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 $MOUNTP
   6 #   and saves the /live/cow (or a different directory) filesystem in it
   7 #   for reuse in another live-initramfs session.
   8 #   Look at the manpage for more informations.
   9 #
  10 # Copyright (C) 2006-2008 Marco Amadori <marco.amadori@gmail.com>
  11 # Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>
  12 #
  13 # This program is free software: you can redistribute it and/or modify
  14 # it under the terms of the GNU General Public License as published by
  15 # the Free Software Foundation, either version 3 of the License, or
  16 # (at your option) any later version.
  17 #
  18 # This program is distributed in the hope that it will be useful,
  19 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  21 # GNU General Public License for more details.
  22 #
  23 # You should have received a copy of the GNU General Public License
  24 # along with this program. If not, see <http://www.gnu.org/licenses/>.
  25 #
  26 # On Debian systems, the complete text of the GNU General Public License
  27 # can be found in /usr/share/common-licenses/GPL-3 file.
  28
  29 # declare here two vars from /etc/live.conf because of "set -u"
  30 ROOTSNAP=""
  31 HOMESNAP=""
  32
  33 set -eu
  34
  35 . /usr/share/initramfs-tools/scripts/live-helpers
  36
  37 LIVE_CONF="/etc/live.conf"
  38 . "${LIVE_CONF}"
  39
  40 export USERNAME USERFULLNAME HOSTNAME
  41
  42 EXECUTABLE="${0}"
  43 PROGRAM=$(basename "${EXECUTABLE}")
  44
  45 # Needs to be available at run and reboot time
  46 SAFE_TMPDIR="/live"
  47
  48 # Permits multiple runs
  49 MOUNTP="$(mktemp -d -p ${SAFE_TMPDIR} live-snapshot-mnt.XXXXXX)"
  50 DEST="${MOUNTP}/live-sn.cpio.gz"
  51 DEF_SNAP_COW="/live/cow"
  52 TMP_FILELIST="${PROGRAM}.list"
  53
  54 # Command line defaults and declarations
  55 SNAP_COW="${DEF_SNAP_COW}"
  56 SNAP_DEV=""
  57 SNAP_OUTPUT=""
  58 SNAP_RESYNC_STRING=""
  59 SNAP_TYPE="cpio"
  60 SNAP_LIST="/etc/live-snapshot.list"
  61
  62 Error ()
  63 {
  64         echo "${PROGRAM}: error:" ${@}
  65         exit 1
  66 }
  67
  68 panic ()
  69 {
  70         Error ${@}
  71 }
  72
  73 Header ()
  74 {
  75         echo "${PROGRAM} - utility to perform snapshots of Debian Live systems"
  76         echo
  77         echo "usage: ${PROGRAM} [-c|--cow DIRECTORY] [-d|--device DEVICE] [-o|--output FILE] [-t|--type TYPE]"
  78         echo "       ${PROGRAM} [-r|--resync-string STRING]"
  79         echo "       ${PROGRAM} [-f|--refresh]"
  80         echo "       ${PROGRAM} [-h|--help]"
  81         echo "       ${PROGRAM} [-u|--usage]"
  82         echo "       ${PROGRAM} [-v|--version]"
  83 }
  84
  85 Help ()
  86 {
  87         Header
  88
  89         echo
  90         echo "Options:"
  91         echo "  -c, --cow: copy on write directory (default: ${SNAP_COW})."
  92         echo "  -d, --device: output snapshot device (default: ${SNAP_DEV:-auto})."
  93         echo "  -o, --output: output image file (default: ${DEST})."
  94         echo "  -r, --resync-string: internally used to resync previous made snapshots."
  95         echo "  -f, --refresh: try to sync a running snapshot."
  96         echo "  -t, --type: snapshot filesystem type. Options: \"squashfs\", \"ext2\", \"ext3\", \"jffs2\" or \"cpio\".gz archive (default: ${SNAP_TYPE})"
  97         echo
  98         echo "Look at live-snapshot(1) man page for more information."
  99
 100         exit 0
 101 }
 102
 103 Usage ()
 104 {
 105         Header
 106
 107         echo
 108         echo "Try \"${PROGRAM} --help\" for more information."
 109
 110         exit 0
 111 }
 112
 113 Version ()
 114 {
 115         echo "${PROGRAM}"
 116         echo
 117         echo "Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>"
 118         echo "Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>"
 119         echo
 120         echo "This program is free software; you can redistribute it and/or modify"
 121         echo "it under the terms of the GNU General Public License as published by"
 122         echo "the Free Software Foundation; either version 2 of the License, or"
 123         echo "(at your option) any later version."
 124         echo
 125         echo "This program is distributed in the hope that it will be useful,"
 126         echo "but WITHOUT ANY WARRANTY; without even the implied warranty of"
 127         echo "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the"
 128         echo "GNU General Public License for more details."
 129         echo
 130         echo "You should have received a copy of the GNU General Public License"
 131         echo "along with this program; if not, write to the Free Software"
 132         echo "Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA"
 133         echo
 134         echo "On Debian systems, the complete text of the GNU General Public License"
 135         echo "can be found in /usr/share/common-licenses/GPL-2 file."
