aur: Prepare for AUR package

* This copied from the upstream repository and unfortunately history is
  lost as every commit needs to include a .SRCINFO file.
* Add .SRCINFO to Makefile
* Update .gitignore to ignore src tarballs

9 files changed, 1131 insertions, 0 deletions

diff --git a/.SRCINFO b/.SRCINFO
new file mode 100644
index 000000000000..46ced9520c9a
--- /dev/null
+++ b/.SRCINFO
@@ -0,0 +1,15 @@
+pkgbase = digitalocean-synchronize
+	pkgdesc = DigitalOcean Synchronization (passwords, keys, networks)
+	pkgver = 2.4
+	pkgrel = 2
+	url = https://github.com/gh2o/digitalocean-debian-to-arch
+	install = digitalocean-synchronize.install
+	arch = any
+	license = GPL
+	source = digitalocean-synchronize
+	source = digitalocean-synchronize.service
+	sha256sums = 2115bcf34d80186103e4399f5a20d410145ee50d316a67bdfe6f43c4b11d2064
+	sha256sums = 5888d367a08604b17528d58aa26050209d8ececf7ed35f90b5e96b31165b6a1c
+
+pkgname = digitalocean-synchronize
+
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 000000000000..c57f3cc85950
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+.swp
+.*.swp
+*pkg.tar*
+/install.pkg.sh
+*.src.tar.gz
diff --git a/Makefile b/Makefile
new file mode 100644
index 000000000000..30089ce1572f
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,30 @@
+PKGNAME = $(shell grep ^pkgname PKGBUILD | sed -e 's:.*=::')
+PKGVER  = $(shell grep ^pkgver PKGBUILD | sed -e 's:.*=::')
+PKGREL  = $(shell grep ^pkgrel PKGBUILD | sed -e 's:.*=::')
+PKGARCH = $(shell grep ^arch PKGBUILD | sed -e 's:.*=::')
+
+PKG     = $(PKGNAME)-$(PKGVER)-$(PKGREL)-$(PKGARCH).pkg.tar.xz
+PKG_SRC = $(PKGNAME)-$(PKGVER)-$(PKGREL).src.tar.gz
+
+DEPS    = digitalocean-synchronize \
+		  digitalocean-synchronize.service \
+		  digitalocean-synchronize.install \
+		  PKGBUILD \
+		  Makefile
+
+install.pkg.sh: $(PKG)
+	@cat $(subst .pkg,,$@) > $@
+	@echo -e '\ncat <<EMBEDDED\n\n!!!!digitalocean-synchronize.pkg.tar.xz' >> $@
+	@base64 $< >> $@
+	@echo -e '!!!!\n\nEMBEDDED' >> $@
+
+	$(info Build complete!)
+	$(info Output file: $@)
+
+$(PKG): $(DEPS)
+	updpkgsums
+	mksrcinfo
+	makepkg -fc
+
+clean:
+	rm -f $(PKG) install.pkg.sh
diff --git a/PKGBUILD b/PKGBUILD
new file mode 100644
index 000000000000..f650732122b3
--- /dev/null
+++ b/PKGBUILD
@@ -0,0 +1,22 @@
+# Maintainer: Gavin Li
+# Contributor: Kyle Manna <kyle at kylemanna dot com>
+
+pkgname=digitalocean-synchronize
+pkgver=2.4
+pkgrel=2
+pkgdesc='DigitalOcean Synchronization (passwords, keys, networks)'
+url='https://github.com/gh2o/digitalocean-debian-to-arch'
+arch=any
+license=GPL
+install=digitalocean-synchronize.install
+
+source=('digitalocean-synchronize'
+        'digitalocean-synchronize.service')
+
+sha256sums=('2115bcf34d80186103e4399f5a20d410145ee50d316a67bdfe6f43c4b11d2064'
+            '5888d367a08604b17528d58aa26050209d8ececf7ed35f90b5e96b31165b6a1c')
+
+package() {
+    install -Dm755 digitalocean-synchronize ${pkgdir}/usr/bin/digitalocean-synchronize
+    install -Dm644 digitalocean-synchronize.service ${pkgdir}/usr/lib/systemd/system/digitalocean-synchronize.service
+}
diff --git a/README.md b/README.md
new file mode 100644
index 000000000000..3b3172054a47
--- /dev/null
+++ b/README.md
@@ -0,0 +1,79 @@
+DigitalOcean Debian to Arch
+===========================
+DigitalOcean deprecated Arch Linux a while back because it was relatively
+difficult to support due to the rolling updates. I wrote this script to
+bring it back! This script downloads a bootstrap Arch Linux image, updates it
+to the latest version, then overwrites the host operating system with it.
+Unlike Debian 7.x, Debian 8.x on DigitalOcean boots traditionally (through the
+MBR and Grub), so no dirty *kexec* magic is needed.
+
+Warning / Disclaimer
+--------------------
+<h3>ALL DATA ON THE DROPLET WILL BE UNCONDITIONALLY DESTROYED.</h3>
+This script may cause your VPS to become unbootable.
+I only recommend running this script on newly created droplets with no
+important data.
+
+Installation
+------------
+1. Create a new Debian 8.x droplet (either 32-bit or 64-bit is fine).
+2. In the droplet, run the following as root:
+        `wget https://raw.githubusercontent.com/gh2o/digitalocean-debian-to-arch/debian8/install.sh && bash install.sh`
+3. Follow the instructions when prompted.
+4. Sit back and relax! The system will automatically reboot once complete,
+   and you should have a fully updated Arch Linux system in within minutes.
+
+Advanced Configuration
+----------------------
+This script supports several flags, all of which are optional.
