#! /bin/bash

# This script is only needed to uninstall old KMPs when updating
# SLE10 to SLE11+. weak-modules2 is the script what should be used by new
# packages

unset LANG LC_ALL LC_COLLATE

NM=
if command -v nm >/dev/null; then
    NM=nm
elif command -v eu-nm >/dev/null; then
    NM=eu-nm
else
    echo "ERROR: nm not found" >&2
    exit 1
fi

# Check if MODULE is compatible with kernel release KREL.
module_is_compatible() {
    declare module=$1 krel=$2 module_krel=$(krel_of_module "$module")

    if [ ! -e $tmpdir/all-symvers-$krel-$module_krel ]; then
	# Symbols exported by the "new" kernel
	if [ ! -e $tmpdir/symvers-$krel ]; then
	    if [ -e /boot/symvers-$krel.gz ]; then
		zcat /boot/symvers-$krel.gz \
		| sed -r -ne 's:^0x0*([0-9a-f]+\t[0-9a-zA-Z_]+)\t.*:\1:p'
	    fi > $tmpdir/symvers-$krel
	fi

	# Symbols that other add-on modules of the "old" kernel export
	# (and that this module may require)
	if [ ! -e $tmpdir/extra-symvers-$module_krel ]; then
	    if [ -e /lib/modules/$module_krel/updates ]; then
		find /lib/modules/$module_krel/updates -name '*.ko' \
		| xargs $NM -B \
		| sed -nre 's:^0*([0-9a-f]+) A __crc_(.*):\1 \2:p'
	    fi > $tmpdir/extra-symvers-$module_krel
	fi

	sort -u $tmpdir/symvers-$krel $tmpdir/extra-symvers-$module_krel \
	> $tmpdir/all-symvers-$krel-$module_krel
    fi

    # If the module does not have modversions enabled, $tmpdir/modvers
    # will be empty.
    /sbin/modprobe --dump-modversions "$module" \
    | sed -r -e 's:^0x0*([0-9a-f]+\t.*):\1:' \
    | sort -u \
    > $tmpdir/modvers

    # Only include lines of the second file in the output that don't
    # match lines in the first file. (The default separator is
    # <space>, so we are matching the whole line.)
    join -j 1 -v 2 $tmpdir/all-symvers-$krel-$module_krel \
		   $tmpdir/modvers > $tmpdir/join

    if [ ! -s $tmpdir/modvers ]; then
	echo "Warning: Module ${module##*/} from kernel $module_krel has no" \
	     "modversions, so it cannot be reused for kernel $krel" >&2
    elif [ -s $tmpdir/join ]; then
	[ -n "$verbose" ] &&
	echo "Module ${module##*/} from kernel $module_krel is not compatible" \
	     "with kernel $krel in symbols:" $(sed -e 's:.* ::' $tmpdir/join)
    elif [ "$krel" != "$module_krel" ]; then
	[ -n "$verbose" ] &&
	echo "Module ${module##*/} from kernel $module_krel is compatible" \
	     "with kernel $krel"
	return 0
    fi
    return 1
}

# Compute the kernel release of a module.
krel_of_module() {
    declare module=$1
    set -- $(/sbin/modinfo -F vermagic "$module")
    echo "$1"
}

# Read a list of modules from standard input, convert the filenames into
# absolute names, and compute the kernel release of each module.
read_modules_list() {
    local saved_IFS=$IFS
    IFS=$'\n'
    modules=($(cat))
    IFS=$saved_IFS

    for ((n = 0; n < ${#modules[@]}; n++)); do
	if [ ${modules[n]:0:1} != / ]; then
	    modules[n]=$PWD/${modules[n]}
	fi
	if [ -f "${modules[n]}" ]; then
	    module_krels[n]=$(krel_of_module "${modules[n]}")
	else
	    # Try to extract the kernel release from the path
	    set -- "${modules[n]#/lib/modules/}"
	    module_krels[n]=${1%%/*}
	fi
    done
}

doit() {
    [ -n "$verbose" ] && echo "$@"
    [ -n "$dry_run" ] || "$@"
}

usage() {
    cat <<'EOF'
Usage: ${0##*/} [options] {--add-modules|--remove-modules}
       ${0##*/} [options] {--add-kernel|--remove-kernel} {kernel-release}

--add-modules
	Add a list of modules read from standard input. Create
	symlinks in compatible kernel's weak-updates/ directory.
	The list of modules is read from standard input.

--remove-modules
	Remove compatibility symlinks from weak-updates/ directories
	for a list of modules.  The list of modules is read from
	standard input.

--add-kernel
	Add compatibility symlinks for all compatible modules to the
	specified or running kernel.

--remove-kernel
	Remove all compatibility symlinks for the specified or current
	kernel.

--verbose
	Print the commands executed.

-dry-run
	Do not create/remove any files.
EOF
    exit $1
}

[ -e /etc/sysconfig/kernel ] && source /etc/sysconfig/kernel

unset ${!changed_modules_*} ${!changed_initrd_*}

module_has_changed() {
    declare module=$1 krel=$2

    module=${module%.ko}
    module=${module##*/}

    eval "changed_modules_${krel//[^a-zA-Z0-9]/_}=$krel"
    case " $INITRD_MODULES " in
    *" $module "*)
	eval "changed_initrd_${krel//[^a-zA-Z0-9]/_}=$krel"
	;;
    esac
}

options=`getopt -o h --long help,add-modules,remove-modules \
		     --long add-kernel,remove-kernel,dry-run,verbose -- "$@"`