 136         echo
 137         echo "Homepage: <http://debian-live.alioth.debian.org/>"
 138
 139         exit 0
 140 }
 141
 142 Try_refresh ()
 143 {
 144         FOUND=""
 145         if [ -n "${ROOTSNAP}" ]; then
 146                 "${EXECUTABLE}" --resync-string="${ROOTSNAP}"
 147                 FOUND="Yes"
 148         fi
 149
 150         if [ -n "${HOMESNAP}" ]; then
 151                 "${EXECUTABLE}" --resync-string="${HOMESNAP}"
 152                 FOUND="Yes"
 153         fi
 154
 155         if [ -z "${FOUND}" ]
 156         then
 157                 echo "No autoconfigured snapshots found at boot;" > /dev/null 1>&2
 158                 echo "(no resync string in ${LIVE_CONF})." > /dev/null 1>&2
 159                 exit 1
 160         fi
 161 }
 162
 163 Parse_args ()
 164 {
 165         # Parse command line
 166         ARGS="${*}"
 167         ARGUMENTS="$(getopt --longoptions cow:,device:,output,resync-string:,refresh,type:,help,usage,version --name=${PROGRAM} --options c:d:o:t:r:fhuv --shell sh -- ${ARGS})"
 168
 169         eval set -- "${ARGUMENTS}"
 170
 171         while true
 172         do
 173                 case "${1}" in
 174                         -c|--cow)
 175                                 SNAP_COW="${2}"
 176                                 shift 2
 177                                 ;;
 178
 179                         -d|--device)
 180                                 SNAP_DEV="${2}"
 181                                 shift 2
 182                                 ;;
 183
 184                         -o|--output)
 185                                 SNAP_OUTPUT="${2}"
 186                                 shift 2
 187                                 ;;
 188
 189                         -t|--type)
 190                                 SNAP_TYPE="${2}"
 191                                 shift 2
 192                                 ;;
 193
 194                         -r|--resync-string)
 195                                 SNAP_RESYNC_STRING="${2}"
 196                                 break
 197                                 ;;
 198
 199                         -f|--refresh)
 200                                 Try_refresh
 201                                 exit 0
 202                                 ;;
 203
 204                         -h|--help)
 205                                 Help
 206                                 ;;
 207
 208                         -u|--usage)
 209                                 Usage
 210                                 ;;
 211
 212                         -v|--version)
 213                                 Version
 214                                 ;;
 215
 216                         --)
 217                                 shift
 218                                 break
 219                                 ;;
 220
 221                         *)
 222                                 Error "internal error."
 223                                 ;;
 224
 225                 esac
 226         done
 227 }
 228
 229 Defaults ()
 230 {
 231         # Parse resync string
 232         if [ -n "${SNAP_RESYNC_STRING}" ]
 233         then
 234                 SNAP_COW=$(echo "${SNAP_RESYNC_STRING}" | cut -f1 -d ':')
 235                 SNAP_DEV=$(echo "${SNAP_RESYNC_STRING}" | cut -f2 -d ':')
 236                 DEST="${MOUNTP}/$(echo ${SNAP_RESYNC_STRING} | cut -f3 -d ':')"
 237
 238                 case "${DEST}" in
 239                         *.cpio.gz)
 240                                 SNAP_TYPE="cpio"
 241                                 ;;
 242
 243                         *.squashfs)
 244                                 SNAP_TYPE="squashfs"
 245                                 ;;
 246
 247                         *.jffs2)
 248                                 SNAP_TYPE="jffs2"
 249                                 ;;
 250
 251                         ""|*.ext2|*.ext3)
 252                                 SNAP_TYPE="ext2"
 253                                 ;;
 254                         *)
 255                                 Error "unrecognized resync string"
 256                                 ;;
 257                 esac
 258         elif [ -z "${SNAP_OUTPUT}" ]
 259         then
 260                 # Set target file based on image
 261                 case "${SNAP_TYPE}" in
 262                         cpio)
 263                                 DEST="${MOUNTP}/live-sn.cpio.gz"
 264                                 ;;
 265
 266                         squashfs|jffs2|ext2)
 267                                 DEST="${MOUNTP}/live-sn.${SNAP_TYPE}"
 268                                 ;;
 269
 270                         ext3)
 271                                 DEST="${MOUNTP}/live-sn.ext2"
 272                                 ;;
 273                 esac
 274         else
 275                 DEST="${SNAP_OUTPUT}"
 276         fi
 277 }
 278
 279 Validate_input ()
 280 {
 281         case "${SNAP_TYPE}" in
 282                 cpio|squashfs|jffs2|ext2|ext3)
 283                         ;;
 284
 285                 *)
 286                         Error "invalid filesystem type \"${SNAP_TYPE}\""
 287                         ;;
 288         esac
 289
 290         if [ ! -d "${SNAP_COW}" ]
 291         then
 292                 Error "${SNAP_COW} is not a directory"
 293         fi
 294
 295         if [ "$(id -u)" -ne 0 ]
 296         then
