[OE-core] [OE-Core][RFC PATCH 02/11] systemd: Reinstate systemd-hwdb-update.service

[Alex Kiernan]

systemd supports a distribution hwdb.bin in /usr/lib/udev/hwdb.bin,
which is used if /etc/udev/hwdb.bin is not present. When generating the
install time hwdb, for systemd, ensure that we put it in /usr/lib/udev,
which then ensures that at boot time we do not regenerate it, unless the
system is marked for update.

This allows fragments dropped into /etc/udev/hwdb.d to be processed
correctly, but without requiring a first boot time build:

root at qemumips:~# systemctl status systemd-hwdb-update.service
* systemd-hwdb-update.service - Rebuild Hardware Database
     Loaded: loaded (/usr/lib/systemd/system/systemd-hwdb-update.service; static; vendor preset: disabled)
     Active: inactive (dead)
  Condition: start condition failed at Wed 2020-03-04 15:18:11 UTC; 44s ago
             |- ConditionPathExists=|!/usr/lib/udev/hwdb.bin was not met
             |- ConditionPathExists=|/etc/udev/hwdb.bin was not met
             `- ConditionDirectoryNotEmpty=|/etc/udev/hwdb.d was not met
       Docs: man:hwdb(7)
             man:systemd-hwdb(8)

Signed-off-by: Alex Kiernan <alex.kiernan at gmail.com>
---

 meta/recipes-core/systemd/systemd_244.3.bb   | 10 ++++------
 scripts/postinst-intercepts/update_udev_hwdb | 16 ++++++++++++++--
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/meta/recipes-core/systemd/systemd_244.3.bb b/meta/recipes-core/systemd/systemd_244.3.bb
index bb799831996c..048021000448 100644
--- a/meta/recipes-core/systemd/systemd_244.3.bb
+++ b/meta/recipes-core/systemd/systemd_244.3.bb
@@ -293,10 +293,6 @@ do_install() {
 	# install default policy for presets
 	# https://www.freedesktop.org/wiki/Software/systemd/Preset/#howto
 	install -Dm 0644 ${WORKDIR}/99-default.preset ${D}${systemd_unitdir}/system-preset/99-default.preset
-
-    # We use package postinsts for the hwdb update, as the update service is
-    # easily triggered for no reason and will slow down boots.
-    find ${D} -name systemd-hwdb-update.service -delete
 }
 
 python populate_packages_prepend (){
@@ -636,7 +632,9 @@ FILES_udev += "${base_sbindir}/udevd \
                ${datadir}/bash-completion/completions/udevadm \
               "
 
-FILES_udev-hwdb = "${rootlibexecdir}/udev/hwdb.d"
+FILES_udev-hwdb = "${rootlibexecdir}/udev/hwdb.d \
+                   ${systemd_unitdir}/system/systemd-hwdb-update.service \
+                   "
 
 RCONFLICTS_${PN} = "tiny-init ${@bb.utils.contains('PACKAGECONFIG', 'resolved', 'resolvconf', '', d)}"
 
@@ -696,7 +694,7 @@ pkg_prerm_${PN}_libc-glibc () {
 PACKAGE_WRITE_DEPS += "qemu-native"
 pkg_postinst_udev-hwdb () {
 	if test -n "$D"; then
-		$INTERCEPT_DIR/postinst_intercept update_udev_hwdb ${PKG} mlprefix=${MLPREFIX} binprefix=${MLPREFIX}
+		$INTERCEPT_DIR/postinst_intercept update_udev_hwdb ${PKG} mlprefix=${MLPREFIX} binprefix=${MLPREFIX} rootlibexecdir="${rootlibexecdir}" PREFERRED_PROVIDER_udev="${PREFERRED_PROVIDER_udev}"
 	else
 		udevadm hwdb --update
 	fi
diff --git a/scripts/postinst-intercepts/update_udev_hwdb b/scripts/postinst-intercepts/update_udev_hwdb
index c4fb2bffcbf0..102e99b94725 100644
--- a/scripts/postinst-intercepts/update_udev_hwdb
+++ b/scripts/postinst-intercepts/update_udev_hwdb
@@ -5,5 +5,17 @@
 
 set -e
 
-PSEUDO_UNLOAD=1 ${binprefix}qemuwrapper -L $D $D${libexecdir}/${binprefix}udevadm hwdb --update --root $D
-chown root:root $D${sysconfdir}/udev/hwdb.bin
+case "${PREFERRED_PROVIDER_udev}" in
+	systemd)
+		UDEV_EXTRA_ARGS="--usr"
+		UDEVLIBDIR="${rootlibexecdir}"
+		;;
+
+	*)
+		UDEV_EXTRA_ARGS=""
+		UDEVLIBDIR="${sysconfdir}"
+		;;
+esac
+
+PSEUDO_UNLOAD=1 ${binprefix}qemuwrapper -L $D $D${libexecdir}/${binprefix}udevadm hwdb --update --root $D ${UDEV_EXTRA_ARGS}
+chown root:root $D${UDEVLIBDIR}/udev/hwdb.bin
-- 
2.17.1