d patches/$* ] ; then                                    \
	    echo Applying patches from patches/$*... ;                 \
	    for i in $$(cat patches/$*/series) ; do                    \
	        echo ... $$i ;                                         \
	        patch -d $(@D) -p1 --quiet <patches/$*/$$i || exit 1 ; \
	     done ;                                                    \
	fi
	touch $@ # update timestamp to avoid rebuild
endif

$(LINUX_SRCDIR)/.valid-src: ref-linux-$(LINUX_VER)/.valid-ref
	rm -rf $(LINUX_SRCDIR)
	cp -al $(<D) $(LINUX_SRCDIR)
	# Apply arch-xen patches
	( cd linux-$(LINUX_SERIES)-xen-sparse && \
          LINUX_ARCH=$(LINUX_ARCH) bash ./mkbuildtree ../$(LINUX_SRCDIR) )
	( cd $(LINUX_SRCDIR) && [ -e buildconfigs ] || ln -s $(PWD)/buildconfigs buildconfigs )
	touch $@

linux-2.6-xen.patch: ref-linux-$(LINUX_VER)/.valid-ref
	rm -rf tmp-$@
	cp -al $(<D) tmp-$@
	( cd linux-2.6-xen-sparse && bash ./mkbuildtree ../tmp-$@ )
	diff -Nurp $(patsubst ref%,pristine%,$(<D)) tmp-$@ > $@ || true
	rm -rf tmp-$@