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\", \"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                                 Error "unrecognized resync string"
 262                                 ;;
 263                 esac
 264         elif [ -z "${SNAP_OUTPUT}" ]
 265         then
 266                 # Set target file based on image
 267                 case "${SNAP_TYPE}" in
 268                         cpio)
 269                                 DEST="${MOUNTP}/live-sn.cpio.gz"
 270                                 ;;
 271
 272                         squashfs|jffs2|ext2)
 273                                 DEST="${MOUNTP}/live-sn.${SNAP_TYPE}"
 274                                 ;;
 275
 276                         ext3)
 277                                 DEST="${MOUNTP}/live-sn.ext2"
 278                                 ;;
 279                 esac
 280         else
 281                 DEST="${SNAP_OUTPUT}"
 282         fi
 283 }
 284
 285 Validate_input ()
 286 {
 287         case "${SNAP_TYPE}" in
 288                 cpio|squashfs|jffs2|ext2|ext3)
 289                         ;;
 290
 291                 *)
 292                         Error "invalid filesystem type \"${SNAP_TYPE}\""
 293                         ;;
 294         esac
 295
 296         if [ ! -d "${SNAP_COW}" ]
 297         then
 298                 Error "${SNAP_COW} is not a directory"
 299         fi
 300
 301         if [ "$(id -u)" -ne 0 ]
 302         then
 303                 Error "you are not root"
 304         fi
 305 }
 306
 307 Mount_device ()
 308 {
 309         case "${SNAP_DEV}" in
 310                 "")
 311                         # create a temp
 312                         mount -t tmpfs -o rw tmpfs "${MOUNTP}"
 313                         ;;
 314
 315                 *)
 316                         if [ -b "${SNAP_DEV}" ]
 317                         then
 318                                 try_mount "${SNAP_DEV}" "${MOUNTP}" rw
 319                         fi
 320                         ;;
 321         esac
 322 }
 323
 324 Entry_is_modified ()
 325 {
 326         # Returns true if file exists and it is also present in "cow" directory
 327         # This means it is modified in respect to read-only media, so it deserve
 328         # to be saved
 329
 330         entry="${1}"
 331
 332         if [ -e "${entry}" ] || [ -L "${entry}" ]
 333         then
 334                 if [ -e "${DEF_SNAP_COW}/${entry}" ] || [ -L "${DEF_SNAP_COW}/${entry}" ]
 335                 then
 336                         return 0
 337                 fi
 338         fi
 339         return 1
 340 }
 341
 342 Do_filelist ()
 343 {
 344         # BUGS: supports only cpio.gz types, and do not handle deleted files yet
 345
 346         TMP_FILELIST=$1
 347         if [ -f "${SNAP_LIST}" ]
 348         then
 349                 # Generate include list
 350                 for entry in $(cat "${SNAP_LIST}" | grep -v '^#.*$' | grep -v '^ *$')
 351                 do
 352                         if [ -d "${entry}" ]
 353                         then
 354                                 cd /
 355                                 find "${entry}" | while read line
 356                                 do
 357                                         if Entry_is_modified "${line}"
 358                                         then
 359                                                 printf "%s\000" "${line}" >> "${TMP_FILELIST}"
 360                                         fi
 361                                 done
 362                                 cd "${OLDPWD}"
 363                         elif Entry_is_modified "${entry}"
 364                         then
 365                                 # if file exists and it is modified
 366                                 printf "%s\000" "${entry}" >> "${TMP_FILELIST}"
 367                         fi
 368                 done
 369
 370                 if [ "${SNAP_COW}" = "${DEF_SNAP_COW}" ]
 371                 then
 372                         # Relative to rootfs
 373                         echo "/"
 374                 else
 375                         # Mostly "/home"
 376                         echo "${SNAP_COW}"
 377                 fi
 378         else
 379                 cd "${SNAP_COW}"
 380                 find . -path '*.wh.*' -prune -o -print0 >> "${TMP_FILELIST}"
 381                 cd "${OLDPWD}"
 382                 echo "${SNAP_COW}"
 383         fi
 384 }
 385
