lxc-download.in revision 33aa351ac13936fb2549403f18a44fed32b2edfb
#!/bin/sh
# Client script for LXC container images.
#
# Copyright © 2014 Stéphane Graber <stgraber@ubuntu.com>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
# This library 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
# Lesser General Public License for more details.
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
# USA
set -eu
LXC_TEMPLATE_CONFIG="@LXCTEMPLATECONFIG@"
LXC_HOOK_DIR="@LXCHOOKDIR@"
LOCALSTATEDIR="@LOCALSTATEDIR@"
# Defaults
DOWNLOAD_DIST=
DOWNLOAD_RELEASE=
DOWNLOAD_ARCH=
DOWNLOAD_VARIANT="default"
DOWNLOAD_SERVER="images.linuxcontainers.org"
DOWNLOAD_KEYID="0xBAEFF88C22F6E216"
DOWNLOAD_KEYSERVER="pool.sks-keyservers.net"
DOWNLOAD_VALIDATE="true"
DOWNLOAD_FLUSH_CACHE="false"
DOWNLOAD_MODE="system"
DOWNLOAD_USE_CACHE="false"
DOWNLOAD_URL=
DOWNLOAD_SHOW_HTTP_WARNING="true"
DOWNLOAD_SHOW_GPG_WARNING="true"
DOWNLOAD_COMPAT_LEVEL=1
LXC_NAME=
LXC_PATH=
LXC_ROOTFS=
LXC_MAPPED_UID=
# Some useful functions
cleanup() {
if [ -d "$DOWNLOAD_TEMP" ]; then
rm -Rf $DOWNLOAD_TEMP
fi
}
download_file() {
if ! wget -q https://${DOWNLOAD_SERVER}/$1 -O $2 >/dev/null 2>&1; then
if ! wget -q http://${DOWNLOAD_SERVER}/$1 -O $2 >/dev/null 2>&1; then
if [ "$3" = "noexit" ]; then
return 1
else
echo "ERROR: Failed to download http://${DOWNLOAD_SERVER}/$1" 1>&2
exit 1
fi
elif [ "$DOWNLOAD_SHOW_HTTP_WARNING" = "true" ]; then
DOWNLOAD_SHOW_HTTP_WARNING="false"
echo "WARNING: Failed to download the file over HTTPs." 1>&2
echo -n " The file was instead download over HTTP. " 1>&2
echo "A server replay attack may be possible!" 1>&2
fi
fi
}
download_sig() {
if ! download_file $1 $2 noexit; then
if [ "$DOWNLOAD_VALIDATE" = "true" ]; then
if [ "$3" = "normal" ]; then
echo "ERROR: Failed to download http://${DOWNLOAD_SERVER}/$1" 1>&2
exit 1
else
return 1
fi
else
return 0
fi
fi
}
gpg_setup() {
if [ "$DOWNLOAD_VALIDATE" = "false" ]; then
return
fi
echo "Setting up the GPG keyring"
mkdir -p "$DOWNLOAD_TEMP/gpg"
chmod 700 "$DOWNLOAD_TEMP/gpg"
export GNUPGHOME="$DOWNLOAD_TEMP/gpg"
if ! gpg --keyserver $DOWNLOAD_KEYSERVER \
--recv-keys ${DOWNLOAD_KEYID} >/dev/null 2>&1; then
echo "ERROR: Unable to fetch GPG key from keyserver."