+
+* `--archlinux_mirror`  
+  The Arch Linux mirror from which the bootstrap image and packages should be
+  downloaded. Defaults to the DigitalOcean mirror at
+  http://mirrors.digitalocean.com/archlinux.
+* `--kernel_package`  
+  The kernel package to install. Defaults to the vanilla `linux` package.
+  Other options include `linux-lts` for long term support and `linux-grsec` for
+  a kernel with grsecurity/PaX patches.
+* `--target_architecture`  
+  The architecture of the new Arch Linux installation. Defaults to the
+  architecture of the original Debian image as provided by `uname -m`.
+  A 64-bit Debian image may convert to either `x86_64` or `i686`.
+  A 32-bit Debian image may only convert to `i686`.
+* `--target_disklabel`  
+  The type of partition table to use. Defaults to `gpt` (GUID partition table
+  as used by EFI). The alternative is `dos` (traditional MBR).
+* `--target_filesystem`  
+  The filesystem on which the Arch Linux installation should be installed.
+  Defaults to `ext4`. The alternative is `btrfs`.
+  
+How it Works
+------------
+1. A sparse disk image is created with the same size of the droplet's disk.
+2. Three partitions are made and formatted.
+   * **DORoot**: A "dummy" partition to keep DigitalOcean happy. When snapshots
+       are restored, new passwords are written here.
+   * **BIOSBoot**: The virtual machine BIOS cannot boot from GPT partitions
+       directly, so a small partition is placed here for bootloader code.
+   * **ArchRoot**: The main root filesystem for Arch Linux.
+3. The Arch Linux bootstrap image is downloaded and unpacked onto ArchRoot.
+4. `pacman -Syu` is called inside the image to pull in all the base packages
+   along with OpenSSH.
+5. The root password and SSH host keys are copied into the image.
+6. A special script called `digitalocean-synchronize` is installed into
+   the image. This script is run at every startup to autodetect the network
+   settings from the metadata service. It also detects if the droplet
+   was just restored, and if so, it resets the root password and regenerates
+   the host SSH keys.
+7. The image is now ready. The script then generates a "blockplan". It is
+   essentially a list of instructions to image the virtual disk with the
+   sparse disk image without requiring any extra space.
+8. A minimal root filesystem is generated on RAM so that the disk can
+   be unmounted.
+9. The script calls `systemctl switch-root` to enter the minimal
+   root filesystem.
+10. The disk is unmounted.
+11. The blockplan is executed.
+12. The bootloader (Grub) is installed.
+13. Reboot!
+14. Done!
diff --git a/digitalocean-synchronize b/digitalocean-synchronize
new file mode 100644
index 000000000000..35593fa1900f
--- /dev/null
+++ b/digitalocean-synchronize
@@ -0,0 +1,162 @@
+#!/bin/bash
+
+meta_base=http://169.254.169.254/metadata/v1/
+
+set -eu
+set -o pipefail
+shopt -s nullglob
+shopt -s dotglob
+umask 022
+
+log() {
+	logger -t digitalocean-synchronize "$@" || \
+		echo "[$(date)]" "$@" >&2
+}
+
+netmask_to_prefix() {
+	local pfx=0 cmp msk
+	for cmp in ${1//./ } 0; do
+		for msk in 128 64 32 16 8 4 2 1; do
+			if (( cmp & msk )); then
+				(( pfx += 1 ))
+			else
+				echo ${pfx}
+				return
+			fi
+		done
+	done
+}
+
+update_shadow_if_changed() {
+	local etcdir=$1/etc
+	mkdir -p ${etcdir} || return 0
+	if [ -e ${etcdir}/shadow ]; then
+		# change password if file was touched
+		local encrypted_password=$(awk -F: '$1 == "root" { print $2 }' ${etcdir}/shadow)
+		if [ "${encrypted_password}" != "z" ]; then
+			log "Snapshot restore detected."
+			usermod -p "${encrypted_password}" root
+			if [ ${#encrypted_password} -gt 1 ]; then
+				chage -d 0 root
+			fi
+			log "Password has been reset."
+			rm -f /etc/ssh/ssh_host_key /etc/ssh/ssh_host_*_key
+			log "SSH host keys will be regenerated."
+		fi
+	fi
+	cat > ${etcdir}/shadow <<-EOF
+		root:z:1::::::
+		nobody:z:1::::::
+	EOF
+	chmod 0600 ${etcdir}/shadow
+}
+
+process_interface() {
+	local url=$1
+	local attrs=$2
+	local mac=$(curl -Ssf ${url}mac)
+	local type=$(curl -Ssf ${url}type)
+	local interface=
+	local cand path
+	for cand in $(ls /sys/class/net); do
+		path=/sys/class/net/${cand}/address
+		if [ -e ${path} ] && [ "$(<${path})" = "${mac}" ]; then
+			interface=${cand}
+			break
+		fi
+	done
+	[ -n "${interface}" ] || return 0
+	mkdir -p /run/systemd/network
+	{
+		cat <<-EOF
+			# Generated by digitalocean-synchronize
+			[Match]
+			Name=${interface}
+			[Network]
+		EOF
+		if [[ " ${attrs} " =~ " ipv4/ " ]]; then
+			local address=$(curl -sf ${url}ipv4/address)
+			local prefix=$(netmask_to_prefix $(curl -sf ${url}ipv4/netmask))
+			echo "Address=${address}/${prefix}"
+			if [ "${type}" != "private" ]; then
+				echo "Gateway=$(curl -sf ${url}ipv4/gateway)"
+			fi
+			log "Added IPv4 address ${address}/${prefix} on ${interface}."