 386 Do_snapshot ()
 387 {
 388         TMP_FILELIST=$(mktemp -p "${SAFE_TMPDIR}" "${TMP_FILELIST}.XXXXXX")
 389
 390         case "${SNAP_TYPE}" in
 391                 squashfs)
 392                         echo ".${TMP_FILELIST}" > "${TMP_FILELIST}"
 393                         # Removing whiteheads of unionfs
 394                         cd "${SNAP_COW}"
 395                         find . -name '*.wh.*' >> "${TMP_FILELIST}"
 396
 397                         if [ -e "${EXCLUDE_LIST}" ]
 398                         then
 399                                 # Add explicitly excluded files
 400                                 cat "${EXCLUDE_LIST}" | grep -v '^#.*$' | grep -v '^ *$' >> "${TMP_FILELIST}"
 401                         fi
 402
 403                         cd "${OLDPWD}"
 404                         mksquashfs "${SNAP_COW}" "${DEST}" -ef "${TMP_FILELIST}"
 405                         ;;
 406
 407                 cpio)
 408                         WORKING_DIR=$(Do_filelist "${TMP_FILELIST}")
 409                         cd "${WORKING_DIR}"
 410                         if [ -e "${EXCLUDE_LIST}" ]
 411                         then
 412                                 # Convert \0 to \n and tag existing (rare but possible) \n in filenames,
 413                                 # this to let grep -F -v do a proper work in filtering out
 414                                 cat "${TMP_FILELIST}" | tr '\n' '\1' | tr '\0' '\n' | grep -F -v -f "${EXCLUDE_LIST}" | tr '\n' '\0' | tr '\1' '\n' | cpio --quiet -o0 -H newc | gzip -9c > "${DEST}" || exit 1
 415                         else
 416                                 cat "${TMP_FILELIST}" | cpio --quiet -o0 -H newc | gzip -9c > "${DEST}" || exit 1
 417                         fi
 418                         cd "${OLDPWD}"
 419                         ;;
 420
 421                 # ext2|ext3 and jffs2 does not support easely an exclude list, files should be copied in another directory in order to filter content
 422                 ext2|ext3)
 423                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 424                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 425                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-percentage=0 --root="${SNAP_COW}" "${DEST}"
 426                         ;;
 427
 428                 jffs2)
 429                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 430                         ;;
 431         esac
 432
 433         if [ -f "${TMP_FILELIST}" ]
 434         then
 435                 rm -f "${TMP_FILELIST}"
 436         fi
 437 }
 438
 439 Clean ()
 440 {
 441         if [ -z "${SNAP_RESYNC_STRING}" ] && echo "${DEST}" | grep -q "${MOUNTP}"
 442         then
 443                 echo "${DEST} is present on ${MOUNTP}, therefore no automatic unmounting the latter." > /dev/null 1>&2
 444         else
 445                 umount "${MOUNTP}"
 446                 rmdir "${MOUNTP}"
 447         fi
 448 }
 449
 450 Warn_user ()
 451 {
 452         if [ -z "${SNAP_RESYNC_STRING}" ]
 453         then
 454                 case ${SNAP_TYPE} in
 455                         cpio|ext2|ext3)
 456                                 echo "Please move ${DEST} (if is not already in it)" > /dev/null 1>&2
 457                                 echo "in a supported writable partition (e.g ext3, vfat)." > /dev/null 1>&2
 458                                 ;;
 459
 460                         squashfs)
 461                                 echo "To use ${DEST} you need to rebuild your media or add it" > /dev/null 1>&2
 462                                 echo "to your multisession disc under the \"/live\" directory." > /dev/null 1>&2
 463                                 ;;
 464
 465                         jffs2)
 466                                 echo "Please cat or flashcp ${DEST} to your partition in order to start using it." > /dev/null 1>&2
 467                                 ;;
 468                 esac
 469
 470                 if grep -qv persistent /proc/cmdline
 471                 then
 472                         echo "Remember to boot this live system with \"persistent\" specified at boot prompt." > /dev/null 1>&2
 473                 fi
 474         fi
 475 }
 476
 477 Main ()
 478 {
 479         Parse_args "${@}"
 480         Defaults
 481         Validate_input
 482         trap 'Clean' EXIT
 483         Mount_device
 484         Do_snapshot
 485         Warn_user
 486 }
 487
 488 Main "${@:-}"