upstream_archive_base = $(OPK_SOURCE)-$(OPK_SOURCE_VERSION_UPSTREAM).tar
upstream_mirror = http://mirrors.edge.kernel.org/pub/software/utils/pciutils
upstream_url = $(upstream_mirror)/$(upstream_archive_base)
source_archive = ../$(OPK_SOURCE)-$(OPK_SOURCE_VERSION_UPSTREAM).orig.tar.xz

gpg = GNUPGHOME=gnupghome/ gpg --no-default-keyring --keyring ../keyring.gpg
keys = \
	'5558 F939 9CD7 8368 5055  3C6E C28E 7847 ED70 F82D'

$(source_archive):
	wget -c '$(upstream_url).xz' '$(upstream_url).sign'
	install -m 0700 -d gnupghome/
	[ -e ../keyring.gpg ] || \
		$(gpg) --keyserver hkp://pool.sks-keyservers.net \
			--recv-keys $(keys); \
	rm -f ../keyring.gpg~; \
	if ! unxz -c '$(upstream_archive_base).xz' | \
			$(gpg) --verify '$(upstream_archive_base).sign' -; then\
		rm -Rf gnupghome/; \
		exit 1; \
	fi
	rm -Rf gnupghome/
	mv '$(upstream_archive_base).xz' '$@'

source: $(source_archive)