#!/bin/sh
set -e -f ${DRY_RUN:+-n} -u

tool=${0%/*}
. "$tool"/env.sh

rule_help () {
	cat >&2 <<-EOF
		DESCRIPTION: ce script regroupe des fonctions utilitaires
		             pour gérer la VM des ateliers _depuis_ son hôte ;
		             il sert à la fois d'outil et de documentation.
		             Voir \`$tool/ateliers_hosted' pour les utilitaires côté VM hébergée.
		SYNTAX: $0 \$RULE \${RULE}_SYNTAX
		RULES:
		$(sed -ne 's/^rule_\([^_][^ ]*\) () {\( *#.*\|\)/\t\1\2/p' "$0")
		ENVIRONMENT:
		  TRACE # affiche les commandes avant leur exécution
		$(sed -ne 's/^readonly \([^ =]*\).*}\( *#.*\|\)$/\t$\1\2/p' "$tool"/env.sh "$0")
		EOF
 }

readonly vm_dev_disk="/dev/xvda"
readonly vm_dev_disk_boot="${vm_dev_disk}1"
readonly vm_dev_disk_swap="${vm_dev_disk}5"
readonly vm_dev_disk_root="${vm_dev_disk}6"
readonly vm_dev_disk_var="${vm_dev_disk}7"
readonly vm_dev_disk_home="${vm_dev_disk}8"

rule_xen_config_init () {
	sudo tee /etc/xen/$vm_fqdn.cfg <<-EOF
		#  -*- mode: python; -*-
		import os, re
		name         = "$vm_fqdn"
		arch         = os.uname()[4]
		memory       = 2048
		vcpus        = 1
		vif          = ['mac=$vm_mac,bridge=$vm_bridge']
		disk         = ['phy:/dev/domU/$vm_fqdn-disk,hda,w']
		kernel       = "/usr/lib/xen-4.0/boot/hvmloader"
		builder      = 'hvm'
		device_model = 'qemu-dm'
		acpi         = 1
		apic         = 1
		# boot on floppy (a), hard disk (c) or CD-ROM (d)
		#boot         = 'd'
		
		#vnc        = 1
		#sdl        = 0
		#vncconsole = 0
		#vnclisten  = "0.0.0.0"
		#vncpasswd  = ""
		#usbdevice  = 'tablet'
		
		keymap      = 'fr'
		serial      = 'pty'
		on_poweroff = 'destroy'
		on_reboot   = 'restart'
		on_crash    = 'restart'
		EOF
 }
rule_xen_on () {
	sudo xm create $vm_fqdn.cfg
 }
rule_xen_off () {
	sudo xm shutdown $vm_fqdn.cfg
 }

rule_disk_mount () { # DESCRIPTION: montage du disque de la VM depuis l'hôte
	test -e $vm_dev_disk ||
	sudo xm block-attach 0 phy:/dev/domU/$vm_fqdn-disk $vm_dev_disk w
	# NOTE: on pourrait utiliser kpartx à la place je pense ; détail.
 }
rule_disk_umount () { # DESCRIPTION: démontage du disque de la VM depuis l'hôte
	mountpoint /mnt/$vm_fqdn ||
	sudo xm block-detach 0 $vm_dev_disk
 }
rule_disk_part () { # DESCRIPTION: partitionage du disque de la VM
 # NOTE: on fait le choix de ne pas utiliser LVM sur la machine virtuelle car :
 # - pour l'extension de mémoire:
 #   1. on créera une nouvelle partition sur le LVM de l'hôte
 #   2. on l'ajoutera comme un disque supplémentaire dans /etc/xen/$vm_fqdn.cfg
 #   3. on le montera sur /home2 en pensant à changer DHOME=/home2 dans /etc/adduser.conf
 # - pour la sauvegarde: LVM snapshoot est trop 
 #   1. sauvegarde au niveau applicatif (pgdump, mysqldump)
 #   2. sauvegarde des configurations (etckeeper, git)
 #   3. sauvegarde incrémentale et chiffrée des autres fichiers (duplicity)
	sudo sfdisk -d $vm_dev_disk <<-EOF
		# partition table of $vm_dev_disk
		unit: sectors
		
