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 $MOUNTP
   6 #   and saves the /live/cow (or a different directory) filesystem in it
   7 #   for reuse in another live-initramfs session.
   8 #   Look at the manpage for more informations.
   9 #
  10 # Copyright (C) 2006-2008 Marco Amadori <marco.amadori@gmail.com>
  11 # Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>
  12 #
  13 # This program is free software: you can redistribute it and/or modify
  14 # it under the terms of the GNU General Public License as published by
  15 # the Free Software Foundation, either version 3 of the License, or
  16 # (at your option) any later version.
  17 #
  18 # This program is distributed in the hope that it will be useful,
  19 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  21 # GNU General Public License for more details.
  22 #
  23 # You should have received a copy of the GNU General Public License
  24 # along with this program. If not, see <http://www.gnu.org/licenses/>.
  25 #
  26 # On Debian systems, the complete text of the GNU General Public License
  27 # can be found in /usr/share/common-licenses/GPL-3 file.
  28
  29 # declare here two vars from /etc/live.conf because of "set -u"
  30 ROOTSNAP=""
  31 HOMESNAP=""
  32
  33 if [ -n "${LIVE_SNAPSHOT_CHECK_UNBOUND}" ]
  34 then
  35         set -eu
  36 else
  37         set -e
  38 fi
  39
  40 . /usr/share/initramfs-tools/scripts/live-helpers
  41
  42 LIVE_CONF="/etc/live.conf"
  43 . "${LIVE_CONF}"
  44
  45 export USERNAME USERFULLNAME HOSTNAME
  46
  47 EXECUTABLE="${0}"
  48 PROGRAM=$(basename "${EXECUTABLE}")
  49
  50 # Needs to be available at run and reboot time
  51 SAFE_TMPDIR="/live"
  52
  53 # Permits multiple runs
  54 MOUNTP="$(mktemp -d -p ${SAFE_TMPDIR} live-snapshot-mnt.XXXXXX)"
  55 DEST="${MOUNTP}/live-sn.cpio.gz"
  56 DEF_SNAP_COW="/live/cow"
  57 TMP_FILELIST="${PROGRAM}.list"
  58
  59 # Command line defaults and declarations
  60 SNAP_COW="${DEF_SNAP_COW}"
  61 SNAP_DEV=""
  62 SNAP_MNT=""
  63 SNAP_OUTPUT=""
  64 SNAP_RESYNC_STRING=""
  65 SNAP_TYPE="cpio"
  66 SNAP_LIST="/etc/live-snapshot.list"
  67 EXCLUDE_LIST="/etc/live-snapshot.exclude_list"
  68
  69 Error ()
  70 {
  71         echo "${PROGRAM}: error:" ${@}
  72         exit 1
  73 }
  74
  75 panic ()
  76 {
  77         Error ${@}
  78 }
  79
  80 Header ()
  81 {
  82         echo "${PROGRAM} - utility to perform snapshots of Debian Live systems"
  83         echo
  84         echo "usage: ${PROGRAM} [-c|--cow DIRECTORY] [-d|--device DEVICE] [-o|--output FILE] [-t|--type TYPE]"
  85         echo "       ${PROGRAM} [-r|--resync-string STRING]"
  86         echo "       ${PROGRAM} [-f|--refresh]"
  87         echo "       ${PROGRAM} [-h|--help]"
  88         echo "       ${PROGRAM} [-u|--usage]"
  89         echo "       ${PROGRAM} [-v|--version]"
  90 }
  91
  92 Help ()
  93 {
  94         Header
  95
  96         echo
  97         echo "Options:"
  98         echo "  -c, --cow: copy on write directory (default: ${SNAP_COW})."
  99         echo "  -d, --device: output snapshot device (default: ${SNAP_DEV:-auto})."
 100         echo "  -o, --output: output image file (default: ${DEST})."
 101         echo "  -r, --resync-string: internally used to resync previous made snapshots."
 102         echo "  -f, --refresh: try to sync a running snapshot."
 103         echo "  -t, --type: snapshot filesystem type. Options: \"squashfs\", \"ext2\", \"ext3\", \"ext4\", \"jffs2\" or \"cpio\".gz archive (default: ${SNAP_TYPE})"
 104         echo
 105         echo "Look at live-snapshot(1) man page for more information."
 106
 107         exit 0
 108 }
 109
 110 Usage ()
 111 {
 112         Header
 113
 114         echo
 115         echo "Try \"${PROGRAM} --help\" for more information."