+		fi
+		if [[ " ${attrs} " =~ " ipv6/ " ]]; then
+			local address=$(curl -sf ${url}ipv6/address)
+			local prefix=$(curl -sf ${url}ipv6/cidr)
+			echo "Address=${address}/${prefix}"
+			if [ "${type}" != "private" ]; then
+				echo "Gateway=$(curl -sf ${url}ipv6/gateway)"
+			fi
+			log "Added IPv6 address ${address}/${prefix} on ${interface}."
+		fi
+		local network_tail=/etc/systemd/network/template/dosync-${interface}.network.tail
+		if [[ -r "${network_tail}" ]]; then
+			cat ${network_tail}
+			log "Appended user specified config for ${interface}."
+		fi
+	} > /run/systemd/network/dosync-${interface}.network
+}
+
+traverse_interfaces() {
+	local url=$1
+	set -- $(curl -Ssf ${url})
+	if [[ " $* " =~ " mac " ]]; then
+		process_interface ${url} "$*"
+	else
+		local dir
+		for dir in $*; do
+			# only want dirs with slash suffix
+			[ "${dir}" = "${dir%/}" ] && continue
+			traverse_interfaces ${url}${dir}
+		done
+	fi
+}
+
+setup_from_metadata_service() {
+	local sshkeys
+	if sshkeys=$(curl -Ssf ${meta_base}public-keys) && test -n "${sshkeys}"; then
+		[ -d /root/.ssh ] || mkdir -m 0700 /root/.ssh
+		[ -e /root/.ssh/authorized_keys ] || touch /root/.ssh/authorized_keys
+		if ! grep -q "${sshkeys}" /root/.ssh/authorized_keys; then
+			printf '\n%s\n' "${sshkeys}" >> /root/.ssh/authorized_keys
+			log "Added SSH public keys from metadata service."
+		fi
+	fi
+	local hostname
+	if ! test -e /etc/hostname && hostname=$(curl -Ssf ${meta_base}hostname); then
+		echo "${hostname}" > /etc/hostname
+		hostname "${hostname}"
+		log "Hostname set to ${hostname} from metadata service."
+	fi
+	traverse_interfaces ${meta_base}interfaces/
+}
+
+digitalocean_synchronize() {
+	if test -e /dev/disk/by-label/DOROOT && mkdir -p /mnt/doroot; then
+		mount /dev/disk/by-label/DOROOT /mnt/doroot
+		update_shadow_if_changed /mnt/doroot
+		umount /mnt/doroot
+	else
+		log "Unable to check DOROOT for snapshot check!"
+	fi
+
+	ip link set dev eth0 up
+	ip addr add dev eth0 169.254.169.252/30 2>/dev/null || true
+	local retry
+	for retry in {1..20}; do
+		log "Attempting to connect to metadata service ..."
+		if curl -Ssf -m 1 ${meta_base} >/dev/null; then
+			setup_from_metadata_service
+			break
+		else
+			log "Unable to connect to metadata service!"
+			sleep 1
+		fi
+	done
+	ip addr del dev eth0 169.254.169.252/30 2>/dev/null || true
+}
+
+digitalocean_synchronize
diff --git a/digitalocean-synchronize.install b/digitalocean-synchronize.install
new file mode 100644
index 000000000000..ca8c7b497d9f
--- /dev/null
+++ b/digitalocean-synchronize.install
@@ -0,0 +1,4 @@
+#!/bin/sh
+post_install() {
+    systemctl enable digitalocean-synchronize.service
+}
diff --git a/digitalocean-synchronize.service b/digitalocean-synchronize.service
new file mode 100644
index 000000000000..74a0c1cd3596
--- /dev/null
+++ b/digitalocean-synchronize.service
@@ -0,0 +1,12 @@
+[Unit]
+Description=DigitalOcean Synchronization
+DefaultDependencies=no
+Before=systemd-networkd.service
+After=systemd-udevd.service
+
+[Service]
+Type=oneshot
+ExecStart=/usr/sbin/digitalocean-synchronize
+
+[Install]
+WantedBy=multi-user.target
diff --git a/install.sh b/install.sh
new file mode 100755
index 000000000000..e4b4c3fb1843
--- /dev/null
+++ b/install.sh
@@ -0,0 +1,802 @@
+#!/bin/bash
+
+################################################################################
+### INSTRUCTIONS AT https://github.com/gh2o/digitalocean-debian-to-arch/     ###
+################################################################################
+
+run_from_file() {
+	local f t
+	for f in /dev/fd/*; do
+		[ -h $f ] || continue
+		[ $f -ef "$0" ] && return
+	done
+	t=$(mktemp)
+	cat > $t
+	if [ "$(head -n 1 $t)" = '#!/bin/bash' ]; then
+		chmod +x $t
+		exec /bin/bash $t "$@" </dev/fd/2
+	else
+		rm -f $t
+		echo "Direct execution not supported with this shell ($_)." >&2
+		echo "Please try bash instead." >&2
+		exit 1
+	fi
+}
+
+# do not modify the two lines below
+[ -h /dev/fd/0 ] && run_from_file
+#!/bin/bash
+
+########################################
+### DEFAULT CONFIGURATION            ###
+########################################
+
+# mirror from which to download archlinux packages
+archlinux_mirror="http://mirrors.digitalocean.com/archlinux"
+
+# package to use as kernel (linux or linux-lts)
+kernel_package=linux
+
+# migrated machine architecture (x86_64/i686)
+target_architecture="$(uname -m)"
+
+# new disklabel type (gpt/dos)
+target_disklabel="gpt"
+
+# new filesystem type (ext4/btrfs)
+target_filesystem="ext4"
+
+# NOT EXPOSED NORMALLY: don't prompt
+continue_without_prompting=0
+
+########################################
+### END OF CONFIGURATION             ###
+########################################
+
+if [ -n "${POSIXLY_CORRECT}" ] || [ -z "${DEBIAN_TO_ARCH_ENV_CLEARED}" ]; then
+	exec /usr/bin/env -i \
+		TERM="$TERM" \
+		PATH=/usr/sbin:/sbin:/usr/bin:/bin \
+		DEBIAN_TO_ARCH_ENV_CLEARED=1 \
+		/bin/bash "$0" "$@"
+fi
+
+set -eu
+set -o pipefail
+shopt -s nullglob
+shopt -s dotglob
+umask 022
+
+sector_size=512
+
+flag_variables=(
+	archlinux_mirror
+	kernel_package
+	target_architecture
+	target_disklabel
+	target_filesystem
+)
+
+host_packages=(
+	haveged
+	parted
+)
+
+arch_packages=(
+	grub
+	openssh
+)
+
+gpt1_size_MiB=1
+doroot_size_MiB=6
+biosboot_size_MiB=1
+archroot_size_MiB=
+gpt2_size_MiB=1
+
+doroot_offset_MiB=$((gpt1_size_MiB))
+biosboot_offset_MiB=$((doroot_offset_MiB + doroot_size_MiB))
+archroot_offset_MiB=$((biosboot_offset_MiB + biosboot_size_MiB))
+
+log() {
+	echo "[$(date)]" "$@" >&2
+}
+
+fatal() {
+	log "$@"
+	log "Exiting."
