scripts/boot/snapshot.sh

   1 #!/bin/sh
   2
   3 #set -e
   4
   5 do_snap_copy ()
   6 {
   7         fromdev="${1}"
   8         todir="${2}"
   9         snap_type="${3}"
  10         size=$(fs_size "${fromdev}" "" "used")
  11
  12         if [ -b "${fromdev}" ]
  13         then
  14                 log_success_msg "Copying snapshot ${fromdev} to ${todir}..."
  15
  16                 # look for free mem
  17                 if [ -n "${HOMEMOUNTED}" -a "${snap_type}" = "HOME" ]
  18                 then
  19                         todev=$(awk -v pat="$(base_path ${todir})" '$2 == pat { print $1 }' /proc/mounts)
  20                         freespace=$(df -k | awk '/'${todev}'/{print $4}')
  21                 else
  22                         freespace=$(awk '/^MemFree:/{f=$2} /^Cached:/{c=$2} END{print f+c}' /proc/meminfo)
  23                 fi
  24
  25                 tomount="/mnt/tmpsnap"
  26
  27                 if [ ! -d "${tomount}" ]
  28                 then
  29                         mkdir -p "${tomount}"
  30                 fi
  31
  32                 fstype=$(get_fstype "${fromdev}")
  33
  34                 if [ -n "${fstype}" ]
  35                 then
  36                         # Copying stuff...
  37                         mount -o ro -t "${fstype}" "${fromdev}" "${tomount}" || log_warning_msg "Error in mount -t ${fstype} -o ro ${fromdev} ${tomount}"
  38                         cp -a "${tomount}"/* ${todir}
  39                         umount "${tomount}"
  40                 else
  41                         log_warning_msg "Unrecognized fstype: ${fstype} on ${fromdev}:${snap_type}"
  42                 fi
  43
  44                 rmdir "${tomount}"
  45
  46                 if echo ${fromdev} | grep -qs loop
  47                 then
  48                         losetup -d "${fromdev}"
  49                 fi
  50
  51                 return 0
  52         else
  53                 log_warning_msg "Unable to find the snapshot ${snap_type} medium"
  54                 return 1
  55         fi
  56 }
  57
  58 try_snap ()
  59 {
  60         # copy the contents of previously found snapshot to ${snap_mount}
  61         # and remember the device and filename for resync on exit in live-boot.init
  62
  63         snapdata="${1}"
  64         snap_mount="${2}"
  65         snap_type="${3}"
  66         snap_relpath="${4}"
  67
  68         if [ -z "${snap_relpath}" ]
  69         then
  70                 # root snapshot, default usage
  71                 snap_relpath="/"
  72         else
  73                 # relative snapshot (actually used just for "/home" snapshots)
  74                 snap_mount="${2}${snap_relpath}"
  75         fi
  76
  77         if [ -n "${snapdata}" ] && [ ! -b "${snapdata}" ]
  78         then
  79                 log_success_msg "found snapshot: ${snapdata}"
  80                 snapdev="$(echo ${snapdata} | cut -f1 -d ' ')"
  81                 snapback="$(echo ${snapdata} | cut -f2 -d ' ')"
  82                 snapfile="$(echo ${snapdata} | cut -f3 -d ' ')"
  83
  84                 if ! try_mount "${snapdev}" "${snapback}" "ro"
  85                 then
  86                         break
  87                 fi
  88
  89                 RES="0"
  90
  91                 if echo "${snapfile}" | grep -qs '\(squashfs\|ext2\|ext3\|ext4\|jffs2\)'
  92                 then
  93                         # squashfs, jffs2 or ext2/ext3/ext4 snapshot
  94                         dev=$(get_backing_device "${snapback}/${snapfile}")
  95
  96                         do_snap_copy "${dev}" "${snap_mount}" "${snap_type}"
  97                         RES="$?"
  98                 else
  99                         # cpio.gz snapshot
 100
 101                         # Unfortunately klibc's cpio is incompatible with the
 102                         # rest of the world; everything else requires -u -d,
 103                         # while klibc doesn't implement them. Try to detect
 104                         # whether it's in use.
 105                         cpiopath="$(which cpio)" || true
 106                         if [ "$cpiopath" ] && grep -aq /lib/klibc "$cpiopath"
 107                         then
 108                                 cpioargs=
 109                         else
 110                                 cpioargs='--unconditional --make-directories'
 111                         fi
 112
 113                         if [ -s "${snapback}/${snapfile}" ]
 114                         then
 115                                 BEFOREDIR="$(pwd)"
 116                                 cd "${snap_mount}" && zcat "${snapback}/${snapfile}" | $cpiopath $cpioargs --extract --preserve-modification-time --no-absolute-filenames --sparse 2>/dev/null
 117                                 RES="$?"
 118                                 cd "${BEFOREDIR}"
 119                         else
 120                                 log_warning_msg "${snapback}/${snapfile} is empty, adding it for sync on reboot."
 121                                 RES="0"
 122                         fi
 123
 124                         if [ "${RES}" != "0" ]
 125                         then
 126                                 log_warning_msg "failure to \"zcat ${snapback}/${snapfile} | $cpiopath $cpioargs --extract --preserve-modification-time --no-absolute-filenames --sparse\""
 127                         fi
 128                 fi
 129
 130                 umount "${snapback}" ||  log_warning_msg "failure to \"umount ${snapback}\""
 131
 132                 if [ "${RES}" != "0" ]
 133                 then
 134                         log_warning_msg "Impossible to include the ${snapfile} Snapshot file"
 135                 fi
 136
 137         elif [ -b "${snapdata}" ]
 138         then
 139                 # Try to find if it could be a snapshot partition
 140                 dev="${snapdata}"
 141                 log_success_msg "found snapshot ${snap_type} device on ${dev}"
 142                 if echo "${dev}" | grep -qs loop
 143                 then
 144                         # strange things happens, user confused?
 145                         snaploop=$( losetup ${dev} | awk '{print $3}' | tr -d '()' )
 146                         snapfile=$(basename ${snaploop})
 147                         snapdev=$(awk -v pat="$( dirname ${snaploop})" '$2 == pat { print $1 }' /proc/mounts)
 148                 else
 149                         snapdev="${dev}"
 150                 fi
 151
 152                 if ! do_snap_copy "${dev}" "${snap_mount}" "${snap_type}"
 153                 then
 154                         log_warning_msg "Impossible to include the ${snap_type} Snapshot (i)"
 155                         return 1
 156                 else
 157                         if [ -n "${snapfile}" ]
 158                         then
 159                                 # it was a loop device, user confused
 160                                 umount ${snapdev}
 161                         fi
 162                 fi
 163         else
 164                 log_warning_msg "Impossible to include the ${snap_type} Snapshot (o)"
 165                 return 1
 166         fi
 167
 168         if [ -z ${PERSISTENCE_READONLY} ]
 169         then
 170                 echo "export ${snap_type}SNAP=${snap_relpath}:${snapdev}:${snapfile}" >> snapshot.conf # for resync on reboot/halt
 171         fi
 172         return 0
 173 }