5 files changed, 90 insertions, 23 deletions
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d7f2aee..29e0783 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -5,14 +5,14 @@ shellcheck:
     - apt-get update
     - apt-get dist-upgrade --yes
     - apt-get --no-install-recommends --yes install shellcheck
-    - shellcheck -P tests bin/* tests/*.sh
+    - shellcheck -P tests bin/* share/*.sh tests/*.sh
 
 codespell:
   script:
     - apt-get update
     - apt-get dist-upgrade --yes
     - apt-get --no-install-recommends --yes install codespell
-    - codespell bin/* tests/*.sh
+    - codespell bin/* share/*.sh tests/*.sh
 
 release_test:
   parallel:
diff --git a/bin/debvm-create b/bin/debvm-create
index 0dc619b..9d637b1 100755
--- a/bin/debvm-create
+++ b/bin/debvm-create
@@ -97,6 +97,8 @@ SSHKEY=
 SUITE=unstable
 VMNAME=testvm
 
+SHARE_DIR="${0%/*}/../share"
+
 nth_arg() {
 	shift "$1"
 	printf "%s" "$1"
@@ -255,14 +257,7 @@ fi
 if test "$DEBVER" -ge 9; then
 	INCLUDE_PACKAGES="$INCLUDE_PACKAGES,libnss-resolve"
 fi
-if test "$DEBVER" -le 11; then
-	set -- '--customize-hook=chroot "$1" systemctl enable systemd-resolved.service' "$@"
-fi
-if test "$DEBVER" -le 9; then
-	set -- '--customize-hook=ln -fs ../run/systemd/resolve/resolv.conf "$1/etc/resolv.conf"' "$@"
-elif test "$DEBVER" -le 11; then
-	set -- '--customize-hook=ln -fs ../run/systemd/resolve/stub-resolv.conf "$1/etc/resolv.conf"' "$@"
-fi
+set -- "--customize-hook=$SHARE_DIR/customize-resolved.sh" "$@"
 
 # construct mmdebstrap options as $@:
 set -- \
@@ -285,15 +280,7 @@ set -- \
 set -- '--customize-hook=chroot "$1" passwd --delete root' "$@"
 
 # dhcp on all network interfaces
-SYSD_NET_MATCH='Name=en*\n'
-test "$DEBVER" -le 8 && SYSD_NET_MATCH="${SYSD_NET_MATCH}Name=eth*\\n"
-SYSD_NET_NET='DHCP=yes\n'
-# This anchor is included by default since bullseye. Fails DNSSEC validation when missing.
-test "$DEBVER" -le 11 && SYSD_NET_NET="${SYSD_NET_NET}DNSSECNegativeTrustAnchors=home.arpa\\n"
-set -- \
-	'--customize-hook=chroot "$1" systemctl enable systemd-networkd.service' \
-	"--customize-hook=printf \"[Match]\\n$SYSD_NET_MATCH\\n[Network]\\n$SYSD_NET_NET"'\n[DHCP]\nUseDomains=yes\n" > "$1/etc/systemd/network/20-wired.network"' \
-	"$@"
+set -- "--customize-hook=$SHARE_DIR/customize-networkd.sh" "$@"
 
 # add ssh key for root
 if test -n "$SSHKEY"; then
@@ -320,10 +307,7 @@ if test "$DEBVER" -ge 12; then
 	set -- --hook-dir=/usr/share/mmdebstrap/hooks/merged-usr "$@"
 fi
 
-set -- \
-	'--customize-hook=mkdir "$1/etc/systemd/system/serial-getty@.service.d"' \
-	"--customize-hook=sed -n -e '1i[Service]' -e '1iExecStart=' -e 's,^ExecStart=-/sbin/agetty ,&-a root ,p'"' "$1/lib/systemd/system/serial-getty@.service" > "$1/etc/systemd/system/serial-getty@.service.d/autologin.conf"' \
-	"$@"
+set -- "--customize-hook=$SHARE_DIR/customize-autologin.sh" "$@"
 
