#!/bin/bash
# SPDX-License-Identifier: GPL-2.0-or-later
#
# Copyright © 2020      Christian Kastner <ckk@debian.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see
# <http://www.gnu.org/licenses/>.
#
#######################################################################


set -e
umask 0022


VMROOT="$1"
if [ -z "$VMROOT" ]
then
	echo "$0 expects the mounted root of the VM as first argument." >&2
	exit 1
elif ! mountpoint -q "$VMROOT"
then
	echo "$VMROOT is not a mountpoint." >&2
	exit 1
fi


echo "### Customizing base image ###"

if [ -n "$SQC_SKEL" ]
then
	echo "Copying contents of $SQC_SKEL"
	if [ ! -d "$SQC_SKEL" ]
	then
		echo "$SQC_SKEL is not a directory." >&2
		exit 1
	fi
	cp -pr "$SQC_SKEL/." "$VMROOT/root"
fi

if [ -n "$SQC_AUTH_KEYS" ]
then
	echo "Copying $SQC_AUTH_KEYS to /root/.ssh/"
	if [ ! -f "$SQC_AUTH_KEYS" ]
	then
		echo "$SQC_AUTH_KEYS is not a regular file." >&2
		exit 1
	fi

	TARGET_KEYS="$VMROOT/root/.ssh/authorized_keys"
	if [ ! -d "$VMROOT/root/.ssh" ]
	then
		mkdir --mode=0700 "$VMROOT/root/.ssh"
	fi
	cp "$SQC_AUTH_KEYS" "$VMROOT/root/.ssh/authorized_keys"
	chroot "$VMROOT" chmod 0600 /root/.ssh/authorized_keys
	chroot "$VMROOT" chown root:root /root/.ssh/authorized_keys
	chroot "$VMROOT" apt-get install --quiet --assume-yes openssh-server
fi

if [ -n "$SQC_INSTALL_PACKAGES" ]
then
	echo "Installing additional packages"
	chroot "$VMROOT" apt-get install --quiet --assume-yes $SQC_INSTALL_PACKAGES
fi

if [ -n "$SQC_EXTRA_DEBS" ]
then
	echo "Installing extra .debs"
	VMTMP=`mktemp -d -p "$VMROOT"`
	cp -t "$VMTMP" $SQC_EXTRA_DEBS
	chroot "$VMROOT" dpkg --recursive -i `basename "$VMTMP"`
	chroot "$VMROOT" apt-get update
	rm -rf "$VMTMP"
fi

# Mount point for a shared folder, if the VM is launched with one
echo "Adding 9p to initramfs"
echo -e "9p\n9pnet\n9pnet_virtio" >> "$VMROOT/etc/initramfs-tools/modules"
chroot "$VMROOT" update-initramfs -u
echo "Adding shared folder to fstab"
mkdir -m 755 "$VMROOT/shared"
echo "sbuild-qemu /shared 9p trans=virtio,version=9p2000.L,auto,nofail 0 0" >> "$VMROOT/etc/fstab"

echo "Updating GRUB menu"
echo "GRUB_TIMEOUT=1" >> "$VMROOT/etc/default/grub"
chroot "$VMROOT" update-grub

# Enable automatically setting terminal rows/columns if the host passes us the
# params using -fw_cfg
echo "Creating script in /etc/profile.d/ to set terminal geometry to host"
cat > "$VMROOT/etc/profile.d/sbuild-qemu-terminal-settings.sh" <<"EOF"
#!/bin/sh
# Set VM tty rows/columns to host rows/columns
#
# This only works if the guest kernel was compiled with CONFIG_FW_CFG_FSYS, and
# the host rows/columns were passed on through QEMU using -fw_cfg. Regular
# users will also need permission to read this file (see the udev rule).

ROWSFILE="/sys/firmware/qemu_fw_cfg/by_name/opt/sbuild-qemu/tty-rows/raw"
COLSFILE="/sys/firmware/qemu_fw_cfg/by_name/opt/sbuild-qemu/tty-cols/raw"

DEB_HOST_ARCH="`dpkg-architecture -qDEB_HOST_ARCH`"
if [ "$DEB_HOST_ARCH" = "armhf" ] || [ "$DEB_HOST_ARCH" = "arm64" ]
then
	TTY=/dev/ttyAMA0
else
	TTY=/dev/ttyS0
fi

if [ -f "$ROWSFILE" ]
then
    stty -F "$TTY" rows `cat "$ROWSFILE"`
fi

if [ -f "$COLSFILE" ]
then
    stty -F "$TTY" cols `cat "$COLSFILE"`
fi
EOF

# Makes the image significantly smaller
chroot "$VMROOT" apt-get --option Dir::Etc::SourceList=/dev/null --option Dir::Etc::SourceParts=/dev/null update
chroot "$VMROOT" apt-get  clean

echo "### Customization of base image complete. ###"