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 $MOUNTP
   6 #   and saves the /live/cow (or a different dir) filesystem in it for reuse
   7 #   in another live-initramfs session. Look at manpage for more info.
   8 #
   9 # Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>
  10 # Copyright (C) 2008 Chris Lamb <chris@chris-lamb.co.uk>
  11 #
  12 # This program is free software; you can redistribute it and/or modify
  13 # it under the terms of the GNU General Public License as published by
  14 # the Free Software Foundation; either version 2 of the License, or
  15 # (at your option) any later version.
  16 #
  17 # This program is distributed in the hope that it will be useful,
  18 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  20 # GNU General Public License for more details.
  21 #
  22 # You should have received a copy of the GNU General Public License
  23 # along with this program; if not, write to the Free Software
  24 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  25 #
  26 # On Debian systems, the complete text of the GNU General Public License
  27 # can be found in /usr/share/common-licenses/GPL-2 file.
  28
  29 set -eu
  30
  31 . /usr/share/initramfs-tools/scripts/live-helpers
  32 . /etc/live.conf
  33
  34 export USERNAME USERFULLNAME HOSTNAME
  35
  36 PROGRAM="$(basename $0)"
  37
  38 # Needs to be available at run and reboot time
  39 SAFE_TMPDIR="/live"
  40
  41 # Permits multiple runs
  42 MOUNTP="$(mktemp -d -p ${SAFE_TMPDIR} live-snapshot-mnt.XXXXXX)"
  43 SNAP_COW="/live/cow"
  44 SNAP_DEV=""
  45 DEST="${MOUNTP}/live-sn.cpio.gz"
  46 SNAP_TYPE="cpio"
  47 DESKTOP_LINK="/home/${USERNAME}/Desktop/live-snapshot"
  48 SNAP_RESYNC_STRING=""
  49
  50 Error ()
  51 {
  52         echo "${PROGRAM}: error:" ${@}
  53         exit 1
  54 }
  55
  56 panic ()
  57 {
  58         Error ${@}
  59 }
  60
  61 Header ()
  62 {
  63         echo "${PROGRAM} - utility to perform snapshots of Debian Live systems"
  64         echo
  65         echo "usage: ${PROGRAM} [-c|--cow DIRECTORY] [-d|--device DEVICE] [-o|--output FILE] [-t|--type TYPE]"
  66         echo "       ${PROGRAM} [-r|--resync-string STRING]"
  67         echo "       ${PROGRAM} [-h|--help]"
  68         echo "       ${PROGRAM} [-u|--usage]"
  69         echo "       ${PROGRAM} [-v|--version]"
  70 }
  71
  72 Help ()
  73 {
  74         Header
  75
  76         echo
  77         echo "Options:"
  78         echo "  -c, --cow: copy on write directory (default: ${SNAP_COW})."
  79         echo "  -d, --device: output snapshot device (default: ${SNAP_DEV:-auto})."
  80         echo "  -o, --output: output image file (default: ${DEST})."
  81         echo "  -r, --resync-string: internally used to resync previous made snapshots."
  82         echo "  -t, --type: snapshot filesystem type. Options: \"squashfs\", \"ext2\", \"ext3\", \"jffs2\" or \"cpio\".gz archive (default: ${SNAP_TYPE})"
  83         echo
  84         echo "Look at live-snapshot(1) man page for more information."
  85
  86         exit 0
  87 }
  88
  89 Usage ()
  90 {
  91         Header
  92
  93         echo
  94         echo "Try \"${PROGRAM} --help\" for more information."
  95
  96         exit 0
  97 }
  98
  99 Version ()
 100 {
 101         echo "${PROGRAM}"
 102         echo
 103         echo "Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>"
 104         echo
 105         echo "This program is free software; you can redistribute it and/or modify"
 106         echo "it under the terms of the GNU General Public License as published by"
 107         echo "the Free Software Foundation; either version 2 of the License, or"
 108         echo "(at your option) any later version."
 109         echo
 110         echo "This program is distributed in the hope that it will be useful,"
 111         echo "but WITHOUT ANY WARRANTY; without even the implied warranty of"
 112         echo "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the"
 113         echo "GNU General Public License for more details."
 114         echo
 115         echo "You should have received a copy of the GNU General Public License"
 116         echo "along with this program; if not, write to the Free Software"
 117         echo "Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA"
 118         echo
 119         echo "On Debian systems, the complete text of the GNU General Public License"
 120         echo "can be found in /usr/share/common-licenses/GPL-2 file."
 121         echo
 122         echo "Homepage: <http://debian-live.alioth.debian.org/>"
 123
 124         exit 0
 125 }
 126
 127 Is_same_mount ()
 128 {
 129         dir1="$(Base_path ${1})"
 130         dir2="$(Base_path ${2})"
 131
 132         if [ "${dir1}" = "${dir2}" ]
 133         then
 134                 return 0
 135         else
 136                 return 1
 137         fi
 138 }
 139
 140 Parse_args ()
 141 {
 142         # Parse command line
 143         ARGS="${*}"
 144         ARGUMENTS="$(getopt --longoptions cow:,device:,output,resync-string:,type:,help,usage,version --name=${PROGRAM} --options c:d:o:t:r:,h,u,v --shell sh -- ${ARGS})"
 145
 146         eval set -- "${ARGUMENTS}"
 147
 148         while true
 149         do
 150                 case "${1}" in
 151                         -c|--cow)
 152                                 SNAP_COW="${2}"
 153                                 shift 2
 154                                 ;;
 155
 156                         -d|--device)
 157                                 SNAP_DEV="${2}"
 158                                 shift 2
 159                                 ;;
 160
 161                         -o|--output)
 162                                 SNAP_OUTPUT="${2}"
 163                                 shift 2
 164                                 ;;
 165
 166                         -t|--type)
 167                                 SNAP_TYPE="${2}"
 168                                 shift 2
 169                                 ;;
 170
 171                         -r|--resync-string)
 172                                 SNAP_RESYNC_STRING="${2}"
 173                                 break
 174                                 ;;
 175
 176                         -h|--help)
 177                                 Help
 178                                 ;;
 179
 180                         -u|--usage)
 181                                 Usage
 182                                 ;;
 183
 184                         -v|--version)
 185                                 Version
 186                                 ;;
 187
 188                         --)
 189                                 shift
 190                                 break
 191                                 ;;
 192
 193                         *)
