Remove version suffixes in DT_SONAME/DT_NEEDED in a set of ELF objects

fixlibs.sh

#! /bin/bash
#
# SPDX-License-Identifier: MIT
#

set -eu -o pipefail

LOG_COMMANDS=false

do_log () {
	local prefix
	prefix=$1
	shift
	echo "$prefix $*"
} 1>&2

if [[ $# -eq 0 ]] ; then
	do_log 'Usage:' "$0 path/to/libdir [extralib...]"
	exit 1
fi

info () {
	do_log '[INFO]' "$@"
}

warn () {
	do_log '[WARN]' "$@"
}

if $LOG_COMMANDS ; then
	logcmd () { do_log ';;' "$@" ; "$@" ; }
else
	logcmd () { "$@" ; }
fi

declare -A all_libs=()
declare -A extra_objects=()
declare -A mappings=()

is_elf () {
	local typ
	typ=$(file -b -L "$1")
	[[ $typ = ELF* ]]
}

scan_one () {
	if ! is_elf "$1" ; then
		info "Skipping non-ELF object: $1"
		return
	fi

	all_libs["$1"]=:
	if [[ -L $1 ]] ; then
		local soname=$(patchelf --print-soname "$1")
		local simplename=$(basename "$1")
		mappings["$soname"]=$simplename
		# Replace .so with actual file
		local real_file
		real_file=$(readlink -f "$1")
		logcmd rm "$1"
		logcmd mv "$real_file" "$1"
		logcmd patchelf --set-soname "$simplename" "$1"
	fi
}

libdir=$1
shift

for item in "$libdir"/*.so ; do
	scan_one "${item}"
done

if [[ ${#mappings[@]} -gt 0 ]] ; then
	declare -a patchelf_args
	for soname_from in "${!mappings[@]}" ; do
		soname_to=${mappings["$soname_from"]}
		patchelf_args+=( --replace-needed "$soname_from" "$soname_to" )
	done

	# Filter out non-ELF extra objects passed in the command line.
	for f in "$@" ; do
		if is_elf "$f" ; then
			extra_objects["$f"]=:
		else
			info "Skipping non-ELF object: $f"
		fi
	done

	logcmd patchelf "${patchelf_args[@]}" "${!all_libs[@]}" "${!extra_objects[@]}"
else
	info 'No soname mappings to apply'
fi

# Clean dangling symlinks
for f in "$libdir"/* ; do
	if [[ -L $f ]] ; then
		ff=$(readlink -f "$f")
		if [[ ! -r $ff ]] ; then
			logcmd rm "$f"
		fi
	fi
done

This uses patchelf to edit ELF objects and remove version suffixes in their DT_SONAME and DT_NEEDED headers. Typically used like this:

bash fixlibs.sh path/to/sysroot/lib/ path/to/sysroot/bin/*

This will edit the libraries in the lib/ subdirectory, and the additional files passed after the directory (all the files under the bin/ subdirectory), rename libraries, and remove stale versioned library symlinks.