+	exit 1
+}
+
+extract_embedded_file() {
+	awk -v n="$1" '$0=="!!!!"{p=0};p;$0=="!!!!"n{p=1}' "$0" | base64 --decode
+}
+
+parse_flags() {
+	local c conf_key conf_val
+	while [ $# -gt 0 ]; do
+		conf_key=
+		conf_val=
+		for c in ${flag_variables[@]}; do
+			case "$1" in
+				--$c)
+					shift
+					[ $# -gt 0 ] || fatal "Option $c requires a value."
+					conf_key="$c"
+					conf_val="$1"
+					shift
+					break
+					;;
+				--$c=*)
+					conf_key="$c"
+					conf_val="${1#*=}"
+					shift
+					break
+					;;
+				--i_understand_that_this_droplet_will_be_completely_wiped)
+					continue_without_prompting=1
+					conf_key=option_acknowledged
+					shift
+					break
+					;;
+				--help)
+					print_help_and_exit
+					;;
+			esac
+		done
+		[ "${conf_key}" = option_acknowledged ] && continue
+		[ -n "${conf_key}" ] || fatal "Unknown option: $1"
+		[ -n "${conf_val}" ] || fatal "Empty value for option ${conf_key}."
+		local -n conf_ref=${conf_key}
+		conf_ref="${conf_val}"
+	done
+	log "Configuration:"
+	for conf_key in ${flag_variables[@]}; do
+		local -n conf_ref=${conf_key}
+		log "- ${conf_key} = ${conf_ref}"
+	done
+}
+
+print_help_and_exit() {
+	local conf_key
+	echo "Available options: (see script for details)" >&2
+	for conf_key in ${flag_variables[@]}; do
+		local -n conf_ref=${conf_key}
+		echo "  --${conf_key}=[${conf_ref}]" >&2
+	done
+	exit 1
+}
+
+validate_flags_and_augment_globals() {
+	arch_packages+=(${kernel_package})
+	case "${target_disklabel}" in
+		gpt)
+			;;
+		dos)
+			;;
+		*)
+			fatal "Unknown disklabel type: ${target_disklabel}"
+			;;
+	esac
+	case "${target_filesystem}" in
+		ext4)
+			;;
+		btrfs)
+			host_packages+=(btrfs-tools)
+			arch_packages+=(btrfs-progs)
+			;;
+		*)
+			fatal "Unknown filesystem type: ${target_filesystem}"
+			;;
+	esac
+	local disk_MiB=$(($(cat /sys/block/vda/size) >> 11))
+	archroot_size_MiB=$((disk_MiB - gpt2_size_MiB - archroot_offset_MiB))
+}
+
+read_flags() {
+	local filename=$1
+	source ${filename}
+}
+
+write_flags() {
+	local filename=$1
+	{
+		local conf_key
+		for conf_key in ${flag_variables[@]}; do
+			local -n conf_ref=${conf_key}
+			printf "%s=%q\n" "${conf_key}" "${conf_ref}"
+		done
+	} > ${filename}
+}
+
+sanity_checks() {
+	[ ${EUID} -eq 0 ] || fatal "Script must be run as root."
+	[ ${UID} -eq 0 ] || fatal "Script must be run as root."
+	[ -e /dev/vda ] || fatal "Script must be run on a KVM machine."
+	[[ "$(cat /etc/debian_version)" == 8.? ]] || \
+		fatal "This script only supports Debian 8.x."
+}
+
+prompt_for_destruction() {
+	(( continue_without_prompting )) && return 0
+	log "*** ALL DATA ON THIS DROPLET WILL BE WIPED. ***"
+	log "Please backup all important data on this droplet before continuing."
+	log 'Type "wipe this droplet" to continue or anything else to cancel.'
+	local response
+	read -p ' > ' response
+	if [ "${response}" = "wipe this droplet" ]; then
+		return 0
+	else
+		log "Cancelled."
