Revise installer

archlive/airootfs/root/.zlogin

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+chmod +x ~/install.sh && ~/install.sh

archlive/airootfs/root/README.md

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+# Base system installer
+
+Installs and configures the minimal base system, i.e. just enough to hand over
+to ansible (bootloader, fs, network, SSH, python). Based on the installation
+[guide](https://wiki.archlinux.org/index.php/Installation_guide).
+
+- Supports UEFI and BIOS.
+- RTC in localtime (for Win XP compatibility).
+- Installs on the largest disk present.
+- Single root partition (btrfs with subvolumes) + swap [+ FAT32 ESP when on
+  UEFI].
+- If `/etc/pacman.d/mirrorlist.override` exists, it is used as the mirrorlist
+  (during installation and for the installed system). Else a mirrorlist is
+  generated at installation time using
+  [reflector](https://wiki.archlinux.org/index.php/Reflector).
+- Installs the packages specified in `/root/packages` (one package name per
+  line) to the new system.
+- Uses `/root/config/` as an overlay directory for the new system (i.e. copies
+  anything under it to the corresponding location in the new system). **NOTE**
+  that file ownership and permissions are _lost_ when creating the image with
+  [archiso](https://wiki.archlinux.org/index.php/Archiso#Adding_files_to_image).
+- Configures DHCP on all ethernet interfaces, using
+  [systemd-networkd](https://wiki.archlinux.org/index.php/Systemd-networkd).
+- If `/root/hostnames` exists, it is used for looking up the desirable hostname
+  by MAC (one entry per line, formatted as IP;MAC;hostname). Else, a default
+  hostname is assigned.
+- Enables and configures both english the greek UTF locales.
+- Generates the
+  [initramfs](https://wiki.archlinux.org/index.php/Arch_boot_process#initramfs)
+  with [mkinitcpio](https://wiki.archlinux.org/index.php/Mkinitcpio), adding the
+  `revert` hook responsible for reverting the file systems state on boot.
+- Uses the contents of `/root/root_password` as the root password in the new
+  system.
+- Sets up root SSH access, key-only, using the public key in
+  `/root/ssh_key.pub`.

archlive/airootfs/root/config/etc/initcpio/hooks/revert

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+#!/bin/sh
+
+run_hook() {
+	mkdir -p /mnt/btrfs-root
+	mount -o subvol=/ -L ROOT /mnt/btrfs-root
+
+	rec-sub-del.sh rootfs /mnt/btrfs-root
+	# This will, as always, not snapshot any subvolumes below rootfs-snap (but
+	# there shouldn't be any)
+	btrfs subvolume snapshot /mnt/btrfs-root/rootfs-snap /mnt/btrfs-root/rootfs
+
+	umount /mnt/btrfs-root
+	rmdir /mnt/btrfs-root
+}

archlive/airootfs/root/config/etc/initcpio/install/revert

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+#!/bin/sh
+
+build() {
+	add_binary btrfs
+	add_binary rec-sub-del.sh
+	add_runscript
+}

archlive/airootfs/root/config/usr/local/sbin/rec-sub-del.sh

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+#!/bin/sh
+
+# Recursively delete all subvolumes under the directory given in the first
+# argument (as a path relative to the top level subvolume). If this directory
+# is a subvolume, delete it as well. Need to provide the mount point for the
+# top level subvolume as the second argument as an absolute path.
+
+if [ $# -lt 2 ]
+then
+	echo "Usage: ${0} <target-dir> <top-level-mount-point>"
+	exit
+fi
+target=${1}
+# Mount point for top level subvolume (remove trailing / if there is any)
+top=${2%/}
+
+# List of subvolume paths (relative to the top level subvolume) under the target
+# subvolume (including the target), sorted by their path (descending, ie bottom-up).
+# 'btrfs subvolume list' lists all subvolumes in the filesystem.
+# NOTE: '^${target}' instead of '^${target}$|^${target}/' would include eg
+# 'home-snap' when target is 'home'
+subvols=$(btrfs subvolume list --sort=-path ${top} | awk '{print $NF}' | grep -E "^${target}$|^${target}/")
+
+# Delete all subvolumes in subvols
+for sub in ${subvols}
+do
+	btrfs subvolume delete ${top}/${sub}
+done

archlive/airootfs/root/config/usr/local/sbin/replace-snap.sh

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+#!/bin/sh
+
+# Replace root filesystem snapshot with one taken of the current filesystem
+# (when it powers off). In essence, make the system state when it is next
+# powered off permanent.
+
+mv /root/btrfs-root/rootfs /root/btrfs-root/rootfs-tmp
+mv /root/btrfs-root/rootfs-snap /root/btrfs-root/rootfs
+mv /root/btrfs-root/rootfs-tmp /root/btrfs-root/rootfs-snap
+
+# Swapping the subvolumes above means that on the next boot, the bootloader will
+# load the kernel image in /root/btrfs-root/rootfs/boot, which is the OLD one
+# (the one from the previous snapshot). To correct that, we copy /boot from the
+# current system there.
+rm -rf /root/btrfs-root/rootfs/boot
+cp -r /boot /root/btrfs-root/rootfs/
+
+# TODO OPT: Keep a temporary backup of /boot on the snapshot?

