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