z = gz
keys = \
	'357D CB0E EC95 A01A EBA1  F0D2 DE63 B9C7 04EB E9EF'

debrev = 4
pool = https://ftp.debian.org/debian/pool/main/s/stress/
deb_tar = $(OPK_SOURCE)_$(OPK_SOURCE_VERSION_UPSTREAM).orig.tar.$(z)
deb_dsc = $(OPK_SOURCE)_$(OPK_SOURCE_VERSION_UPSTREAM)-$(debrev).dsc
source_archive = ../$(OPK_SOURCE)-$(OPK_SOURCE_VERSION_UPSTREAM).orig.tar.$(z)

GNUPGHOME = gnupghome
# TODO: When GnuPG is built with TLS support, delete the second "keyserver" line
# to switch to a non-SKS keyserver.  We can't switch yet, because the Web server
# at keys.openpgp.org redirects (HTTP 301) to HTTPS (and enforces it with HSTS).
keyserver = hkps://keys.openpgp.org
keyserver = hkp://pool.sks-keyservers.net
keyring = ../keyring.gpg
cleanup = gpgconf --kill all; rm -Rf '$(GNUPGHOME)'; sleep 5

dsc_sed = \
	/^Checksums-Sha256:$$/,/^[^ ]/{ \
		s/ \([0-9a-f][0-9a-f]*\) [0-9][0-9]* \($(deb_tar)\)$$/\1  \2/p;\
	};

$(keyring):
	gpg --recv-keys $(keys) || { rm -Rf '$@'; exit 1; }
	rm -f '$@~'

$(source_archive): $(keyring)
	wget -c '$(pool)/$(deb_dsc)' '$(pool)/$(deb_tar)'
	gpg --verify '$(deb_dsc)'
	sed -n '$(dsc_sed)' '$(deb_dsc)' | sha256sum -c -
	mv '$(deb_tar)' '$(source_archive)'

source:
	install -m 0700 -d '$(GNUPGHOME)'
	umask 0177; printf 'keyserver $(keyserver)\n' \
		1>'$(GNUPGHOME)/dirmngr.conf'
	umask 0177; printf 'no-default-keyring\nkeyring $(keyring)\nverbose\n' \
		1>'$(GNUPGHOME)/gpg.conf'
	GNUPGHOME='$(GNUPGHOME)' $(MAKE) -f ../source.mk "$(source_archive)" \
		|| { $(cleanup); exit 1; }
	$(cleanup)