+		exit 0
+	fi
+}
+
+download_and_verify() {
+	local file_url="$1"
+	local local_path="$2"
+	local expected_sha1="$3"
+	for try in {0..3}; do
+		if [ ${try} -eq 0 ]; then
+			[ -e "${local_path}" ] || continue
+		else
+			wget -O "${local_path}" "${file_url}"
+		fi
+		set -- $(sha1sum "${local_path}")
+		if [ $1 = "${expected_sha1}" ]; then
+			return 0
+		else
+			rm -f "${local_path}"
+		fi
+	done
+	return 1
+}
+
+build_parted_cmdline() {
+	local cmdline=
+	local biosboot_name=BIOSBoot
+	local doroot_name=DORoot
+	local archroot_name=ArchRoot
+	if [ ${target_disklabel} = dos ]; then
+		cmdline="mklabel msdos"
+		biosboot_name=primary
+		doroot_name=primary
+		archroot_name=primary
+	else
+		cmdline="mklabel ${target_disklabel}"
+	fi
+	local archroot_end_MiB=$((archroot_offset_MiB + archroot_size_MiB))
+	cmdline+=" mkpart ${doroot_name} ${doroot_offset_MiB}MiB ${biosboot_offset_MiB}MiB"
+	cmdline+=" mkpart ${biosboot_name} ${biosboot_offset_MiB}MiB ${archroot_offset_MiB}MiB"
+	cmdline+=" mkpart ${archroot_name} ${archroot_offset_MiB}MiB ${archroot_end_MiB}MiB"
+	if [ ${target_disklabel} = gpt ]; then
+		cmdline+=" set 2 bios_grub on"
+	fi
+	echo "${cmdline}"
+}
+
+setup_loop_device() {
+	local offset_MiB=$1
+	local size_MiB=$2
+	losetup --find --show --offset ${offset_MiB}MiB --size ${size_MiB}MiB /d2a/work/image
+}
+
+package_digitalocean_synchronize() {
+	local destination=$1
+
+	extract_embedded_file digitalocean-synchronize.pkg.tar.xz > ${destination}
+}
+
+kill_processes_in_mountpoint() {
+	if mountpoint -q $1; then
+		fuser -kms $1 || true
+		find /proc -maxdepth 2 -name root -lname $1 | \
+			grep -o '[0-9]*' | xargs -r kill || true
+	fi
+}
+
+quietly_umount() {
+	if mountpoint -q $1; then
+		umount -d $1
+	fi
+}
+
+cleanup_work_directory() {
+	kill_processes_in_mountpoint /d2a/work/doroot
+	kill_processes_in_mountpoint /d2a/work/archroot
+	quietly_umount /d2a/work/doroot
+	quietly_umount /d2a/work/archroot/var/cache/pacman/pkg
+	quietly_umount /d2a/work/archroot/dev/pts
+	quietly_umount /d2a/work/archroot/dev
+	quietly_umount /d2a/work/archroot/sys
+	quietly_umount /d2a/work/archroot/proc
+	quietly_umount /d2a/work/archroot
+	rm -rf --one-file-system /d2a/work
+}
+
+stage1_install_exit() {
+	set +e
+	cleanup_work_directory
+}
+
+stage1_install() {
+	trap stage1_install_exit EXIT
+	cleanup_work_directory
+	mkdir -p /d2a/work
+
+	log "Installing required packages ..."
+	DEBIAN_FRONTEND=noninteractive apt-get install -y ${host_packages[@]}
+
+	log "Partitioning image ..."
+	local disk_sectors=$(cat /sys/block/vda/size)
+	rm -f /d2a/work/image
+	truncate -s $((disk_sectors * sector_size)) /d2a/work/image
+	parted /d2a/work/image $(build_parted_cmdline)
+
+	log "Formatting image ..."
+	local doroot_loop=$(setup_loop_device ${doroot_offset_MiB} ${doroot_size_MiB})
+	local archroot_loop=$(setup_loop_device ${archroot_offset_MiB} ${archroot_size_MiB})
+	mkfs.ext4 -L DOROOT ${doroot_loop}
+	mkfs.${target_filesystem} -L ArchRoot ${archroot_loop}
+
+	log "Mounting image ..."
+	mkdir -p /d2a/work/{doroot,archroot}
+	mount ${doroot_loop} /d2a/work/doroot
+	mount ${archroot_loop} /d2a/work/archroot
+
+	log "Setting up DOROOT ..."
+	mkdir -p /d2a/work/doroot/etc/network
+	touch /d2a/work/doroot/etc/network/interfaces
+	cat > /d2a/work/doroot/README <<-EOF
+		DO NOT TOUCH FILES ON THIS PARTITION.
+
+		The DOROOT partition is where DigitalOcean writes passwords and other data
+		when a droplet is rebuilt from an image or restored from a snapshot.
+		If certain files are missing, restores/rebuilds will not work and you will
+		end up with an unusable image.
+
+		The digitalocean-synchronize script also watches this partition.
+		If this partition (particularly etc/shadow) is written to, the script will
+		reset the root password to the one provided by DigitalOcean and wipe all
+		SSH host keys for security.
+	EOF
+	chmod 0444 /d2a/work/doroot/README
+
+	log "Downloading bootstrap tarball ..."
+	set -- $(wget -qO- ${archlinux_mirror}/iso/latest/sha1sums.txt |
+		grep "archlinux-bootstrap-[^-]*-${target_architecture}.tar.gz")
+	local expected_sha1=$1
+	local bootstrap_filename=$2
+	download_and_verify \
+		${archlinux_mirror}/iso/latest/${bootstrap_filename} \
+		/d2a/bootstrap.tar.gz \
+		${expected_sha1}
+
+	log "Extracting bootstrap tarball ..."
