templates/lxc-local.in

   1 #!/bin/sh
   2
   3 # Client script for LXC container images.
   4 #
   5 # Copyright © 2018 Stéphane Graber <stgraber@ubuntu.com>
   6 # Copyright © 2018 Christian Brauner <christian.brauner@ubuntu.com>
   7 #
   8 #  This library is free software; you can redistribute it and/or
   9 #  modify it under the terms of the GNU Lesser General Public
  10 #  License as published by the Free Software Foundation; either
  11 #  version 2.1 of the License, or (at your option) any later version.
  12
  13 #  This library is distributed in the hope that it will be useful,
  14 #  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 #  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 #  Lesser General Public License for more details.
  17
  18 #  You should have received a copy of the GNU Lesser General Public
  19 #  License along with this library; if not, write to the Free Software
  20 #  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
  21 #  USA
  22
  23 set -eu
  24
  25 LXC_HOOK_DIR="@LXCHOOKDIR@"
  26 LXC_TEMPLATE_CONFIG="@LXCTEMPLATECONFIG@"
  27
  28 LXC_NAME=
  29 LXC_PATH=
  30 LXC_ROOTFS=
  31 LXC_CONFIG=
  32 MODE="system"
  33 COMPAT_LEVEL=5
  34
  35 # Make sure the usual locations are in PATH
  36 export PATH=$PATH:/usr/sbin:/usr/bin:/sbin:/bin
  37
  38 in_userns() {
  39   [ -e /proc/self/uid_map ] || { echo no; return; }
  40
  41   while read -r line; do
  42     fields="$(echo "$line" | awk '{ print $1 " " $2 " " $3 }')"
  43     if [ "${fields}" = "0 0 4294967295" ]; then
  44       echo no;
  45       return;
  46     fi
  47
  48     if echo "${fields}" | grep -q " 0 1$"; then
  49       echo userns-root;
  50       return;
  51     fi
  52   done < /proc/self/uid_map
  53
  54   [ "$(cat /proc/self/uid_map)" = "$(cat /proc/1/uid_map)" ] && { echo userns-root; return; }
  55     echo yes
  56 }
  57
  58 usage() {
  59   cat <<EOF
  60 LXC container image downloader
  61
  62 Special arguments:
  63 [ -h | --help ]: Print this help message and exit.
  64 [ -l | --list ]: List all available images and exit.
  65 [ -m | --metadata ]: Path to the metadata for the image.
  66 [ -f | --fstree ]: Path to the filesystem tree for the image.
  67
  68 LXC internal arguments (do not pass manually!):
  69 [ --name <name> ]: The container name
  70 [ --path <path> ]: The path to the container
  71 [ --rootfs <rootfs> ]: The path to the container's rootfs
  72 [ --mapped-uid <map> ]: A uid map (user namespaces)
  73 [ --mapped-gid <map> ]: A gid map (user namespaces)
  74 EOF
  75   return 0
  76 }
  77
  78 if ! options=$(getopt -o hm:f: -l help,metadata:,fstree:,name:,path:,rootfs:,mapped-uid:,mapped-gid: -- "$@"); then
  79   usage
  80   exit 1
  81 fi
  82 eval set -- "$options"
  83
  84 while :; do
  85   case "$1" in
  86     -h|--help)     usage && exit 1;;
  87     --name)        LXC_NAME="$2"; shift 2;;
  88     --path)        LXC_PATH="$2"; shift 2;;
  89     --rootfs)      LXC_ROOTFS="$2"; shift 2;;
  90     -m|--metadata) LXC_CONFIG="$2"; shift 2;;
  91     -f|--fstree)   LXC_FSTREE="$2"; shift 2;;
  92     --mapped-uid)  LXC_MAPPED_UID="$2"; shift 2;;
  93     --mapped-gid)  LXC_MAPPED_GID="$2"; shift 2;;
  94     *)             break;;
  95   esac
  96 done
  97
  98 # Check for required binaries
  99 for bin in tar xz; do
 100   if ! command -V "${bin}" >/dev/null 2>&1; then
 101     echo "ERROR: Missing required tool: ${bin}" 1>&2
 102     exit 1
 103   fi
 104 done
 105
 106 cleanup() {
 107   if [ -d "${LOCAL_TEMP}" ]; then
 108     rm -Rf "${LOCAL_TEMP}"
 109   fi
 110 }
 111
 112 # Trap all exit signals
 113 trap cleanup EXIT HUP INT TERM
 114
 115 USERNS="$(in_userns)"
 116
 117 if [ "${USERNS}" != "no" ]; then
 118   if [ "${USERNS}" = "yes" ]; then
 119     if [ -z "${LXC_MAPPED_UID}" ] || [ "${LXC_MAPPED_UID}" = "-1" ]; then
 120       echo "ERROR: In a user namespace without a map" 1>&2
 121       exit 1
 122     fi
 123     MODE="user"
 124   else
 125     MODE="user"
 126   fi
 127 fi
 128
 129 relevant_file() {
 130   FILE_PATH="${LOCAL_TEMP}/$1"
 131
 132   if [ -e "${FILE_PATH}-${MODE}" ]; then
 133     FILE_PATH="${FILE_PATH}-${MODE}"
 134   fi
 135
 136   if [ -e "${FILE_PATH}.${COMPAT_LEVEL}" ]; then
 137     FILE_PATH="${FILE_PATH}.${COMPAT_LEVEL}"
 138   fi
 139
 140   echo "${FILE_PATH}"
 141 }
 142
 143
 144 # Unpack the rootfs
 145 echo "Unpacking the rootfs"
 146
 147 # Create temporary directory to
 148 if ! command -V mktemp >/dev/null 2>&1; then
 149   LOCAL_TEMP=/tmp/lxc-local.$$
 150   mkdir -p "${LOCAL_TEMP}"
 151 else
 152   LOCAL_TEMP=$(mktemp -d)
 153 fi
 154
 155 # Unpack file that contains meta.tar.xz
 156 if ! tar Jxf "${LXC_CONFIG}" -C "${LOCAL_TEMP}"; then
 157   echo "ERROR: Invalid metadata file" 2>&1
 158   exit 1
 159 fi
 160
 161 EXCLUDES=""
 162 excludelist=$(relevant_file excludes)
 163 if [ -f "${excludelist}" ]; then
 164     while read -r line; do
 165         EXCLUDES="${EXCLUDES} --exclude=${line}"
 166     done < "${excludelist}"
 167 fi
 168
 169 # Do not surround ${EXCLUDES} by quotes. This does not work. The solution could
 170 # use array but this is not POSIX compliant. The only POSIX compliant solution
 171 # is to use a function wrapper, but the latter can't be used here as the args
 172 # are dynamic. We thus need to ignore the warning brought by shellcheck.
