scripts/boot/snapshot.sh

   1 #!/bin/sh
   2
   3 do_snap_copy ()
   4 {
   5         fromdev="${1}"
   6         todir="${2}"
   7         snap_type="${3}"
   8         size=$(fs_size "${fromdev}" "" "used")
   9
  10         if [ -b "${fromdev}" ]
  11         then
  12                 log_success_msg "Copying snapshot ${fromdev} to ${todir}..."
  13
  14                 # look for free mem
  15                 if [ -n "${HOMEMOUNTED}" -a "${snap_type}" = "HOME" ]
  16                 then
  17                         todev=$(awk -v pat="$(base_path ${todir})" '$2 == pat { print $1 }' /proc/mounts)
  18                         freespace=$(df -k | awk '/'${todev}'/{print $4}')
  19                 else
  20                         freespace=$(awk '/^MemFree:/{f=$2} /^Cached:/{c=$2} END{print f+c}' /proc/meminfo)
  21                 fi
  22
  23                 tomount="/mnt/tmpsnap"
  24
  25                 if [ ! -d "${tomount}" ]
  26                 then
  27                         mkdir -p "${tomount}"
  28                 fi
  29
  30                 fstype=$(get_fstype "${fromdev}")
  31
  32                 if [ -n "${fstype}" ]
  33                 then
  34                         # Copying stuff...
  35                         mount -o ro -t "${fstype}" "${fromdev}" "${tomount}" || log_warning_msg "Error in mount -t ${fstype} -o ro ${fromdev} ${tomount}"
  36                         cp -a "${tomount}"/* ${todir}
  37                         umount "${tomount}"
  38                 else
  39                         log_warning_msg "Unrecognized fstype: ${fstype} on ${fromdev}:${snap_type}"
  40                 fi
  41
  42                 rmdir "${tomount}"
  43
  44                 if echo ${fromdev} | grep -qs loop
  45                 then
  46                         losetup -d "${fromdev}"
  47                 fi
  48
  49                 return 0
  50         else
  51                 log_warning_msg "Unable to find the snapshot ${snap_type} medium"
  52                 return 1
  53         fi
  54 }
  55
  56 try_snap ()
  57 {
  58         # copy the contents of previously found snapshot to ${snap_mount}
  59         # and remember the device and filename for resync on exit in live-boot.init
  60
  61         snapdata="${1}"
  62         snap_mount="${2}"
  63         snap_type="${3}"
  64         snap_relpath="${4}"
  65
  66         if [ -z "${snap_relpath}" ]
  67         then
  68                 # root snapshot, default usage
  69                 snap_relpath="/"
  70         else
  71                 # relative snapshot (actually used just for "/home" snapshots)
  72                 snap_mount="${2}${snap_relpath}"
  73         fi
  74
  75         if [ -n "${snapdata}" ] && [ ! -b "${snapdata}" ]
  76         then
  77                 log_success_msg "found snapshot: ${snapdata}"
  78                 snapdev="$(echo ${snapdata} | cut -f1 -d ' ')"
  79                 snapback="$(echo ${snapdata} | cut -f2 -d ' ')"
  80                 snapfile="$(echo ${snapdata} | cut -f3 -d ' ')"
  81
  82                 if ! try_mount "${snapdev}" "${snapback}" "ro"
  83                 then
  84                         break
  85                 fi
  86
  87                 RES="0"
  88
  89                 if echo "${snapfile}" | grep -qs '\(squashfs\|ext2\|ext3\|ext4\|jffs2\)'
  90                 then
  91                         # squashfs, jffs2 or ext2/ext3/ext4 snapshot
  92                         dev=$(get_backing_device "${snapback}/${snapfile}")
  93
  94                         do_snap_copy "${dev}" "${snap_mount}" "${snap_type}"
  95                         RES="$?"
  96                 else
  97                         # cpio.gz snapshot
  98
  99                         # Unfortunately klibc's cpio is incompatible with the
 100                         # rest of the world; everything else requires -u -d,
 101                         # while klibc doesn't implement them. Try to detect
 102                         # whether it's in use.
 103                         cpiopath="$(which cpio)" || true
 104                         if [ "$cpiopath" ] && grep -aq /lib/klibc "$cpiopath"
 105                         then
 106                                 cpioargs=
 107                         else
 108                                 cpioargs='--unconditional --make-directories'
 109                         fi
 110
 111                         if [ -s "${snapback}/${snapfile}" ]
 112                         then
 113                                 BEFOREDIR="$(pwd)"
 114                                 cd "${snap_mount}" && zcat "${snapback}/${snapfile}" | $cpiopath $cpioargs --extract --preserve-modification-time --no-absolute-filenames --sparse 2>/dev/null
 115                                 RES="$?"
 116                                 cd "${BEFOREDIR}"
 117                         else
 118                                 log_warning_msg "${snapback}/${snapfile} is empty, adding it for sync on reboot."
 119                                 RES="0"
 120                         fi
 121
 122                         if [ "${RES}" != "0" ]
 123                         then
 124                                 log_warning_msg "failure to \"zcat ${snapback}/${snapfile} | $cpiopath $cpioargs --extract --preserve-modification-time --no-absolute-filenames --sparse\""
 125                         fi
 126                 fi
 127
 128                 umount "${snapback}" ||  log_warning_msg "failure to \"umount ${snapback}\""
 129
 130                 if [ "${RES}" != "0" ]
 131                 then
 132                         log_warning_msg "Impossible to include the ${snapfile} Snapshot file"
 133                 fi
 134
 135         elif [ -b "${snapdata}" ]
 136         then
 137                 # Try to find if it could be a snapshot partition
 138                 dev="${snapdata}"
 139                 log_success_msg "found snapshot ${snap_type} device on ${dev}"
 140                 if echo "${dev}" | grep -qs loop
 141                 then
 142                         # strange things happens, user confused?
 143                         snaploop=$( losetup ${dev} | awk '{print $3}' | tr -d '()' )
 144                         snapfile=$(basename ${snaploop})
 145                         snapdev=$(awk -v pat="$( dirname ${snaploop})" '$2 == pat { print $1 }' /proc/mounts)
 146                 else
 147                         snapdev="${dev}"
 148                 fi
 149
 150                 if ! do_snap_copy "${dev}" "${snap_mount}" "${snap_type}"
 151                 then
 152                         log_warning_msg "Impossible to include the ${snap_type} Snapshot (i)"
 153                         return 1
 154                 else
 155                         if [ -n "${snapfile}" ]
 156                         then
 157                                 # it was a loop device, user confused
 158                                 umount ${snapdev}
 159                         fi
 160                 fi
 161         else
 162                 log_warning_msg "Impossible to include the ${snap_type} Snapshot (o)"
 163                 return 1
 164         fi
 165
 166         if [ -z ${PERSISTENCE_READONLY} ]
 167         then
 168                 echo "export ${snap_type}SNAP=${snap_relpath}:${snapdev}:${snapfile}" >> snapshot.conf # for resync on reboot/halt
 169         fi
 170         return 0
 171 }