 # suite target mirror
 set -- "$@" "$SUITE" "$IMAGE" "deb $MIRROR $SUITE main"
diff --git a/share/customize-autologin.sh b/share/customize-autologin.sh
new file mode 100755
index 0000000..5592a03
--- /dev/null
+++ b/share/customize-autologin.sh
@@ -0,0 +1,20 @@
+#!/bin/sh
+# Copyright 2022 Helmut Grohne <helmut@subdivi.de>
+# SPDX-License-Identifier: MIT
+#
+# This is a mmdebstrap customize hook that configures automatic root login on a
+# serial console.
+
+set -eu
+
+TARGET=$1
+
+UNIT=serial-getty@.service
+
+mkdir "$TARGET/etc/systemd/system/$UNIT.d"
+
+(
+	echo '[Service]'
+	echo 'ExecStart='
+	sed -n 's,^ExecStart=-/sbin/agetty ,&-a root ,p' "$TARGET/lib/systemd/system/$UNIT"
+) > "$TARGET/etc/systemd/system/$UNIT.d/autologin.conf"
diff --git a/share/customize-networkd.sh b/share/customize-networkd.sh
new file mode 100755
index 0000000..c89aae2
--- /dev/null
+++ b/share/customize-networkd.sh
@@ -0,0 +1,37 @@
+#!/bin/sh
+# Copyright 2022 Helmut Grohne <helmut@subdivi.de>
+# SPDX-License-Identifier: MIT
+#
+# This is a mmdebstrap customize hook that enables and configures
+# systemd-networkd on various Debian releases.
+
+set -eu
+
+TARGET=$1
+
+SYSTEMD_VERSION=$(dpkg-query --root "$TARGET" -f '${Version}' -W systemd)
+
+if test "${MMDEBSTRAP_MODE:-}" = chrootless; then
+	systemctl --root "$TARGET" enable systemd-networkd.service
+else
+	chroot "$TARGET" systemctl enable systemd-networkd.service
+fi
+
+{
+	echo '[Match]'
+	echo 'Name=en*'
+	if dpkg --compare-versions "$SYSTEMD_VERSION" lt 220-7~; then
+		echo 'Name=eth*'
+	fi
+
+	echo '[Network]'
+	echo 'DHCP=yes'
+
+	if dpkg --compare-versions "$SYSTEMD_VERSION" lt 249; then
+		# This anchor is included by default since bullseye. Fails DNSSEC
+		# validation when missing.
+		echo 'DNSSECNegativeTrustAnchors=home.arpa'
+	fi
+	echo '[DHCP]'
+	echo 'UseDomains=yes'
+} >"$TARGET/etc/systemd/network/20-wired.network"
diff --git a/share/customize-resolved.sh b/share/customize-resolved.sh
new file mode 100755
index 0000000..e8fe248
--- /dev/null
+++ b/share/customize-resolved.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+# Copyright 2022 Helmut Grohne <helmut@subdivi.de>
+# SPDX-License-Identifier: MIT
+#
+# This is a mmdebstrap customize hook that enables systemd-resolved on various
+# Debian releases.
+
+set -eu
+
+TARGET=$1
+
+LIBNSS_RESOLVE_VERSION=$(dpkg-query --root "$TARGET" -f '${Version}' -W libnss-resolve 2>/dev/null) || :
+
+if dpkg --compare-versions "$LIBNSS_RESOLVE_VERSION" lt 251.3-2~exp1; then
+	if test "${MMDEBSTRAP_MODE:-}" = chrootless; then
+		systemctl --root "$TARGET" enable systemd-resolved.service
+	else
+		chroot "$TARGET" systemctl enable systemd-resolved.service
+	fi
+
+	if test -z "$LIBNSS_RESOLVE_VERSION"; then
+		ln -fs ../run/systemd/resolve/resolv.conf "$TARGET/etc/resolv.conf"
+	else
+		ln -fs ../run/systemd/resolve/stub-resolv.conf "$TARGET/etc/resolv.conf"
+	fi
+fi