 173 # shellcheck disable=SC2086
 174 tar  --anchored ${EXCLUDES} --numeric-owner -xpJf "${LXC_FSTREE}" -C "${LXC_ROOTFS}"
 175
 176 mkdir -p "${LXC_ROOTFS}/dev/pts/"
 177
 178 # Setup the configuration
 179 # Setup the configuration
 180 configfile="$(relevant_file config)"
 181 if [ ! -e "${configfile}" ]; then
 182     echo "ERROR: meta tarball is missing the configuration file" 1>&2
 183     exit 1
 184 fi
 185
 186 ## Extract all the network config entries
 187 sed -i -e "/lxc.net.0/{w ${LXC_PATH}/config-network" -e "d}" "${LXC_PATH}/config"
 188
 189 ## Extract any other config entry
 190 sed -i -e "/lxc./{w ${LXC_PATH}/config-auto" -e "d}" "${LXC_PATH}/config"
 191
 192 ## Append the defaults
 193 {
 194   echo ""
 195   echo "# Distribution configuration"
 196   cat "$configfile"
 197 } >> "${LXC_PATH}/config"
 198
 199 ## Add the container-specific config
 200 {
 201   echo ""
 202   echo "# Container specific configuration"
 203   if [ -e "${LXC_PATH}/config-auto" ]; then
 204     cat "${LXC_PATH}/config-auto"
 205     rm "${LXC_PATH}/config-auto"
 206   fi
 207 } >> "${LXC_PATH}/config"
 208
 209 fstab="$(relevant_file fstab)"
 210 if [ -e "${fstab}" ]; then
 211   echo "lxc.mount.fstab = ${LXC_PATH}/fstab" >> "${LXC_PATH}/config"
 212 fi
 213 echo "lxc.uts.name = ${LXC_NAME}" >> "${LXC_PATH}/config"
 214
 215 ## Re-add the previously removed network config
 216 if [ -e "${LXC_PATH}/config-network" ]; then
 217   {
 218     echo ""
 219     echo "# Network configuration"
 220     cat "${LXC_PATH}/config-network"
 221     rm "${LXC_PATH}/config-network"
 222   } >> "${LXC_PATH}/config"
 223 fi
 224
 225 TEMPLATE_FILES="${LXC_PATH}/config"
 226
 227 # Setup the fstab
 228 if [ -e "${fstab}" ]; then
 229   cp "${fstab}" "${LXC_PATH}/fstab"
 230   TEMPLATE_FILES="${TEMPLATE_FILES};${LXC_PATH}/fstab"
 231 fi
 232
 233 # Look for extra templates
 234 if [ -e "$(relevant_file templates)" ]; then
 235   while read -r line; do
 236     fullpath="${LXC_ROOTFS}/${line}"
 237     [ ! -e "${fullpath}" ] && continue
 238     TEMPLATE_FILES="${TEMPLATE_FILES};${fullpath}"
 239   done < "$(relevant_file templates)"
 240 fi
 241
 242
 243 # Replace variables in all templates
 244 OLD_IFS=${IFS}
 245 IFS=";"
 246 for file in ${TEMPLATE_FILES}; do
 247   [ ! -f "${file}" ] && continue
 248
 249   sed -i "s#LXC_NAME#${LXC_NAME}#g" "${file}"
 250   sed -i "s#LXC_PATH#${LXC_PATH}#g" "${file}"
 251   sed -i "s#LXC_ROOTFS#${LXC_ROOTFS}#g" "${file}"
 252   sed -i "s#LXC_TEMPLATE_CONFIG#${LXC_TEMPLATE_CONFIG}#g" "${file}"
 253   sed -i "s#LXC_HOOK_DIR#${LXC_HOOK_DIR}#g" "${file}"
 254 done
 255 IFS=${OLD_IFS}
 256
 257 # prevent mingetty from calling vhangup(2) since it fails with userns on CentOS / Oracle
 258 if [ -f "${LXC_ROOTFS}/etc/init/tty.conf" ]; then
 259   sed -i 's|mingetty|mingetty --nohangup|' "${LXC_ROOTFS}/etc/init/tty.conf"
 260 fi
 261
 262
 263 if [ -e "$(relevant_file create-message)" ]; then
 264   echo ""
 265   echo "---"
 266   cat "$(relevant_file create-message)"
 267 fi
 268
 269 exit 0