debian

copying home to overlayfs might not be a good idea

menhera.sh

@@ -3,68 +3,25 @@ set -Eeuo pipefail
 # disable command path hashing as we are going to move fast and break things
 set +h
 
-# config
 WORKDIR="/tmp/menhera"
-ROOTFS=""
+MIRROR="https://iso.meson.cc/ultralite/archlinux"
-
+ROOTFS="${MIRROR}/iso/latest/arch/x86_64/airootfs.sfs"
-declare -A ARCH_MAP=(
-    ["x86_64"]="amd64"
-)
 
 # internal global variables
 OLDROOT="/"
 NEWROOT=""
 
-MACHINE_TYPE=$(uname -m)
+[[ "$(uname -m)" == "x86_64" ]] || { echo "error: wrong arch $(uname -m) (not x86_64)"; exit 1; }
-ARCH_ID=${ARCH_MAP[$MACHINE_TYPE]:-$MACHINE_TYPE}
 
-# fix possible PATH pMYMAP[missing]+_roblems
+PUBKEY="./key.pub"
-export PATH="$PATH:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+[ -f "$PUBKEY" ] || { echo "error: you should put your ssh public key at ${PUBKEY} in order to ssh with root account and this key later"; exit 1; }
 
-menhera::reset_sshd_config() {
+if [[ $EUID -ne 0 ]]; then
-    cat > /etc/ssh/sshd_config <<EOF
+    echo "This script must be run as root"
-PermitRootLogin yes
-AcceptEnv LANG LC_*
-EOF
-}
-
-# environment compatibility
-menhera::__compat_restart_ssh() {
-    if [ -x "$(command -v systemctl)" ]; then
-        systemctl daemon-reload
-        if ! systemctl restart ssh; then
-            echo "SSH daemon start failed, try resetting config..."
-            menhera::reset_sshd_config
-            if ! systemctl restart ssh; then
-                echo "SSH daemon fail to start, dropping you to a shell..."
-                sh
-            fi
-        fi
-    elif [ -x "$(command -v service)" ]; then
-        if ! service ssh restart; then
-            echo "SSH daemon start failed, try resetting config..."
-            menhera::reset_sshd_config
-            if ! service ssh restart; then
-                echo "SSH daemon fail to start, dropping you to a shell..."
-                sh
-            fi
-        fi
-    else
-        echo "ERROR: Cannot restart SSH server, init system not recoginzed" >&2
     exit 1
 fi
-}
 
-menhera::__compat_reload_init() {
+systemctl status > /dev/null || { echo "error: no systemd"; exit 1; }
-    if [ -x "$(command -v systemctl)" ]; then
-        systemctl daemon-reexec
-    elif [ -x "$(command -v telinit)" ]; then
-        telinit u
-    else
-        echo "ERROR: Cannot re-exec init, init system not recoginzed" >&2
-        exit 1
-    fi
-}
 
 # helper functions
 # https://stackoverflow.com/a/3232082/2646069
@@ -81,32 +38,19 @@ menhera::confirm() {
     esac
 }
 
-# jobs
+echo -e "We will start a temporary RAM system as your recovery environment."
-menhera::get_rootfs() {
+echo -e "Note that this script will kill programs and umount filesystems without prompting."
-    if [ -n ${ROOTFS} ]; then 
+echo -e "Please confirm:"
-        echo "Getting rootfs URL..."
+echo -e "\tYou have closed all programs you can, and backed up all important data"
+echo -e "\tYou can SSH into your system as root user"
+menhera::confirm || exit -1
 
-        # forgive me for parsing HTML with these shit
+# fix possible PATH problems
-        # and hope it works
+export PATH="$PATH:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
-        ROOTFS_TIME=$(wget -qO- --show-progress "https://images.linuxcontainers.org/images/debian/buster/${ARCH_ID}/default/?C=M;O=D" | grep -oP '(\d{8}_\d{2}:\d{2})' | head -n 1)
 
-        ROOTFS="https://images.linuxcontainers.org/images/debian/buster/${ARCH_ID}/default/${ROOTFS_TIME}/rootfs.squashfs"
-    else 
-        echo "\$ROOTFS is set to '$ROOTFS'"
-    fi
-}
-
-menhera::sync_filesystem() {
-    echo "Syncing..."
-    sync
-    sync
-}
-
-menhera::prepare_environment() {
 echo "Loading kernel modules..."
 modprobe overlay
 modprobe squashfs
-
 sysctl kernel.panic=10
 
 echo "Creating workspace in '${WORKDIR}'..."
@@ -114,64 +58,25 @@ menhera::prepare_environment() {
 mkdir -p "${WORKDIR}"
 mount -t tmpfs -o size=100% tmpfs "${WORKDIR}"
 
-    # new rootfs
+mkdir -p "${WORKDIR}/newroot" # where iso is stored
-    mkdir -p "${WORKDIR}/newroot"
+mkdir -p "${WORKDIR}/newrootro" # lower
-    # readonly part of new rootfs
+mkdir -p "${WORKDIR}/newrootrw" # upper
-    mkdir -p "${WORKDIR}/newrootro"
+mkdir -p "${WORKDIR}/overlayfs_workdir" # work
-    # writeable part of new rootfs
-    mkdir -p "${WORKDIR}/newrootrw"
-    # overlayfs workdir
-    mkdir -p "${WORKDIR}/overlayfs_workdir"
 
 echo "Downloading temporary rootfs..."
-    wget -q --show-progress -O "${WORKDIR}/rootfs.squashfs" "${ROOTFS}"
+wget -O "${WORKDIR}/rootfs.squashfs" "${ROOTFS}"
-}
 
