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