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