scripts/casper-helpers

   1 ## Casper helper functions, used by casper on boot and by casper-snapshot
   2
   3 if [ "${BUILD_SYSTEM}" == "Ubuntu" ]; then
   4     MP_QUIET="-Q"
   5 else
   6     MP_QUIET="-q"
   7 fi
   8
   9 sys2dev() {
  10     sysdev=${1#/sys}
  11     echo "/dev/$(udevinfo -q name -p ${sysdev} 2>/dev/null|| echo ${sysdev##*/})"
  12 }
  13
  14 subdevices() {
  15     sysblock=$1
  16     r=""
  17     for dev in "${sysblock}" "${sysblock}"/*; do
  18         if [ -e "${dev}/dev" ]; then
  19             r="${r} ${dev}"
  20         fi
  21     done
  22     echo ${r}
  23 }
  24
  25 where_is_mounted() {
  26     device=$1
  27     if grep -q "^$device " /proc/mounts; then
  28         grep "^$device " /proc/mounts | read d mountpoint rest
  29         echo $mountpoint
  30         return 0
  31     fi
  32     return 1
  33 }
  34
  35 lastline() {
  36     while read lines ; do
  37         line=${lines}
  38     done
  39     echo "${line}"
  40 }
  41
  42 base_path ()
  43 {
  44     testpath="${1}"
  45     mounts="$(awk '{print $2}' /proc/mounts)"
  46     testpath="$(busybox realpath ${testpath})"
  47
  48     while true ; do
  49         if echo "${mounts}" | grep -qs "^${testpath}" ; then
  50             set -- `echo "${mounts}" | grep "^${testpath}" | lastline`
  51             echo ${1}
  52             break
  53         else
  54             testpath=`dirname $testpath`
  55         fi
  56     done
  57 }
  58
  59 used_fs_size ()
  60 {
  61     # Returns used fs kbytes + 5% more
  62     # You could pass a block device as $1 or the mount point as $2
  63
  64     dev="${1}"
  65     mountp="${2}"
  66
  67     if [ -z "${mountp}" ]; then
  68         mountp=$(where_is_mounted "${dev}")
  69         if [ "$?" -gt 0 ]; then
  70             mountp=/mnt/tmp_fs_size
  71             mkdir -p "${mountp}"
  72             mount -t $(get_fstype "${dev}") -o ro "${dev}" "${mountp}"
  73             doumount=1
  74         fi
  75     fi
  76
  77     size=$(du -ks ${mountp} | cut -f1)
  78     size=$(expr ${size} + ${size}/20 ) # FIXME: 5% more to be sure
  79     needed_space=$(expr ${size} * 1024)
  80
  81     if [ ! -z "${doumount}" ]; then
  82         umount "${mountp}"
  83         rmdir "${mountp}"
  84     fi
  85     echo "${needed_space}"
  86 }
  87
  88 setup_loop() {
  89     local fspath=$1
  90     local module=$2
  91     local pattern=$3
  92
  93     modprobe "${MP_QUIET}" -b "$module"
  94     udevsettle
  95
  96     for loopdev in $pattern; do
  97         if [ "$(cat $loopdev/size)" -eq 0 ]; then
  98             dev=$(sys2dev "${loopdev}")
  99             losetup "$dev" "$fspath"
 100             echo "$dev"
 101             return 0
 102         fi
 103     done
 104     panic "No loop devices available"
 105 }
 106
 107 try_mount ()
 108 {
 109     dev="${1}"
 110     mountp="${2}"
 111     opts="${3}"
 112
 113     if where_is_mounted ${dev} > /dev/null; then
 114         mount -o remount,"${opts}" ${dev} $(where_is_mounted ${dev}) || panic "Remounting failed"
 115         mount -o bind $(where_is_mounted ${dev}) ${mountp} || panic "Cannot bind-mount"
 116     else
 117         mount -t $(get_fstype "${dev}") -o "${opts}" "${dev}" "${mountp}" || panic "Cannot mount ${dev} on ${mountp}"
 118     fi
 119 }
 120
 121 find_cow_device() {
 122     pers_label="${1}"
 123     cow_backing="/${pers_label}-backing"
 124     for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
 125         for dev in $(subdevices "${sysblock}"); do
 126             devname=$(sys2dev "${dev}")
 127             if [ "$(/lib/udev/vol_id -l $devname 2>/dev/null)" = "${pers_label}" ]; then
 128                 echo "$devname"
 129                 return
 130             elif [ "$(get_fstype ${devname})" = "vfat" ]; then # FIXME: all supported block devices should be scanned
 131                 mkdir -p "${cow_backing}"
 132                 try_mount "${devname}" "${cow_backing}" "rw"
 133                 if [ -e "${cow_backing}/${pers_label}" ]; then
 134                     echo $(setup_loop "${cow_backing}/${pers_label}" "loop" "/sys/block/loop*")
 135                     return 0
 136                 else
 137                     umount ${cow_backing}
 138                 fi
 139             fi
 140         done
 141     done
 142 }
 143
 144 find_files()
 145 # return the first of $filenames found on vfat and ext2 devices
 146 # FIXME: merge with above function
 147 {
 148     filenames="${1}"
 149     snap_backing="/snap-backing"
 150     for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
 151         for dev in $(subdevices "${sysblock}"); do
 152             devname=$(sys2dev "${dev}")
 153             devfstype="$(get_fstype ${devname})"
 154             if [ "${devfstype}" = "vfat" ] ||  [ "${devfstype}" = "ext2" ] ; then # FIXME: all supported block devices should be scanned
 155                 mkdir -p "${snap_backing}"
 156                 try_mount "${devname}" "${snap_backing}" "ro"
 157                 for filename in ${filenames}; do
 158                     if [ -e "${snap_backing}/${filename}" ]; then
 159                         echo "${devname} ${snap_backing} ${filename}"
 160                         return 0
 161                     fi
 162                 done
 163                 umount ${snap_backing}
 164             fi
 165         done
 166     done
 167 }
 168
 169