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