 116
 117         exit 0
 118 }
 119
 120 Version ()
 121 {
 122         echo "${PROGRAM}"
 123         echo
 124         echo "Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>"
 125         echo "Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>"
 126         echo
 127         echo "This program is free software; you can redistribute it and/or modify"
 128         echo "it under the terms of the GNU General Public License as published by"
 129         echo "the Free Software Foundation; either version 2 of the License, or"
 130         echo "(at your option) any later version."
 131         echo
 132         echo "This program is distributed in the hope that it will be useful,"
 133         echo "but WITHOUT ANY WARRANTY; without even the implied warranty of"
 134         echo "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the"
 135         echo "GNU General Public License for more details."
 136         echo
 137         echo "You should have received a copy of the GNU General Public License"
 138         echo "along with this program; if not, write to the Free Software"
 139         echo "Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA"
 140         echo
 141         echo "On Debian systems, the complete text of the GNU General Public License"
 142         echo "can be found in /usr/share/common-licenses/GPL-2 file."
 143         echo
 144         echo "Homepage: <http://debian-live.alioth.debian.org/>"
 145
 146         exit 0
 147 }
 148
 149 Try_refresh ()
 150 {
 151         FOUND=""
 152         if [ -n "${ROOTSNAP}" ]; then
 153                 "${EXECUTABLE}" --resync-string="${ROOTSNAP}"
 154                 FOUND="Yes"
 155         fi
 156
 157         if [ -n "${HOMESNAP}" ]; then
 158                 "${EXECUTABLE}" --resync-string="${HOMESNAP}"
 159                 FOUND="Yes"
 160         fi
 161
 162         if [ -z "${FOUND}" ]
 163         then
 164                 echo "No autoconfigured snapshots found at boot;" > /dev/null 1>&2
 165                 echo "(no resync string in ${LIVE_CONF})." > /dev/null 1>&2
 166                 exit 1
 167         fi
 168 }
 169
 170 Parse_args ()
 171 {
 172         # Parse command line
 173         ARGS="${*}"
 174         ARGUMENTS="$(getopt --longoptions cow:,device:,output,resync-string:,refresh,type:,help,usage,version --name=${PROGRAM} --options c:d:o:t:r:fhuv --shell sh -- ${ARGS})"
 175
 176         eval set -- "${ARGUMENTS}"
 177
 178         while true
 179         do
 180                 case "${1}" in
 181                         -c|--cow)
 182                                 SNAP_COW="${2}"
 183                                 shift 2
 184                                 ;;
 185
 186                         -d|--device)
 187                                 SNAP_DEV="${2}"
 188                                 shift 2
 189                                 ;;
 190
 191                         -o|--output)
 192                                 SNAP_OUTPUT="${2}"
 193                                 shift 2
 194                                 ;;
 195
 196                         -t|--type)
 197                                 SNAP_TYPE="${2}"
 198                                 shift 2
 199                                 ;;
 200
 201                         -r|--resync-string)
 202                                 SNAP_RESYNC_STRING="${2}"
 203                                 break
 204                                 ;;
 205
 206                         -f|--refresh)
 207                                 Try_refresh
 208                                 exit 0
 209                                 ;;
 210
 211                         -h|--help)
 212                                 Help
 213                                 ;;
 214
 215                         -u|--usage)
 216                                 Usage
 217                                 ;;
 218
 219                         -v|--version)
 220                                 Version
 221                                 ;;
 222
 223                         --)
 224                                 shift
 225                                 break
 226                                 ;;
 227
 228                         *)