-menhera::mount_new_rootfs() {
 echo "Mounting temporary rootfs..."
 mount -t squashfs "${WORKDIR}/rootfs.squashfs" "${WORKDIR}/newrootro"
 mount -t overlay overlay -o rw,lowerdir="${WORKDIR}/newrootro",upperdir="${WORKDIR}/newrootrw",workdir="${WORKDIR}/overlayfs_workdir" "${WORKDIR}/newroot"
-
 NEWROOT="${WORKDIR}/newroot"
-}
 
-menhera::install_software() {
+rm -f "${NEWROOT}/etc/resolv.conf"
-    echo "Installing OpenSSH Server into new rootfs..."
+cat "${OLDROOT}/etc/resolv.conf" > "${NEWROOT}/etc/resolv.conf"
+install -DTm0600 <(cat "$PUBKEY") "${NEWROOT}/root/.ssh/authorized_keys"
+chmod 0700 "${NEWROOT}/root/.ssh"
+sync && sync # why sync twice? idk
 
-    # disable APT cache
-    echo -e 'Dir::Cache "";\nDir::Cache::archives "";' > "${NEWROOT}/etc/apt/apt.conf.d/00_disable-cache-directories"
-
-    DEBIAN_FRONTEND=noninteractive chroot "${NEWROOT}" apt-get update -y
-    DEBIAN_FRONTEND=noninteractive chroot "${NEWROOT}" apt-get -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" install -y openssh-server
-}
-
-menhera::copy_config() {
-    echo "Copying important config into new rootfs..."
-    ! cp -axL "${OLDROOT}/etc/resolv.conf" "${NEWROOT}/etc"
-    ! cp -axr "${OLDROOT}/etc/ssh" "${NEWROOT}/etc"
-    ! cp -ax "${OLDROOT}/etc/"{passwd,shadow} "${NEWROOT}/etc"
-    ! cp -axr "${OLDROOT}/root/.ssh" "${NEWROOT}/root"
-
-    chroot "${NEWROOT}" chsh -s /bin/bash root
-
-    cat > "${NEWROOT}/etc/motd" <<EOF
-
-Download menhera.sh at https://github.com/Jamesits/menhera.sh
-
-!!!NOTICE!!!
-
-This is a minimal RAM system created by menhera.sh. Feel free to format your disk, but don't blame anyone
-except yourself if you lost important files or your system is broken.
-
-If you think you've done something wrong, reboot immediately -- there is still hope.
-
-Your original rootfs is at /mnt/oldroot. Be careful dealing with it.
-
-Have a lot of fun...
-EOF
-}
-
-menhera::swap_root() {
 echo "Swapping rootfs..."
 # prepare future mount point for our old rootfs
 mkdir -p "${WORKDIR}/newroot/mnt/oldroot"
@@ -195,69 +100,27 @@ menhera::swap_root() {
 mount --move "${OLDROOT}/${WORKDIR}" "${WORKDIR}"
 
 echo "Restarting SSH daemon..."
-    menhera::__compat_restart_ssh
+systemctl daemon-reload
-}
+systemctl is-active ssh && systemctl stop ssh || true
+systemctl restart sshd
 
-menhera::clear_processes() {
 echo "Disabling swap..."
 swapoff -a
 
 echo "Restarting init process..."
-    menhera::__compat_reload_init
+systemctl daemon-reexec
-    # hope 15s is enough
-    sleep 15
 
-    echo "Killing all programs still using the old root..."
+systemctl --quiet is-system-running || true
-    fuser -kvm "${OLDROOT}" -15
-    # in most cases the parent process of this script will be killed, so goodbye
-}
-
-# main procedure
-LIBRARY_ONLY=0
-
-while test $# -gt 0
-do
-    case "$1" in
-        --lib) LIBRARY_ONLY=1
-            ;;
-    esac
-    shift
-done
-
-if [[ $LIBRARY_ONLY -eq 1 ]]; then
-    # acting as a library only
-    return 0
-fi
-
-if [[ $EUID -ne 0 ]]; then
-    echo "This script must be run as root" 
-    exit 1
-fi
-
-echo -e "We will start a temporary RAM system as your recovery environment."
-echo -e "Note that this script will kill programs and umount filesystems without prompting."
-echo -e "Please confirm:"
-echo -e "\tYou have closed all programs you can, and backed up all important data"
-echo -e "\tYou can SSH into your system as root user"
-menhera::confirm || exit -1
-
-menhera::get_rootfs
-menhera::sync_filesystem
-
-menhera::prepare_environment
-menhera::mount_new_rootfs
-menhera::copy_config
-menhera::install_software
-menhera::swap_root
 
 echo -e "If you are connecting from SSH, please create a second session to this host use root and"
 echo -e "confirm you can get a shell."
 echo -e "After your confirmation, we are going to kill the old SSH server."
 
 if menhera::confirm; then
-    menhera::clear_processes
+    echo "Killing all programs still using the old root..."
+    fuser -kvm "${OLDROOT}" -15
+    # in most cases the parent process of this script will be killed, so goodbye
 else
     echo -e "Please manually issue a reboot to recover your old OS. If you believe there is a bug in menhera.sh, "
     echo -e "raise a ticket at https://github.com/Jamesits/menhera.sh/issues ."
-    exit 1
 fi