[ $? -eq 0 ] || usage 1

eval set -- "$options"

while :; do
    case "$1" in
    --add-modules)
	add_modules=1
	;;
    --remove-modules)
	remove_modules=1
	;;
    --add-kernel)
	add_kernel=1
	;;
    --remove-kernel)
	remove_kernel=1
	;;
    --dry-run)
	dry_run=1
	;;
    --verbose)
	verbose=1
	;;
    -h|--help)
	usage 0
	;;
    --)
	shift
	break
	;;
    esac
    shift
done

if [ "$add_modules$remove_modules$add_kernel$remove_kernel" != 1 ]; then
    usage 1
fi
if [ -n "$add_kernel" -o -n "$remove_kernel" ]; then
    [ $# -gt 1 ] && usage 1
else
    [ $# -ne 0 ] && usage 1
fi

tmpdir=$(mktemp -td ${0##*/}.XXXXXX)
trap "rm -rf $tmpdir" EXIT

if [ -n "$add_modules" ]; then
    read_modules_list || exit 1
    if [ ${#modules[@]} -gt 0 ]; then
	for krel in $(ls /lib/modules/); do
	    [ -e /boot/symvers-$krel.gz ] || continue
	    for ((n = 0; n < ${#modules[@]}; n++)); do
		module=${modules[n]}
		module_krel=${module_krels[n]}
		case "$module" in
		/lib/modules/$krel/*)
		    continue ;;
		esac
		subpath=${module#/lib/modules/$module_krel/updates}
		weak_module=/lib/modules/$krel/weak-updates/${subpath#/}
		if [ -r "$weak_module" ]; then
		    weak_krel=$(krel_of_module "$weak_module")
		    if [ "$weak_krel" != "$module_krel" ] &&
		       [ "$(printf "%s\n" "$weak_krel" "$module_krel" \
			    | /usr/lib/rpm/rpmsort | head -n 1)" = \
			 "$module_krel" ]; then
			# Keep modules from more recent kernels.
			[ -n "$verbose" ] && echo \
"Keeping module ${module##*/} from kernel $weak_krel for kernel $krel"
			continue
		    fi
		fi
		if module_is_compatible $module $krel; then
		    doit mkdir -p $(dirname $weak_module)
		    doit ln -sf $module $weak_module
		    module_has_changed $module $krel
		fi
	    done
	done
    fi
elif [ -n "$remove_modules" ]; then
    read_modules_list || exit 1
    if [ ${#modules[@]} -gt 0 ]; then
	krels=($(ls /lib/modules/ | /usr/lib/rpm/rpmsort -r))
	for krel in "${krels[@]}"; do
	    [ -e /boot/symvers-$krel.gz ] || continue
	    for ((n = 0; n < ${#modules[@]}; n++)); do
		module=${modules[n]}
		[ -e "$module" ] && continue
		module_krel=${module_krels[n]}
		subpath=${module#/lib/modules/$module_krel/updates}
		weak_module=/lib/modules/$krel/weak-updates/${subpath#/}
		if [ "$(readlink "$weak_module")" = "$module" ]; then
		    [ -n "$verbose" ] && echo \
"Removing compatible module ${subpath#/} from kernel $krel"
		    doit rm -f "$weak_module"
		    for krel2 in "${krels[@]}"; do
			[ -e /boot/symvers-$krel2.gz ] || continue
			module=/lib/modules/$krel2/updates/${subpath#/}
			[ -e "$module" ] || continue
			if module_is_compatible "$module" "$krel2"; then
			    [ -n "$verbose" ] && echo \
"Adding compatible module ${module##*/} from kernel $krel2 instead"
			    doit ln -s "$module" "$weak_module"
			    break
			fi
		    done
		    doit rmdir --parents --ignore-fail-on-non-empty \
			       "$(dirname "$weak_module")"
		    module_has_changed $module $krel
		fi
	    done
	done
    fi
elif [ -n "$add_kernel" ]; then
    add_krel=${1:-$(uname -r)}
    if [ ! -e /boot/symvers-$add_krel.gz ]; then
	echo "Symvers dump file /boot/symvers-$add_krel.gz" \
	     "not found" >&2
	exit 1
    fi
    for krel in $(ls /lib/modules/ | /usr/lib/rpm/rpmsort -r); do
	[ "$add_krel" = "$krel" ] && continue
	[ -d /lib/modules/$krel/updates ] || continue
	for module in $(find /lib/modules/$krel/updates -name '*.ko'); do
	    subpath=${module#/lib/modules/$krel/updates}
	    weak_module=/lib/modules/$add_krel/weak-updates/${subpath#/}
	    [ -e "$weak_module" ] && continue
	    if module_is_compatible $module $add_krel; then
		doit mkdir -p $(dirname $weak_module)
		doit ln -sf $module $weak_module
	    fi
	done
    done
elif [ -n "$remove_kernel" ]; then
    remove_krel=${1:-$(uname -r)}
    weak_modules=/lib/modules/$remove_krel/weak-updates
    doit rm -rf "$weak_modules"
fi

for krel in ${!changed_modules_*}; do
    krel=${!krel}
    [ -e /boot/System.map-$krel ] || continue
    /sbin/depmod -ae -F /boot/System.map-$krel $krel
done

for krel in ${!changed_initrd_*}; do
    krel=${!krel}
    [ -e /boot/System.map-$krel ] || continue

    image=
    for x in vmlinuz image vmlinux linux bzImage uImage; do
	if [ -f /boot/$x-$krel ]; then
	    image=$x
	    break
	fi
    done
    if [ -n "$image" ]; then
	/sbin/mkinitrd -k /boot/$image-$krel -i /boot/initrd-$krel
    fi
done

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