 229                                 Error "internal error."
 230                                 ;;
 231
 232                 esac
 233         done
 234 }
 235
 236 Defaults ()
 237 {
 238         # Parse resync string
 239         if [ -n "${SNAP_RESYNC_STRING}" ]
 240         then
 241                 SNAP_COW=$(echo "${SNAP_RESYNC_STRING}" | cut -f1 -d ':')
 242                 SNAP_DEV=$(echo "${SNAP_RESYNC_STRING}" | cut -f2 -d ':')
 243                 SNAP_MNT=$(echo "${SNAP_RESYNC_STRING}" | cut -f3 -d ':')
 244                 DEST="${MOUNTP}/${SNAP_MNT}"
 245
 246                 case "${SNAP_MNT}" in
 247                         *.cpio.gz)
 248                                 SNAP_TYPE="cpio"
 249                                 ;;
 250
 251                         *.squashfs)
 252                                 SNAP_TYPE="squashfs"
 253                                 ;;
 254
 255                         *.jffs2)
 256                                 SNAP_TYPE="jffs2"
 257                                 ;;
 258
 259                         *.ext2|*.ext3)
 260                                 SNAP_TYPE="ext2"
 261                                 ;;
 262
 263                         "")
 264                                 SNAP_TYPE="whole_partition"
 265                                 ;;
 266
 267                         *.ext4)
 268                                 SNAP_TYPE="ext4"
 269                                 ;;
 270
 271                         *)
 272                                 Error "unrecognized resync string"
 273                                 ;;
 274                 esac
 275         elif [ -z "${SNAP_OUTPUT}" ]
 276         then
 277                 # Set target file based on image
 278                 case "${SNAP_TYPE}" in
 279                         cpio)
 280                                 DEST="${MOUNTP}/live-sn.cpio.gz"
 281                                 ;;
 282
 283                         squashfs|jffs2|ext2)
 284                                 DEST="${MOUNTP}/live-sn.${SNAP_TYPE}"
 285                                 ;;
 286
 287                         ext3)
 288                                 DEST="${MOUNTP}/live-sn.ext2"
 289                                 ;;
 290
 291                         ext4)
 292                                 DEST="${MOUNTP}/live-sn.ext4"
 293                                 ;;
 294                 esac
 295         else
 296                 DEST="${SNAP_OUTPUT}"
 297         fi
 298 }
 299
 300 Validate_input ()
 301 {
 302         case "${SNAP_TYPE}" in
 303                 cpio|squashfs|jffs2|ext2|ext3|ext4|whole_partition)
 304                         ;;
 305
 306                 *)
 307                         Error "invalid filesystem type \"${SNAP_TYPE}\""
 308                         ;;
 309         esac
 310
 311         if [ ! -d "${SNAP_COW}" ]
 312         then
 313                 Error "${SNAP_COW} is not a directory"
 314         fi
 315
 316         if [ "$(id -u)" -ne 0 ]
 317         then
 318                 Error "you are not root"
 319         fi
 320 }
 321
 322 Mount_device ()
 323 {
 324         case "${SNAP_DEV}" in
 325                 "")
 326                         # create a temp
 327                         mount -t tmpfs -o rw tmpfs "${MOUNTP}"
 328                         ;;
 329
 330                 *)
 331                         if [ -b "${SNAP_DEV}" ]
 332                         then
 333                                 try_mount "${SNAP_DEV}" "${MOUNTP}" rw
 334                         fi
 335                         ;;
 336         esac
 337 }
 338
 339 Entry_is_modified ()
 340 {
 341         # Returns true if file exists and it is also present in "cow" directory
 342         # This means it is modified in respect to read-only media, so it deserve
 343         # to be saved
 344
 345         entry="${1}"
 346
 347         if [ -e "${entry}" ] || [ -L "${entry}" ]
 348         then
 349                 if [ -e "${DEF_SNAP_COW}/${entry}" ] || [ -L "${DEF_SNAP_COW}/${entry}" ]
 350                 then
 351                         return 0
 352                 fi
 353         fi
 354         return 1
 355 }
 356
 357 Do_filelist ()
 358 {
 359         # BUGS: supports only cpio.gz types, and does not handle deleted files yet
 360
 361         TMP_FILELIST=$1
 362         if [ -f "${SNAP_LIST}" ]
 363         then
 364                 # Generate include list removing empty and commented lines
 365                 for entry in $(sed -e '/^ *$/d' -e '/^#.*$/d' "${SNAP_LIST}")
 366                 do
 367                         if [ -d "${entry}" ]
 368                         then
 369                                 cd /
 370                                 find "${entry}" | while read line
 371                                 do
 372                                         if Entry_is_modified "${line}"
 373                                         then
 374                                                 printf "%s\000" "${line}" >> "${TMP_FILELIST}"
 375                                         fi
 376                                 done
 377                                 cd "${OLDPWD}"
 378                         elif Entry_is_modified "${entry}"
 379                         then
 380                                 # if file exists and it is modified
 381                                 printf "%s\000" "${entry}" >> "${TMP_FILELIST}"
 382                         fi
 383                 done
 384
 385                 if [ "${SNAP_COW}" = "${DEF_SNAP_COW}" ]
 386                 then
