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 $MOUNTP
   6 #   and saves the /live/overlway (or a different directory) filesystem in it
   7 #   for reuse in another live-boot session.
   8 #   Look at the manpage for more informations.
   9 #
  10 # Copyright (C) 2006-2011 Marco Amadori <marco.amadori@gmail.com>
  11 # Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>
  12 #
  13 # This program is free software: you can redistribute it and/or modify
  14 # it under the terms of the GNU General Public License as published by
  15 # the Free Software Foundation, either version 3 of the License, or
  16 # (at your option) any later version.
  17 #
  18 # This program is distributed in the hope that it will be useful,
  19 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  21 # GNU General Public License for more details.
  22 #
  23 # You should have received a copy of the GNU General Public License
  24 # along with this program. If not, see <http://www.gnu.org/licenses/>.
  25 #
  26 # The complete text of the GNU General Public License
  27 # can be found in /usr/share/common-licenses/GPL-3 file.
  28
  29 # declare here two vars from /etc/live.conf because of "set -u"
  30 ROOTSNAP=""
  31 HOMESNAP=""
  32
  33 if [ -n "${LIVE_SNAPSHOT_CHECK_UNBOUND}" ]
  34 then
  35         set -eu
  36 else
  37         set -e
  38 fi
  39
  40 ## Begin FIXME: this is an embedded copy of the old 'live-helpers' initramfs script
  41 if [ ! -x "/bin/fstype" ]
  42 then
  43         # klibc not in path -> not in initramfs
  44         export PATH="${PATH}:/usr/lib/klibc/bin"
  45 fi
  46
  47 # handle upgrade path from old udev (using udevinfo) to
  48 # recent versions of udev (using udevadm info)
  49 if [ -x /sbin/udevadm ]
  50 then
  51         udevinfo='/sbin/udevadm info'
  52 else
  53         udevinfo='udevinfo'
  54 fi
  55
  56 old_root_overlay_label="live-rw"
  57 old_home_overlay_label="home-rw"
  58 custom_overlay_label="custom-ov"
  59 root_snapshot_label="live-sn"
  60 old_root_snapshot_label="live-sn"
  61 home_snapshot_label="home-sn"
  62 persistence_list="live-persistence.conf"
  63
  64 # include all scripts for the time being until snapshots are either dropped or cleaned up
  65 for _SCRIPT in /lib/live/boot/*
  66 do
  67         if [ -e "${_SCRIPT}" ]
  68         then
  69                 . ${_SCRIPT}
  70         fi
  71 done
  72 ## End FIXME: this is an embedded copy of the old 'live-helpers' initramfs script
  73
  74 LIVE_CONF="/etc/live/boot.d/snapshot.conf"
  75
  76 if [ -r "${LIVE_CONF}" ]
  77 then
  78         . "${LIVE_CONF}"
  79 fi
  80
  81 export USERNAME USERFULLNAME HOSTNAME
  82
  83 EXECUTABLE="${0}"
  84 PROGRAM=$(basename "${EXECUTABLE}")
  85
  86 # Needs to be available at run and reboot time
  87 SAFE_TMPDIR="/live"
  88
  89 # Permits multiple runs
  90 MOUNTP="$(mktemp -d -p ${SAFE_TMPDIR} live-snapshot-mnt.XXXXXX)"
  91 DEST="${MOUNTP}/live-sn.cpio.gz"
  92 DEF_SNAP_COW="/live/overlay"
  93 TMP_FILELIST="${PROGRAM}.list"
  94
  95 # Command line defaults and declarations
  96 SNAP_COW="${DEF_SNAP_COW}"
  97 SNAP_DEV=""
  98 SNAP_MNT=""
  99 SNAP_OUTPUT=""
 100 SNAP_RESYNC_STRING=""
 101 SNAP_TYPE="cpio"
 102 SNAP_LIST="/etc/live-snapshot.list"
 103 EXCLUDE_LIST="/etc/live-snapshot.exclude_list"
 104
 105 Error ()
 106 {
 107         echo "${PROGRAM}: error:" ${@}
 108         exit 1
 109 }
 110
 111 panic ()
 112 {
 113         Error ${@}
 114 }
 115
 116 Header ()
 117 {
 118         echo "${PROGRAM} - utility to perform snapshots of Debian Live systems"
 119         echo
 120         echo "usage: ${PROGRAM} [-c|--cow DIRECTORY] [-d|--device DEVICE] [-o|--output FILE] [-t|--type TYPE]"
 121         echo "       ${PROGRAM} [-r|--resync-string STRING]"
 122         echo "       ${PROGRAM} [-f|--refresh]"
 123         echo "       ${PROGRAM} [-h|--help]"
 124         echo "       ${PROGRAM} [-u|--usage]"
 125         echo "       ${PROGRAM} [-v|--version]"
 126 }
 127
 128 Help ()
 129 {
 130         Header
 131
 132         echo
 133         echo "Options:"
 134         echo "  -c, --cow: copy on write directory (default: ${SNAP_COW})."
