From 6c4201fcd12cd82195b80e30fd8320da941b400e Mon Sep 17 00:00:00 2001
From: Oliver Frommel <ofr@zetalab.de>
Date: Sun, 30 Sep 2018 08:03:32 +0200
Subject: [PATCH] Add option to activate serial console

Resolves #6

Co-Authored-By: Jakub Jirutka <jakub@jirutka.cz>
I just refactored the code.
---
 alpine-make-vm-image | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/alpine-make-vm-image b/alpine-make-vm-image
index 8e50331..5ccb2d1 100755
--- a/alpine-make-vm-image
+++ b/alpine-make-vm-image
@@ -60,6 +60,8 @@
 #   -c --script-chroot (SCRIPT_CHROOT)    Bind <script>'s directory at /mnt inside image and chroot
 #                                         into the image before executing <script>.
 #
+#   -t --serial-console (SERIAL_CONSOLE)  Add configuration for a serial console on ttyS0.
+#
 #   -h --help                             Show this help message and exit.
 #
 #   -v --version                          Print version and exit.
@@ -247,7 +249,11 @@ setup_extlinux() {
 	local root_dev="$2"  # root device
 	local modules="$3"  # modules which should be loaded before pivot_root
 	local kernel_flavor="$4"  # name of default kernel to boot
+	local serial_port="$5"  # serial port number for serial console
 	local default_kernel="$kernel_flavor"
+	local kernel_opts=''
+
+	[ -z "$serial_port" ] || kernel_opts="console=$serial_port"
 
 	if [ "$kernel_flavor" = 'virt' ]; then
 		_apk search --root . --exact --quiet linux-lts | grep -q . \
@@ -255,10 +261,12 @@ setup_extlinux() {
 			|| default_kernel='vanilla'
 	fi
 
-	sed -Ei -e "s|^[# ]*(root)=.*|\1=$root_dev|" \
-		-e "s|^[# ]*(default_kernel_opts)=.*|\1=\"\"|" \
+	sed -Ei \
+		-e "s|^[# ]*(root)=.*|\1=$root_dev|" \
+		-e "s|^[# ]*(default_kernel_opts)=.*|\1=\"$kernel_opts\"|" \
 		-e "s|^[# ]*(modules)=.*|\1=\"$modules\"|" \
 		-e "s|^[# ]*(default)=.*|\1=$default_kernel|" \
+		-e "s|^[# ]*(serial_port)=.*|\1=$serial_port|" \
 		"$mnt"/etc/update-extlinux.conf
 
 	chroot "$mnt" extlinux --install /boot
@@ -303,8 +311,8 @@ wgets() (
 
 #=============================  M a i n  ==============================#
 
-opts=$(getopt -n $PROGNAME -o b:cCf:hi:k:p:r:s:v \
-	-l branch:,image-format:,image-size:,initfs-features:,kernel-flavor:,keys-dir:,mirror-uri:,no-cleanup,packages:,repositories-file:,rootfs:,script-chroot,help,version \
+opts=$(getopt -n $PROGNAME -o b:cCf:hi:k:p:r:s:tv \
+	-l branch:,image-format:,image-size:,initfs-features:,kernel-flavor:,keys-dir:,mirror-uri:,no-cleanup,packages:,repositories-file:,rootfs:,script-chroot,serial-console,help,version \
 	-- "$@") || help 1 >&2
 
 eval set -- "$opts"
@@ -322,6 +330,7 @@ while [ $# -gt 0 ]; do
 		-p | --packages) PACKAGES="${PACKAGES:-} $2";;
 		-r | --repositories-file) REPOS_FILE="$(realpath "$2")";;
 		     --rootfs) ROOTFS="$2";;
+		-t | --serial-console) SERIAL_CONSOLE='yes'; n=1;;
 		-c | --script-chroot) SCRIPT_CHROOT='yes'; n=1;;
 		-h | --help) help 0;;
 		-V | --version) echo "$PROGNAME $VERSION"; exit 0;;
@@ -342,6 +351,7 @@ done
 : ${REPOS_FILE:="/etc/apk/repositories"}
 : ${ROOTFS:="ext4"}
 : ${SCRIPT_CHROOT:="no"}
+: ${SERIAL_CONSOLE:="no"}
 
 if [ -f /etc/alpine-release ]; then
 	: ${INSTALL_HOST_PKGS:="yes"}
@@ -349,6 +359,9 @@ else
 	: ${INSTALL_HOST_PKGS:="no"}
 fi
 
+SERIAL_PORT=
+[ "$SERIAL_CONSOLE" = 'no' ] || SERIAL_PORT='ttyS0'
+
 [ $# -ne 0 ] || help 1 >&2
 
 IMAGE_FILE="$1"; shift
@@ -447,13 +460,19 @@ _apk add --root . linux-$KERNEL_FLAVOR
 einfo 'Setting up extlinux bootloader'
 
 _apk add --root . --no-scripts syslinux
-setup_extlinux . "UUID=$root_uuid" "$ROOTFS" "$KERNEL_FLAVOR"
+setup_extlinux . "UUID=$root_uuid" "$ROOTFS" "$KERNEL_FLAVOR" "$SERIAL_PORT"
 
 cat > etc/fstab <<-EOF
 	# <fs>		<mountpoint>	<type>	<opts>		<dump/pass>
 	UUID=$root_uuid	/		$ROOTFS	noatime		0 1
 EOF
 
+#-----------------------------------------------------------------------
+if [ "$SERIAL_PORT" ]; then
+	echo "$SERIAL_PORT" >> "$mount_dir"/etc/securetty
+	sed -Ei "s|^[# ]*($SERIAL_PORT:.*)|\1|" "$mount_dir"/etc/inittab
+fi
+
 #-----------------------------------------------------------------------
 einfo 'Enabling base system services'