kbuild: deb-pkg: use more debhelper commands in builddeb

Commit 36862e1 ("kbuild: deb-pkg: use dh_listpackages to know
enabled packages") started to require the debhelper tool suite.

Use more dh_* commands in create_package():

 - dh_installdocs to install copyright
 - dh_installchangelogs to install changelog
 - dh_compress to compress changelog
 - dh_fixperms to replace the raw chmod command
 - dh_gencontrol to replace the raw dpkg-gencontrol command
 - dh_md5sums to record the md5sum of included files
 - dh_builddeb to replace the raw dpkg-deb command

Set DEB_RULES_REQUIRES_ROOT to 'no' in case debian/rules is executed
directly.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>

scripts/package/builddeb

@@ -26,23 +26,16 @@ if_enabled_echo() {
 
 create_package() {
 	local pname="$1" pdir="$2"
-	local dpkg_deb_opts
-
-	mkdir -m 755 -p "$pdir/DEBIAN"
-	mkdir -p "$pdir/usr/share/doc/$pname"
-	cp debian/copyright "$pdir/usr/share/doc/$pname/"
-	cp debian/changelog "$pdir/usr/share/doc/$pname/changelog.Debian"
-	gzip -n -9 "$pdir/usr/share/doc/$pname/changelog.Debian"
-	sh -c "cd '$pdir'; find . -type f ! -path './DEBIAN/*' -printf '%P\0' \
-		| xargs -r0 md5sum > DEBIAN/md5sums"
-
-	# a+rX in case we are in a restrictive umask environment like 0077
-	# ug-s in case we build in a setuid/setgid directory
-	chmod -R go-w,a+rX,ug-s "$pdir"
-
-	# Create the package
-	dpkg-gencontrol -p$pname -P"$pdir"
-	dpkg-deb --root-owner-group ${KDEB_COMPRESS:+-Z$KDEB_COMPRESS} --build "$pdir" ..
+
+	export DH_OPTIONS="-p${pname} -P${pdir}"
+
+	dh_installdocs
+	dh_installchangelogs
+	dh_compress
+	dh_fixperms
+	dh_gencontrol
+	dh_md5sums
+	dh_builddeb -- ${KDEB_COMPRESS:+-Z$KDEB_COMPRESS}
 }
 
 install_linux_image () {

scripts/package/debian/rules

@@ -1,6 +1,9 @@
 #!/usr/bin/make -f
 # SPDX-License-Identifier: GPL-2.0-only
 
+# in case debian/rules is executed directly
+export DEB_RULES_REQUIRES_ROOT := no
+
 include debian/rules.vars
 
 ifneq (,$(filter-out parallel=1,$(filter parallel=%,$(DEB_BUILD_OPTIONS))))

scripts/package/mkdebian

@@ -193,7 +193,7 @@ Section: kernel
 Priority: optional
 Maintainer: $maintainer
 Rules-Requires-Root: no
-Build-Depends: debhelper
+Build-Depends: debhelper-compat (= 12)
 Build-Depends-Arch: bc, bison, cpio, flex, kmod, libelf-dev:native, libssl-dev:native, rsync
 Homepage: https://www.kernel.org/