at: add systemd support

Add systemd support for at.

This patch mainly comes from meta-systemd.

[YOCTO #4420]

(From OE-Core rev: b71670bfbd8e394521cfd969eeafad4adc34c285)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/at/at_3.1.14.bb

@@ -22,6 +22,7 @@ SRC_URI = "${DEBIAN_MIRROR}/main/a/at/at_${PV}.orig.tar.gz \
     file://posixtm.h \
     file://file_replacement_with_gplv2.patch \
     file://S99at \
+    file://atd.service \
     ${@base_contains('DISTRO_FEATURES', 'pam', '${PAM_SRC_URI}', '', d)}"
 
 PAM_SRC_URI = "file://pam.conf.patch \
@@ -37,7 +38,9 @@ EXTRA_OECONF += "ac_cv_path_SENDMAIL=/bin/true \
                  --with-atspool=/var/spool/at/spool \
                  ac_cv_header_security_pam_appl_h=${@base_contains('DISTRO_FEATURES', 'pam', 'yes', 'no', d)} "
 
-inherit autotools
+inherit autotools systemd
+
+SYSTEMD_SERVICE_${PN} = "atd.service"
 
 PARALLEL_MAKE = ""
 
@@ -53,6 +56,11 @@ do_install () {
 	install -m 0755    ${WORKDIR}/S99at		${D}${sysconfdir}/init.d/atd
 	ln -sf ../init.d/atd ${D}${sysconfdir}/rcS.d/S99at
 
+	# install systemd unit files
+	install -d ${D}${systemd_unitdir}/system
+	install -m 0644 ${WORKDIR}/atd.service ${D}${systemd_unitdir}/system
+	sed -i -e 's,@SBINDIR@,${sbindir},g' ${D}${systemd_unitdir}/system/atd.service
+
 	if [ "${@base_contains('DISTRO_FEATURES', 'pam', 'pam', '', d)}" = "pam" ]; then
 		install -D -m 0644 ${WORKDIR}/${BP}/pam.conf ${D}${sysconfdir}/pam.d/atd
 	fi

meta/recipes-extended/at/files/atd.service

@@ -0,0 +1,9 @@
+[Unit]
+Description=Job spooling tools
+After=syslog.target
+
+[Service]
+ExecStart=@SBINDIR@/atd -f
+
+[Install]
+WantedBy=multi-user.target