scripts/casper-helpers

   1 ## Casper helper functions, used by casper on boot and by casper-snapshot
   2
   3 if [ "${BUILD_SYSTEM}" == "Ubuntu" ]; then
   4     MP_QUIET="-Q"
   5 else
   6     MP_QUIET="-q"
   7 fi
   8
   9 if [ ! -x "/bin/fstype" ]; then
  10     # klibc not in path -> not in initramfs
  11     export PATH="${PATH}:/usr/lib/klibc/bin"
  12 fi
  13
  14 sys2dev() {
  15     sysdev=${1#/sys}
  16     echo "/dev/$(udevinfo -q name -p ${sysdev} 2>/dev/null|| echo ${sysdev##*/})"
  17 }
  18
  19 subdevices() {
  20     sysblock=$1
  21     r=""
  22     for dev in "${sysblock}" "${sysblock}"/*; do
  23         if [ -e "${dev}/dev" ]; then
  24             r="${r} ${dev}"
  25         fi
  26     done
  27     echo ${r}
  28 }
  29
  30 get_fstype() {
  31     local FSTYPE
  32     local FSSIZE
  33     eval $(fstype < $1)
  34     if [ "$FSTYPE" != "unknown" ]; then
  35         echo $FSTYPE
  36         return 0
  37     fi
  38     /lib/udev/vol_id -t $1 2>/dev/null
  39 }
  40
  41 where_is_mounted() {
  42     device=$1
  43     if grep -q "^$device " /proc/mounts; then
  44         grep "^$device " /proc/mounts | read d mountpoint rest
  45         echo $mountpoint
  46         return 0
  47     fi
  48     return 1
  49 }
  50
  51 lastline() {
  52     while read lines ; do
  53         line=${lines}
  54     done
  55     echo "${line}"
  56 }
  57
  58 base_path ()
  59 {
  60     testpath="${1}"
  61     mounts="$(awk '{print $2}' /proc/mounts)"
  62     testpath="$(busybox realpath ${testpath})"
  63
  64     while true ; do
  65         if echo "${mounts}" | grep -qs "^${testpath}" ; then
  66             set -- `echo "${mounts}" | grep "^${testpath}" | lastline`
  67             echo ${1}
  68             break
  69         else
  70             testpath=`dirname $testpath`
  71         fi
  72     done
  73 }
  74
  75 fs_size ()
  76 {
  77     # Returns used/free fs kbytes + 5% more
  78     # You could pass a block device as $1 or the mount point as $2
  79
  80     dev="${1}"
  81     mountp="${2}"
  82     used="${3}"
  83
  84     if [ -z "${mountp}" ]; then
  85         mountp=$(where_is_mounted "${dev}")
  86         if [ "$?" -gt 0 ]; then
  87             mountp="/mnt/tmp_fs_size"
  88             mkdir -p "${mountp}"
  89             mount -t $(get_fstype "${dev}") -o ro "${dev}" "${mountp}"
  90             doumount=1
  91         fi
  92     fi
  93
  94     if [ "${used}" = "used" ]; then
  95         size=$(du -ks ${mountp} | cut -f1)
  96         size=$(expr ${size} + ${size} / 20 ) # FIXME: 5% more to be sure
  97     else
  98         # free space
  99         size="$(df -k | grep -s ${mountp} | awk '{print $4}')"
 100     fi
 101
 102     if [ -n "${doumount}" ]; then
 103         umount "${mountp}"
 104         rmdir "${mountp}"
 105     fi
 106     echo "${size}"
 107 }
 108
 109 setup_loop() {
 110     local fspath=$1
 111     local module=$2
 112     local pattern=$3
 113
 114     modprobe "${MP_QUIET}" -b "$module"
 115     udevsettle
 116
 117     for loopdev in $pattern; do
 118         if [ "$(cat $loopdev/size)" -eq 0 ]; then
 119             dev=$(sys2dev "${loopdev}")
 120             losetup "$dev" "$fspath"
 121             echo "$dev"
 122             return 0
 123         fi
 124     done
 125     panic "No loop devices available"
 126 }
 127
 128 try_mount ()
 129 {
 130     dev="${1}"
 131     mountp="${2}"
 132     opts="${3}"
 133
 134     if where_is_mounted ${dev} > /dev/null; then
 135         mount -o remount,"${opts}" ${dev} $(where_is_mounted ${dev}) || panic "Remounting failed"
 136         mount -o bind $(where_is_mounted ${dev}) ${mountp} || panic "Cannot bind-mount"
 137     else
 138         mount -t $(get_fstype "${dev}") -o "${opts}" "${dev}" "${mountp}" || panic "Cannot mount ${dev} on ${mountp}"
 139     fi
 140 }
 141
 142 find_cow_device() {
 143     pers_label="${1}"
 144     cow_backing="/${pers_label}-backing"
 145     for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
 146         for dev in $(subdevices "${sysblock}"); do
 147             devname=$(sys2dev "${dev}")
 148             if [ "$(/lib/udev/vol_id -l $devname 2>/dev/null)" = "${pers_label}" ]; then
 149                 echo "$devname"
 150                 return
 151             elif [ "$(get_fstype ${devname})" = "vfat" ]; then # FIXME: all supported block devices should be scanned
 152                 mkdir -p "${cow_backing}"
 153                 try_mount "${devname}" "${cow_backing}" "rw"
 154                 if [ -e "${cow_backing}/${pers_label}" ]; then
 155                     echo $(setup_loop "${cow_backing}/${pers_label}" "loop" "/sys/block/loop*")
 156                     return 0
 157                 else
 158                     umount ${cow_backing}
 159                 fi
 160             fi
 161         done
 162     done
 163 }
 164
 165 find_files()
 166 # return the first of $filenames found on vfat and ext2 devices
 167 # FIXME: merge with above function
 168 {
 169     filenames="${1}"
 170     snap_backing="/snap-backing"
 171     for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
 172         for dev in $(subdevices "${sysblock}"); do
 173             devname=$(sys2dev "${dev}")
 174             devfstype="$(get_fstype ${devname})"
 175             if [ "${devfstype}" = "vfat" ] ||  [ "${devfstype}" = "ext2" ] ; then # FIXME: all supported block devices should be scanned
 176                 mkdir -p "${snap_backing}"
 177                 try_mount "${devname}" "${snap_backing}" "ro"
 178                 for filename in ${filenames}; do
 179                     if [ -e "${snap_backing}/${filename}" ]; then
 180                         echo "${devname} ${snap_backing} ${filename}"
 181                         return 0
 182                     fi
 183                 done
 184                 umount ${snap_backing}
 185             fi
 186         done
 187     done
 188 }
 189
 190