ltsp-server 5.4.2-6+deb7u1 / usr / sbin / ltsp-update-image

#!/bin/sh
#
#  Copyright (c) 2007 Canonical LTD
#
#  Author: Oliver Grawert <ogra@canonical.com>
#
#  2007, Scott Balneaves <sbalneav@ltsp.org>
#        Warren Togami <wtogami@redhat.com>
#  2008, Vagrant Cascadian <vagrant@freegeek.org>
#  2010, Gideon Romm <gadi@ltsp.org>
#  2012, Alkis Georgopoulos <alkisg@gmail.com>
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License as
#  published by the Free Software Foundation; either version 2 of the
#  License, or (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program.  If not, you can find it on the World Wide
#  Web at http://www.gnu.org/copyleft/gpl.html, or write to the Free
#  Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
#  MA 02110-1301, USA.
#

usage() {
    cat <<EOF
Usage: $0 [OPTION] [CHROOT...]
Generates an NBD image from an LTSP chroot, to be served by nbd-server.
Chroot can be a full path or a subdirectory of the LTSP base directory,
and it defaults to the host architecture if unset.

Options:
  -b, --base=          The LTSP base directory. Defaults to "/opt/ltsp".
  -c, --cleanup        Temporarily remove user accounts, logs, caches etc from
                       the chroot before exporting the image. The chroot arch
                       is required to be compatible with the server arch.
  -e, --exclude=       List of dirs/files to exclude from the image.
                       This is in addition to /etc/ltsp/ltsp-update-image.excludes.
  -f, --config-nbd     Generate appropriate nbd-server configuration files.
                       It's automatically set if NFS isn't used or if other LTSP
                       generated nbd-server configuration files already exist.
  -h, --help           This message.
  -m, --no-compress    Don't compress the generated image.
  -n, --no-backup      Don't backup chroot.img to chroot.img.old.
  -r, --revert         Swap chroot.img with chroot.img.old and update kernels.
EOF
}

trap_cleanup() {
    # Don't stop on errors within this function.
    # Save and restore flags in a way that works with dash and bash.
    local orig_flags
    orig_flags=$(set +o)
    set +e

    # Stop trapping
    trap - 0 HUP INT QUIT KILL SEGV PIPE TERM
    umount_marked
    rmdir "$cu_chroot"
    rmdir "$cu_cow"
    rmdir "$cu_rofs"
    rmdir "$cu_base"
    unlock_package_management
    eval "$orig_flags"
}

# Get a sorted list of all "real" mount points under $chroot,
# with $chroot included, even if it's not a mount point.
get_mounts() {
    local chroot mounts src system point type rest excluded found_chroot
    chroot=$1

    excluded=",${EXCLUDED_MOUNTS:-/home},"
    echo "$chroot"
    while read system point type rest; do
        case "$excluded" in
            ,$point,) continue ;;
        esac
        # Avoid CDs, USB sticks, virtual file systems etc.
        case "$type" in
            btrfs|ext*) true ;;
            *) continue ;;
        esac
        case "$point/" in
            $chroot/|/dev/*|/proc/*|/run/*|/sys/*) continue ;;
            ${chroot%/}/*) echo "$point" ;;
        esac
    done < /proc/mounts | sort -u
}

# Create a temporary copy of the chroot and run ltsp-cleanup in it.
run_cleanup() {
    local chroot name point
    chroot=$1
    name=$2

    if [ ! -x "$chroot/usr/share/ltsp/ltsp-cleanup" ]; then
        warn "Script $chroot/usr/share/ltsp/ltsp-cleanup does not exist, cannot cleanup the chroot."
        return 0
    fi
    lock_package_management
    cu_base=$(mktemp -d)
    cu_rofs="$cu_base/rofs"
    cu_cow="$cu_base/cow"
    cu_chroot="$cu_base/$name"
    mkdir "$cu_rofs"
    mkdir "$cu_cow"
    mkdir "$cu_chroot"
    trap "trap_cleanup" 0 HUP INT QUIT KILL SEGV PIPE TERM
    while IFS= read -r point; do
        mark_mount --bind "$chroot${point%/}" "$cu_rofs${point%/}"
    done <<EOF
$(get_mounts "$chroot")
EOF
    mark_mount -t tmpfs -o mode=0755 tmpfs "$cu_cow"

    # If this is the first time that run_cleanup() is called,
    # ensure that the overlayfs or aufs module are loaded.
    if [ -z "$union_type" ]; then
        # '' is to check if some of them is already loaded
        for module in '' overlayfs aufs; do
            if [ -n "$module" ]; then
                modprobe "$module" || true
            fi
            # detect which unionfs to use
            while read nodev filesystem; do
                filesystem=${filesystem:-$nodev}
                case "$filesystem" in
                    overlayfs) 
                        union_type=overlayfs
                        union_opts="upperdir=$cu_cow,lowerdir=$cu_rofs"
                        # We prefer overlayfs to aufs, so break when found
                        break
                        ;;
                    aufs) 
                        union_type=aufs
                        union_opts="dirs=$cu_cow=rw:$cu_rofs=ro"
                        ;;
                esac
            done < /proc/filesystems
            test -n "$union_type" && break
        done
        test -n "$union_type" || die "No overlayfs or aufs support detected"
        mark_mount -t "$union_type" -o "$union_opts" "$union_type" "$cu_chroot"
        if [ "aufs" = "$union_type" ]; then
            # Aufs doesn't handle sub-mounts, so mount each needed sub-mount
            # directly. If we do not mount the sub-mounts directly, systems 
            # with a separate /boot partition end up with no kernels for 
            # network boot.
            while IFS= read -r point; do
                case "$point" in
                    "$cu_rofs"*|/) 
                    ;;
                    *)
                    mkdir -p "$cu_cow${point%/}"
                    mark_mount -t "$union_type" -o "dirs=$cu_cow${point%/}=rw:$cu_rofs${point%/}=ro" "$union_type" "$cu_chroot${point%/}"
                    ;;
                esac
            done <<EOF
$(get_mounts "$chroot")
EOF
	fi
    fi
    chroot "$cu_chroot" /usr/share/ltsp/ltsp-cleanup --yes
}