exit 1
fi
}
gpg_validate() {
if [ "$DOWNLOAD_VALIDATE" = "false" ]; then
if [ "$DOWNLOAD_SHOW_GPG_WARNING" = "true" ]; then
echo "WARNING: Running without gpg validation!" 1>&2
fi
DOWNLOAD_SHOW_GPG_WARNING="false"
return 0
fi
if ! gpg --verify $1 >/dev/zero 2>&1; then
echo "ERROR: Invalid signature for $1" 1>&2
exit 1
fi
}
in_userns() {
[ -e /proc/self/uid_map ] || { echo no; return; }
[ "$(wc -l /proc/self/uid_map | awk '{ print $1 }')" -eq 1 ] || \
{ echo yes; return; }
line=$(awk '{ print $1 " " $2 " " $3 }' /proc/self/uid_map)
[ "$line" = "0 0 4294967295" ] && { echo no; return; }
echo yes
}
relevant_file() {
FILE_PATH="${LXC_CACHE_PATH}/$1"
if [ -e "${FILE_PATH}-${DOWNLOAD_MODE}" ]; then
FILE_PATH="${FILE_PATH}-${DOWNLOAD_MODE}"
fi
if [ -e "$FILE_PATH.${DOWNLOAD_COMPAT_LEVEL}" ]; then
FILE_PATH="${FILE_PATH}.${DOWNLOAD_COMPAT_LEVEL}"
fi
echo $FILE_PATH
}
usage() {
cat <<EOF
LXC container image downloader
Required arguments:
[ -d | --dist <distribution> ]: The name of the distribution
[ -r | --release <release> ]: Release name/version
[ -a | --arch <architecture> ]: Architecture of the container
[ -h | --help ]: This help message
Optional arguments:
[ --variant <variant> ]: Variant of the image (default: "default")
[ --server <server> ]: Image server (default: "images.linuxcontainers.org")
[ --keyid <keyid> ]: GPG keyid (default: 0x...)
[ --keyserver <keyserver> ]: GPG keyserver to use
[ --no-validate ]: Disable GPG validation (not recommended)
[ --flush-cache ]: Flush the local copy (if present)
LXC internal arguments (do not pass manually!):
[ --name <name> ]: The container name
[ --path <path> ]: The path to the container
[ --rootfs <rootfs> ]: The path to the container's rootfs
[ --mapped-uid <map> ]: A uid/gid map (user namespaces)
EOF
return 0
}
options=$(getopt -o d:r:a:h -l dist:,release:,arch:,help,variant:,server:,\
keyid:,no-validate,flush-cache,name:,path:,rootfs:,mapped-uid: -- "$@")
if [ $? -ne 0 ]; then
usage
exit 1
fi
eval set -- "$options"
while :; do
case "$1" in
-h|--help) usage $0 && exit 0;;
-d|--dist) DOWNLOAD_DIST=$2; shift 2;;
-r|--release) DOWNLOAD_RELEASE=$2; shift 2;;
-a|--arch) DOWNLOAD_ARCH=$2; shift 2;;
--variant) DOWNLOAD_VARIANT=$2; shift 2;;
--server) DOWNLOAD_SERVER=$2; shift 2;;
--keyid) DOWNLOAD_KEYID=$2; shift 2;;
--no-validate) DOWNLOAD_VALIDATE="false"; shift 1;;
--flush-cache) DOWNLOAD_FLUSH_CACHE="true"; shift 1;;
--name) LXC_NAME=$2; shift 2;;
--path) LXC_PATH=$2; shift 2;;
--rootfs) LXC_ROOTFS=$2; shift 2;;
--mapped-uid) LXC_MAPPED_UID=$2; shift 2;;
*) break;;
esac
done
# Check for required binaries
for bin in tar xz wget; do
if ! type $bin >/dev/null 2>&1; then
echo "ERROR: Missing required tool: $bin" 1>&2
exit 1
fi
done
# Check for GPG
if [ "$DOWNLOAD_VALIDATE" = "true" ]; then
if ! type gpg >/dev/null 2>&1; then
echo "ERROR: Missing recommended tool: gpg" 1>&2
echo "You can workaround this by using --no-validate." 1>&2
exit 1
fi
fi
# Check that we have all variables we need
if [ -z "$LXC_NAME" ] || [ -z "$LXC_PATH" ] || [ -z "$LXC_ROOTFS" ]; then
echo "ERROR: Not running through LXC." 1>&2
exit 1
fi
if [ "$(in_userns)" = "yes" ]; then
if [ -z "$LXC_MAPPED_UID" ] || [ "$LXC_MAPPED_UID" = "-1" ]; then
echo "ERROR: In a user namespace without a map." 1>&2
exit 1
fi
DOWNLOAD_MODE="user"
fi
if [ -z "$DOWNLOAD_DIST" ] || [ -z "$DOWNLOAD_RELEASE" ] || \
[ -z "$DOWNLOAD_ARCH" ]; then
echo "ERROR: Missing required argument" 1>&2
usage
exit 1
fi
# Trap all exit signals
trap cleanup EXIT HUP INT TERM
DOWNLOAD_TEMP=$(mktemp -d)
# Setup the cache
if [ "$DOWNLOAD_MODE" = "system" ]; then
LXC_CACHE_BASE="$LOCALSTATEDIR/cache/"
LXC_CACHE_PATH="$LOCALSTATEDIR/cache/lxc/download/$DOWNLOAD_DIST"
LXC_CACHE_PATH="$LXC_CACHE_PATH/$DOWNLOAD_RELEASE/$DOWNLOAD_ARCH"
else
LXC_CACHE_BASE="$HOME/.cache/lxc/"
LXC_CACHE_PATH="$HOME/.cache/lxc/download/$DOWNLOAD_DIST"
LXC_CACHE_PATH="$LXC_CACHE_PATH/$DOWNLOAD_RELEASE/$DOWNLOAD_ARCH"
fi
if [ -d "$LXC_CACHE_PATH" ]; then
if [ "$DOWNLOAD_FLUSH_CACHE" = "true" ]; then
echo "Flushing the cache..."
