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     local offset=$4
 114
 115     modprobe "${MP_QUIET}" -b "$module"
 116     udevsettle
 117
 118     for loopdev in $pattern; do
 119         if [ "$(cat $loopdev/size)" -eq 0 ]; then
 120             dev=$(sys2dev "${loopdev}")
 121             if [ -n "$offset" ]; then
 122                 losetup -o "$offset" "$dev" "$fspath"
 123             else
 124                 losetup "$dev" "$fspath"
 125             fi
 126             echo "$dev"
 127             return 0
 128         fi
 129     done
 130     panic "No loop devices available"
 131 }
 132
 133 try_mount ()
 134 {
 135     dev="${1}"
 136     mountp="${2}"
 137     opts="${3}"
 138
 139     if where_is_mounted ${dev} > /dev/null; then
 140         mount -o remount,"${opts}" ${dev} $(where_is_mounted ${dev}) || panic "Remounting failed"
 141         mount -o bind $(where_is_mounted ${dev}) ${mountp} || panic "Cannot bind-mount"
 142     else
 143         mount -t $(get_fstype "${dev}") -o "${opts}" "${dev}" "${mountp}" || panic "Cannot mount ${dev} on ${mountp}"
 144     fi
 145 }
 146
 147 find_cow_device() {
 148     pers_label="${1}"
 149     cow_backing="/${pers_label}-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             if [ "$(/lib/udev/vol_id -l $devname 2>/dev/null)" = "${pers_label}" ]; then
 154                 echo "$devname"
 155                 return
 156             elif [ "$(get_fstype ${devname})" = "vfat" ]; then # FIXME: all supported block devices should be scanned
 157                 mkdir -p "${cow_backing}"
 158                 try_mount "${devname}" "${cow_backing}" "rw"
 159                 if [ -e "${cow_backing}/${pers_label}" ]; then
 160                     echo $(setup_loop "${cow_backing}/${pers_label}" "loop" "/sys/block/loop*")
 161                     return 0
 162                 else
 163                     umount ${cow_backing}
 164                 fi
 165             fi
 166         done
 167     done
 168 }
 169
 170 find_files()
 171 # return the first of $filenames found on vfat and ext2 devices
 172 # FIXME: merge with above function
 173 {
 174     filenames="${1}"
 175     snap_backing="/snap-backing"
 176     for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
 177         for dev in $(subdevices "${sysblock}"); do
 178             devname=$(sys2dev "${dev}")
 179             devfstype="$(get_fstype ${devname})"
 180             if [ "${devfstype}" = "vfat" ] ||  [ "${devfstype}" = "ext2" ] ; then # FIXME: all supported block devices should be scanned
 181                 mkdir -p "${snap_backing}"
 182                 try_mount "${devname}" "${snap_backing}" "ro"
 183                 for filename in ${filenames}; do
 184                     if [ -e "${snap_backing}/${filename}" ]; then
 185                         echo "${devname} ${snap_backing} ${filename}"
 186                         return 0
 187                     fi
 188                 done
 189                 umount ${snap_backing}
 190             fi
 191         done
 192     done
 193 }
 194
 195