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