systemd: add rc-once mechanism

This allows to place skripts for initial execution after system install in
${sysconfdir}/rc.once.d/

Signed-off-by: Enrico Jorns <ejo@pengutronix.de>

4 files changed, 148 insertions, 0 deletions

diff --git a/recipes-core/systemd/systemd-rc-once.bb b/recipes-core/systemd/systemd-rc-once.bb
new file mode 100644
index 0000000..6c7055b
--- /dev/null
+++ b/recipes-core/systemd/systemd-rc-once.bb
@@ -0,0 +1,37 @@
+SUMMARY = "Execute initial services once with rw mount"
+SECTION = "examples"
+LICENSE = "MIT"
+LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MIT;md5=0835ade698e0bcf8506ecda2f7b4f302"
+
+SRC_URI = "\
+  file://rc-once.service \
+  file://rc-once.sh \
+  file://systemd-rc-once \
+  "
+
+S = "${WORKDIR}"
+
+inherit allarch systemd
+
+do_install() {
+	install -d ${D}${base_libdir}/init
+	install -m 0755 ${WORKDIR}/rc-once.sh ${D}${base_libdir}/init/
+	install -d ${D}${systemd_unitdir}/system
+	install -m 0755 ${WORKDIR}/systemd-rc-once ${D}${systemd_unitdir}/
+	install -m 0644 ${WORKDIR}/rc-once.service ${D}${systemd_unitdir}/system/
+	install -d ${D}${systemd_unitdir}/system/system-update.target.wants
+	ln -sf ../rc-once.service ${D}${systemd_unitdir}/system/system-update.target.wants/rc-once.service
+	install -d ${D}${sysconfdir}/rc.once.d
+}
+
+FILES_${PN} += "\
+  /lib/init/rc-once.sh \
+  /lib/systemd/systemd-rc-once \
+  /lib/systemd/system/system-update.target.wants/rc-once.service \
+"
+
+SYSTEMD_SERVICE_${PN} = "rc-once.service"
+
+pkg_postinst_${PN}() {
+	ln -sf etc/rc.once.d $D/system-update
+}
diff --git a/recipes-core/systemd/systemd-rc-once/rc-once.service b/recipes-core/systemd/systemd-rc-once/rc-once.service
new file mode 100644
index 0000000..d3377b3
--- /dev/null
+++ b/recipes-core/systemd/systemd-rc-once/rc-once.service
@@ -0,0 +1,13 @@
+[Unit]
+Description=First boot services
+DefaultDependencies=no
+After=local-fs.target
+Requires=local-fs.target
+After=system-update.target
+
+[Service]
+Type=oneshot
+RemainAfterExit=no
+ExecStart=/lib/systemd/systemd-rc-once
+StandardOutput=syslog+console
+
diff --git a/recipes-core/systemd/systemd-rc-once/rc-once.sh b/recipes-core/systemd/systemd-rc-once/rc-once.sh
new file mode 100644
index 0000000..c7aad00
--- /dev/null
+++ b/recipes-core/systemd/systemd-rc-once/rc-once.sh
@@ -0,0 +1,51 @@
+#!/bin/sh
+
+RC_ONCE_DIR=/etc/rc.once.d
+DONE_DIR="$RC_ONCE_DIR/.done"
+STAMP="$DONE_DIR/rc-once"
+
+mount_root_rw() {
+
+    touch "/.root_is_rw" > /dev/null 2>&1 && return
+
+    echo -n "remounting root rw..."
+    mount /dev/root / -n -o remount,rw > /dev/null 2>&1
+    if [ "$?" -ne "0" ]; then
+        echo "failed, aborting"
+        return 1
+    fi
+    echo "done"
+}
+
+mount_root_restore() {
+
+    rm "/.root_is_rw" > /dev/null 2>&1 && return
+
+    echo -n "remounting root ro..."
+    mount /dev/root / -n -o remount,ro > /dev/null 2>&1
+    if [ "$?" -ne "0" ]; then
+        echo "failed, aborting"
+        return 1
+    fi
+    echo "done"
+}
+
+run_rc_once() {
+	failed=0
+	echo "running rc.once.d services..."
+	cd "$RC_ONCE_DIR" || exit 1
+	mkdir -p "$DONE_DIR"
+	for script in *; do
+		test -x "$script" || continue
+		test -e "$DONE_DIR/$script" && continue
+		"$RC_ONCE_DIR/$script"
+		if [ $? -ne 0 ]; then
+			echo "running $script failed."
+			failed=1
+		else
+			: > "$DONE_DIR/$script"
+		fi
+	done
+	return $failed
+}
+
diff --git a/recipes-core/systemd/systemd-rc-once/systemd-rc-once b/recipes-core/systemd/systemd-rc-once/systemd-rc-once
new file mode 100644
index 0000000..fdb198c
--- /dev/null
+++ b/recipes-core/systemd/systemd-rc-once/systemd-rc-once
@@ -0,0 +1,47 @@
+#!/bin/sh
+
+. /lib/init/rc-once.sh
+
+start() {
+	mount_root_rw || exit 1
+	if run_rc_once; then
+		rm -f /system-update
+	fi
+	systemctl daemon-reexec
+	sleep 1
+	touch /var/lib/systemd/clock
+	exec "$0" umount
+}
+
+umount() {
+	if ! mount_root_restore; then
+		# remounting rw/ro during the second boot will flush anything
+		# left in the filesystem journal
+		ln -sf /etc/rc.once.d /system-update
+		systemctl reboot
+	else
+		if [ -e /system-update ]; then
+			systemctl rescue
+		else
+			systemctl default
+		fi
+	fi
+}
+
+case "$1" in
+
+	start|"")
+		start
+		;;
+	umount)
+		umount
+		;;
+	*)
+		echo "Usage: $0 {start|umount}" >&2
+		exit 1
+		;;
+esac
+
+exit 0
+
+