rm -Rf $LXC_CACHE_PATH
else
DOWNLOAD_USE_CACHE="true"
if [ -e "$(relevant_file expiry)" ]; then
if [ "$(cat $(relevant_file expiry))" -lt $(date +%s) ]; then
echo "The cached copy has expired, re-downloading..."
DOWNLOAD_USE_CACHE="false"
rm -Rf $LXC_CACHE_PATH
fi
fi
fi
fi
# Download what's needed
if [ "$DOWNLOAD_USE_CACHE" = "false" ]; then
# Initialize GPG
gpg_setup
# Grab the index
DOWNLOAD_INDEX_PATH=/meta/1.0/index-${DOWNLOAD_MODE}
echo "Downloading the image index"
if ! download_file ${DOWNLOAD_INDEX_PATH}.${DOWNLOAD_COMPAT_LEVEL} \
${DOWNLOAD_TEMP}/index noexit ||
! download_sig ${DOWNLOAD_INDEX_PATH}.${DOWNLOAD_COMPAT_LEVEL}.asc \
${DOWNLOAD_TEMP}/index.asc noexit; then
download_file ${DOWNLOAD_INDEX_PATH} ${DOWNLOAD_TEMP}/index normal
download_sig ${DOWNLOAD_INDEX_PATH}.asc \
${DOWNLOAD_TEMP}/index.asc normal
fi
gpg_validate ${DOWNLOAD_TEMP}/index.asc
# Parse it
while read line; do
# Basic CSV parser
OLD_IFS=$IFS
IFS=";"
set -- $line
IFS=$OLD_IFS
if [ "$1" != "$DOWNLOAD_DIST" ] || \
[ "$2" != "$DOWNLOAD_RELEASE" ] || \
[ "$3" != "$DOWNLOAD_ARCH" ] || \
[ "$4" != "$DOWNLOAD_VARIANT" ] || \
[ -z "$6" ]; then
continue
fi
DOWNLOAD_URL=$6
break
done < ${DOWNLOAD_TEMP}/index
if [ -z "$DOWNLOAD_URL" ]; then
echo "ERROR: Couldn't find a matching image." 1>&1
exit 1
fi
# Download the actual files
echo "Downloading the rootfs"
download_file $DOWNLOAD_URL/rootfs.tar.xz \
${DOWNLOAD_TEMP}/rootfs.tar.xz normal
download_sig $DOWNLOAD_URL/rootfs.tar.xz.asc \
${DOWNLOAD_TEMP}/rootfs.tar.xz.asc normal
gpg_validate ${DOWNLOAD_TEMP}/rootfs.tar.xz.asc
echo "Downloading the metadata"
download_file $DOWNLOAD_URL/meta.tar.xz \
${DOWNLOAD_TEMP}/meta.tar.xz normal
download_sig $DOWNLOAD_URL/meta.tar.xz.asc \
${DOWNLOAD_TEMP}/meta.tar.xz.asc normal
gpg_validate ${DOWNLOAD_TEMP}/meta.tar.xz.asc
mkdir -p $LXC_CACHE_PATH
mv ${DOWNLOAD_TEMP}/rootfs.tar.xz $LXC_CACHE_PATH
if ! tar Jxf ${DOWNLOAD_TEMP}/meta.tar.xz -C $LXC_CACHE_PATH; then
echo "ERROR: Invalid rootfs tarball." 2>&1
exit 1
fi
if [ -n "$LXC_MAPPED_UID" ] && [ "$LXC_MAPPED_UID" != "-1" ]; then
chown $LXC_MAPPED_UID -Rf $LXC_CACHE_BASE >/dev/null 2>&1 || true
fi
echo "The image cache is now ready"
else
echo "Using image from local cache"
fi
# Unpack the rootfs
echo "Unpacking the rootfs"
if [ "$DOWNLOAD_MODE" = "system" ]; then
tar --numeric-owner -xpJf ${LXC_CACHE_PATH}/rootfs.tar.xz -C ${LXC_ROOTFS}