 297                 Error "you are not root"
 298         fi
 299 }
 300
 301 Mount_device ()
 302 {
 303         case "${SNAP_DEV}" in
 304                 "")
 305                         # create a temp
 306                         mount -t tmpfs -o rw tmpfs "${MOUNTP}"
 307                         ;;
 308
 309                 *)
 310                         if [ -b "${SNAP_DEV}" ]
 311                         then
 312                                 try_mount "${SNAP_DEV}" "${MOUNTP}" rw
 313                         fi
 314                         ;;
 315         esac
 316 }
 317
 318 Do_filelist ()
 319 {
 320         # BUGS: supports only cpio.gz types right now
 321         TMP_FILELIST=$1
 322         if [ -f "${SNAP_LIST}" ]
 323         then
 324                 # Generate include list
 325                 for entry in $(cat "${SNAP_LIST}" | grep -v '^#.*$' | grep -v '^ *$')
 326                 do
 327                         if [ -f "${entry}" ]
 328                         then
 329                                 printf "%s\000" "${entry}" >> "${TMP_FILELIST}"
 330                         elif [ -d "${entry}" ]
 331                         then
 332                                 cd /
 333                                 find "${entry}" -print0 >> "${TMP_FILELIST}"
 334                                 cd "${OLDPWD}"
 335                         fi
 336                 done
 337
 338                 if [ "${SNAP_COW}" = "${DEF_SNAP_COW}" ]
 339                 then
 340                         # Relative to rootfs
 341                         echo "/"
 342                 else
 343                         # Mostly "/home"
 344                         echo "${SNAP_COW}"
 345                 fi
 346         else
 347                 cd "${SNAP_COW}"
 348                 find . -path '*.wh.*' -prune -o -print0 >> "${TMP_FILELIST}"
 349                 cd "${OLDPWD}"
 350                 echo "${SNAP_COW}"
 351         fi
 352 }
 353
 354 Do_snapshot ()
 355 {
 356         TMP_FILELIST=$(mktemp -p "${SAFE_TMPDIR}" "${TMP_FILELIST}.XXXXXX")
 357
 358         case "${SNAP_TYPE}" in
 359                 squashfs)
 360                         echo ".${TMP_FILELIST}" > "${TMP_FILELIST}"
 361                         # Removing whiteheads of unionfs
 362                         cd "${SNAP_COW}"
 363                         find . -name '*.wh.*' >> "${TMP_FILELIST}"
 364                         cd "${OLDPWD}"
 365                         mksquashfs "${SNAP_COW}" "${DEST}" -ef "${TMP_FILELIST}"
 366                         ;;
 367
 368                 cpio)
 369                         WORKING_DIR=$(Do_filelist "${TMP_FILELIST}")
 370                         cd "${WORKING_DIR}"
 371                         cat "${TMP_FILELIST}" | cpio --quiet -o0 -H newc | gzip -9c > "${DEST}" || exit 1
 372                         cd "${OLDPWD}"
 373                         ;;
 374
 375                 ext2|ext3)
 376                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 377                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 378                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-percentage=0 --root="${SNAP_COW}" "${DEST}"
 379                         ;;
 380
 381                 jffs2)
 382                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 383                         ;;
 384         esac
 385
 386         if [ -f "${TMP_FILELIST}" ]
 387         then
 388                 rm -f "${TMP_FILELIST}"
 389         fi
 390 }
 391
 392 Clean ()
 393 {
 394         if [ -z "${SNAP_RESYNC_STRING}" ] && echo "${DEST}" | grep -q "${MOUNTP}"
 395         then
 396                 echo "${DEST} is present on ${MOUNTP}, therefore no automatic unmounting the latter." > /dev/null 1>&2
 397         else
 398                 umount "${MOUNTP}"
 399                 rmdir "${MOUNTP}"
 400         fi
 401 }
 402
 403 Warn_user ()
 404 {
 405         if [ -z "${SNAP_RESYNC_STRING}" ]
 406         then
 407                 case ${SNAP_TYPE} in
 408                         cpio|ext2|ext3)
 409                                 echo "Please move ${DEST} (if is not already in it)" > /dev/null 1>&2
 410                                 echo "in a supported writable partition (e.g ext3, vfat)." > /dev/null 1>&2
 411                                 ;;
 412
 413                         squashfs)
 414                                 echo "To use ${DEST} you need to rebuild your media or add it" > /dev/null 1>&2
 415                                 echo "to your multisession disc under the \"/live\" directory." > /dev/null 1>&2
 416                                 ;;
 417
 418                         jffs2)
 419                                 echo "Please cat or flashcp ${DEST} to your partition in order to start using it." > /dev/null 1>&2
 420                                 ;;
 421                 esac
 422
 423                 if grep -qv persistent /proc/cmdline
 424                 then
 425                         echo "Remember to boot this live system with \"persistent\" specified at boot prompt." > /dev/null 1>&2
 426                 fi
 427         fi
 428 }
 429
 430 Main ()
 431 {
 432         Parse_args "${@}"
 433         Defaults
 434         Validate_input
 435         trap 'Clean' EXIT
 436         Mount_device
 437         Do_snapshot
 438         Warn_user
 439 }
 440
 441 Main "${@:-}"