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 $MOUNTP
   6 #   and saves the /live/cow (or a different directory) filesystem in it
   7 #   for reuse in another live-initramfs session.
   8 #   Look at the manpage for more informations.
   9 #
  10 # Copyright (C) 2006-2008 Marco Amadori <marco.amadori@gmail.com>
  11 # Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>
  12 #
  13 # This program is free software: you can redistribute it and/or modify
  14 # it under the terms of the GNU General Public License as published by
  15 # the Free Software Foundation, either version 3 of the License, or
  16 # (at your option) any later version.
  17 #
  18 # This program is distributed in the hope that it will be useful,
  19 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  21 # GNU General Public License for more details.
  22 #
  23 # You should have received a copy of the GNU General Public License
  24 # along with this program. If not, see <http://www.gnu.org/licenses/>.
  25 #
  26 # On Debian systems, the complete text of the GNU General Public License
  27 # can be found in /usr/share/common-licenses/GPL-3 file.
  28
  29 # declare here two vars from /etc/live.conf because of "set -u"
  30 ROOTSNAP=""
  31 HOMESNAP=""
  32
  33 set -eu
  34
  35 . /usr/share/initramfs-tools/scripts/live-helpers
  36
  37 LIVE_CONF="/etc/live.conf"
  38 . "${LIVE_CONF}"
  39
  40 export USERNAME USERFULLNAME HOSTNAME
  41
  42 EXECUTABLE="${0}"
  43 PROGRAM=$(basename "${EXECUTABLE}")
  44
  45 # Needs to be available at run and reboot time
  46 SAFE_TMPDIR="/live"
  47
  48 # Permits multiple runs
  49 MOUNTP="$(mktemp -d -p ${SAFE_TMPDIR} live-snapshot-mnt.XXXXXX)"
  50 DEST="${MOUNTP}/live-sn.cpio.gz"
  51
  52 # Command line defaults and declarations
  53 SNAP_COW="/live/cow"
  54 SNAP_DEV=""
  55 SNAP_OUTPUT=""
  56 SNAP_RESYNC_STRING=""
  57 SNAP_TYPE="cpio"
  58
  59 Error ()
  60 {
  61         echo "${PROGRAM}: error:" ${@}
  62         exit 1
  63 }
  64
  65 panic ()
  66 {
  67         Error ${@}
  68 }
  69
  70 Header ()
  71 {
  72         echo "${PROGRAM} - utility to perform snapshots of Debian Live systems"
  73         echo
  74         echo "usage: ${PROGRAM} [-c|--cow DIRECTORY] [-d|--device DEVICE] [-o|--output FILE] [-t|--type TYPE]"
  75         echo "       ${PROGRAM} [-r|--resync-string STRING]"
  76         echo "       ${PROGRAM} [-f|--refresh]"
  77         echo "       ${PROGRAM} [-h|--help]"
  78         echo "       ${PROGRAM} [-u|--usage]"
  79         echo "       ${PROGRAM} [-v|--version]"
  80 }
  81
  82 Help ()
  83 {
  84         Header
  85
  86         echo
  87         echo "Options:"
  88         echo "  -c, --cow: copy on write directory (default: ${SNAP_COW})."
  89         echo "  -d, --device: output snapshot device (default: ${SNAP_DEV:-auto})."
  90         echo "  -o, --output: output image file (default: ${DEST})."
  91         echo "  -r, --resync-string: internally used to resync previous made snapshots."
  92         echo "  -f, --refresh: try to sync a running snapshot."
  93         echo "  -t, --type: snapshot filesystem type. Options: \"squashfs\", \"ext2\", \"ext3\", \"jffs2\" or \"cpio\".gz archive (default: ${SNAP_TYPE})"
  94         echo
  95         echo "Look at live-snapshot(1) man page for more information."
  96
  97         exit 0
  98 }
  99
 100 Usage ()
 101 {
 102         Header
 103
 104         echo
 105         echo "Try \"${PROGRAM} --help\" for more information."
 106
 107         exit 0
 108 }
 109
 110 Version ()
 111 {
 112         echo "${PROGRAM}"
 113         echo
 114         echo "Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>"
 115         echo "Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>"
 116         echo
 117         echo "This program is free software; you can redistribute it and/or modify"
 118         echo "it under the terms of the GNU General Public License as published by"
 119         echo "the Free Software Foundation; either version 2 of the License, or"
 120         echo "(at your option) any later version."
 121         echo
 122         echo "This program is distributed in the hope that it will be useful,"
 123         echo "but WITHOUT ANY WARRANTY; without even the implied warranty of"
 124         echo "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the"
 125         echo "GNU General Public License for more details."
