bin/live-snapshot

   1 #!/bin/sh
   2
   3 # live-snapshot - utility to manage Debian Live systems snapshots
   4 #
   5 #   This program mounts a device (fallback to /tmpfs under $MOUNTP
   6 #   and saves the /live/cow (or a different dir) filesystem in it for reuse
   7 #   in another live-initramfs session. Look at manpage for more info.
   8 #
   9 # Copyright (C) 2006-2008 Marco Amadori <marco.amadori@gmail.com>
  10 # Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>
  11 #
  12 # This program is free software; you can redistribute it and/or modify
  13 # it under the terms of the GNU General Public License as published by
  14 # the Free Software Foundation; either version 2 of the License, or
  15 # (at your option) any later version.
  16 #
  17 # This program is distributed in the hope that it will be useful,
  18 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  20 # GNU General Public License for more details.
  21 #
  22 # You should have received a copy of the GNU General Public License
  23 # along with this program; if not, write to the Free Software
  24 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  25 #
  26 # On Debian systems, the complete text of the GNU General Public License
  27 # can be found in /usr/share/common-licenses/GPL-2 file.
  28
  29 set -eu
  30
  31 . /usr/share/initramfs-tools/scripts/live-helpers
  32 . /etc/live.conf
  33
  34 export USERNAME USERFULLNAME HOSTNAME
  35
  36 PROGRAM="$(basename $0)"
  37
  38 # Needs to be available at run and reboot time
  39 SAFE_TMPDIR="/live"
  40
  41 # Permits multiple runs
  42 MOUNTP="$(mktemp -d -p ${SAFE_TMPDIR} live-snapshot-mnt.XXXXXX)"
  43 DEST="${MOUNTP}/live-sn.cpio.gz"
  44
  45 # Command line defaults and declarations
  46 SNAP_COW="/live/cow"
  47 SNAP_DEV=""
  48 SNAP_OUTPUT=""
  49 SNAP_RESYNC_STRING=""
  50 SNAP_TYPE="cpio"
  51
  52 Error ()
  53 {
  54         echo "${PROGRAM}: error:" ${@}
  55         exit 1
  56 }
  57
  58 panic ()
  59 {
  60         Error ${@}
  61 }
  62
  63 Header ()
  64 {
  65         echo "${PROGRAM} - utility to perform snapshots of Debian Live systems"
  66         echo
  67         echo "usage: ${PROGRAM} [-c|--cow DIRECTORY] [-d|--device DEVICE] [-o|--output FILE] [-t|--type TYPE]"
  68         echo "       ${PROGRAM} [-r|--resync-string STRING]"
  69         echo "       ${PROGRAM} [-h|--help]"
  70         echo "       ${PROGRAM} [-u|--usage]"
  71         echo "       ${PROGRAM} [-v|--version]"
  72 }
  73
  74 Help ()
  75 {
  76         Header
  77
  78         echo
  79         echo "Options:"
  80         echo "  -c, --cow: copy on write directory (default: ${SNAP_COW})."
  81         echo "  -d, --device: output snapshot device (default: ${SNAP_DEV:-auto})."
  82         echo "  -o, --output: output image file (default: ${DEST})."
  83         echo "  -r, --resync-string: internally used to resync previous made snapshots."
  84         echo "  -t, --type: snapshot filesystem type. Options: \"squashfs\", \"ext2\", \"ext3\", \"jffs2\" or \"cpio\".gz archive (default: ${SNAP_TYPE})"
  85         echo
  86         echo "Look at live-snapshot(1) man page for more information."
  87
  88         exit 0
  89 }
  90
  91 Usage ()
  92 {
  93         Header
  94
  95         echo
  96         echo "Try \"${PROGRAM} --help\" for more information."
  97
  98         exit 0
  99 }
 100
 101 Version ()
 102 {
 103         echo "${PROGRAM}"
 104         echo
 105         echo "Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>"
 106         echo "Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>"
 107         echo
 108         echo "This program is free software; you can redistribute it and/or modify"
 109         echo "it under the terms of the GNU General Public License as published by"
 110         echo "the Free Software Foundation; either version 2 of the License, or"
 111         echo "(at your option) any later version."
 112         echo
 113         echo "This program is distributed in the hope that it will be useful,"
 114         echo "but WITHOUT ANY WARRANTY; without even the implied warranty of"
 115         echo "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the"
 116         echo "GNU General Public License for more details."
 117         echo
 118         echo "You should have received a copy of the GNU General Public License"
 119         echo "along with this program; if not, write to the Free Software"
 120         echo "Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA"
 121         echo
 122         echo "On Debian systems, the complete text of the GNU General Public License"
 123         echo "can be found in /usr/share/common-licenses/GPL-2 file."
 124         echo
 125         echo "Homepage: <http://debian-live.alioth.debian.org/>"
 126
 127         exit 0
 128 }
 129
 130 Parse_args ()
 131 {
 132         # Parse command line
 133         ARGS="${*}"
 134         ARGUMENTS="$(getopt --longoptions cow:,device:,output,resync-string:,type:,help,usage,version --name=${PROGRAM} --options c:d:o:t:r:,h,u,v --shell sh -- ${ARGS})"
 135
 136         eval set -- "${ARGUMENTS}"
 137
 138         while true
 139         do
 140                 case "${1}" in
 141                         -c|--cow)
 142                                 SNAP_COW="${2}"
 143                                 shift 2
 144                                 ;;
 145
 146                         -d|--device)
 147                                 SNAP_DEV="${2}"
 148                                 shift 2
 149                                 ;;
 150
 151                         -o|--output)
 152                                 SNAP_OUTPUT="${2}"
 153                                 shift 2
 154                                 ;;
 155
 156                         -t|--type)
 157                                 SNAP_TYPE="${2}"
 158                                 shift 2
 159                                 ;;
 160
 161                         -r|--resync-string)
 162                                 SNAP_RESYNC_STRING="${2}"
 163                                 break
 164                                 ;;
 165
 166                         -h|--help)
 167                                 Help
 168                                 ;;
 169
 170                         -u|--usage)
 171                                 Usage
 172                                 ;;
 173
 174                         -v|--version)
 175                                 Version
 176                                 ;;
 177
 178                         --)
 179                                 shift
 180                                 break
 181                                 ;;
 182
 183                         *)