 135         echo "  -d, --device: output snapshot device (default: ${SNAP_DEV:-auto})."
 136         echo "  -o, --output: output image file (default: ${DEST})."
 137         echo "  -r, --resync-string: internally used to resync previous made snapshots."
 138         echo "  -f, --refresh: try to sync a running snapshot."
 139         echo "  -t, --type: snapshot filesystem type. Options: \"squashfs\", \"ext2\", \"ext3\", \"ext4\", \"jffs2\" or \"cpio\".gz archive (default: ${SNAP_TYPE})"
 140         echo
 141         echo "Look at live-snapshot(1) man page for more information."
 142
 143         exit 0
 144 }
 145
 146 Usage ()
 147 {
 148         Header
 149
 150         echo
 151         echo "Try \"${PROGRAM} --help\" for more information."
 152
 153         exit 0
 154 }
 155
 156 Version ()
 157 {
 158         echo "${PROGRAM}"
 159         echo
 160         echo "Copyright (C) 2006-2011 Marco Amadori <marco.amadori@gmail.com>"
 161         echo "Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>"
 162         echo
 163         echo "This program is free software; you can redistribute it and/or modify"
 164         echo "it under the terms of the GNU General Public License as published by"
 165         echo "the Free Software Foundation; either version 3 of the License, or"
 166         echo "(at your option) any later version."
 167         echo
 168         echo "This program is distributed in the hope that it will be useful,"
 169         echo "but WITHOUT ANY WARRANTY; without even the implied warranty of"
 170         echo "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the"
 171         echo "GNU General Public License for more details."
 172         echo
 173         echo "You should have received a copy of the GNU General Public License"
 174         echo "along with this program; if not, write to the Free Software"
 175         echo "Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA"
 176         echo
 177         echo "The complete text of the GNU General Public License"
 178         echo "can be found in /usr/share/common-licenses/GPL-3 file."
 179         echo
 180         echo "Homepage: <http://live.debian.net/>"
 181
 182         exit 0
 183 }
 184
 185 Try_refresh ()
 186 {
 187         FOUND=""
 188         if [ -n "${ROOTSNAP}" ]; then
 189                 "${EXECUTABLE}" --resync-string="${ROOTSNAP}"
 190                 FOUND="true"
 191         fi
 192
 193         if [ -n "${HOMESNAP}" ]; then
 194                 "${EXECUTABLE}" --resync-string="${HOMESNAP}"
 195                 FOUND="true"
 196         fi
 197
 198         if [ -z "${FOUND}" ]
 199         then
 200                 echo "No autoconfigured snapshots found at boot;" > /dev/null 1>&2
 201                 echo "(no resync string in ${LIVE_CONF})." > /dev/null 1>&2
 202                 exit 1
 203         fi
 204 }
 205
 206 Parse_args ()
 207 {
 208         # Parse command line
 209         ARGS="${*}"
 210         ARGUMENTS="$(getopt --longoptions cow:,device:,output,resync-string:,refresh,type:,help,usage,version --name=${PROGRAM} --options c:d:o:t:r:fhuv --shell sh -- ${ARGS})"
 211
 212         eval set -- "${ARGUMENTS}"
 213
 214         while true
 215         do
 216                 case "${1}" in
 217                         -c|--cow)
 218                                 SNAP_COW="${2}"
 219                                 shift 2
 220                                 ;;
 221
 222                         -d|--device)
 223                                 SNAP_DEV="${2}"
 224                                 shift 2
 225                                 ;;
 226
 227                         -o|--output)
 228                                 SNAP_OUTPUT="${2}"
 229                                 shift 2
 230                                 ;;
 231
 232                         -t|--type)
 233                                 SNAP_TYPE="${2}"
 234                                 shift 2
 235                                 ;;
 236
 237                         -r|--resync-string)
 238                                 SNAP_RESYNC_STRING="${2}"
 239                                 break
 240                                 ;;
 241
 242                         -f|--refresh)
 243                                 Try_refresh
 244                                 exit 0
 245                                 ;;
 246
 247                         -h|--help)
 248                                 Help
 249                                 ;;
 250
 251                         -u|--usage)
 252                                 Usage
 253                                 ;;
 254
 255                         -v|--version)
 256                                 Version
 257                                 ;;
 258
 259                         --)
 260                                 shift
 261                                 break
 262                                 ;;
 263
 264                         *)
