scripts/live-helpers

   1 ## Casper helper functions, used by casper on boot and by casper-snapshot
   2
   3 if [ "${BUILD_SYSTEM}" = "Ubuntu" ]; then
   4     MP_QUIET="-Q"
   5 elif [ "${BUILD_SYSTEM}" = "Debian" ]; then
   6     MP_QUIET="-q"
   7 else
   8     MP_QUIET=""
   9 fi
  10
  11 if [ ! -x "/bin/fstype" ]; then
  12     # klibc not in path -> not in initramfs
  13     export PATH="${PATH}:/usr/lib/klibc/bin"
  14 fi
  15
  16 sys2dev() {
  17     sysdev=${1#/sys}
  18     echo "/dev/$(udevinfo -q name -p ${sysdev} 2>/dev/null|| echo ${sysdev##*/})"
  19 }
  20
  21 subdevices() {
  22     sysblock=$1
  23     r=""
  24     for dev in "${sysblock}" "${sysblock}"/*; do
  25         if [ -e "${dev}/dev" ]; then
  26             r="${r} ${dev}"
  27         fi
  28     done
  29     echo ${r}
  30 }
  31
  32 get_fstype() {
  33     local FSTYPE
  34     local FSSIZE
  35     eval $(fstype < $1)
  36     if [ "$FSTYPE" != "unknown" ]; then
  37         echo $FSTYPE
  38         return 0
  39     fi
  40     /lib/udev/vol_id -t $1 2>/dev/null
  41 }
  42
  43 where_is_mounted() {
  44     device=$1
  45     if grep -q "^$device " /proc/mounts; then
  46         grep "^$device " /proc/mounts | read d mountpoint rest
  47         echo $mountpoint
  48         return 0
  49     fi
  50     return 1
  51 }
  52
  53 lastline() {
  54     while read lines ; do
  55         line=${lines}
  56     done
  57     echo "${line}"
  58 }
  59
  60 base_path ()
  61 {
  62     testpath="${1}"
  63     mounts="$(awk '{print $2}' /proc/mounts)"
  64     testpath="$(busybox realpath ${testpath})"
  65
  66     while true ; do
  67         if echo "${mounts}" | grep -qs "^${testpath}" ; then
  68             set -- `echo "${mounts}" | grep "^${testpath}" | lastline`
  69             echo ${1}
  70             break
  71         else
  72             testpath=`dirname $testpath`
  73         fi
  74     done
  75 }
  76
  77 fs_size ()
  78 {
  79     # Returns used/free fs kbytes + 5% more
  80     # You could pass a block device as $1 or the mount point as $2
  81
  82     dev="${1}"
  83     mountp="${2}"
  84     used="${3}"
  85
  86     if [ -z "${mountp}" ]; then
  87         mountp=$(where_is_mounted "${dev}")
  88         if [ "$?" -gt 0 ]; then
  89             mountp="/mnt/tmp_fs_size"
  90             mkdir -p "${mountp}"
  91             mount -t $(get_fstype "${dev}") -o ro "${dev}" "${mountp}"
  92             doumount=1
  93         fi
  94     fi
  95
  96     if [ "${used}" = "used" ]; then
  97         size=$(du -ks ${mountp} | cut -f1)
  98         size=$(expr ${size} + ${size} / 20 ) # FIXME: 5% more to be sure
  99     else
 100         # free space
 101         size="$(df -k | grep -s ${mountp} | awk '{print $4}')"
 102     fi
 103
 104     if [ -n "${doumount}" ]; then
 105         umount "${mountp}"
 106         rmdir "${mountp}"
 107     fi
 108     echo "${size}"
 109 }
 110
 111 setup_loop() {
 112     local fspath=$1
 113     local module=$2
 114     local pattern=$3
 115     local offset=$4
 116
 117     modprobe ${MP_QUIET} -b "$module"
 118     udevsettle
 119
 120     for loopdev in $pattern; do
 121         if [ "$(cat $loopdev/size)" -eq 0 ]; then
 122             dev=$(sys2dev "${loopdev}")
 123             if [ -n "$offset" ]; then
 124                 losetup -o "$offset" "$dev" "$fspath"
 125             else
 126                 losetup "$dev" "$fspath"
 127             fi
 128             echo "$dev"
 129             return 0
 130         fi
 131     done
 132     panic "No loop devices available"
 133 }
 134
 135 try_mount ()
 136 {
 137     dev="${1}"
 138     mountp="${2}"
 139     opts="${3}"
 140
 141     if where_is_mounted ${dev} > /dev/null; then
 142         mount -o remount,"${opts}" ${dev} $(where_is_mounted ${dev}) || panic "Remounting failed"
 143         mount -o bind $(where_is_mounted ${dev}) ${mountp} || panic "Cannot bind-mount"
 144     else
 145         mount -t $(get_fstype "${dev}") -o "${opts}" "${dev}" "${mountp}" || panic "Cannot mount ${dev} on ${mountp}"
 146     fi
 147 }
 148
 149 find_cow_device() {
 150     pers_label="${1}"
 151     cow_backing="/${pers_label}-backing"
 152     for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
 153         for dev in $(subdevices "${sysblock}"); do
 154             devname=$(sys2dev "${dev}")
 155             if [ "$(/lib/udev/vol_id -l $devname 2>/dev/null)" = "${pers_label}" ]; then
 156                 echo "$devname"
 157                 return
 158             elif [ "$(get_fstype ${devname})" = "vfat" ]; then # FIXME: all supported block devices should be scanned
 159                 mkdir -p "${cow_backing}"
 160                 try_mount "${devname}" "${cow_backing}" "rw"
 161                 if [ -e "${cow_backing}/${pers_label}" ]; then
 162                     echo $(setup_loop "${cow_backing}/${pers_label}" "loop" "/sys/block/loop*")
 163                     return 0
 164                 else
 165                     umount ${cow_backing}
 166                 fi
 167             fi
 168         done
 169     done
 170 }
 171
 172 find_files()
 173 # return the first of $filenames found on vfat and ext2 devices
 174 # FIXME: merge with above function
 175 {
 176     filenames="${1}"
 177     snap_backing="/snap-backing"
 178     for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
 179         for dev in $(subdevices "${sysblock}"); do
 180             devname=$(sys2dev "${dev}")
 181             devfstype="$(get_fstype ${devname})"
 182             if [ "${devfstype}" = "vfat" ] ||  [ "${devfstype}" = "ext2" ] ; then # FIXME: all supported block devices should be scanned
 183                 mkdir -p "${snap_backing}"
 184                 try_mount "${devname}" "${snap_backing}" "ro"
 185                 for filename in ${filenames}; do
 186                     if [ -e "${snap_backing}/${filename}" ]; then
 187                         echo "${devname} ${snap_backing} ${filename}"
 188                         return 0
 189                     fi
 190                 done
 191                 umount ${snap_backing}
 192             fi
 193         done
 194     done
 195 }
 196
 197