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
 100 Version ()
 101 {
 102         echo "${PROGRAM}"
 103         echo
 104         echo "Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>"
 105         echo
 106         echo "This program is free software; you can redistribute it and/or modify"
 107         echo "it under the terms of the GNU General Public License as published by"
 108         echo "the Free Software Foundation; either version 2 of the License, or"
 109         echo "(at your option) any later version."
 110         echo
 111         echo "This program is distributed in the hope that it will be useful,"
 112         echo "but WITHOUT ANY WARRANTY; without even the implied warranty of"
 113         echo "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the"
 114         echo "GNU General Public License for more details."
 115         echo
 116         echo "You should have received a copy of the GNU General Public License"
 117         echo "along with this program; if not, write to the Free Software"
 118         echo "Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA"
 119         echo
 120         echo "On Debian systems, the complete text of the GNU General Public License"
 121         echo "can be found in /usr/share/common-licenses/GPL-2 file."
 122         echo
 123         echo "Homepage: <http://debian-live.alioth.debian.org/>"
 124
 125         exit 0
 126 }
 127
 128 Is_same_mount ()
 129 {
 130         dir1="$(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
 203 Defaults ()
 204 {
 205         # Parse resync string
 206         if [ -n "${SNAP_RESYNC_STRING}" ]
 207         then
 208                 SNAP_COW=$(echo "${SNAP_RESYNC_STRING}" | cut -f1 -d ':')
 209                 SNAP_DEV=$(echo "${SNAP_RESYNC_STRING}" | cut -f2 -d ':')
 210                 DEST=$(echo "${SNAP_RESYNC_STRING}" | cut -f3 -d ':')
 211
 212                 case "${DEST}" in
 213                         *.cpio.gz)
 214                                 SNAP_TYPE="cpio"
 215                                 ;;
 216
 217                         *.squashfs)
 218                                 SNAP_TYPE="squashfs"
 219                                 ;;
 220
 221                         *.jffs2)
 222                                 SNAP_TYPE="jffs2"
 223                                 ;;
 224
 225                         ""|*.ext2|*.ext3)
 226                                 SNAP_TYPE="ext2"
 227                                 ;;
 228                         *)
 229                                 Error "unrecognized resync string"
 230                                 ;;
 231                 esac
 232
 233         else
 234                 # Set target file based on image
 235                 case "${SNAP_TYPE}" in
 236                         cpio)
 237                                 DEST="${MOUNTP}/live-sn.cpio.gz"
 238                                 ;;
 239
 240                         squashfs|jffs2|ext2)
 241                                 DEST="${MOUNTP}/live-sn.${SNAP_TYPE}"
 242                                 ;;
 243
 244                         ext3)
 245                                 DEST="${MOUNTP}/live-sn.ext2"
 246                                 ;;
 247                 esac
 248         fi
 249
 250 }
 251
 252 Validate_input ()
 253 {
 254         case "${SNAP_TYPE}" in
 255                 cpio|squashfs|jffs2|ext2|ext3)
 256                         ;;
 257                 *)
 258                         Error "invalid filesystem type \"${SNAP_TYPE}\""
 259                         ;;
 260         esac
 261
 262         if [ ! -d "${SNAP_COW}" ]
 263         then
 264                 Error "${SNAP_COW} is not a directory"
 265         fi
 266
 267         if [ "$(id -u)" -ne 0 ]
 268         then
 269                 Error "you are not root"
 270         fi
 271 }
 272
 273 Mount_device ()
 274 {
 275         mkdir -p "${MOUNTP}"
 276
 277         case "${SNAP_DEV}" in
 278                 "")
 279                         # create a temp
 280                         mount -t tmpfs -o rw tmpfs "${MOUNTP}"
 281                         ;;
 282                 *)
 283                         if [ -b "${SNAP_DEV}" ]
 284                         then
 285                                 try_mount "${SNAP_DEV}" "${MOUNTP}" rw
 286                         fi
 287                         ;;
 288         esac
 289 }
 290
 291 Do_snapshot ()
 292 {
 293         case "${SNAP_TYPE}" in
 294                 squashfs)
 295                         EXCLUDE_LIST="$(mktemp -p ${SAFE_TMPDIR} live-snapshot-exclude-list.XXXXXX)"
 296                         echo "./${EXCLUDE_LIST}" > "${EXCLUDE_LIST}"
 297                         cd "${SNAP_COW}"
 298                         find . -name '*.wh.*' >> "${EXCLUDE_LIST}"
 299                         cd "${OLDPWD}"
 300                         mksquashfs "${SNAP_COW}" "${DEST}" -ef "${EXCLUDE_LIST}"
 301                         rm -f "${EXCLUDE_LIST}"
 302                         ;;
 303
 304                 cpio)
 305                         ( cd "${SNAP_COW}" && find . -path '*.wh.*' -prune -o -print0 | cpio --quiet -o0 -H newc | gzip -9c > "${DEST}" ) || exit 1
 306                         ;;
 307
 308                 ext2|ext3)
 309                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 310                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 311                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-percentage=0 --root="${SNAP_COW}" "${DEST}"
 312                         ;;
 313
 314                 jffs2)
 315                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 316                         ;;
 317         esac
 318 }
 319
 320 Clean ()
 321 {
 322         if echo "${DEST}" | grep -q "${MOUNTP}"
 323         then
 324                 echo "${DEST} is present on ${MOUNTP}, therefore no automatic unmounting the latter." > /dev/null 1>&2
 325         else
 326                 umount "${MOUNTP}"
 327                 rmdir "${MOUNTP}"
 328         fi
 329 }
 330
 331 Main ()
 332 {
 333         Parse_args "${@}"
 334         Defaults
 335         Validate_input
 336         trap 'Clean' EXIT
 337         Mount_device
 338         Do_snapshot
 339 }
 340
 341 Main "${@:-}"