#! /bin/sh
#
# This script determines whether certain earlier versions of the
# Modula-3 port exist on the system in a place where the linker or
# dynamic linker would find them.  These earlier versions must be
# removed before installing the current port, because they use higher
# major version numbers for the shared libraries than this port uses.
# This situation arose because of an ill-considered choice for the
# major version numbers in those early ports.  I am intentionally
# breaking the rule that the version number should never be decreased,
# in order to nip this unfortunate situation in the bud.

if [ x$2 != xPRE-INSTALL ]; then
    exit 0
fi

check() {
    local list i lib_path oldIFS status

    status=0

    # Check the dynamic linker's hints.

    list=$(/sbin/ldconfig -r | grep "libm3\.so\.35[34]\." | sed "s/^.* => //")
    for file in ${list}; do
	if [ -f ${file} ]; then  # The file actually exists
	    echo $(dirname ${file})
	    status=1
	fi
    done

    # Check any directories in LD_LIBRARY_PATH.  Also, check the directory
    # where we intend to install the new libraries.

    lib_path=${PREFIX:-/usr/local}/lib/m3/FreeBSD2:${LD_LIBRARY_PATH}
    oldIFS=${IFS}; IFS=":"; set ${lib_path}; IFS=${oldIFS}
    for dir; do
	if [ x${dir} != x ]; then
	    if echo ${dir}/libm3.so.35[34].* | grep -q "\*"; then # Not found
		:
	    else  # Found
		echo ${dir}
		status=1
	    fi
	fi
    done

    return ${status}
}

tmp=/tmp/m3-inst$$a
trap "rm -f ${tmp}" 1 2 3 15
touch ${tmp}

if check > ${tmp}; then
    rm -f ${tmp}
    exit 0
else
    echo "*****************************************************************"
    echo "*                        IMPORTANT                              *"
    echo "* You currently have an older version of the Modula-3 port on   *"
    echo "* your system.  You must remove the older version before you    *"
    echo "* install this one.  Otherwise, a problem with the shared       *"
    echo "* libraries in the older version will cause utter confusion.    *"
    echo "* Please remove the older version and try again.                *"
    echo "*                                                               *"
    echo "* Old Modula-3 shared libraries were found in the following     *"
    echo "* directories:                                                  *"
    echo "*                                                               *"
    sort -u ${tmp} | awk '{ printf "*   %-59s *\n", $0 }'
    echo "*****************************************************************"
    rm -f ${tmp}
    exit 1
fi