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   if [ -e /proc/1/uid_map ]; then
  55     if [ "$(cat /proc/self/uid_map)" = "$(cat /proc/1/uid_map)" ]; then
  56       echo userns-root
  57       return
  58     fi
  59   fi
  60   echo yes
  61 }
  62
  63 usage() {
  64   cat <<EOF
  65 LXC container image downloader
  66
  67 Special arguments:
  68 [ -h | --help ]: Print this help message and exit.
  69 [ -m | --metadata ]: Path to the metadata for the image.
  70 [ -f | --fstree ]: Path to the filesystem tree for the image.
  71
  72 LXC internal arguments (do not pass manually!):
  73 [ --name <name> ]: The container name
  74 [ --path <path> ]: The path to the container
  75 [ --rootfs <rootfs> ]: The path to the container's rootfs
  76 [ --mapped-uid <map> ]: A uid map (user namespaces)
  77 [ --mapped-gid <map> ]: A gid map (user namespaces)
  78 EOF
  79   return 0
  80 }
  81
  82 if ! options=$(getopt -o hm:f: -l help,metadata:,fstree:,name:,path:,rootfs:,mapped-uid:,mapped-gid: -- "$@"); then
  83   usage
  84   exit 1
  85 fi
  86 eval set -- "$options"
  87
  88 while :; do
  89   case "$1" in
  90     -h|--help)     usage && exit 1;;
  91     --name)        LXC_NAME="$2"; shift 2;;
  92     --path)        LXC_PATH="$2"; shift 2;;
  93     --rootfs)      LXC_ROOTFS="$2"; shift 2;;
  94     -m|--metadata) LXC_CONFIG="$2"; shift 2;;
  95     -f|--fstree)   LXC_FSTREE="$2"; shift 2;;
  96     --mapped-uid)  LXC_MAPPED_UID="$2"; shift 2;;
  97     --mapped-gid)  LXC_MAPPED_GID="$2"; shift 2;;
  98     *)             break;;
  99   esac
 100 done
 101
 102 # Check for required binaries
 103 for bin in tar xz; do
 104   if ! command -V "${bin}" >/dev/null 2>&1; then
 105     echo "ERROR: Missing required tool: ${bin}" 1>&2
 106     exit 1
 107   fi
 108 done
 109
 110 cleanup() {
 111   if [ -d "${LOCAL_TEMP}" ]; then
 112     rm -Rf "${LOCAL_TEMP}"
 113   fi
 114 }
 115
 116 # Trap all exit signals
 117 trap cleanup EXIT HUP INT TERM
 118
 119 USERNS="$(in_userns)"
 120
 121 if [ "${USERNS}" != "no" ]; then
 122   if [ "${USERNS}" = "yes" ]; then
 123     if [ -z "${LXC_MAPPED_UID}" ] || [ "${LXC_MAPPED_UID}" = "-1" ]; then
 124       echo "ERROR: In a user namespace without a map" 1>&2
 125       exit 1
 126     fi
 127     MODE="user"
 128   else
 129     MODE="user"
 130   fi
 131 fi
 132
 133 relevant_file() {
 134   FILE_PATH="${LOCAL_TEMP}/$1"
 135
 136   if [ -e "${FILE_PATH}-${MODE}" ]; then
 137     FILE_PATH="${FILE_PATH}-${MODE}"
 138   fi
 139
 140   if [ -e "${FILE_PATH}.${COMPAT_LEVEL}" ]; then
 141     FILE_PATH="${FILE_PATH}.${COMPAT_LEVEL}"
 142   fi
 143
 144   echo "${FILE_PATH}"
 145 }
 146
 147
 148 # Unpack the rootfs
 149 echo "Unpacking the rootfs"
 150
 151 # Create temporary directory to
 152 if ! command -V mktemp >/dev/null 2>&1; then
 153   LOCAL_TEMP=/tmp/lxc-local.$$
 154   mkdir -p "${LOCAL_TEMP}"
 155 else
 156   LOCAL_TEMP=$(mktemp -d)
 157 fi
 158
 159 # Unpack file that contains meta.tar.xz
 160 if ! tar Jxf "${LXC_CONFIG}" -C "${LOCAL_TEMP}"; then
 161   echo "ERROR: Invalid metadata file" 2>&1
 162   exit 1
 163 fi
 164
 165 EXCLUDES=""
 166 excludelist=$(relevant_file excludes)
 167 if [ -f "${excludelist}" ]; then
 168     while read -r line; do
 169         EXCLUDES="${EXCLUDES} --exclude=${line}"
 170     done < "${excludelist}"
 171 fi
 172
 173 # Do not surround ${EXCLUDES} by quotes. This does not work. The solution could
 174 # use array but this is not POSIX compliant. The only POSIX compliant solution
 175 # is to use a function wrapper, but the latter can't be used here as the args
 176 # are dynamic. We thus need to ignore the warning brought by shellcheck.
