diff --git a/subr/pkg_install.subr b/subr/pkg_install.subr
index 4bc789e..ffe2d8d 100644
--- a/subr/pkg_install.subr
+++ b/subr/pkg_install.subr
@@ -22,7 +22,21 @@ pkg_install() {
 				return 1;
 			fi;
 		done; IFS="${_ifs_old}";
+		(set +o errexit -o noglob; trap "rm -f \"${BUILD_DLCACHEDIR}/install.lock\"" EXIT;
+		date; echo trying to grab lock
+		while true; do
+			if flock -E 622 -w 600 4; then
+				break;
+			elif [ "${?}" -eq 622 ]; then
+				continue;
+			else
+				exit "${?}";
+			fi;
+		done;
 		if ! tar -C "${PKG_DESTDIR}" -cpf - . | tar -C "${PKG_PREFIX}" --overwrite -xpf -; then
+			exit 1;
+		fi) 4<>"${BUILD_WORKDIR}/install.lock";
+		if [ "${?}" -ne 0 ]; then
 			return 1;
 		elif [ "${PKG_PKGLIST_DISABLE:-0}" -eq 0 ]; then
 			if [ ! -e "${PREFIX}/pkglist.${PKG_BUILD_TYPE}" ]\