else
tar --anchored --exclude="./dev/*" --numeric-owner -xpJf \
${LXC_CACHE_PATH}/rootfs.tar.xz -C ${LXC_ROOTFS}
mkdir -p ${LXC_ROOTFS}/dev/pts/
fi
# Setup the configuration
configfile=$(relevant_file config)
fstab=$(relevant_file fstab)
if [ ! -e $configfile ]; then
echo "ERROR: meta tarball is missing the configuration file" 1>&2
exit 1
fi
## Extract all the network config entries
sed -i -e "/lxc.network/{w ${LXC_PATH}/config-network" -e "d}" \
${LXC_PATH}/config
## Extract any other config entry
sed -i -e "/lxc./{w ${LXC_PATH}/config-auto" -e "d}" ${LXC_PATH}/config
## Append the defaults
echo "" >> ${LXC_PATH}/config
echo "# Distribution configuration" >> ${LXC_PATH}/config
cat $configfile >> ${LXC_PATH}/config
## Add the container-specific config
echo "" >> ${LXC_PATH}/config
echo "# Container specific configuration" >> ${LXC_PATH}/config
if [ -e "${LXC_PATH}/config-auto" ]; then
cat ${LXC_PATH}/config-auto >> ${LXC_PATH}/config
rm ${LXC_PATH}/config-auto
fi
if [ -e "$fstab" ]; then
echo "lxc.mount = ${LXC_PATH}/fstab" >> ${LXC_PATH}/config
fi
echo "lxc.utsname = ${LXC_NAME}" >> ${LXC_PATH}/config
## Re-add the previously removed network config
if [ -e "${LXC_PATH}/config-network" ]; then
echo "" >> ${LXC_PATH}/config
echo "# Network configuration" >> ${LXC_PATH}/config
cat ${LXC_PATH}/config-network >> ${LXC_PATH}/config
rm ${LXC_PATH}/config-network
fi
TEMPLATE_FILES="${LXC_PATH}/config"
# Setup the fstab
if [ -e $fstab ]; then
cp ${fstab} ${LXC_PATH}/fstab
TEMPLATE_FILES="$TEMPLATE_FILES ${LXC_PATH}/fstab"
fi
# Look for extra templates
if [ -e "$(relevant_file templates)" ]; then
while read line; do
fullpath=${LXC_ROOTFS}/$line
[ ! -e "$fullpath" ] && continue
TEMPLATE_FILES="$TEMPLATE_FILES $fullpath"
done < $(relevant_file templates)
fi
# Replace variables in all templates
for file in $TEMPLATE_FILES; do
[ ! -f "$file" ] && continue
sed -i "s#LXC_NAME#$LXC_NAME#g" $file
sed -i "s#LXC_PATH#$LXC_PATH#g" $file
sed -i "s#LXC_ROOTFS#$LXC_ROOTFS#g" $file
sed -i "s#LXC_TEMPLATE_CONFIG#$LXC_TEMPLATE_CONFIG#g" $file
sed -i "s#LXC_HOOK_DIR#$LXC_HOOK_DIR#g" $file
done
if [ -n "$LXC_MAPPED_UID" ] && [ "$LXC_MAPPED_UID" != "-1" ]; then
chown $LXC_MAPPED_UID -f $LXC_PATH/config $LXC_PATH/fstab || true
fi
if [ -e "$(relevant_file create-message)" ]; then
echo ""
echo "---"
cat "$(relevant_file create-message)"
fi
exit 0