 265                                 Error "internal error."
 266                                 ;;
 267
 268                 esac
 269         done
 270 }
 271
 272 Defaults ()
 273 {
 274         # Parse resync string
 275         if [ -n "${SNAP_RESYNC_STRING}" ]
 276         then
 277                 SNAP_COW=$(echo "${SNAP_RESYNC_STRING}" | sed -r -e 's#^([^:]*).*$#'"${DEF_SNAP_COW}"'\1#')
 278                 SNAP_DEV=$(echo "${SNAP_RESYNC_STRING}" | cut -f2 -d ':')
 279                 SNAP_MNT=$(echo "${SNAP_RESYNC_STRING}" | cut -f3 -d ':')
 280                 DEST="${MOUNTP}/${SNAP_MNT}"
 281
 282                 case "${SNAP_MNT}" in
 283                         *.cpio.gz)
 284                                 SNAP_TYPE="cpio"
 285                                 ;;
 286
 287                         *.squashfs)
 288                                 SNAP_TYPE="squashfs"
 289                                 ;;
 290
 291                         *.jffs2)
 292                                 SNAP_TYPE="jffs2"
 293                                 ;;
 294
 295                         *.ext2|*.ext3)
 296                                 SNAP_TYPE="ext2"
 297                                 ;;
 298
 299                         "")
 300                                 SNAP_TYPE="whole_partition"
 301                                 ;;
 302
 303                         *.ext4)
 304                                 SNAP_TYPE="ext4"
 305                                 ;;
 306
 307                         *)
 308                                 Error "unrecognized resync string"
 309                                 ;;
 310                 esac
 311         elif [ -z "${SNAP_OUTPUT}" ]
 312         then
 313                 # Set target file based on image
 314                 case "${SNAP_TYPE}" in
 315                         cpio)
 316                                 DEST="${MOUNTP}/live-sn.cpio.gz"
 317                                 ;;
 318
 319                         squashfs|jffs2|ext2)
 320                                 DEST="${MOUNTP}/live-sn.${SNAP_TYPE}"
 321                                 ;;
 322
 323                         ext3)
 324                                 DEST="${MOUNTP}/live-sn.ext2"
 325                                 ;;
 326
 327                         ext4)
 328                                 DEST="${MOUNTP}/live-sn.ext4"
 329                                 ;;
 330                 esac
 331         else
 332                 DEST="${SNAP_OUTPUT}"
 333         fi
 334 }
 335
 336 Validate_input ()
 337 {
 338         case "${SNAP_TYPE}" in
 339                 cpio|squashfs|jffs2|ext2|ext3|ext4|whole_partition)
 340                         ;;
 341
 342                 *)
 343                         Error "invalid filesystem type \"${SNAP_TYPE}\""
 344                         ;;
 345         esac
 346
 347         if [ ! -d "${SNAP_COW}" ]
 348         then
 349                 Error "${SNAP_COW} is not a directory"
 350         fi
 351
 352         if [ "$(id -u)" -ne 0 ]
 353         then
 354                 Error "you are not root"
 355         fi
 356 }
 357
 358 Mount_device ()
 359 {
 360         case "${SNAP_DEV}" in
 361                 "")
 362                         # create a temp
 363                         mount -t tmpfs -o rw tmpfs "${MOUNTP}"
 364                         ;;
 365
 366                 *)
 367                         if [ -b "${SNAP_DEV}" ]
 368                         then
 369                                 try_mount "${SNAP_DEV}" "${MOUNTP}" rw
 370                         fi
 371                         ;;
 372         esac
 373 }
 374
 375 Entry_is_modified ()
 376 {
 377         # Returns true if file exists and it is also present in "cow" directory
 378         # This means it is modified in respect to read-only media, so it deserve
 379         # to be saved
 380
 381         entry="${1}"
 382
 383         if [ -e "${entry}" ] || [ -L "${entry}" ]
 384         then