		${vm_dev_disk}1 : start=       63, size=   497952, Id=83, bootable
		${vm_dev_disk}2 : start=   498015, size=418927005, Id= 5
		${vm_dev_disk}3 : start=        0, size=        0, Id= 0
		${vm_dev_disk}4 : start=        0, size=        0, Id= 0
		${vm_dev_disk}5 : start=   498078, size=  1959867, Id=82
		${vm_dev_disk}6 : start=  2458008, size= 29302497, Id=83
		${vm_dev_disk}7 : start= 31760568, size=  9767457, Id=83
		${vm_dev_disk}8 : start= 41528088, size=377896932, Id=83
	EOF
 }

rule_part_randomize () { # SYNTAX: $part # NOTE: à anticiper
	local part=$1
	eval "sudo dd if=/dev/urandom of=\$vm_dev_disk_$part"
 }
rule_part_randomize_stat () { # SYNTAX: $part # DESCRIPTION: fait afficher la progression de rule_part_clean
	local part=$1
	eval "pkill -USR1 -f \"^dd if=/dev/urandom of=\$vm_dev_disk_$part\""
 }
rule__part_encrypted_format () { # SYNTAX: $part # DESCRIPTION: formatage d'une partition distincte de /
 # NOTE: la clef de chiffrement est dérivée de celle de /,
 #       / doit être déchiffrée pour que cela fonctionne.
	local part=$1
	eval "local dev=\$vm_dev_disk_$part"
	test ! -e /dev/mapper/${vm}_root_deciphered ||
	sudo /lib/cryptsetup/scripts/decrypt_derived ${vm}_root_deciphered |
	sudo cryptsetup luksFormat --hash=sha512 --key-size=512 \
	 --cipher=aes-xts-essiv:sha256 --key-file=- --align-payload=8 $dev
 }
rule__part_encrypted_mount () { # SYNTAX: $part
	local part=$1
	eval "local dev=\$vm_dev_disk_$part"
	test ! -e /dev/mapper/${vm}_root_deciphered ||
	sudo /lib/cryptsetup/scripts/decrypt_derived ${vm}_root_deciphered |
	sudo cryptsetup luksOpen --key-file=- $dev ${vm}_${part}_deciphered
 }
rule__part_encrypted_umount () { # SYNTAX: $part
	local part=$1
	eval "local dev=\$vm_dev_disk_$part"
	test ! -e     /dev/mapper/${vm}_${part}_deciphered ||
	sudo cryptsetup luksClose ${vm}_${part}_deciphered
 }
rule_part_root_format () {
	if ! mount | grep -q "^$vm_dev_disk_root "
	 then
		sudo cryptsetup luksFormat --hash=sha512 --key-size=512 \
		 --cipher=aes-xts-essiv:sha256 --key-file=- --align-payload=8 $vm_dev_disk_root
		sudo cryptsetup luksOpen --key-file=- $vm_dev_disk_root ${vm}_root_deciphered
		sudo mkfs.ext4 -m 5 -T ext4 -L ${vm}_root -E stripe_width=32,resize=15G \
		 /dev/mapper/${vm}_root_deciphered
		! mountpoint /mnt/$vm_fqdn
		sudo mount -v /dev/mapper/${vm}_root_deciphered /mnt/$vm_fqdn
		mk_dir mod=0770 own=root:root /mnt/$vm_fqdn/boot
		mk_dir mod=0770 own=root:root /mnt/$vm_fqdn/dev
		mk_dir mod=0770 own=root:root /mnt/$vm_fqdn/home
		mk_dir mod=0770 own=root:root /mnt/$vm_fqdn/proc
		mk_dir mod=0770 own=root:root /mnt/$vm_fqdn/sys
		mk_dir mod=0770 own=root:root /mnt/$vm_fqdn/var
		sudo umount -v /mnt/$vm_fqdn
	 fi
 }
rule_part_root_mount () {
	test -e /dev/mapper/${vm}_root_deciphered ||
	sudo cryptsetup luksOpen $vm_dev_disk_root ${vm}_root_deciphered
	! mountpoint /mnt/$vm_fqdn ||
	sudo mount -v /dev/mapper/${vm}_root_deciphered /mnt/$vm_fqdn
 }
rule_part_root_umount () {
	! mountpoint   /mnt/$vm_fqdn ||
	sudo umount -v /mnt/$vm_fqdn
	! test -e     /dev/mapper/${vm}_root_deciphered ||
	sudo cryptsetup luksClose ${vm}_root_deciphered
 }
rule_part_swap_format () {
	rule__part_encrypted_format swap
	rule__part_encrypted_mount  swap
	sudo mkswap -f -L ${vm}_swap /dev/mapper/${vm}_swap_deciphered
	rule__part_encrypted_umount swap
 }
rule_part_boot_format () {
	mount | grep -q "^$vm_dev_disk_boot " ||
	sudo mkfs.ext2 -m 0 -T small -L ${vm}_boot $vm_dev_disk_boot
 }
rule_part_boot_mount () {
	mountpoint /mnt/$vm_fqdn
	test -d /mnt/$vm_fqdn/boot
	mountpoint                      /mnt/$vm_fqdn/boot ||
	sudo mount -v $vm_dev_disk_boot /mnt/$vm_fqdn/boot
 }
rule_part_boot_umount () {
	! mountpoint   /mnt/$vm_fqdn/boot ||
	sudo umount -v /mnt/$vm_fqdn/boot
 }
rule_part_var_format () {
	rule__part_encrypted_format var
	rule__part_encrypted_mount  var
	sudo mkfs.ext4 -m 5 -T ext4 -L ${vm}_var -E stripe_width=32,resize=5G \
	 /dev/mapper/${vm}_${part}_deciphered
	rule__part_encrypted_umount var
 }
rule_part_var_mount () {
	rule__part_encrypted_mount  var
	mountpoint /mnt/$vm_fqdn/var ||
	sudo mount -v /dev/mapper/${vm}_var_deciphered /mnt/$vm_fqdn/var
 }
rule_part_var_umount () {
	! mountpoint   /mnt/$vm_fqdn/var ||
	sudo umount -v /mnt/$vm_fqdn/var
	rule__part_encrypted_umount var
 }
rule_part_home_format () {
	rule__part_encrypted_format home
	rule__part_encrypted_mount  home
	sudo mkfs.ext4 -m 0 -T ext4 -L ${vm}_home -E stripe_width=32,resize=200G \
	 /dev/mapper/${vm}_home_deciphered
	rule__part_encrypted_umount home
 }
rule_part_home_mount () {
	rule__part_encrypted_mount home
	mountpoint /mnt/$vm_fqdn/home ||
	sudo mount -v /dev/mapper/${vm}_home_deciphered /mnt/$vm_fqdn/home
 }
rule_part_home_umount () {
	! mountpoint   /mnt/$vm_fqdn/home ||
	sudo umount -v /mnt/$vm_fqdn/home
	rule__part_encrypted_umount home
 }