+	tar -xzf /d2a/bootstrap.tar.gz \
+		--directory=/d2a/work/archroot \
+		--strip-components=1
+
+	log "Mounting virtual filesystems ..."
+	mount -t proc proc /d2a/work/archroot/proc
+	mount -t sysfs sys /d2a/work/archroot/sys
+	mount -t devtmpfs dev /d2a/work/archroot/dev
+	mkdir -p /d2a/work/archroot/dev/pts
+	mount -t devpts pts /d2a/work/archroot/dev/pts
+
+	log "Binding packages directory ..."
+	mkdir -p /d2a/packages
+	mount --bind /d2a/packages /d2a/work/archroot/var/cache/pacman/pkg
+
+	log "Preparing bootstrap filesystem ..."
+	echo "Server = ${archlinux_mirror}/\$repo/os/\$arch" > /d2a/work/archroot/etc/pacman.d/mirrorlist
+	echo 'nameserver 8.8.8.8' > /d2a/work/archroot/etc/resolv.conf
+
+	log "Installing base system ..."
+	chroot /d2a/work/archroot pacman-key --init
+	chroot /d2a/work/archroot pacman-key --populate archlinux
+	local chroot_pacman="chroot /d2a/work/archroot pacman --arch ${target_architecture}"
+	${chroot_pacman} -Sy
+	${chroot_pacman} -Su --noconfirm --needed \
+		$(${chroot_pacman} -Sgq base | grep -v '^linux$') \
+		${arch_packages[@]}
+
+	log "Configuring base system ..."
+	hostname > /d2a/work/archroot/etc/hostname
+	cp /etc/ssh/ssh_host_* /d2a/work/archroot/etc/ssh/
+	local encrypted_password=$(awk -F: '$1 == "root" { print $2 }' /etc/shadow)
+	chroot /d2a/work/archroot usermod -p "${encrypted_password}" root
+	chroot /d2a/work/archroot systemctl enable systemd-networkd.service
+	chroot /d2a/work/archroot systemctl enable sshd.service
+	package_digitalocean_synchronize /d2a/work/archroot/dosync.pkg.tar
+	${chroot_pacman} -U --noconfirm /dosync.pkg.tar
+	rm /d2a/work/archroot/dosync.pkg.tar
+
+	log "Finishing up image generation ..."
+	ln -f /d2a/work/image /d2a/image
+	cleanup_work_directory
+	trap - EXIT
+}
+
+bisect_left_on_allocation() {
+	local alloc_start_sector=$1
+	local alloc_end_sector=$2
+	local -n bisection_output=$3
+	local -n allocation_map=$4
+	local lo=0 hi=${#allocation_map[@]}
+	while (( lo < hi )); do
+		local mid=$(((lo+hi)/2))
+		set -- ${allocation_map[$mid]}
+		if (( $# == 0 )) || (( $1 < alloc_start_sector )); then
+			lo=$((mid+1))
+		else
+			hi=$((mid))
+		fi
+	done
+	bisection_output=$lo
+}
+
+check_for_allocation_overlap() {
+	local check_start_sector=$1
+	local check_end_sector=$2
+	local -n overlap_start_sector=$3
+	local -n overlap_end_sector=$4
+	shift 4
+	local allocation_maps="$*"
+
+	# overlap_end_sector = 0 if no overlap
+	overlap_start_sector=0
+	overlap_end_sector=0
+
+	local map_name
+	for map_name in ${allocation_maps}; do
+		local -n allocation_map=${map_name}
+		local map_length=${#allocation_map[@]}
+		(( ${map_length} )) || continue
+		local bisection_index
+		bisect_left_on_allocation ${check_start_sector} ${check_end_sector} \
+			bisection_index ${map_name}
+		local check_index
+		for check_index in $((bisection_index - 1)) $((bisection_index)); do
+			(( check_index < 0 || check_index >= map_length )) && continue
+			set -- ${allocation_map[${check_index}]}
+			(( $# == 0 )) && continue
+			local alloc_start_sector=$1
+			local alloc_end_sector=$2
+			(( check_start_sector >= alloc_end_sector || alloc_start_sector >= check_end_sector )) && continue
+			# overlap detected
+			overlap_start_sector=$((alloc_start_sector > check_start_sector ?
+				alloc_start_sector : check_start_sector))
+			overlap_end_sector=$((alloc_end_sector < check_end_sector ?
+				alloc_end_sector : check_end_sector))
+			return
+		done
+	done
+}
+
+insert_into_allocation_map() {
+	local -n allocation_map=$1
+	shift
+	local alloc_start_sector=$1
+	local alloc_end_sector=$2
+	if (( ${#allocation_map[@]} == 0 )); then
+		allocation_map=("$*")
+	else
+		local bisection_index
+		bisect_left_on_allocation ${alloc_start_sector} ${alloc_end_sector} \
+			bisection_index ${!allocation_map}
+		allocation_map=(
+			"${allocation_map[@]:0:${bisection_index}}"
+			"$*"
+			"${allocation_map[@]:${bisection_index}}")
+	fi
+}
+
+stage2_arrange() {
+	local disk_sectors=$(cat /sys/block/vda/size)
+	local root_device=$(awk '$2 == "/" { root = $1 } END { print root }' /proc/mounts)
+	local root_offset_sectors=$(cat /sys/block/vda/${root_device#/dev/}/start)
+	local srcdst_map=()     # original source to target map
+	local unalloc_map=()    # extents not used by either source or target (for tmpdst_map)
+	local tmpdst_map=()     # extents on temporary redirection (allocated from unalloc_map)
+	local source_start_sector source_end_sector target_start_sector target_end_sector
+
+	log "Creating block rearrangement plan ..."
