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