bin/live-snapshot

   1 #!/bin/sh
   2
   3 # live-snapshot - utility to manage Debian Live systems snapshots
   4 #
   5 #   This program mount a device (fallback to /tmpfs under $MOUNTP
   6 #   and save the /live/cow (or a different dir) filesystem in it for reusing
   7 #   in another live-initramfs session. Look at manpage for more info.
   8 #
   9 # Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>
  10 # Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>
  11 #
  12 # This program is free software; you can redistribute it and/or modify
  13 # it under the terms of the GNU General Public License as published by
  14 # the Free Software Foundation; either version 2 of the License, or
  15 # (at your option) any later version.
  16 #
  17 # This program is distributed in the hope that it will be useful,
  18 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  20 # GNU General Public License for more details.
  21 #
  22 # You should have received a copy of the GNU General Public License
  23 # along with this program; if not, write to the Free Software
  24 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  25 #
  26 # On Debian systems, the complete text of the GNU General Public License
  27 # can be found in /usr/share/common-licenses/GPL-2 file.
  28
  29 set -eu
  30
  31 . /usr/share/initramfs-tools/scripts/live-helpers
  32 . /etc/live.conf
  33
  34 export USERNAME USERFULLNAME HOSTNAME
  35
  36 PROGRAM="$(basename $0)"
  37 VERSION=0.0.2
  38
  39 # Needs to be available at run and reboot time
  40 SAFE_TMPDIR="/live"
  41
  42 # Permits multiple runs
  43 MOUNTP="$(mktemp -d -p ${SAFE_TMPDIR} live-snapshot-mnt.XXXXXX)"
  44 SNAP_COW="/live/cow"
  45 SNAP_DEV=""
  46 DEST="${MOUNTP}/live-sn.cpio.gz"
  47 SNAP_TYPE="cpio"
  48 DESKTOP_LINK="/home/${USERNAME}/Desktop/live-snapshot"
  49 SNAP_RESYNC_STRING=""
  50
  51 Error ()
  52 {
  53         echo "${PROGRAM}: error:" ${@}
  54         exit 1
  55 }
  56
  57 panic ()
  58 {
  59         Error ${@}
  60 }
  61
  62 Header ()
  63 {
  64         echo "${PROGRAM} - utility to perform snapshots of Debian Live systems"
  65         echo
  66         echo "usage: ${PROGRAM} [-c|--cow DIRECTORY] [-d|--device DEVICE] [-o|--output FILE] [-t|--type TYPE]"
  67         echo "       ${PROGRAM} [-r|--resync-string STRING]"
  68         echo "       ${PROGRAM} [-h|--help]"
  69         echo "       ${PROGRAM} [-u|--usage]"
  70         echo "       ${PROGRAM} [-v|--version]"
  71 }
  72
  73 Help ()
  74 {
  75         Header
  76
  77         echo
  78         echo "Options:"
  79         echo "  -c, --cow: copy on write directory (default: ${SNAP_COW})."
  80         echo "  -d, --device: output snapshot device (default: ${SNAP_DEV:-auto})."
  81         echo "  -o, --output: output image file (default: ${DEST})."
  82         echo "  -r, --resync-string: internally used to resync previous made snapshots."
  83         echo "  -t, --type: snapshot filesystem type. Options: \"squashfs\", \"ext2\", \"ext3\", \"jffs2\" or \"cpio\".gz archive (default: ${SNAP_TYPE})"
  84         echo
  85         echo "Look at live-snapshot(1) man page for more information."
  86
  87         exit 0
  88 }
  89
  90 Usage ()
  91 {
  92         Header
  93
  94         echo
  95         echo "Try \"${PROGRAM} --help\" for more information."
  96
  97         exit 0
  98 }
  99
 100
 101 Version ()
 102 {
 103         echo "${PROGRAM}, version ${VERSION}"
 104         echo
 105         echo "Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>"
 106         echo
 107         echo "This program is free software; you can redistribute it and/or modify"
 108         echo "it under the terms of the GNU General Public License as published by"
 109         echo "the Free Software Foundation; either version 2 of the License, or"
 110         echo "(at your option) any later version."
 111         echo
 112         echo "This program is distributed in the hope that it will be useful,"
 113         echo "but WITHOUT ANY WARRANTY; without even the implied warranty of"
 114         echo "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the"
 115         echo "GNU General Public License for more details."
 116         echo
 117         echo "You should have received a copy of the GNU General Public License"
 118         echo "along with this program; if not, write to the Free Software"
 119         echo "Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA"
 120         echo
 121         echo "On Debian systems, the complete text of the GNU General Public License"
 122         echo "can be found in /usr/share/common-licenses/GPL-2 file."
 123         echo
 124         echo "Homepage: <http://debian-live.alioth.debian.org/>"
 125
 126         exit 0
 127 }
 128
 129 Is_same_mount ()
 130 {
 131         dir1="$(Base_path ${1})"
 132         dir2="$(Base_path ${2})"
 133
 134         if [ "${dir1}" = "${dir2}" ]
 135         then
 136                 return 0
 137         else
 138                 return 1
 139         fi
 140 }
 141
 142 Parse_args ()
 143 {
 144         # Parse command line
 145         ARGS="${*}"
 146         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 -- ${ARGS})"
 147
 148         eval set -- "${ARGUMENTS}"
 149
 150         while true
 151         do
 152                 case "${1}" in
 153                         -c|--cow)
 154                                 SNAP_COW="${2}"
 155                                 shift 2
 156                                 ;;
 157
 158                         -d|--device)
 159                                 SNAP_DEV="${2}"
 160                                 shift 2
 161                                 ;;
 162
 163                         -o|--output)
 164                                 SNAP_OUTPUT="${2}"
 165                                 shift 2
 166                                 ;;
 167
 168                         -t|--type)
 169                                 SNAP_TYPE="${2}"
 170                                 shift 2
 171                                 ;;
 172
 173                         -r|--resync-string)
 174                                 SNAP_RESYNC_STRING="${2}"
 175                                 break
 176                                 ;;
 177
 178                         -h|--help)
 179                                 Help
 180                                 ;;
 181
 182                         -u|--usage)
 183                                 Usage
 184                                 ;;
 185
 186                         -v|--version)
 187                                 Version
 188                                 ;;
 189
 190                         --)
 191                                 shift
 192                                 break
 193                                 ;;
 194
 195                         *)