+
+	# get and sort extents
+	filefrag -e -s -v -b${sector_size} /d2a/image | \
+		sed '/^ *[0-9]*:/!d;s/[:.]/ /g' | \
+		sort -nk4 > /d2a/imagemap
+	while read line; do
+		set -- ${line}
+		source_start_sector=$(($4 + root_offset_sectors))
+		source_end_sector=$((source_start_sector + $6))
+		target_start_sector=$2
+		target_end_sector=$((target_start_sector + $6))
+		echo ${source_start_sector} ${source_end_sector}
+		echo ${target_start_sector} ${target_end_sector}
+		srcdst_map+=("${source_start_sector} ${source_end_sector} ${target_start_sector}")
+	done < /d2a/imagemap > /d2a/unsortedallocs
+	sort -n < /d2a/unsortedallocs > /d2a/sortedallocs
+
+	# build map of unallocated sectors
+	local unalloc_start_sector=0 unalloc_end_sector=${disk_sectors}
+	while read source_start_sector source_end_sector; do
+		if (( source_end_sector <= unalloc_start_sector )); then
+			# does not overlap unallocated part
+			continue
+		elif (( source_start_sector > unalloc_start_sector )); then
+			# full overlap with unallocated part
+			unalloc_map+=("${unalloc_start_sector} ${source_start_sector}")
+			unalloc_start_sector=${source_end_sector}
+		else
+			# partial overlap
+			unalloc_start_sector=${source_end_sector}
+		fi
+	done < /d2a/sortedallocs
+	if (( unalloc_start_sector != unalloc_end_sector )); then
+		unalloc_map+=("${unalloc_start_sector} ${unalloc_end_sector}")
+	fi
+
+	# open blockplan
+	exec {blockplan_fd}>/d2a/blockplan
+
+	# arrange sectors
+	while (( ${#srcdst_map[@]} )); do
+		set -- ${srcdst_map[-1]}
+		source_start_sector=$1
+		source_end_sector=$2
+		target_start_sector=$3
+		target_end_sector=$((target_start_sector + (source_end_sector - source_start_sector)))
+		if (( source_start_sector == target_start_sector )); then
+			unset 'srcdst_map[-1]'
+			continue
+		elif (( target_start_sector >= source_end_sector ||
+				source_start_sector >= target_end_sector )); then
+			unset 'srcdst_map[-1]'
+		else
+			local new_extent_sectors=$((target_start_sector - source_start_sector))
+			new_extent_sectors=${new_extent_sectors#-}  # absolute value
+			set -- \
+				$((source_start_sector + new_extent_sectors)) \
+				$((source_end_sector)) \
+				$((target_start_sector + new_extent_sectors))
+			srcdst_map[-1]="$*"
+			source_end_sector=$((source_start_sector + new_extent_sectors))
+		fi
+		local overlap_start_sector overlap_end_sector
+		check_for_allocation_overlap \
+			${target_start_sector} ${target_end_sector} \
+			overlap_start_sector overlap_end_sector \
+			srcdst_map
+		if (( overlap_end_sector )); then
+			# insert non-overlapping parts back into srcdst_map
+			if (( target_start_sector < overlap_start_sector )); then
+				local nonoverlap_length_sectors=$((overlap_start_sector - target_start_sector))
+				insert_into_allocation_map srcdst_map \
+					${source_start_sector} \
+					$((source_start_sector + nonoverlap_length_sectors)) \
+					${target_start_sector}
+			fi
+			if (( target_end_sector > overlap_end_sector )); then
+				local nonoverlap_length_sectors=$((target_end_sector - overlap_end_sector))
+				insert_into_allocation_map srcdst_map \
+					$((source_end_sector - nonoverlap_length_sectors)) \
+					${source_end_sector} \
+					${overlap_end_sector}
+			fi
+			# copy overlapping portion into tmpdst_map
+			while (( overlap_start_sector < overlap_end_sector )); do
+				set -- ${unalloc_map[-1]}
+				unset 'unalloc_map[-1]'  # or nullglob will eat it up
+				local unalloc_start_sector=$1
+				local unalloc_end_sector=$2
+				local unalloc_length_sectors=$((unalloc_end_sector - unalloc_start_sector))
+				local overlap_length_sectors=$((overlap_end_sector - overlap_start_sector))
+				if (( overlap_length_sectors < unalloc_length_sectors )); then
+					# return unused portion to unalloc_map
+					unalloc_map+=("${unalloc_start_sector} $((unalloc_end_sector - overlap_length_sectors))")
+					unalloc_start_sector=$((unalloc_end_sector - overlap_length_sectors))
+					unalloc_length_sectors=${overlap_length_sectors}
+				fi
+				echo >&${blockplan_fd} \
+					$((source_start_sector + (overlap_start_sector - target_start_sector))) \
+					${unalloc_start_sector} \
+					${unalloc_length_sectors}
+				insert_into_allocation_map tmpdst_map \
+					${unalloc_start_sector} \
+					${unalloc_end_sector} \
+					${overlap_start_sector}
+				(( overlap_start_sector += unalloc_length_sectors ))
+			done
+		else
+			echo >&${blockplan_fd} \
+				${source_start_sector} \
+				${target_start_sector} \