 387                         # Relative to rootfs
 388                         echo "/"
 389                 else
 390                         # Mostly "/home"
 391                         echo "${SNAP_COW}"
 392                 fi
 393         else
 394                 cd "${SNAP_COW}"
 395                 find . -path '*.wh.*' -prune -o -print0 >> "${TMP_FILELIST}"
 396                 cd "${OLDPWD}"
 397                 echo "${SNAP_COW}"
 398         fi
 399 }
 400
 401 Do_snapshot ()
 402 {
 403         TMP_FILELIST=$(mktemp -p "${SAFE_TMPDIR}" "${TMP_FILELIST}.XXXXXX")
 404
 405         case "${SNAP_TYPE}" in
 406                 squashfs)
 407                         echo ".${TMP_FILELIST}" > "${TMP_FILELIST}"
 408                         # Removing whiteheads of unionfs
 409                         cd "${SNAP_COW}"
 410                         find . -name '*.wh.*' >> "${TMP_FILELIST}"
 411
 412                         if [ -e "${EXCLUDE_LIST}" ]
 413                         then
 414                                 # Add explicitly excluded files
 415                                 grep -v '^#.*$' "${EXCLUDE_LIST}" | grep -v '^ *$' >> "${TMP_FILELIST}"
 416                         fi
 417
 418                         cd "${OLDPWD}"
 419                         mksquashfs "${SNAP_COW}" "${DEST}" -ef "${TMP_FILELIST}"
 420                         ;;
 421
 422                 cpio|whole_partition)
 423                         if [ "${SNAP_TYPE}" = "cpio" ]
 424                         then
 425                                 COPY_CMD="cpio --quiet -o0 -H newc | gzip -9c > ${DEST}"
 426                         else
 427                                 COPY_CMD="cpio --quiet -pumd0 ${DEST}/"
 428                         fi
 429
 430                         WORKING_DIR=$(Do_filelist "${TMP_FILELIST}")
 431                         cd "${WORKING_DIR}"
 432                         if [ -e "${EXCLUDE_LIST}" ]
 433                         then
 434                                 # Convert \0 to \n and tag existing (rare but possible) \n in filenames,
 435                                 # this to let grep -F -v do a proper work in filtering out
 436                                 cat "${TMP_FILELIST}" | \
 437                                         tr '\n' '\1' | \
 438                                         tr '\0' '\n' | \
 439                                         grep -F -v -f "${EXCLUDE_LIST}" | \
 440                                         tr '\n' '\0' | \
 441                                         tr '\1' '\n' | \
 442                                         $COPY_CMD || exit 1
 443                         else
 444                                 cat "${TMP_FILELIST}" | \
 445                                         $COPY_CMD || exit 1
 446                         fi
 447                         cd "${OLDPWD}"
 448                         ;;
 449
 450                 # ext2|ext3|ext4 and jffs2 does not easily support an exclude list; files
 451                 # should be copied to another directory in order to filter content
 452                 ext2|ext3|ext4)
 453                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 454                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 455                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-percentage=0 --root="${SNAP_COW}" "${DEST}"
 456                         ;;
 457
 458                 jffs2)
 459                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 460                         ;;
 461         esac
 462
 463         if [ -f "${TMP_FILELIST}" ]
 464         then
 465                 rm -f "${TMP_FILELIST}"
 466         fi
 467 }
 468
 469 Clean ()
 470 {
 471         if [ -z "${SNAP_RESYNC_STRING}" ] && echo "${DEST}" | grep -q "${MOUNTP}"
 472         then
 473                 echo "${DEST} is present on ${MOUNTP}, therefore no automatic unmounting the latter." > /dev/null 1>&2
 474         else
 475                 umount "${MOUNTP}"
 476                 rmdir "${MOUNTP}"
 477         fi
 478 }
 479
 480 Warn_user ()
 481 {
 482         if [ -z "${SNAP_RESYNC_STRING}" ]
 483         then
 484                 case ${SNAP_TYPE} in
 485                         cpio|ext2|ext3|ext4)
 486                                 echo "Please move ${DEST} (if is not already in it)" > /dev/null 1>&2
 487                                 echo "in a supported writable partition (e.g ext3, vfat)." > /dev/null 1>&2
 488                                 ;;
 489
 490                         squashfs)
 491                                 echo "To use ${DEST} you need to rebuild your media or add it" > /dev/null 1>&2
 492                                 echo "to your multisession disc under the \"/live\" directory." > /dev/null 1>&2
 493                                 ;;
 494
 495                         jffs2)
 496                                 echo "Please cat or flashcp ${DEST} to your partition in order to start using it." > /dev/null 1>&2
 497                                 ;;
 498                 esac
 499
 500                 if grep -qv persistent /proc/cmdline
 501                 then
 502                         echo "Remember to boot this live system with \"persistent\" specified at boot prompt." > /dev/null 1>&2
 503                 fi
 504         fi
 505 }
 506
 507 Main ()
 508 {
 509         Parse_args "${@}"
 510         Defaults
 511         Validate_input
 512         trap 'Clean' EXIT
 513         Mount_device
 514         Do_snapshot
 515         Warn_user
 516 }
 517
 518 Main "${@:-}"