mac-os.relocate-listed-dynamic-shared-libraries.sh

#!/bin/bash
## Make all references relocatable in each dynamic shared library listed on stdin.
## By Stephen D. Rogers <inbox.c7r@steve-rogers.com>, 2019. 
##
## Arguments:
##
##     [--relative-to anchor_directory_pn]
##
## Typical uses:
##
##     for d1 in My.app/Contents/Frameworks ; do 
##     
##         find -H "$d1" -maxdepth 1 -type f -name '*.dylib' |
##             mac-os.relocate-listed-dynamic-shared-libraries --relative-to "$d1"
##     done
##
## If `anchor_directory_pn` is not specified, it defaults to the current directory.
##

set -e

set -o pipefail 2>&- || :

##
## from snippet library:
##

function xx() { # ...

	echo 1>&2 "${PS4:-+}" "$@"
	"$@"
}

function list_id_and_references_specified_in_dynamic_shared_library() { # dynamic_shared_library_pn

	local dynamic_shared_library_pn="${1:?missing argument: dynamic_shared_library_pn}" ; shift 1

	objdump -macho -dylib-id "${dynamic_shared_library_pn:?}" | perl -lne '

		chomp;

		if (0) {}
		elsif ($. == 1 && m#^\s*(.*?\S):\s*$#) {

			printf STDOUT "%-10s %s$/", "pathname", $1;
		}
		elsif ($. == 2) {

			printf STDOUT "%-10s %s$/", "id", $_;
		}
	';

	objdump -macho -dylibs-used "${dynamic_shared_library_pn:?}" | perl -lne '

		chomp;

		if (0) {}
		elsif ($. == 1 && m#^\s*(.*?\S):\s*$#) {

			printf STDOUT "%-10s %s$/", "pathname", $1;
		}
		elsif ($. >= 2 && m#^\s*(.*?\S)(?:\s+\(compatibility version ([\d.]+), current version ([\d.]+)\))#) {

			printf STDOUT "%-10s %s$/", "reference", $1;
		}
		else {
			printf STDERR "Unexpected dylib reference: %s$/", $_;

			next;
		}
	';
}

function relocate_mac_os_dynamic_shared_library() { # [--relative-to anchor_directory_pn] dynamic_shared_library_pn

	local anchor_directory_pn
	local dynamic_shared_library_pn

	while [ $# -gt 0 ] ; do
	case "${1}" in
	--relative-to)
		anchor_directory_pn="${2}"
		shift 2
		break
		;;
	--)
		shift 1
		break
		;;
	*)
		break
		;;
	esac;done

	anchor_directory_pn="${anchor_directory_pn:-.}"

	dynamic_shared_library_pn="${1:?missing argument: dynamic_shared_library_pn}" ; shift 1

	if [ $# -gt 0 ] ; then

		echo 1>&2 "Unexpected argument(s): ${@}"
		false
	fi

	##

	list_id_and_references_specified_in_dynamic_shared_library "${dynamic_shared_library_pn:?}" |
	(
		change_set=()

		while read type value ; do
		case "${type}" in
		id)
			corrected_value="$(relocate_mac_os_dynamic_shared_library_pathname_relative_to "${anchor_directory_pn}" "${value}")"

			if [ -n "${corrected_value}" -a "${corrected_value}" != "${value}" ] ; then

				change_set+=( -id "${corrected_value}" )
			fi
			;;

		pathname)
			dynamic_shared_library_pn02="${value}"
			;;

		reference)
			corrected_value="$(relocate_mac_os_dynamic_shared_library_pathname_relative_to "${anchor_directory_pn}" "${value}")"

			if [ -n "${corrected_value}" -a "${corrected_value}" != "${value}" ] ; then

				change_set+=( -change "${value}" "${corrected_value}" )
			fi
			;;
		esac;done

		if [ ${#change_set[@]} -gt 0 ] ; then

			xx install_name_tool "${change_set[@]}" "${dynamic_shared_library_pn02}"
			xx :
		fi
	)
}

function relocate_mac_os_dynamic_shared_library_pathname_relative_to() { # anchor_directory_pn dynamic_shared_library_pn

	local anchor_directory_pn="${1:?}" ; shift 1
	local dynamic_shared_library_pn="${1:?}" ; shift 1

	local result_untransformed="${dynamic_shared_library_pn}"
	local result="${result_untransformed}"

	case "${result}" in
	'')
		: # no transformation
		;;

	@executable_file/*)
		result="${result#@executable_file/../Frameworks/}"

		case "${result}" in
		@executable_file/*)
			result="${result_untransformed}" # fallback
			;;
		*)
			result="@rpath/${result}"
			;;
		esac
		;;

	@loader_path/*)
		: # no transformation
		;;

	@rpath/*)
		: # no transformation
		;;

	*)
		result="${result#${anchor_directory_pn%/}/}"

		case "${result}" in
		/*)
			result="${result_untransformed}" # fallback
			;;
		*)
			result="@rpath/${result}"
			;;
		esac
		;;
	esac

	echo "${result}"
}

##
## core logic:
##

function main() { # ...

	local f1

	while read -r f1 ; do

		[ -f "$f1" ] || continue

		relocate_mac_os_dynamic_shared_library "$@" "$f1"
	done
}

! [ "$0" = "${BASH_SOURCE}" ] || main "$@"