bin/live-snapshot

   1 #!/bin/sh
   2
   3 # live-snapshot - utility to manage Debian Live systems snapshots
   4 #
   5 #   This program mount a device (fallback to /tmpfs under /mnt/snapshot
   6 #   and save the /live/cow (or a different dir) filesystem in it for reusing
   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 $0)"
  37 VERSION=0.0.2
  38
  39 MOUNTP="/mnt/live-snapshot"
  40 SNAP_COW="/live/cow"
  41 SNAP_DEV=""
  42 DEST="${MOUNTP}/live-sn.cpio.gz"
  43 SNAP_TYPE="cpio"
  44 DESKTOP_LINK="/home/${USERNAME}/Desktop/live-snapshot"
  45 SNAP_RESYNC_STRING=""
  46
  47 Error ()
  48 {
  49         echo "${PROGRAM}: error:" ${@}
  50         exit 1
  51 }
  52
  53 panic ()
  54 {
  55         Error ${@}
  56 }
  57
  58 Header ()
  59 {
  60         echo "${PROGRAM} - utility to perform snapshots of Debian Live systems"
  61         echo
  62         echo "usage: ${PROGRAM} [-c|--cow DIRECTORY] [-d|--device DEVICE] [-o|--output FILE] [-t|--type TYPE]"
  63         echo "       ${PROGRAM} [-r|--resync-string STRING]"
  64         echo "       ${PROGRAM} [-h|--help]"
  65         echo "       ${PROGRAM} [-u|--usage]"
  66         echo "       ${PROGRAM} [-v|--version]"
  67 }
  68
  69 Help ()
  70 {
  71         Header
  72
  73         echo
  74         echo "Options:"
  75         echo "  -c, --cow: copy on write directory (default: ${SNAP_COW})."
  76         echo "  -d, --device: output snapshot device (default: ${SNAP_DEV:-auto})."
  77         echo "  -o, --output: output image file (default: ${DEST})."
  78         echo "  -r, --resync-string: internally used to resync previous made snapshots."
  79         echo "  -t, --type: snapshot filesystem type. Options: \"squashfs\", \"ext2\", \"ext3\", \"jffs2\" or \"cpio\".gz archive (default: ${SNAP_TYPE})"
  80         echo
  81         echo "Look at live-snapshot(1) man page for more information."
  82
  83         exit 0
  84 }
  85
  86 Usage ()
  87 {
  88         Header
  89
  90         echo
  91         echo "Try \"${PROGRAM} --help\" for more information."
  92
  93         exit 0
  94 }
  95
  96
  97 Version ()
  98 {
  99         echo "${PROGRAM}, version ${VERSION}"
 100         echo
 101         echo "Copyright (C) 2006 Marco Amadori <marco.amadori@gmail.com>"
 102         echo
 103         echo "This program is free software; you can redistribute it and/or modify"
 104         echo "it under the terms of the GNU General Public License as published by"
 105         echo "the Free Software Foundation; either version 2 of the License, or"
 106         echo "(at your option) any later version."
 107         echo
 108         echo "This program is distributed in the hope that it will be useful,"
 109         echo "but WITHOUT ANY WARRANTY; without even the implied warranty of"
 110         echo "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the"
 111         echo "GNU General Public License for more details."
 112         echo
 113         echo "You should have received a copy of the GNU General Public License"
 114         echo "along with this program; if not, write to the Free Software"
 115         echo "Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA"
 116         echo
 117         echo "On Debian systems, the complete text of the GNU General Public License"
 118         echo "can be found in /usr/share/common-licenses/GPL-2 file."
