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 $MOUNTP
   6 #   and saves the /live/cow (or a different directory) filesystem in it
   7 #   for reuse in another live-boot session.
   8 #   Look at the manpage for more informations.
   9 #
  10 # Copyright (C) 2006-2008 Marco Amadori <marco.amadori@gmail.com>
  11 # Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>
  12 #
  13 # This program is free software: you can redistribute it and/or modify
  14 # it under the terms of the GNU General Public License as published by
  15 # the Free Software Foundation, either version 3 of the License, or
  16 # (at your option) any later version.
  17 #
  18 # This program is distributed in the hope that it will be useful,
  19 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  21 # GNU General Public License for more details.
  22 #
  23 # You should have received a copy of the GNU General Public License
  24 # along with this program. If not, see <http://www.gnu.org/licenses/>.
  25 #
  26 # On Debian systems, the complete text of the GNU General Public License
  27 # can be found in /usr/share/common-licenses/GPL-3 file.
  28
  29 # declare here two vars from /etc/live.conf because of "set -u"
  30 ROOTSNAP=""
  31 HOMESNAP=""
  32
  33 if [ -n "${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}" | sed -e 's|^/root\([^:.]*\).*$|'"${DEF_SNAP_COW}"'\1|')
 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 "${SNAP_COW}/${entry}" ] || [ -L "${SNAP_COW}/${entry}" ]
 350                 then
 351                         return 0
 352                 fi
 353         fi
 354         return 1
 355 }
 356
 357 Do_filelist ()
 358 {
 359         # BUGS: does not handle deleted files yet
 360         TMP_FILELIST=$1
 361
 362         if [ -f "${SNAP_LIST}" ]
 363         then
 364                 # if SNAP_COW == /live/cow/home, SNAP_RW = /home
 365                 SNAP_RW=$(echo "${SNAP_COW}" | sed -e "s|${DEF_SNAP_COW}||g")
 366                 if [ -z "${SNAP_RW}" ]
 367                 then
 368                         SNAP_RW="/"
 369                 fi
 370
 371                 cd "${SNAP_RW}"
 372                 # Generate include list removing empty and commented lines
 373                 # and transforming paths to relatives
 374                 for entry in $(sed -e '/^ *$/d' -e '/^#.*$/d' -e 's#^.*$#./&#' -e 's#/\+#/#g' "${SNAP_LIST}")
 375                 do
 376                         if [ -d "${entry}" ]
 377                         then
 378                                 find "${entry}" | while read line
 379                                 do
 380                                         if Entry_is_modified "${line}"
 381                                         then
 382                                                 printf "%s\000" "${line}" >> "${TMP_FILELIST}"
 383                                         fi
 384                                 done
 385                         elif Entry_is_modified "${entry}"
 386                         then
 387                                 # if file exists and it is modified
 388                                 printf "%s\000" "${entry}" >> "${TMP_FILELIST}"
 389                         fi
 390                 done
 391                 cd "${OLDPWD}"
 392
 393                 # echo Working dir
 394                 echo "${SNAP_RW}"
 395         else
 396                 cd "${SNAP_COW}"
 397                 # removing whiteouts from list
 398                 find . -path '*.wh.*' -prune -o -print0 >> "${TMP_FILELIST}"
 399                 cd "${OLDPWD}"
 400                 # echo Working dir
 401                 echo "${SNAP_COW}"
 402         fi
 403 }
 404
 405 Do_snapshot ()
 406 {
 407         TMP_FILELIST=$(mktemp -p "${SAFE_TMPDIR}" "${TMP_FILELIST}.XXXXXX")
 408
 409         case "${SNAP_TYPE}" in
 410                 squashfs)
 411                         echo ".${TMP_FILELIST}" > "${TMP_FILELIST}"
 412                         # Removing whiteheads of unionfs
 413                         cd "${SNAP_COW}"
 414                         find . -name '*.wh.*' >> "${TMP_FILELIST}"
 415
 416                         if [ -e "${EXCLUDE_LIST}" ]
 417                         then
 418                                 # Add explicitly excluded files
 419                                 grep -v '^#.*$' "${EXCLUDE_LIST}" | grep -v '^ *$' >> "${TMP_FILELIST}"
 420                         fi