+				$((source_end_sector - source_start_sector))
+		fi
+	done
+
+	# restore overlapped sectors
+	while (( ${#tmpdst_map[@]} )); do
+		set -- ${tmpdst_map[-1]}
+		unset 'tmpdst_map[-1]'
+		source_start_sector=$1
+		source_end_sector=$2
+		target_start_sector=$3
+		echo >&${blockplan_fd} \
+			${source_start_sector} \
+			${target_start_sector} \
+			$((source_end_sector - source_start_sector))
+	done
+
+	# close blockplan
+	exec {blockplan_fd}>&-
+}
+
+cleanup_mid_directory() {
+	quietly_umount /d2a/mid
+	rm -rf --one-file-system /d2a/mid
+}
+
+add_binary_to_mid() {
+	mkdir -p $(dirname /d2a/mid/$1)
+	cp $1 /d2a/mid/$1
+	ldd $1 | grep -o '/[^ ]* (0x[0-9a-f]*)' | \
+			while read libpath ignored; do
+		[ -e /d2a/mid/${libpath} ] && continue
+		mkdir -p $(dirname /d2a/mid/${libpath})
+		cp ${libpath} /d2a/mid/${libpath}
+	done
+}
+
+stage3_prepare_exit() {
+	set +e
+	cleanup_mid_directory
+}
+
+stage3_prepare() {
+	trap stage3_prepare_exit EXIT
+	cleanup_mid_directory
+	mkdir -p /d2a/mid
+
+	# mount tmpfs
+	mount -t tmpfs mid /d2a/mid
+
+	# add binaries
+	add_binary_to_mid /bin/busybox
+	add_binary_to_mid /bin/bash
+
+	# create symlinks
+	local dir
+	for dir in bin sbin usr/bin usr/sbin; do mkdir -p /d2a/mid/${dir}; done
+	ln -s bash /d2a/mid/bin/sh
+	chroot /d2a/mid /bin/busybox --install
+
+	# create directories (will be filled by systemd)
+	mkdir /d2a/mid/{proc,sys,dev}
+
+	# copy in the blockplan
+	cp /d2a/blockplan /d2a/mid/blockplan
+
+	# write out flags
+	write_flags /d2a/mid/flags
+
+	# copy myself
+	cat "$0" > /d2a/mid/init
+	chmod 0755 /d2a/mid/init
+
+	# detach all loop devices
+	losetup -D || true
+
+	# reboot!
+	log "The machine will now reboot."
+	log "Check the console for errors if the machine is still unaccessible after a few minutes."
+	sleep 1
+	trap - EXIT
+	systemctl switch-root /d2a/mid /init
+}
+
+stage4_convert_exit() {
+	log "Error occurred. You're on your own!"
+	exec /bin/bash </dev/console >/dev/console 2>&1
+}
+
+stage4_convert() {
+	trap stage4_convert_exit EXIT
+
+	# unmount old root
+	local retry
+	for retry in 1 2 3 4 5; do
+		if umount /mnt; then
+			retry=0
+			break
+		else
+			sleep 1
+		fi
+	done
+	if (( retry )); then
+		umount -rl /mnt
+	fi
+
+	# get total number of sectors
+	local processed_length=0
+	local total_length=$(awk '{x+=$3}END{print+x}' /blockplan)
+	local prev_percentage=-1
+	local next_percentage=-1
+
+	# execute the block plan
+	local source_sector target_sector extent_length
+	while read source_sector target_sector extent_length; do
+		# increment processed length before extent length gets optimized
+		(( processed_length += extent_length )) || true
+		# optimize extent length
+		local transfer_size=${sector_size}
+		until (( (source_sector & 1) || (target_sector & 1) ||
+				(extent_length & 1) || (transfer_size >= 0x100000) )); do
+			(( source_sector >>= 1 , target_sector >>= 1 , extent_length >>= 1,
+				transfer_size <<= 1 )) || true
+		done
+		# do the actual transfer
+		dd if=/dev/vda of=/dev/vda bs=${transfer_size} \
+			skip=${source_sector} seek=${target_sector} \
+			count=${extent_length} 2>/dev/null
+		# print out the percentage
+		next_percentage=$((100 * processed_length / total_length))
+		if (( next_percentage != prev_percentage )); then
+			printf "\rTransferring blocks ... %s%%" ${next_percentage}
+			prev_percentage=${next_percentage}
+		fi
+	done < /blockplan
+	echo
+
+	# reread partition table
+	blockdev --rereadpt /dev/vda
+
+	# install bootloader
+	mkdir /archroot
+	mount /dev/vda3 /archroot
+	mount -t proc proc /archroot/proc
+	mount -t sysfs sys /archroot/sys
+	mount -t devtmpfs dev /archroot/dev
+	chroot /archroot grub-mkconfig -o /boot/grub/grub.cfg
+	chroot /archroot grub-install /dev/vda
+	umount /archroot/dev
+	umount /archroot/sys
+	umount /archroot/proc
+	umount /archroot
+
+	# we're done!
+	sync
+	reboot -f
+}
+
+reinstall_digitalocean_synchronize() {
+	local package_file=$(mktemp --suffix=.pkg.tar)
+	package_digitalocean_synchronize ${package_file}
+	pacman -U --noconfirm ${package_file}
+	rm ${package_file}
+}
+
+if [ -e /var/lib/pacman ]; then
+	if [ $# -eq 0 ]; then
+		reinstall_digitalocean_synchronize
+	else
+		log "Run this script to install/update the digitalocean-synchronize package."
+	fi
+	exit 0
+fi
+
+if [ $$ -ne 1 ]; then
+	parse_flags "$@"
+	sanity_checks
+	validate_flags_and_augment_globals
+	prompt_for_destruction
+	stage1_install
+	stage2_arrange
+	stage3_prepare
+else
+	read_flags /flags
+	validate_flags_and_augment_globals
+	stage4_convert
+fi
+exit 0