extensions: link on libxtables and check symbols

Have each extension link against libxtables.so; with this, all home
symbols are known at link time and we can use ld's --no-undefined to
run the check, dropping the homebrew solution.

By having libxtables.so required by extensions, package managers'
automatic dependency discovery will become effective so that manual
dependencies for distros with split extension packages (e.g. OpenWRT)
will not be necessary anymore.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

diff --git a/configure.ac b/configure.ac
index 5679098c979de78ca3fea559f8ee6ca8bdae665a..0f85b83160a493c9c1a16e495e8505ca7a98477b 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -58,6 +58,15 @@ AX_CHECK_LINKER_FLAGS([-Wl,--no-as-needed],
        [libiptc_LDFLAGS2="-Wl,--no-as-needed"])
 AC_SUBST([libiptc_LDFLAGS2])
 
+AC_MSG_CHECKING([whether $LD knows -Wl,--no-undefined])
+saved_LDFLAGS="$LDFLAGS";
+LDFLAGS="-Wl,--no-undefined";
+AC_LINK_IFELSE([AC_LANG_SOURCE([int main(void) {}])],
+       [noundef_LDFLAGS="$LDFLAGS"; AC_MSG_RESULT([yes])],
+       [AC_MSG_RESULT([no])]
+)
+LDFLAGS="$saved_LDFLAGS";
+
 blacklist_modules="";
 
 AC_CHECK_HEADERS([linux/dccp.h linux/ip_vs.h linux/magic.h linux/proc_fs.h])
@@ -99,6 +108,7 @@ pkgdatadir='${datadir}/xtables';
 
 AC_SUBST([regular_CFLAGS])
 AC_SUBST([regular_CPPFLAGS])
+AC_SUBST([noundef_LDFLAGS])
 AC_SUBST([kinclude_CPPFLAGS])
 AC_SUBST([kbuilddir])
 AC_SUBST([ksourcedir])

diff --git a/extensions/GNUmakefile.in b/extensions/GNUmakefile.in
index 84c85de799ead8392bf32d943c5f9d14ff34f1b4..218dc3ad42b6725a7de00d1a34dc4ea0e0e6c513 100644 (file)
--- a/extensions/GNUmakefile.in
+++ b/extensions/GNUmakefile.in
@@ -23,6 +23,7 @@ kinclude_CPPFLAGS  = @kinclude_CPPFLAGS@
 AM_CFLAGS       = ${regular_CFLAGS}
 AM_CPPFLAGS     = ${regular_CPPFLAGS} -I${top_builddir}/include -I${top_builddir} -I${top_srcdir}/include ${kinclude_CPPFLAGS}
 AM_DEPFLAGS     = -Wp,-MMD,$(@D)/.$(@F).d,-MT,$@
+AM_LDFLAGS      = @noundef_LDFLAGS@
 
 ifeq (${V},)
 AM_LIBTOOL_SILENT = --silent
@@ -68,16 +69,7 @@ targets_install :=
 
 .PHONY: all install clean distclean FORCE
 
-all: ${targets} check
-
-check: ${targets}
-       @echo "  CHECK    unknown symbols in .so files"; \
-       . ../libxtables/libxtables.la; \
-       for i in lib*.so; do \
-               [ "$$i" = "lib*.so" ] && continue; \
-               LD_PRELOAD="$$dlname" LD_LIBRARY_PATH=../libxtables/.libs \
-                       ldd -r $$i 2>&1 >/dev/null; \
-       done;
+all: ${targets}
 
 install: ${targets_install}
        @mkdir -p "${DESTDIR}${xtlibdir}";
@@ -99,7 +91,7 @@ init%.o: init%.c
 #      Shared libraries
 #
 lib%.so: lib%.oo
-       ${AM_VERBOSE_CCLD} ${CCLD} ${AM_LDFLAGS} -shared ${LDFLAGS} -o $@ $< ${$*_LIBADD};
+       ${AM_VERBOSE_CCLD} ${CCLD} ${AM_LDFLAGS} -shared ${LDFLAGS} -o $@ $< -L../libxtables/.libs -lxtables ${$*_LIBADD};
 
 lib%.oo: ${srcdir}/lib%.c
        ${AM_VERBOSE_CC} ${CC} ${AM_CPPFLAGS} ${AM_DEPFLAGS} ${AM_CFLAGS} -D_INIT=lib$*_init -DPIC -fPIC ${CFLAGS} -o $@ -c $<;