auto-serial-console: add systemd support

Add systemd auto-getty.service to run agetty on the console defined in the
kernel command line on platforms with systemd support.

This service replaces serial-getty@.service as the one responsible for
opening a tty port and prompting for a login name when
TRUSTFENCE_CONSOLE_DISABLE is configured.

https://jira.digi.com/browse/DEL-7242

Signed-off-by: Gonzalo Ruiz <Gonzalo.Ruiz@digi.com>

meta-digi-dey/recipes-digi/auto-serial-console/auto-serial-console/auto-getty-systemd

@@ -0,0 +1,24 @@
+#!/bin/sh
+
+set -e
+
+[ -f "/etc/default/autogetty" ] && . /etc/default/autogetty
+
+[ "${ENABLED}" != "1" ] && exit
+
+for arg in $(cat /proc/cmdline); do
+	case "${arg}" in
+		console=*)
+			eval ${arg}
+			TTY="${console%,*}"
+			SPEED="${console#*,}"
+
+			# If no speed is given default to 115200 and fall-back
+			[ "${SPEED}" = "${TTY}" ] && SPEED="115200,57600,38400,19200,9600"
+
+			if [ -n "${TTY}" ] && grep -qs "${TTY}" /etc/securetty; then
+				setsid /sbin/agetty -8 -L ${TTY} ${SPEED} xterm
+			fi
+			;;
+	esac
+done

meta-digi-dey/recipes-digi/auto-serial-console/auto-serial-console/auto-getty.service

@@ -0,0 +1,26 @@
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+[Unit]
+Description=Serial Auto-Getty
+After=systemd-user-sessions.service plymouth-quit-wait.service
+After=rc-local.service
+
+# If additional gettys are spawned during boot then we should make
+# sure that this is synchronized before getty.target, even though
+# getty.target didn't actually pull it in.
+Before=getty.target
+IgnoreOnIsolate=yes
+
+[Service]
+ExecStart=/usr/bin/auto-getty
+Type=idle
+Restart=always
+RestartSec=0
+
+[Install]
+WantedBy=getty.target

meta-digi-dey/recipes-digi/auto-serial-console/auto-serial-console_0.1.bb

@@ -7,18 +7,22 @@ LIC_FILES_CHKSUM = "\
     file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420 \
 "
 
+AUTOGETTY_FILE="${@bb.utils.contains('DISTRO_FEATURES', 'systemd', 'auto-getty-systemd', 'auto-getty-sysvinit', d)}"
+
 SRC_URI = "\
     file://autogetty \
-    file://auto-getty \
+    file://${AUTOGETTY_FILE} \
+    file://auto-getty.service \
     file://auto-serial-console \
 "
 
 S = "${WORKDIR}"
 
-inherit update-rc.d
+inherit systemd update-rc.d
 
 INITSCRIPT_NAME = "auto-serial-console"
 INITSCRIPT_PARAMS = "start 99 5 ."
+SYSTEMD_SERVICE_${PN} = "auto-getty.service"
 
 do_install () {
 	install -m 0755 -d ${D}${sysconfdir}/default
@@ -29,6 +33,9 @@ do_install () {
 	install -m 0755 -d ${D}${sysconfdir}/init.d
 	install -m 0755 ${WORKDIR}/auto-serial-console ${D}${sysconfdir}/init.d/auto-serial-console
 
+	install -d ${D}${systemd_unitdir}/system/
+	install -m 0644 ${WORKDIR}/auto-getty.service ${D}${systemd_unitdir}/system/auto-getty.service
+
 	install -m 0755 -d ${D}${bindir}
-	install -m 0755 ${WORKDIR}/auto-getty ${D}${bindir}/auto-getty
+	install -m 0755 ${WORKDIR}/${AUTOGETTY_FILE} ${D}${bindir}/auto-getty
 }