 196                                 Error "internal error."
 197                                 ;;
 198
 199                 esac
 200         done
 201
 202 }
 203
 204 Defaults ()
 205 {
 206         # Parse resync string
 207         if [ -n "${SNAP_RESYNC_STRING}" ]
 208         then
 209                 SNAP_COW=$(echo "${SNAP_RESYNC_STRING}" | cut -f1 -d ':')
 210                 SNAP_DEV=$(echo "${SNAP_RESYNC_STRING}" | cut -f2 -d ':')
 211                 DEST=$(echo "${SNAP_RESYNC_STRING}" | cut -f3 -d ':')
 212
 213                 case "${DEST}" in
 214                         *.cpio.gz)
 215                                 SNAP_TYPE="cpio"
 216                                 ;;
 217
 218                         *.squashfs)
 219                                 SNAP_TYPE="squashfs"
 220                                 ;;
 221
 222                         *.jffs2)
 223                                 SNAP_TYPE="jffs2"
 224                                 ;;
 225
 226                         ""|*.ext2|*.ext3)
 227                                 SNAP_TYPE="ext2"
 228                                 ;;
 229                         *)
 230                                 Error "unrecognized resync string"
 231                                 ;;
 232                 esac
 233
 234         else
 235                 # Set target file based on image
 236                 case "${SNAP_TYPE}" in
 237                         cpio)
 238                                 DEST="${MOUNTP}/live-sn.cpio.gz"
 239                                 ;;
 240
 241                         squashfs|jffs2|ext2)
 242                                 DEST="${MOUNTP}/live-sn.${SNAP_TYPE}"
 243                                 ;;
 244
 245                         ext3)
 246                                 DEST="${MOUNTP}/live-sn.ext2"
 247                                 ;;
 248                 esac
 249         fi
 250
 251 }
 252
 253 Validate_input ()
 254 {
 255         case "${SNAP_TYPE}" in
 256                 cpio|squashfs|jffs2|ext2|ext3)
 257                         ;;
 258                 *)
 259                         Error "invalid filesystem type \"${SNAP_TYPE}\""
 260                         ;;
 261         esac
 262
 263         if [ ! -d "${SNAP_COW}" ]
 264         then
 265                 Error "${SNAP_COW} is not a directory"
 266         fi
 267
 268         if [ "$(id -u)" -ne 0 ]
 269         then
 270                 Error "you are not root"
 271         fi
 272 }
 273
 274 Mount_device ()
 275 {
 276         mkdir -p "${MOUNTP}"
 277
 278         case "${SNAP_DEV}" in
 279                 "")
 280                         # create a temp
 281                         mount -t tmpfs -o rw tmpfs "${MOUNTP}"
 282                         ;;
 283                 *)
 284                         if [ -b "${SNAP_DEV}" ]
 285                         then
 286                                 try_mount "${SNAP_DEV}" "${MOUNTP}" rw
 287                         fi
 288                         ;;
 289         esac
 290 }
 291
 292 Do_snapshot ()
 293 {
 294         case "${SNAP_TYPE}" in
 295                 squashfs)
 296                         EXCLUDE_LIST="$(mktemp -p ${SAFE_TMPDIR} live-snapshot-exclude-list.XXXXXX)"
 297                         echo "./${EXCLUDE_LIST}" > "${EXCLUDE_LIST}"
 298                         cd "${SNAP_COW}"
 299                         find . -name '*.wh.*' >> "${EXCLUDE_LIST}"
 300                         cd "${OLDPWD}"
 301                         mksquashfs "${SNAP_COW}" "${DEST}" -ef "${EXCLUDE_LIST}"
 302                         rm -f "${EXCLUDE_LIST}"
 303                         ;;
 304
 305                 cpio)
 306                         ( cd "${SNAP_COW}" && find . -path '*.wh.*' -prune -o -print0 | cpio --quiet -o0 -H newc | gzip -9c > "${DEST}" ) || exit 1
 307                         ;;
 308
 309                 ext2|ext3)
 310                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 311                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 312                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-percentage=0 --root="${SNAP_COW}" "${DEST}"
 313                         ;;
 314
 315                 jffs2)
 316                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 317                         ;;
 318         esac
 319 }
 320
 321 Clean ()
 322 {
 323         if echo "${DEST}" | grep -q "${MOUNTP}"
 324         then
 325                 echo "${DEST} is present on ${MOUNTP}, therefore no automatic unmounting the latter." > /dev/null 1>&2
 326         else
 327                 umount "${MOUNTP}"
 328                 rmdir "${MOUNTP}"
 329         fi
 330 }
 331
 332 Main ()
 333 {
 334         Parse_args "${@}"
 335         Defaults
 336         Validate_input
 337         trap 'Clean' EXIT
 338         Mount_device
 339         Do_snapshot
 340 }
 341
 342 Main "${@:-}"