create-alarmpi.sh

#!/bin/bash
set -eu
#set -x

# via http://archlinuxarm.org/platforms/armv6/raspberry-pi

DISK=/dev/sdb
PARTITION=yes
MKFS=yes
CACHE_DIR=/var/cache

TARBALL_URL=http://archlinuxarm.org/os/ArchLinuxARM-rpi-latest.tar.gz
TARBALL_MD5_URL=http://archlinuxarm.org/os/ArchLinuxARM-rpi-latest.tar.gz.md5



ask() {
	echo -n "$1"
	read answer   || answer=$2
	[ "$answer" ] || answer=$2
	echo "$answer" | egrep -qi '^y(es)?'
}
download() {
	if which curl >/dev/null; then
		curl -L "$1"
	elif which wget >/dev/null; then
		wget -O - "$1"
	else
		echo "error: wget or curl is required." >&2
		exit -1
	fi
}
check_downloaded_files() {
	tarball=$(md5sum ArchLinuxARM-rpi-latest.tar.gz | awk '{ print $1 }')
	md5=$(cat ArchLinuxARM-rpi-latest.tar.gz.md5 | awk '{ print $1 }')
	if [ "$tarball" != "$md5" ]; then
		rm -f ArchLinuxARM-rpi-latest.tar.gz{,.md5}
		echo "error: Downloaded files are broken." >&2
		exit -1
	fi
}


if [ "$(id -u)" -ne 0 ]; then
	echo "error: You must be root." >&2
	exit -1
fi

if ! ask "Will destroy data on '$DISK'. Are you sure? [y/N]: " "N"; then
	echo "Canceled." >&2
	exit -1
fi

if [ ! -d "$CACHE_DIR" ]; then
	echo "error: $CACHE_DIR doesn't exist." >&2
	exit -1
fi
CACHE_DIR=$CACHE_DIR/create-alarmpi
mkdir -p "$CACHE_DIR"
cd "$CACHE_DIR"

if [ "$PARTITION" = "yes" ]; then
	cat <<EOM | fdisk ${DISK}
o
n



+100M
t
c
n




w
EOM
fi

for i in boot root; do
	[ -d $i/ ] && mountpoint -q $i/ && umount $i
done

if [ "$MKFS" = 'yes' ]; then
	yes | mkfs.vfat ${DISK}1
fi
mkdir -p boot
mount ${DISK}1 boot

if [ "$MKFS" = 'yes' ]; then
	yes | mkfs.ext2 ${DISK}2
fi
mkdir -p root
mount ${DISK}2 root

if [ ! -f ArchLinuxARM-rpi-latest.tar.gz ]; then
	download $TARBALL_URL >ArchLinuxARM-rpi-latest.tar.gz
	download $TARBALL_MD5_URL >ArchLinuxARM-rpi-latest.tar.gz.md5
	check_downloaded_files
else
	download $TARBALL_MD5_URL >ArchLinuxARM-rpi-latest.tar.gz.md5.new
	old=$(cat ArchLinuxARM-rpi-latest.tar.gz.md5 | awk '{ print $1 }')
	new=$(cat ArchLinuxARM-rpi-latest.tar.gz.md5.new | awk '{ print $1 }')
	if [ "$old" != "$new" ]; then
		mv -f ArchLinuxARM-rpi-latest.tar.gz.md5{.new,}
		download $TARBALL_URL >ArchLinuxARM-rpi-latest.tar.gz
		check_downloaded_files
	else
		rm -f ArchLinuxARM-rpi-latest.tar.gz.md5.new
	fi
fi

echo -n "Extracting the root filesystem..."
bsdtar -xpf ArchLinuxARM-rpi-latest.tar.gz -C root
mv root/boot/* boot
echo Done.

echo -n "Syncing filesystem..."
sync
echo Done.

echo -n "Unmounting filesystem..."
umount boot root
echo Done.

for i in boot root; do
	rmdir $i || echo "Failed to rmdir: $i/ is not empty?"
done