 421
 422                         cd "${OLDPWD}"
 423                         mksquashfs "${SNAP_COW}" "${DEST}" -ef "${TMP_FILELIST}"
 424                         ;;
 425
 426                 cpio|whole_partition)
 427                         if [ "${SNAP_TYPE}" = "cpio" ]
 428                         then
 429                                 COPY_CMD="cpio --quiet -o0 -H newc | gzip -9c > ${DEST}"
 430                         else
 431                                 COPY_CMD="cpio --quiet -pumd0 ${DEST}/"
 432                         fi
 433
 434                         WORKING_DIR=$(Do_filelist "${TMP_FILELIST}")
 435                         cd "${WORKING_DIR}"
 436                         if [ -e "${EXCLUDE_LIST}" ]
 437                         then
 438                                 # Convert \0 to \n and tag existing (rare but possible) \n in filenames,
 439                                 # this to let grep -F -v do a proper work in filtering out
 440                                 cat "${TMP_FILELIST}" | \
 441                                         tr '\n' '\1' | \
 442                                         tr '\0' '\n' | \
 443                                         grep -F -v -f "${EXCLUDE_LIST}" | \
 444                                         tr '\n' '\0' | \
 445                                         tr '\1' '\n' | \
 446                                         eval $COPY_CMD || exit 1
 447                         else
 448                                 cat "${TMP_FILELIST}" | \
 449                                         eval $COPY_CMD || exit 1
 450                         fi
 451                         cd "${OLDPWD}"
 452                         ;;
 453
 454                 # ext2|ext3|ext4 and jffs2 does not easily support an exclude list; files
 455                 # should be copied to another directory in order to filter content
 456                 ext2|ext3|ext4)
 457                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 458                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 459                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-percentage=0 --root="${SNAP_COW}" "${DEST}"
 460                         ;;
 461
 462                 jffs2)
 463                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 464                         ;;
 465         esac
 466
 467         if [ -f "${TMP_FILELIST}" ]
 468         then
 469                 rm -f "${TMP_FILELIST}"
 470         fi
 471 }
 472
 473 Clean ()
 474 {
 475         if [ -z "${SNAP_RESYNC_STRING}" ] && echo "${DEST}" | grep -q "${MOUNTP}"
 476         then
 477                 echo "${DEST} is present on ${MOUNTP}, therefore no automatic unmounting the latter." > /dev/null 1>&2
 478         else
 479                 umount "${MOUNTP}"
 480                 rmdir "${MOUNTP}"
 481         fi
 482 }
 483
 484 Warn_user ()
 485 {
 486         if [ -z "${SNAP_RESYNC_STRING}" ]
 487         then
 488                 case ${SNAP_TYPE} in
 489                         cpio|ext2|ext3|ext4)
 490                                 echo "Please move ${DEST} (if is not already in it)" > /dev/null 1>&2
 491                                 echo "in a supported writable partition (e.g ext3, vfat)." > /dev/null 1>&2
 492                                 ;;
 493
 494                         squashfs)
 495                                 echo "To use ${DEST} you need to rebuild your media or add it" > /dev/null 1>&2
 496                                 echo "to your multisession disc under the \"/live\" directory." > /dev/null 1>&2
 497                                 ;;
 498
 499                         jffs2)
 500                                 echo "Please cat or flashcp ${DEST} to your partition in order to start using it." > /dev/null 1>&2
 501                                 ;;
 502                 esac
 503
 504                 if grep -qv persistent /proc/cmdline
 505                 then
 506                         echo "Remember to boot this live system with \"persistent\" specified at boot prompt." > /dev/null 1>&2
 507                 fi
 508         fi
 509 }
 510
 511 Main ()
 512 {
 513         Parse_args "${@}"
 514         Defaults
 515         Validate_input
 516         trap 'Clean' EXIT
 517         Mount_device
 518         Do_snapshot
 519         Warn_user
 520 }
 521
 522 Main "${@:-}"