 184                                 Error "internal error."
 185                                 ;;
 186
 187                 esac
 188         done
 189 }
 190
 191 Defaults ()
 192 {
 193         # Parse resync string
 194         if [ -n "${SNAP_RESYNC_STRING}" ]
 195         then
 196                 SNAP_COW=$(echo "${SNAP_RESYNC_STRING}" | cut -f1 -d ':')
 197                 SNAP_DEV=$(echo "${SNAP_RESYNC_STRING}" | cut -f2 -d ':')
 198                 DEST="${MOUNTP}/$(echo ${SNAP_RESYNC_STRING} | cut -f3 -d ':')"
 199
 200                 case "${DEST}" in
 201                         *.cpio.gz)
 202                                 SNAP_TYPE="cpio"
 203                                 ;;
 204
 205                         *.squashfs)
 206                                 SNAP_TYPE="squashfs"
 207                                 ;;
 208
 209                         *.jffs2)
 210                                 SNAP_TYPE="jffs2"
 211                                 ;;
 212
 213                         ""|*.ext2|*.ext3)
 214                                 SNAP_TYPE="ext2"
 215                                 ;;
 216                         *)
 217                                 Error "unrecognized resync string"
 218                                 ;;
 219                 esac
 220         elif [ -z "${SNAP_OUTPUT}" ]
 221         then
 222                 # Set target file based on image
 223                 case "${SNAP_TYPE}" in
 224                         cpio)
 225                                 DEST="${MOUNTP}/live-sn.cpio.gz"
 226                                 ;;
 227
 228                         squashfs|jffs2|ext2)
 229                                 DEST="${MOUNTP}/live-sn.${SNAP_TYPE}"
 230                                 ;;
 231
 232                         ext3)
 233                                 DEST="${MOUNTP}/live-sn.ext2"
 234                                 ;;
 235                 esac
 236         else
 237                 DEST="${SNAP_OUTPUT}"
 238         fi
 239 }
 240
 241 Validate_input ()
 242 {
 243         case "${SNAP_TYPE}" in
 244                 cpio|squashfs|jffs2|ext2|ext3)
 245                         ;;
 246
 247                 *)
 248                         Error "invalid filesystem type \"${SNAP_TYPE}\""
 249                         ;;
 250         esac
 251
 252         if [ ! -d "${SNAP_COW}" ]
 253         then
 254                 Error "${SNAP_COW} is not a directory"
 255         fi
 256
 257         if [ "$(id -u)" -ne 0 ]
 258         then
 259                 Error "you are not root"
 260         fi
 261 }
 262
 263 Mount_device ()
 264 {
 265         case "${SNAP_DEV}" in
 266                 "")
 267                         # create a temp
 268                         mount -t tmpfs -o rw tmpfs "${MOUNTP}"
 269                         ;;
 270
 271                 *)
 272                         if [ -b "${SNAP_DEV}" ]
 273                         then
 274                                 try_mount "${SNAP_DEV}" "${MOUNTP}" rw
 275                         fi
 276                         ;;
 277         esac
 278 }
 279
 280 Do_snapshot ()
 281 {
 282         case "${SNAP_TYPE}" in
 283                 squashfs)
 284                         EXCLUDE_LIST="$(mktemp -p ${SAFE_TMPDIR} live-snapshot-exclude-list.XXXXXX)"
 285                         echo "./${EXCLUDE_LIST}" > "${EXCLUDE_LIST}"
 286                         cd "${SNAP_COW}"
 287                         find . -name '*.wh.*' >> "${EXCLUDE_LIST}"
 288                         cd "${OLDPWD}"
 289                         mksquashfs "${SNAP_COW}" "${DEST}" -ef "${EXCLUDE_LIST}"
 290                         rm -f "${EXCLUDE_LIST}"
 291                         ;;
 292
 293                 cpio)
 294                         ( cd "${SNAP_COW}" && find . -path '*.wh.*' -prune -o -print0 | cpio --quiet -o0 -H newc | gzip -9c > "${DEST}" ) || exit 1
 295                         ;;
 296
 297                 ext2|ext3)
 298                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 299                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 300                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-percentage=0 --root="${SNAP_COW}" "${DEST}"
 301                         ;;
 302
 303                 jffs2)
 304                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 305                         ;;
 306         esac
 307 }
 308
 309 Clean ()
 310 {
 311         if [ -z "${SNAP_RESYNC_STRING}" ] && echo "${DEST}" | grep -q "${MOUNTP}"
 312         then
 313                 echo "${DEST} is present on ${MOUNTP}, therefore no automatic unmounting the latter." > /dev/null 1>&2
 314         else
 315                 umount "${MOUNTP}"
 316                 rmdir "${MOUNTP}"
 317         fi
 318 }
 319
 320 Main ()
 321 {
 322         Parse_args "${@}"
 323         Defaults
 324         Validate_input
 325         trap 'Clean' EXIT
 326         Mount_device
 327         Do_snapshot
 328 }
 329
 330 Main "${@:-}"