rule_debian_install () {
	sudo DEBOOTSTRAP_DIR=/usr/share/debootstrap/ debootstrap \
	 --arch=$vm_arch --verbose --keyring=/usr/share/keyrings/debian-archive-keyring.gpg \
	 --exclude=vim-tiny \
	 --include=$(printf '%s,' \
		 acl \
		 bsdmainutils \
		 busybox \
		 ca-certificates \
		 console-setup \
		 cryptsetup \
		 dash \
		 dnsutils \
		 dropbear \
		 etckeeper \
		 hashalot \
		 htop \
		 ifupdown \
		 initramfs-tools \
		 kbd \
		 less \
		 mosh \
		 ncurses-term \
		 openssh-client \
		 openssh-server \
		 openssl \
		 pciutils \
		 procps \
		 quota \
		 quotatool \
		 rsync \
		 screen \
		 sudo \
		 sysprofile \
		 vim-nox \
		 wget \
		 zsh \
	 ) \
	 $vm_lsb_name /mnt/$vm_fqdn/ \
	 http://ftp.fr.debian.org/debian/
 }
rule_chroot () {
	rule_part_boot_mount
	rule_part_root_mount
	rule_part_var_mount
	#rule_part_home_mount
	mountpoint /mnt/$vm_fqdn/proc ||
	mount -t proc proc /mnt/$vm_fqdn/proc
	mountpoint /mnt/$vm_fqdn/sys ||
	mount -t sysfs sys /mnt/$vm_fqdn/sys
	mountpoint /mnt/$vm_fqdn/dev ||
	mount --bind /dev /mnt/$vm_fqdn/dev
	sudo chroot /mnt/$vm_fqdn /bin/bash || true
	rule__chroot_clean
 }
rule__chroot_clean () {
	umount -v /mnt/$vm_fqdn/dev
	umount -v /mnt/$vm_fqdn/sys
	umount -v /mnt/$vm_fqdn/proc
	#rule_part_home_umount
	rule_part_var_umount
	rule_part_root_umount
	rule_part_boot_umount
 }

rule=${1:-help}
${1+shift}
set "${TRACE:+-x}"
rule_$rule "$@"