 194                                 Error "internal error."
 195                                 ;;
 196
 197                 esac
 198         done
 199 }
 200
 201 Defaults ()
 202 {
 203         # Parse resync string
 204         if [ -n "${SNAP_RESYNC_STRING}" ]
 205         then
 206                 SNAP_COW=$(echo "${SNAP_RESYNC_STRING}" | cut -f1 -d ':')
 207                 SNAP_DEV=$(echo "${SNAP_RESYNC_STRING}" | cut -f2 -d ':')
 208                 DEST=$(echo "${SNAP_RESYNC_STRING}" | cut -f3 -d ':')
 209
 210                 case "${DEST}" in
 211                         *.cpio.gz)
 212                                 SNAP_TYPE="cpio"
 213                                 ;;
 214
 215                         *.squashfs)
 216                                 SNAP_TYPE="squashfs"
 217                                 ;;
 218
 219                         *.jffs2)
 220                                 SNAP_TYPE="jffs2"
 221                                 ;;
 222
 223                         ""|*.ext2|*.ext3)
 224                                 SNAP_TYPE="ext2"
 225                                 ;;
 226                         *)
 227                                 Error "unrecognized resync string"
 228                                 ;;
 229                 esac
 230         else
 231                 # Set target file based on image
 232                 case "${SNAP_TYPE}" in
 233                         cpio)
 234                                 DEST="${MOUNTP}/live-sn.cpio.gz"
 235                                 ;;
 236
 237                         squashfs|jffs2|ext2)
 238                                 DEST="${MOUNTP}/live-sn.${SNAP_TYPE}"
 239                                 ;;
 240
 241                         ext3)
 242                                 DEST="${MOUNTP}/live-sn.ext2"
 243                                 ;;
 244                 esac
 245         fi
 246 }
 247
 248 Validate_input ()
 249 {
 250         case "${SNAP_TYPE}" in
 251                 cpio|squashfs|jffs2|ext2|ext3)
 252                         ;;
 253
 254                 *)
 255                         Error "invalid filesystem type \"${SNAP_TYPE}\""
 256                         ;;
 257         esac
 258
 259         if [ ! -d "${SNAP_COW}" ]
 260         then
 261                 Error "${SNAP_COW} is not a directory"
 262         fi
 263
 264         if [ "$(id -u)" -ne 0 ]
 265         then
 266                 Error "you are not root"
 267         fi
 268 }
 269
 270 Mount_device ()
 271 {
 272         mkdir -p "${MOUNTP}"
 273
 274         case "${SNAP_DEV}" in
 275                 "")
 276                         # create a temp
 277                         mount -t tmpfs -o rw tmpfs "${MOUNTP}"
 278                         ;;
 279
 280                 *)
 281                         if [ -b "${SNAP_DEV}" ]
 282                         then
 283                                 try_mount "${SNAP_DEV}" "${MOUNTP}" rw
 284                         fi
 285                         ;;
 286         esac
 287 }
 288
 289 Do_snapshot ()
 290 {
 291         case "${SNAP_TYPE}" in
 292                 squashfs)
 293                         EXCLUDE_LIST="$(mktemp -p ${SAFE_TMPDIR} live-snapshot-exclude-list.XXXXXX)"
 294                         echo "./${EXCLUDE_LIST}" > "${EXCLUDE_LIST}"
 295                         cd "${SNAP_COW}"
 296                         find . -name '*.wh.*' >> "${EXCLUDE_LIST}"
 297                         cd "${OLDPWD}"
 298                         mksquashfs "${SNAP_COW}" "${DEST}" -ef "${EXCLUDE_LIST}"
 299                         rm -f "${EXCLUDE_LIST}"
 300                         ;;
 301
 302                 cpio)
 303                         ( cd "${SNAP_COW}" && find . -path '*.wh.*' -prune -o -print0 | cpio --quiet -o0 -H newc | gzip -9c > "${DEST}" ) || exit 1
 304                         ;;
 305
 306                 ext2|ext3)
 307                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 308                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 309                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-percentage=0 --root="${SNAP_COW}" "${DEST}"
 310                         ;;
 311
 312                 jffs2)
 313                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 314                         ;;
 315         esac
 316 }
 317
 318 Clean ()
 319 {
 320         if echo "${DEST}" | grep -q "${MOUNTP}"
 321         then
 322                 echo "${DEST} is present on ${MOUNTP}, therefore no automatic unmounting the latter." > /dev/null 1>&2
 323         else
 324                 umount "${MOUNTP}"
 325                 rmdir "${MOUNTP}"
 326         fi
 327 }
 328
 329 Main ()
 330 {
 331         Parse_args "${@}"
 332         Defaults
 333         Validate_input
 334         trap 'Clean' EXIT
 335         Mount_device
 336         Do_snapshot
 337 }
 338
 339 Main "${@:-}"