 385                 if [ -e "${SNAP_COW}/${entry}" ] || [ -L "${SNAP_COW}/${entry}" ]
 386                 then
 387                         return 0
 388                 fi
 389         fi
 390         return 1
 391 }
 392
 393 Do_filelist ()
 394 {
 395         # BUGS: does not handle deleted files yet
 396         TMP_FILELIST=$1
 397
 398         if [ -f "${SNAP_LIST}" ]
 399         then
 400                 # if SNAP_COW == /live/overlay/home, SNAP_RW = /home
 401                 SNAP_RW=$(echo "${SNAP_COW}" | sed -e "s|${DEF_SNAP_COW}||g")
 402                 if [ -z "${SNAP_RW}" ]
 403                 then
 404                         SNAP_RW="/"
 405                 fi
 406
 407                 cd "${SNAP_RW}"
 408                 # Generate include list removing empty and commented lines
 409                 # and transforming paths to relatives
 410                 for entry in $(sed -e '/^ *$/d' -e '/^#.*$/d' -e 's#^.*$#./&#' -e 's#/\+#/#g' "${SNAP_LIST}")
 411                 do
 412                         if [ -d "${entry}" ]
 413                         then
 414                                 find "${entry}" | while read line
 415                                 do
 416                                         if Entry_is_modified "${line}"
 417                                         then
 418                                                 printf "%s\000" "${line}" >> "${TMP_FILELIST}"
 419                                         fi
 420                                 done
 421                         elif Entry_is_modified "${entry}"
 422                         then
 423                                 # if file exists and it is modified
 424                                 printf "%s\000" "${entry}" >> "${TMP_FILELIST}"
 425                         fi
 426                 done
 427                 cd "${OLDPWD}"
 428
 429                 # echo Working dir
 430                 echo "${SNAP_RW}"
 431         else
 432                 cd "${SNAP_COW}"
 433                 # removing whiteouts from list
 434                 find . -path '*.wh.*' -prune -o -print0 >> "${TMP_FILELIST}"
 435                 cd "${OLDPWD}"
 436                 # echo Working dir
 437                 echo "${SNAP_COW}"
 438         fi
 439 }
 440
 441 Do_snapshot ()
 442 {
 443         TMP_FILELIST=$(mktemp -p "${SAFE_TMPDIR}" "${TMP_FILELIST}.XXXXXX")
 444         if [ -e "${EXCLUDE_LIST}" ]
 445         then
 446                 # Create a TMP filelist removing empty lines (grep -f does not like them)
 447                 # and comments (for speedup and LST)
 448                 TMP_EXCLUDE_LIST=$(mktemp -p "${SAFE_TMPDIR}" "${PROGRAM}_excludelist.XXXXXX")
 449                 grep -v '^#.*$' "${EXCLUDE_LIST}" | grep -v '^ *$' > "${TMP_EXCLUDE_LIST}"
 450         fi
 451
 452         case "${SNAP_TYPE}" in
 453                 squashfs)
 454                         echo ".${TMP_FILELIST}" > "${TMP_FILELIST}"
 455                         # Removing whiteheads of unionfs
 456                         cd "${SNAP_COW}"
 457                         find . -name '*.wh.*' >> "${TMP_FILELIST}"
 458
 459                         if [ -e "${EXCLUDE_LIST}" ]
 460                         then
 461                                 # Add explicitly excluded files
 462                                 cat "${TMP_EXCLUDE_LIST}" >> "${TMP_FILELIST}"
 463                         fi
 464
 465                         cd "${OLDPWD}"
 466                         mksquashfs "${SNAP_COW}" "${DEST}" -ef "${TMP_FILELIST}"
 467                         ;;
 468
 469                 cpio|whole_partition)
 470                         if [ "${SNAP_TYPE}" = "cpio" ]
 471                         then
 472                                 COPY_CMD="cpio --quiet -o0 -H newc | gzip -9c > ${DEST}"
 473                         else
 474                                 COPY_CMD="cpio --quiet -pumd0 ${DEST}/"
 475                         fi
 476