 126         echo
 127         echo "You should have received a copy of the GNU General Public License"
 128         echo "along with this program; if not, write to the Free Software"
 129         echo "Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA"
 130         echo
 131         echo "On Debian systems, the complete text of the GNU General Public License"
 132         echo "can be found in /usr/share/common-licenses/GPL-2 file."
 133         echo
 134         echo "Homepage: <http://debian-live.alioth.debian.org/>"
 135
 136         exit 0
 137 }
 138
 139 Try_refresh ()
 140 {
 141         FOUND=""
 142         if [ -n "${ROOTSNAP}" ]; then
 143                 "${EXECUTABLE}" --resync-string="${ROOTSNAP}"
 144                 FOUND="Yes"
 145         fi
 146
 147         if [ -n "${HOMESNAP}" ]; then
 148                 "${EXECUTABLE}" --resync-string="${HOMESNAP}"
 149                 FOUND="Yes"
 150         fi
 151
 152         if [ -z "${FOUND}" ]
 153         then
 154                 echo "No autoconfigured snapshots found at boot;" > /dev/null 1>&2
 155                 echo "(no resync string in ${LIVE_CONF})." > /dev/null 1>&2
 156                 exit 1
 157         fi
 158 }
 159
 160 Parse_args ()
 161 {
 162         # Parse command line
 163         ARGS="${*}"
 164         ARGUMENTS="$(getopt --longoptions cow:,device:,output,resync-string:,refresh,type:,help,usage,version --name=${PROGRAM} --options c:d:o:t:r:fhuv --shell sh -- ${ARGS})"
 165
 166         eval set -- "${ARGUMENTS}"
 167
 168         while true
 169         do
 170                 case "${1}" in
 171                         -c|--cow)
 172                                 SNAP_COW="${2}"
 173                                 shift 2
 174                                 ;;
 175
 176                         -d|--device)
 177                                 SNAP_DEV="${2}"
 178                                 shift 2
 179                                 ;;
 180
 181                         -o|--output)
 182                                 SNAP_OUTPUT="${2}"
 183                                 shift 2
 184                                 ;;
 185
 186                         -t|--type)
 187                                 SNAP_TYPE="${2}"
 188                                 shift 2
 189                                 ;;
 190
 191                         -r|--resync-string)
 192                                 SNAP_RESYNC_STRING="${2}"
 193                                 break
 194                                 ;;
 195
 196                         -f|--refresh)
 197                                 Try_refresh
 198                                 exit 0
 199                                 ;;
 200
 201                         -h|--help)
 202                                 Help
 203                                 ;;
 204
 205                         -u|--usage)
 206                                 Usage
 207                                 ;;
 208
 209                         -v|--version)
 210                                 Version
 211                                 ;;
 212
 213                         --)
 214                                 shift
 215                                 break
 216                                 ;;
 217
 218                         *)
 219                                 Error "internal error."
 220                                 ;;
 221
 222                 esac
 223         done
 224 }
 225
 226 Defaults ()
 227 {
 228         # Parse resync string
 229         if [ -n "${SNAP_RESYNC_STRING}" ]
 230         then
 231                 SNAP_COW=$(echo "${SNAP_RESYNC_STRING}" | cut -f1 -d ':')
 232                 SNAP_DEV=$(echo "${SNAP_RESYNC_STRING}" | cut -f2 -d ':')
 233                 DEST="${MOUNTP}/$(echo ${SNAP_RESYNC_STRING} | cut -f3 -d ':')"
 234
 235                 case "${DEST}" in
 236                         *.cpio.gz)
 237                                 SNAP_TYPE="cpio"
 238                                 ;;
 239
 240                         *.squashfs)
 241                                 SNAP_TYPE="squashfs"
 242                                 ;;
 243
 244                         *.jffs2)
 245                                 SNAP_TYPE="jffs2"
 246                                 ;;
 247
 248                         ""|*.ext2|*.ext3)
 249                                 SNAP_TYPE="ext2"
 250                                 ;;
 251                         *)
 252                                 Error "unrecognized resync string"
 253                                 ;;
 254                 esac
 255         elif [ -z "${SNAP_OUTPUT}" ]
 256         then
 257                 # Set target file based on image
 258                 case "${SNAP_TYPE}" in
 259                         cpio)