generate_image() {
    local chroot name imgdir nice ionice
    chroot=$1

    # If the chroot is a subdir of $BASE, make it an absolute path
    if [ "$chroot" != "/" ]; then
        chroot=${chroot%/}
        test -d "$BASE/$chroot" && chroot="$BASE/$chroot"
    fi
    test -d "$chroot" || die "Chroot $chroot does not exist."
    name=${chroot##*/}
    name=${name%.*}
    # If the chroot has no name part, e.g. /, name it after the host arch
    name=${name:-$(detect_arch)}
    imgdir=$BASE/images
    mkdir -p "$imgdir"

    if [ "$REVERT" = true ]; then
        test -f "$imgdir/$name.img.old" ||
            die "$imgdir/$name.img.old is missing, cannot revert to it"
        if [ -f "$imgdir/$name.img" ]; then
            # Swap old with new file
            mv "$imgdir/$name.img" "$imgdir/$name.img.tmp"
            mv "$imgdir/$name.img.old" "$imgdir/$name.img"
            mv "$imgdir/$name.img.tmp" "$imgdir/$name.img.old"
        else
            mv "$imgdir/$name.img.old" "$imgdir/$name.img"
        fi
        echo "Reverted to $imgdir/$name.img.old, please reboot your clients."
    else
        cu_chroot=$chroot
        if [ "$CLEANUP" = true ]; then
            # run_cleanup sets cu_chroot=$cu_base/$name for mksquashfs
            run_cleanup "$chroot" "$name"
        fi

        test -f /etc/ltsp/ltsp-update-image.excludes && EXCLUDE_FILE="/etc/ltsp/ltsp-update-image.excludes"
        test -x /usr/bin/nice && nice=nice || unset nice
        test -x /usr/bin/ionice && /usr/bin/ionice -c3 true 2>/dev/null && ionice=ionice || unset ionice
        if ! $nice $ionice mksquashfs "$cu_chroot" "$imgdir/$name.img.tmp" \
            -no-recovery -noappend -wildcards ${EXCLUDE_FILE:+-ef "$EXCLUDE_FILE"} \
            ${EXCLUDE:+-e "$EXCLUDE"} ${NO_COMPRESS:+-noF -noD -noI -no-exports}
        then
            rm -f "$imgdir/$name.img.tmp"
            die "mksquashfs failed to build the LTSP image, exiting"
        fi
        if [ -f "$imgdir/$name.img" ] && [ "$NO_BACKUP" != true ]; then
            mv "$imgdir/$name.img" "$imgdir/$name.img.old"
        fi
        mv "$imgdir/$name.img.tmp" "$imgdir/$name.img"
    fi

    PREFER_NBD_IMAGE="$REVERT" ltsp-update-kernels ${BASE:+-b "$BASE"} "$name"

    if [ "$cu_chroot" != "$chroot" ] && [ "$REVERT" != true ]; then
        trap_cleanup
    fi
}


# Distro specific functions

lock_package_management() {
    warn "Your distro doesn't support package management locking, continuing without locking..."
}

unlock_package_management() {
    if [ -n "$lockpid" ]; then
        kill "$lockpid" || true
        unset lockpid
    fi
}


# This also sources vendor functions and .conf file settings
. /usr/share/ltsp/ltsp-server-functions

if ! args=$(getopt -n "$0" -o "b:ce:fhmnr" \
    -l "base:,cleanup,exclude:,config-nbd,help,no-compress,no-backup,revert" -- "$@")
then
    exit 1
fi
eval "set -- $args"
while true ; do
    case "$1" in
        -b|--base) shift; BASE=$1 ;;
        -c|--cleanup) CLEANUP=true ;;
        -e|--exclude) shift; EXCLUDE=$1 ;;
        -f|--config-nbd) CONFIG_NBD=true ;;
        -h|--help) usage; exit 0 ;;
        -m|--no-compress) NO_COMPRESS=true ;;
        -n|--no-backup) NO_BACKUP=true ;;
        -r|--revert) REVERT=$1 ;;
        --) shift ; break ;;
        *) die "$0: Internal error!" ;;
    esac
    shift
done
require_root

BASE=${BASE:-/opt/ltsp}
# Remove trailing /, if present
BASE=${BASE%/}
if [ -z "$CONFIG_NBD" ]; then
    if [ -d /etc/nbd-server/conf.d ] &&
        [ -n "$(find /etc/nbd-server/conf.d/ -type f -name 'ltsp_*.conf' ! -name ltsp_swap.conf)" ]
    then
        CONFIG_NBD=true
    fi
    if [ -z "$CONFIG_NBD" ]; then
        if grep -qsr ^/opt/ltsp /etc/exports /etc/exports.d/; then
            die "Your system seems to be using NFS to serve LTSP chroots.
If you're absolutely certain you want to switch to NBD, run:
    $0 --config-nbd $*"
        fi
    fi
fi

# Chroots can be specified in the command line. If not, update all of them.
if [ $# -eq 0 ]; then
    set -- $(find "$BASE/" -mindepth 1 -maxdepth 1 -type d ! -name images \
        -printf "%f\n")
fi
test $# -gt 0 || die "No chroots found in $BASE"

for chroot in "$@"; do
    generate_image "$chroot"
done

ltsp-config nbd-server