 477                         WORKING_DIR=$(Do_filelist "${TMP_FILELIST}")
 478                         cd "${WORKING_DIR}"
 479                         if [ -e "${EXCLUDE_LIST}" ]
 480                         then
 481
 482                                 # Convert \0 to \n and tag existing (rare but possible) \n in filenames,
 483                                 # this to let grep -F -v do a proper work in filtering out
 484                                 cat "${TMP_FILELIST}" | \
 485                                         tr '\n' '\1' | \
 486                                         tr '\0' '\n' | \
 487                                         grep -F -v -f "${TMP_EXCLUDE_LIST}" | \
 488                                         tr '\n' '\0' | \
 489                                         tr '\1' '\n' | \
 490                                         eval $COPY_CMD || exit 1
 491                         else
 492                                 cat "${TMP_FILELIST}" | \
 493                                         eval $COPY_CMD || exit 1
 494                         fi
 495                         cd "${OLDPWD}"
 496                         ;;
 497
 498                 # ext2|ext3|ext4 and jffs2 does not easily support an exclude list; files
 499                 # should be copied to another directory in order to filter content
 500                 ext2|ext3|ext4)
 501                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 502                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 503                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-percentage=0 --root="${SNAP_COW}" "${DEST}"
 504                         ;;
 505
 506                 jffs2)
 507                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 508                         ;;
 509         esac
 510
 511         # Remove temporary file lists
 512         for filelist in "${TMP_FILELIST}" "${TMP_EXCLUDE_LIST}"
 513         do
 514                 if [ -f "${filelist}" ]
 515                 then
 516                         rm -f "${filelist}"
 517                 fi
 518         done
 519 }
 520
 521 Clean ()
 522 {
 523         if [ -z "${SNAP_RESYNC_STRING}" ] && echo "${DEST}" | grep -q "${MOUNTP}"
 524         then
 525                 echo "${DEST} is present on ${MOUNTP}, therefore no automatic unmounting the latter." > /dev/null 1>&2
 526         else
 527                 umount "${MOUNTP}"
 528                 rmdir "${MOUNTP}"
 529         fi
 530 }
 531
 532 Warn_user ()
 533 {
 534         if [ -z "${SNAP_RESYNC_STRING}" ]
 535         then
 536                 case ${SNAP_TYPE} in
 537                         cpio|ext2|ext3|ext4)
 538                                 echo "Please move ${DEST} (if is not already in it)" > /dev/null 1>&2
 539                                 echo "in a supported writable partition (e.g ext3, vfat)." > /dev/null 1>&2
 540                                 ;;
 541
 542                         squashfs)
 543                                 echo "To use ${DEST} you need to rebuild your media or add it" > /dev/null 1>&2
 544                                 echo "to your multisession disc under the \"/live\" directory." > /dev/null 1>&2
 545                                 ;;
 546
 547                         jffs2)
 548                                 echo "Please cat or flashcp ${DEST} to your partition in order to start using it." > /dev/null 1>&2
 549                                 ;;
 550                 esac
 551
 552                 if grep -qv persistence /proc/cmdline
 553                 then
 554                         echo "Remember to boot this live system with \"persistence\" specified at boot prompt." > /dev/null 1>&2
 555                 fi
 556         fi
 557 }
 558
 559 Main ()
 560 {
 561         Parse_args "${@}"
 562         Defaults
 563         Validate_input
 564         trap 'Clean' EXIT
 565         Mount_device
 566         Do_snapshot
 567         Warn_user
 568 }
 569
 570 Main "${@:-}"