 260                                 DEST="${MOUNTP}/live-sn.cpio.gz"
 261                                 ;;
 262
 263                         squashfs|jffs2|ext2)
 264                                 DEST="${MOUNTP}/live-sn.${SNAP_TYPE}"
 265                                 ;;
 266
 267                         ext3)
 268                                 DEST="${MOUNTP}/live-sn.ext2"
 269                                 ;;
 270                 esac
 271         else
 272                 DEST="${SNAP_OUTPUT}"
 273         fi
 274 }
 275
 276 Validate_input ()
 277 {
 278         case "${SNAP_TYPE}" in
 279                 cpio|squashfs|jffs2|ext2|ext3)
 280                         ;;
 281
 282                 *)
 283                         Error "invalid filesystem type \"${SNAP_TYPE}\""
 284                         ;;
 285         esac
 286
 287         if [ ! -d "${SNAP_COW}" ]
 288         then
 289                 Error "${SNAP_COW} is not a directory"
 290         fi
 291
 292         if [ "$(id -u)" -ne 0 ]
 293         then
 294                 Error "you are not root"
 295         fi
 296 }
 297
 298 Mount_device ()
 299 {
 300         case "${SNAP_DEV}" in
 301                 "")
 302                         # create a temp
 303                         mount -t tmpfs -o rw tmpfs "${MOUNTP}"
 304                         ;;
 305
 306                 *)
 307                         if [ -b "${SNAP_DEV}" ]
 308                         then
 309                                 try_mount "${SNAP_DEV}" "${MOUNTP}" rw
 310                         fi
 311                         ;;
 312         esac
 313 }
 314
 315 Do_snapshot ()
 316 {
 317         case "${SNAP_TYPE}" in
 318                 squashfs)
 319                         EXCLUDE_LIST="$(mktemp -p ${SAFE_TMPDIR} live-snapshot-exclude-list.XXXXXX)"
 320                         echo "./${EXCLUDE_LIST}" > "${EXCLUDE_LIST}"
 321                         cd "${SNAP_COW}"
 322                         find . -name '*.wh.*' >> "${EXCLUDE_LIST}"
 323                         cd "${OLDPWD}"
 324                         mksquashfs "${SNAP_COW}" "${DEST}" -ef "${EXCLUDE_LIST}"
 325                         rm -f "${EXCLUDE_LIST}"
 326                         ;;
 327
 328                 cpio)
 329                         ( cd "${SNAP_COW}" && find . -path '*.wh.*' -prune -o -print0 | cpio --quiet -o0 -H newc | gzip -9c > "${DEST}" ) || exit 1
 330                         ;;
 331
 332                 ext2|ext3)
 333                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 334                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 335                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-percentage=0 --root="${SNAP_COW}" "${DEST}"
 336                         ;;
 337
 338                 jffs2)
 339                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 340                         ;;
 341         esac
 342 }
 343
 344 Clean ()
 345 {
 346         if [ -z "${SNAP_RESYNC_STRING}" ] && echo "${DEST}" | grep -q "${MOUNTP}"
 347         then
 348                 echo "${DEST} is present on ${MOUNTP}, therefore no automatic unmounting the latter." > /dev/null 1>&2
 349         else
 350                 umount "${MOUNTP}"
 351                 rmdir "${MOUNTP}"
 352         fi
 353 }
 354
 355 Warn_user ()
 356 {
 357         if [ -z "${SNAP_RESYNC_STRING}" ]
 358         then
 359                 case ${SNAP_TYPE} in
 360                         cpio|ext2|ext3)
 361                                 echo "Please move ${DEST} (if is not already in it)" > /dev/null 1>&2
 362                                 echo "in a supported writable partition (e.g ext3, vfat)." > /dev/null 1>&2
 363                                 ;;
 364
 365                         squashfs)
 366                                 echo "To use ${DEST} you need to rebuild your media or add it" > /dev/null 1>&2
 367                                 echo "to your multisession disc under the \"/live\" directory." > /dev/null 1>&2
 368                                 ;;
 369
 370                         jffs2)
 371                                 echo "Please cat or flashcp ${DEST} to your partition in order to start using it." > /dev/null 1>&2
 372                                 ;;
 373                 esac
 374
 375                 if grep -qv persistent /proc/cmdline
 376                 then
 377                         echo "Remember to boot this live system with \"persistent\" specified at boot prompt." > /dev/null 1>&2
 378                 fi
 379         fi
 380 }
 381
 382 Main ()
 383 {
 384         Parse_args "${@}"
 385         Defaults
 386         Validate_input
 387         trap 'Clean' EXIT
 388         Mount_device
 389         Do_snapshot
 390         Warn_user
 391 }
 392
 393 Main "${@:-}"