 119         echo
 120         echo "Homepage: <http://debian-live.alioth.debian.org/>"
 121
 122         exit 0
 123 }
 124
 125 Is_same_mount ()
 126 {
 127         dir1="$(Base_path ${1})"
 128         dir2="$(Base_path ${2})"
 129
 130         if [ "${dir1}" = "${dir2}" ]
 131         then
 132                 return 0
 133         else
 134                 return 1
 135         fi
 136 }
 137
 138 Parse_args ()
 139 {
 140         # Parse command line
 141         ARGS="${*}"
 142         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 -- ${ARGS})"
 143
 144         eval set -- "${ARGUMENTS}"
 145
 146         while true
 147         do
 148                 case "${1}" in
 149                         -c|--cow)
 150                                 SNAP_COW="${2}"
 151                                 shift 2
 152                                 ;;
 153
 154                         -d|--device)
 155                                 SNAP_DEV="${2}"
 156                                 shift 2
 157                                 ;;
 158
 159                         -o|--output)
 160                                 SNAP_OUTPUT="${2}"
 161                                 shift 2
 162                                 ;;
 163
 164                         -t|--type)
 165                                 SNAP_TYPE="${2}"
 166                                 shift 2
 167                                 ;;
 168
 169                         -r|--resync-string)
 170                                 SNAP_RESYNC_STRING="${2}"
 171                                 break
 172                                 ;;
 173
 174                         -h|--help)
 175                                 Help
 176                                 ;;
 177
 178                         -u|--usage)
 179                                 Usage
 180                                 ;;
 181
 182                         -v|--version)
 183                                 Version
 184                                 ;;
 185
 186                         --)
 187                                 shift
 188                                 break
 189                                 ;;
 190
 191                         *)
 192                                 Error "internal error."
 193                                 ;;
 194
 195                 esac
 196         done
 197
 198 }
 199
 200 Defaults ()
 201 {
 202         # Parse resync string
 203         if [ -n "${SNAP_RESYNC_STRING}" ]
 204         then
 205                 SNAP_COW=$(echo "${SNAP_RESYNC_STRING}" | cut -f1 -d ':')
 206                 SNAP_DEV=$(echo "${SNAP_RESYNC_STRING}" | cut -f2 -d ':')
 207                 DEST=$(echo "${SNAP_RESYNC_STRING}" | cut -f3 -d ':')
 208
 209                 case "${DEST}" in
 210                         *.cpio.gz)
 211                                 SNAP_TYPE="cpio"
 212                                 ;;
 213
 214                         *.squashfs)
 215                                 SNAP_TYPE="squashfs"
 216                                 ;;
 217
 218                         *.jffs2)
 219                                 SNAP_TYPE="jffs2"
 220                                 ;;
 221
 222                         ""|*.ext2|*.ext3)
 223                                 SNAP_TYPE="ext2"
 224                                 ;;
 225                         *)
 226                                 Error "unrecognized resync string"
 227                                 ;;
 228                 esac
 229
 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="${MOUNTP}/live-sn.ext2"
 243                                 ;;
 244                 esac
 245         fi
 246
 247 }
 248
 249 Validate_input ()
 250 {
 251         case "${SNAP_TYPE}" in
 252                 cpio|squashfs|jffs2|ext2|ext3)
 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 "${MOUNTP}"
 278                         ;;
 279                 *)
 280                         if [ -b "${SNAP_DEV}" ]
 281                         then
 282                                 try_mount "${SNAP_DEV}" "${MOUNTP}" rw
 283                         fi
 284                         ;;
 285         esac
 286 }
 287
 288 Do_snapshot ()
 289 {
 290         case "${SNAP_TYPE}" in
 291                 squashfs)
 292                         echo "./tmp/exclude_list" > /tmp/exclude_list
 293                         ( cd "${SNAP_COW}" && find . -name '*.wh.*' >> /tmp/exclude_list )
 294                         mksquashfs "${SNAP_COW}" "${DEST}" -ef /tmp/exclude_list
 295                         rm /tmp/exclude_list
 296                         ;;
 297
 298                 cpio)
 299                         ( cd "${SNAP_COW}" && find . -path '*.wh.*' -prune -o -print0 | cpio --quiet -o0 -H newc | gzip -9c > "${DEST}" ) || exit 1
 300                         ;;
 301
 302                 ext2|ext3)
 303                         DU_DIM="$(du -ks ${SNAP_COW} | cut -f1)"
 304                         REAL_DIM="$(expr ${DU_DIM} + ${DU_DIM} / 20)" # Just 5% more to be sure, need something more sophistcated here...
 305                         genext2fs --size-in-blocks=${REAL_DIM} --reserved-blocks=0 --root="${SNAP_COW}" "${DEST}"
 306                         ;;
 307
 308                 jffs2)
 309                         mkfs.jffs2 --root="${SNAP_COW}" --output="${DEST}"
 310                         ;;
 311         esac
 312 }
 313
 314 Clean ()
 315 {
 316         umount "${MOUNTP}"
 317         rmdir "${MOUNTP}"
 318 }
 319
 320 Main ()
 321 {
 322         Parse_args "${@}"
 323         Defaults
 324         Validate_input
 325         trap 'Clean' EXIT
 326         Mount_device
 327         Do_snapshot
 328 }
 329
 330 Main "${@:-}"