#!/bin/sh
set -e
export LC_ALL=C

type=$1
if [ "x$2" != "xin-favour" ]; then
preversion=$2
fi

restore_lib64_symlink() {
# Downgrading from a version with a /lib64 directory to a version with
# a /lib64 symlink is extremely dangerous. We need to move the
# directory aside and restore the symlink, otherwise the dynamic
# linker gets lost after unpacking the replacing version.

ldfile=$(readlink -e /lib64/ld-linux-x86-64.so.2)
# Test if libc is of the same architecture as coreutils
# If not, they almost surely have a multiarch system and we can use
# the native ELF interpreter
if ! $ldfile /bin/true 2>/dev/null; then
interpreter=
else
interpreter=$ldfile
fi

# Create the symlink in /lib again
cp -a /lib64/ld-linux-x86-64.so.2 /lib/

# sync before and after the operation to reduce the danger of hosing
# the system
sync
# See if they have anything in /lib64 besides the ELF interpreter.
# If yes, move the directory aside so they can restore it later,
# otherwise we just remove it.
if ls -1A /lib64 | grep -vq "^$(basename /lib64/ld-linux-x86-64.so.2)$"; then
echo "Warning: /lib64 not empty during libc downgrade, renaming it to /lib64.eglibc-old"
mv /lib64 /lib64.eglibc-old
else
rm -rf /lib64
fi

$interpreter /bin/ln -s /lib /lib64
sync
}




if [ "$type" = upgrade ]; then
if dpkg --compare-versions "$preversion" lt 2.13-17; then
if ! test -L /lib64; then
case ${DPKG_MAINTSCRIPT_ARCH:-$(dpkg --print-architecture)} in
amd64 | ppc64 | sparc64)
restore_lib64_symlink ;;
esac
fi
fi
fi

if [ -n "$preversion" ]; then
if dpkg --compare-versions "$preversion" lt 2.13-5; then
# downgrading from a multiarch libc to a pre-multiarch libc; we have
# to blow away /etc/ld.so.cache, otherwise the old unpacked libc
# is still first in the cache and segfaults when combined with
# our newly-unpacked ld.so.
rm -f /etc/ld.so.cache
fi
fi

exit 0