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 Do_filelist ()
 324 {
 325         # BUGS: supports only cpio.gz types right now
 326         TMP_FILELIST=$1
 327         if [ -f "${SNAP_LIST}" ]
 328         then
 329                 # Generate include list
 330                 for entry in $(cat "${SNAP_LIST}" | grep -v '^#.*$' | grep -v '^ *$')
 331                 do
 332                         if [ -f "${entry}" ]
 333                         then
 334                                 printf "%s\000" "${entry}" >> "${TMP_FILELIST}"
 335                         elif [ -d "${entry}" ]
 336                         then
 337                                 cd /
 338                                 find "${entry}" -print0 >> "${TMP_FILELIST}"
 339                                 cd "${OLDPWD}"
 340                         fi
 341                 done
 342
 343                 if [ "${SNAP_COW}" = "${DEF_SNAP_COW}" ]
 344                 then
 345                         # Relative to rootfs
 346                         echo "/"
 347                 else
 348                         # Mostly "/home"
 349                         echo "${SNAP_COW}"
 350                 fi
 351         else
 352                 cd "${SNAP_COW}"
 353                 find . -path '*.wh.*' -prune -o -print0 >> "${TMP_FILELIST}"
 354                 cd "${OLDPWD}"
 355                 echo "${SNAP_COW}"
 356         fi
 357 }
 358
 359 Do_snapshot ()
 360 {
 361         TMP_FILELIST=$(mktemp -p "${SAFE_TMPDIR}" "${TMP_FILELIST}.XXXXXX")
 362
 363         case "${SNAP_TYPE}" in
 364                 squashfs)
 365                         echo ".${TMP_FILELIST}" > "${TMP_FILELIST}"
 366                         # Removing whiteheads of unionfs
 367                         cd "${SNAP_COW}"
 368                         find . -name '*.wh.*' >> "${TMP_FILELIST}"
 369                         cd "${OLDPWD}"
 370                         mksquashfs "${SNAP_COW}" "${DEST}" -ef "${TMP_FILELIST}"
 371                         ;;
 372
 373                 cpio)
 374                         WORKING_DIR=$(Do_filelist "${TMP_FILELIST}")
 375                         cd "${WORKING_DIR}"
 376                         cat "${TMP_FILELIST}" | cpio --quiet -o0 -H newc | gzip -9c > "${DEST}" || exit 1
 377                         cd "${OLDPWD}"
 378                         ;;
 379
 380                 ext2|ext3)
 381                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 382                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 383                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-percentage=0 --root="${SNAP_COW}" "${DEST}"
 384                         ;;
 385
 386                 jffs2)
 387                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 388                         ;;
 389         esac
 390
 391         if [ -f "${TMP_FILELIST}" ]
 392         then
 393                 rm -f "${TMP_FILELIST}"
 394         fi
 395 }
 396
 397 Clean ()
 398 {
 399         if [ -z "${SNAP_RESYNC_STRING}" ] && echo "${DEST}" | grep -q "${MOUNTP}"
 400         then
 401                 echo "${DEST} is present on ${MOUNTP}, therefore no automatic unmounting the latter." > /dev/null 1>&2
 402         else
 403                 umount "${MOUNTP}"
 404                 rmdir "${MOUNTP}"
 405         fi
 406 }
 407
 408 Warn_user ()
 409 {
 410         if [ -z "${SNAP_RESYNC_STRING}" ]
 411         then
 412                 case ${SNAP_TYPE} in
 413                         cpio|ext2|ext3)
 414                                 echo "Please move ${DEST} (if is not already in it)" > /dev/null 1>&2
 415                                 echo "in a supported writable partition (e.g ext3, vfat)." > /dev/null 1>&2
 416                                 ;;
 417
 418                         squashfs)
 419                                 echo "To use ${DEST} you need to rebuild your media or add it" > /dev/null 1>&2
 420                                 echo "to your multisession disc under the \"/live\" directory." > /dev/null 1>&2
 421                                 ;;
 422
 423                         jffs2)
 424                                 echo "Please cat or flashcp ${DEST} to your partition in order to start using it." > /dev/null 1>&2
 425                                 ;;
 426                 esac
 427
 428                 if grep -qv persistent /proc/cmdline
 429                 then
 430                         echo "Remember to boot this live system with \"persistent\" specified at boot prompt." > /dev/null 1>&2
 431                 fi
 432         fi
 433 }
 434
 435 Main ()
 436 {
 437         Parse_args "${@}"
 438         Defaults
 439         Validate_input
 440         trap 'Clean' EXIT
 441         Mount_device
 442         Do_snapshot
 443         Warn_user
 444 }
 445
 446 Main "${@:-}"