219 lines
6 KiB
Text
219 lines
6 KiB
Text
## Casper helper functions, used by casper on boot and by casper-snapshot
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MP_QUIET="-q"
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sys2dev() {
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sysdev=${1#/sys}
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echo "/dev/$(/sbin/udevadm info -q name -p ${sysdev} 2>/dev/null|| echo ${sysdev##*/})"
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}
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subdevices() {
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sysblock=$1
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r=""
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for dev in "${sysblock}" "${sysblock}"/*; do
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if [ -e "${dev}/dev" ]; then
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r="${r} ${dev}"
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fi
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done
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echo ${r}
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}
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is_supported_fs () {
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# FIXME: do something better like the scan of supported filesystems
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fstype="${1}"
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case ${fstype} in
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vfat|iso9660|udf|ext2|ext3|ext4|ntfs)
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return 0
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;;
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esac
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return 1
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}
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get_fstype() {
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/sbin/blkid -s TYPE -o value $1 2>/dev/null
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}
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where_is_mounted() {
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device=$1
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if grep -q "^$device " /proc/mounts; then
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mountpoint="$(grep "^$device " /proc/mounts | awk '{print $2; exit}')"
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grep "^$device " /proc/mounts | read d mountpoint rest
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echo $mountpoint
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return 0
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fi
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return 1
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}
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lastline() {
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while read lines ; do
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line=${lines}
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done
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echo "${line}"
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}
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base_path ()
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{
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testpath="${1}"
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mounts="$(awk '{print $2}' /proc/mounts)"
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testpath="$(busybox realpath ${testpath})"
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while true ; do
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if echo "${mounts}" | grep -qs "^${testpath}" ; then
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set -- `echo "${mounts}" | grep "^${testpath}" | lastline`
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echo ${1}
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break
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else
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testpath=`dirname $testpath`
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fi
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done
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}
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fs_size ()
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{
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# Returns used/free fs kbytes + 5% more
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# You could pass a block device as $1 or the mount point as $2
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dev="${1}"
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mountp="${2}"
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used="${3}"
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if [ -z "${mountp}" ]; then
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mountp=$(where_is_mounted "${dev}")
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if [ "$?" -gt 0 ]; then
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mountp="/mnt/tmp_fs_size"
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mkdir -p "${mountp}"
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mount -t $(get_fstype "${dev}") -o ro "${dev}" "${mountp}"
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doumount=1
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fi
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fi
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if [ "${used}" = "used" ]; then
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size=$(du -ks ${mountp} | cut -f1)
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size=$(expr ${size} + ${size} / 20 ) # FIXME: 5% more to be sure
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else
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# free space
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size="$(df -k | grep -s ${mountp} | awk '{print $4}')"
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fi
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if [ -n "${doumount}" ]; then
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umount "${mountp}"
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rmdir "${mountp}"
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fi
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echo "${size}"
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}
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setup_loop() {
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local fspath=$1
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local module=$2
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local pattern=$3
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local offset=$4
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modprobe ${MP_QUIET} -b "$module"
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/sbin/udevadm settle
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if [ "$module" = loop ]; then
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if [ ! -e /dev/loop0 ]; then
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# temporary workaround for kernel bug
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for i in 0 1 2 3 4 5 6 7; do
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mknod "/dev/loop$i" b 7 "$i" || true
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done
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fi
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dev="$(losetup -f)"
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if [ "$dev" ]; then
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if [ -n "$offset" ]; then
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losetup -o "$offset" "$dev" "$fspath"
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else
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losetup "$dev" "$fspath"
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fi
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echo "$dev"
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return 0
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else
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panic "No loop devices available"
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fi
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else
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for loopdev in $pattern; do
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if [ "$(cat $loopdev/size)" -eq 0 ]; then
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dev=$(sys2dev "${loopdev}")
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if [ -n "$offset" ]; then
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losetup -o "$offset" "$dev" "$fspath"
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else
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losetup "$dev" "$fspath"
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fi
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echo "$dev"
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return 0
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fi
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done
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panic "No loop devices available"
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fi
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}
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try_mount ()
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{
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dev="${1}"
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mountp="${2}"
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opts="${3}"
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if where_is_mounted ${dev} > /dev/null; then
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if [ "${opts}" != "ro" ]; then
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mount -o remount,"${opts}" ${dev} $(where_is_mounted ${dev}) || panic "Remounting failed"
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fi
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mount -o bind $(where_is_mounted ${dev}) ${mountp} || panic "Cannot bind-mount"
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else
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mount -t $(get_fstype "${dev}") -o "${opts}" "${dev}" "${mountp}" || panic "Cannot mount ${dev} on ${mountp}"
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fi
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}
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find_cow_device() {
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pers_label="${1}"
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cow_backing="/${pers_label}-backing"
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for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
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for dev in $(subdevices "${sysblock}"); do
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devname=$(sys2dev "${dev}")
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if [ "$(/sbin/blkid -s LABEL -o value $devname 2>/dev/null)" = "${pers_label}" ]; then
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echo "$devname"
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return
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# Do not add any filesystem types here that might be able to
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# mount a journalled filesystem and replay the journal. Doing so
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# will cause data loss when a live CD is booted on a system
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# where filesystems are in use by hibernated operating systems.
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elif [ "$(get_fstype ${devname})" = "vfat" ]; then
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mkdir -p "${cow_backing}"
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try_mount "${devname}" "${cow_backing}" "rw"
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if [ -e "${cow_backing}/${pers_label}" ]; then
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echo $(setup_loop "${cow_backing}/${pers_label}" "loop" "/sys/block/loop*")
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return 0
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else
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umount ${cow_backing}
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fi
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fi
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done
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done
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}
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find_files()
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# return the first of $filenames found on vfat and ext2 devices
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# FIXME: merge with above function
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{
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filenames="${1}"
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snap_backing="/snap-backing"
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for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
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for dev in $(subdevices "${sysblock}"); do
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devname=$(sys2dev "${dev}")
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devfstype="$(get_fstype ${devname})"
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if [ "${devfstype}" = "vfat" ] || [ "${devfstype}" = "ext2" ] ; then # FIXME: all supported block devices should be scanned
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mkdir -p "${snap_backing}"
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try_mount "${devname}" "${snap_backing}" "ro"
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for filename in ${filenames}; do
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if [ -e "${snap_backing}/${filename}" ]; then
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echo "${devname} ${snap_backing} ${filename}"
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return 0
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fi
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done
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umount ${snap_backing}
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fi
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done
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done
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}
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