 177 # shellcheck disable=SC2086
 178 tar  --anchored ${EXCLUDES} --numeric-owner -xpJf "${LXC_FSTREE}" -C "${LXC_ROOTFS}"
 179
 180 mkdir -p "${LXC_ROOTFS}/dev/pts/"
 181
 182 # Setup the configuration
 183 # Setup the configuration
 184 configfile="$(relevant_file config)"
 185 if [ ! -e "${configfile}" ]; then
 186     echo "ERROR: meta tarball is missing the configuration file" 1>&2
 187     exit 1
 188 fi
 189
 190 ## Extract all the network config entries
 191 sed -i -e "/lxc.net.0/{w ${LXC_PATH}/config-network" -e "d}" "${LXC_PATH}/config"
 192
 193 ## Extract any other config entry
 194 sed -i -e "/lxc./{w ${LXC_PATH}/config-auto" -e "d}" "${LXC_PATH}/config"
 195
 196 ## Append the defaults
 197 {
 198   echo ""
 199   echo "# Distribution configuration"
 200   cat "$configfile"
 201 } >> "${LXC_PATH}/config"
 202
 203 ## Add the container-specific config
 204 {
 205   echo ""
 206   echo "# Container specific configuration"
 207   if [ -e "${LXC_PATH}/config-auto" ]; then
 208     cat "${LXC_PATH}/config-auto"
 209     rm "${LXC_PATH}/config-auto"
 210   fi
 211 } >> "${LXC_PATH}/config"
 212
 213 fstab="$(relevant_file fstab)"
 214 if [ -e "${fstab}" ]; then
 215   echo "lxc.mount.fstab = ${LXC_PATH}/fstab" >> "${LXC_PATH}/config"
 216 fi
 217 echo "lxc.uts.name = ${LXC_NAME}" >> "${LXC_PATH}/config"
 218
 219 ## Re-add the previously removed network config
 220 if [ -e "${LXC_PATH}/config-network" ]; then
 221   {
 222     echo ""
 223     echo "# Network configuration"
 224     cat "${LXC_PATH}/config-network"
 225     rm "${LXC_PATH}/config-network"
 226   } >> "${LXC_PATH}/config"
 227 fi
 228
 229 TEMPLATE_FILES="${LXC_PATH}/config"
 230
 231 # Setup the fstab
 232 if [ -e "${fstab}" ]; then
 233   cp "${fstab}" "${LXC_PATH}/fstab"
 234   TEMPLATE_FILES="${TEMPLATE_FILES};${LXC_PATH}/fstab"
 235 fi
 236
 237 # Look for extra templates
 238 if [ -e "$(relevant_file templates)" ]; then
 239   while read -r line; do
 240     fullpath="${LXC_ROOTFS}/${line}"
 241     [ ! -e "${fullpath}" ] && continue
 242     TEMPLATE_FILES="${TEMPLATE_FILES};${fullpath}"
 243   done < "$(relevant_file templates)"
 244 fi
 245
 246
 247 # Replace variables in all templates
 248 OLD_IFS=${IFS}
 249 IFS=";"
 250 for file in ${TEMPLATE_FILES}; do
 251   [ ! -f "${file}" ] && continue
 252
 253   sed -i "s#LXC_NAME#${LXC_NAME}#g" "${file}"
 254   sed -i "s#LXC_PATH#${LXC_PATH}#g" "${file}"
 255   sed -i "s#LXC_ROOTFS#${LXC_ROOTFS}#g" "${file}"
 256   sed -i "s#LXC_TEMPLATE_CONFIG#${LXC_TEMPLATE_CONFIG}#g" "${file}"
 257   sed -i "s#LXC_HOOK_DIR#${LXC_HOOK_DIR}#g" "${file}"
 258 done
 259 IFS=${OLD_IFS}
 260
 261 # prevent mingetty from calling vhangup(2) since it fails with userns on CentOS / Oracle
 262 if [ -f "${LXC_ROOTFS}/etc/init/tty.conf" ]; then
 263   sed -i 's|mingetty|mingetty --nohangup|' "${LXC_ROOTFS}/etc/init/tty.conf"
 264 fi
 265
 266
 267 if [ -e "$(relevant_file create-message)" ]; then
 268   echo ""
 269   echo "---"
 270   cat "$(relevant_file create-message)"
 271 fi
 272
 273 exit 0