archlive/airootfs/root/config/usr/local/sbin/revert-home.sh

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+#!/bin/sh
+
+# Revert /home before login (assuming we are successfully booted already, /home
+# should be mounted).
+
+if umount -R /home
+then
+	/usr/local/sbin/rec-sub-del.sh home /root/btrfs-root
+	btrfs subvolume snapshot /root/btrfs-root/home-snap /root/btrfs-root/home
+	mount /home
+else
+	rm -rf /home/labuser/
+	cp -r /root/btrfs-root/home-snap/labuser/ /home/	# could use --reflink
+	chown -R labuser:labuser /home/labuser/
+fi

archlive/airootfs/root/install-chroot.sh

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+#!/bin/bash
+
+# Script to perform initial system configuration inside chroot
+
+set -v
+set -o pipefail
+
+# Figure out which device we are on
+# TODO OPT: Receive as argument
+disk=$(lsblk --nodeps --noheadings --list --output PKNAME \
+	$(findmnt --noheadings --list --nofsroot --output SOURCE / \
+		| head --lines 1)) || exit 1
+echo "chroot disk=${disk}"
+# Enable TRIM, if supported
+trim=$(lsblk --nodeps --noheadings --list --output DISC-GRAN "/dev/${disk}" \
+	| head --lines 1 | xargs) || exit 1   # xargs to remove whitespace
+[[ "${trim}" != "0B" ]] && systemctl enable fstrim.timer
+
+# Timezone
+# We can't use timedatectl under a chroot because it requires an active dbus
+# (see note in https://wiki.archlinux.org/index.php/Time#Time_standard)
+ln -sf /usr/share/zoneinfo/Europe/Athens /etc/localtime &&
+	hwclock --systohc --localtime || exit 1 # necessary to create /etc/adjtime
+
+# Localization
+# Uncomment en_US.UTF-8 UTF-8 and el_GR.UTF-8 UTF-8 in /etc/locale.gen
+sed -i -e 's/#en_US\.UTF-8 UTF-8/en_US\.UTF-8 UTF-8/g
+	   s/#el_GR\.UTF-8 UTF-8/el_GR\.UTF-8 UTF-8/g' /etc/locale.gen &&
+	locale-gen &&
+	cat > /etc/locale.conf <<-'EOF' || exit 1
+	LANG=en_US.UTF-8
+	LC_NUMERIC=el_GR.UTF-8
+	LC_TIME=el_GR.UTF-8
+	LC_MONETARY=el_GR.UTF-8
+	LC_PAPER=el_GR.UTF-8
+	LC_MEASUREMENT=el_GR.UTF-8
+	EOF
+
+# Network configuration
+hostname="${1}"
+echo ${hostname} > /etc/hostname &&
+	cat >> /etc/hosts <<-EOF &&
+	127.0.0.1	localhost
+	::1		localhost
+	127.0.1.1	${hostname}.localdomain	${hostname}
+	EOF
+	cat > /etc/systemd/network/20-wired.network <<-EOF &&
+	[Match]
+	Type=ether
+
+	[Network]
+	DHCP=yes
+	EOF
+	systemctl enable systemd-networkd.service systemd-resolved.service || exit 1
+
+# Initramfs
+# Add 'revert' as the last hook in mkinitcpio.conf
+gawk -i inplace -f - /etc/mkinitcpio.conf <<-'EOF' &&
+	BEGIN		{ FS = ")" }
+
+	/^HOOKS=/	{
+		print $1 " revert)"
+		next
+	}
+
+	{ print }	# Default action
+	EOF
+	mkinitcpio -P || exit 1
+
+# Root password
+root_password="${2}"
+echo "root:${root_password}" | chpasswd || exit 1
+
+# Configure SSH (root access, only with a key)
+ssh_key="${3}"
+install --directory --mode 700 /root/.ssh &&
+	echo "${ssh_key}" > /root/.ssh/authorized_keys &&
+	chmod 600 /root/.ssh/authorized_keys &&
+	cat >> /etc/ssh/sshd_config <<-'EOF' &&
+	# Disable password logins (only use SSH keys)
+	PasswordAuthentication no
+	EOF
+	systemctl enable sshd.service || exit 1
+
+# Boot loader
+# Check if / and /boot are on different devices to see if on UEFI or not
+if [[ $(stat -c '%d' /) = $(stat -c '%d' /boot) ]]; then
+	grub-install --target=i386-pc "/dev/${disk}" || exit 1
+else
+	grub-install \
+		--target=x86_64-efi \
+		--efi-directory=/boot \
+		--bootloader-id=GRUB || exit 1
+fi
+grub-mkconfig -o /boot/grub/grub.cfg || exit 1