Add slx_service helper function to add service-script to init

This should be called in a module install script, to add a script
in <moddir>/hooks/ to the init, and create a service file with
configurable dependencies.

slx_service <script name without .sh> <service description> [options]

Options are:
--before, --after, --wants, --requires, --wbefore --wafter
--wbefore is shorthand for doing
--before <something> --wants <something>
same for --wafter.

For example, assuming a script ./hooks/s3-init-foo.sh, call
slx_service "s3-init-foo" "Initialize all foo" --wafter \
	s3-finish-bar.service --before s3-something.service

1 files changed, 70 insertions, 0 deletions

diff --git a/build-initramfs.sh b/build-initramfs.sh
index e41a642a..5b5e9597 100755
--- a/build-initramfs.sh
+++ b/build-initramfs.sh
@@ -348,6 +348,76 @@ initialize_dracut() {
 	./configure || exit 1
 	make dracut-install || exit 1
 	make dracut-util
+	# add a few handy functions to dracut
+	if ! [ -s dracut-init.sh ]; then
+		echo "no dracut-init.sh"
+		exit 1
+	fi
+	# One tab then 4 spaces, tab will get removed by -EOF
+	cat >> dracut-init.sh <<-"EOF"
+
+	slx_service() {
+	    local _name _desc _tmpfile
+	    declare -a _before=() _after=() _requires=() _wants=()
+	    _name="$1"
+	    _desc="$2"
+	    shift 2
+	    while (( $# > 0 )); do
+	        case "$1" in
+	            --wbefore)
+	                _wants+=("$2")
+	                ;&
+	            --before)
+	                _before+=("$2")
+	                ;;
+	            --wafter)
+	                _wants+=("$2")
+	                ;&
+	            --after)
+	                _after+=("$2")
+	                ;;
+	            --wants)
+	                _wants+=("$2")
+	                ;;
+	            --requires)
+	                _requires+=("$2")
+	                ;;
+	            *)
+	                dfatal "Invalid option: '$1'"
+	                exit 10
+	        esac
+	        shift 2
+	    done
+	    if [ -z "$_desc" ]; then
+	        dfatal "Cannot install service without description"
+	        exit 1
+	    fi
+	    mkdir --parents "${initdir}/usr/local/slx-services"
+	    _tmpfile="/tmp/dracut-service-$RANDOM"
+	    inst "$moddir/hooks/${_name}.sh" \
+	            "/usr/local/slx-services/${_name}.sh" || exit 10
+	    {
+	        echo "[Unit]"
+	        echo "Description=${_desc}"
+	        [ -n "${_wants}" ] && echo "Wants=${_wants[*]}"
+	        [ -n "${_requires}" ] && echo "Requires=${_requires[*]}"
+	        [ -n "${_before}" ] && echo "Before=${_before[*]}"
+	        [ -n "${_after}" ] && echo "After=${_after[*]}"
+	        echo ""
+	        echo "[Service]"
+	        echo "Type=oneshot"
+	        echo "RemainAfterExit=yes"
+	        echo "ExecStart=/usr/local/slx-services/${_name}.sh"
+	    } > "${_tmpfile}"
+	    inst_simple "${_tmpfile}" \
+	            "${systemdsystemunitdir}/${_name}.service" || exit 10
+	    rm -f -- "${_tmpfile}"
+	    mkdir --parents \
+	            "${initdir}/${systemdsystemunitdir}/initrd.target.wants" || exit 10
+	    ln_r "${systemdsystemunitdir}/${_name}.service" \
+	            "${systemdsystemunitdir}/initrd.target.wants/${_name}.service" || exit 10
+	}
+	EOF
 	popd || exit 1
 	return $?
 }