Prepare rtld for symbol versioning. Disable it by default for now.

libexec/rtld-elf/Makefile

@@ -16,34 +16,27 @@ SYMLINKS=	${BINDIR}/${PROG} /usr/libexec/${PROG}
 MLINKS=		rtld.1 ld-elf.so.1.1 \
 		rtld.1 ld.so.1
 
-.if exists(${.CURDIR}/${MACHINE_ARCH}/Makefile.inc)
-.include "${.CURDIR}/${MACHINE_ARCH}/Makefile.inc"
-.endif
-
-# If LDSCRIPT is defined, we build the dynamic linker as an
-# executable.  Otherwise we build it as a shared object.  We ignore
-# LDSCRIPT if the running kernel is too old to support it.
-.if defined(LDSCRIPT)
-KERN_OSRELDATE!=	/sbin/sysctl -n kern.osreldate 2>/dev/null || echo 0
-.if ${KERN_OSRELDATE} >= 400001
-LDSO_IS_EXECUTABLE=
-.endif
-.endif
-
-.ifdef LDSO_IS_EXECUTABLE
-OBJS+=		dyn_hack.so
-LDFLAGS+=	-Wl,-T,${LDSCRIPT} -Wl,-E -Wl,-Bstatic
-DPADD=		${LIBC}
-LDADD=		-lc
-.else
 CFLAGS+=	-fpic -DPIC
 LDFLAGS+=	-shared -Wl,-Bsymbolic
 DPADD=		${LIBC_PIC}
 LDADD=		-lc_pic
+
+.if defined(SYMVER_ENABLED)
+SYMBOL_MAPS=	${.CURDIR}/Symbol.map
+VERSION_DEF=	${.CURDIR}/Versions.def
+VERSION_MAP=	Version.map
+LDFLAGS+=	-Wl,--version-script=${VERSION_MAP}
+
+${PROG}:	${VERSION_MAP}
+
+.if exists(${.CURDIR}/${MACHINE_ARCH}/Symbol.map)
+SYMBOL_MAPS+=	${.CURDIR}/${MACHINE_ARCH}/Symbol.map
+.endif
 .endif
 
-dyn_hack.so:
-	${CC} -shared -nostdlib -o dyn_hack.so -x c /dev/null
+.if exists(${.CURDIR}/${MACHINE_ARCH}/Makefile.inc)
+.include "${.CURDIR}/${MACHINE_ARCH}/Makefile.inc"
+.endif
 
 # Since moving rtld-elf to /libexec, we need to create a symlink.
 # Fixup the existing binary that's there so we can symlink over it.
@@ -54,4 +47,5 @@ beforeinstall:
 
 .PATH: ${.CURDIR}/${MACHINE_ARCH}
 
+.include <bsd.symver.mk>
 .include <bsd.prog.mk>

libexec/rtld-elf/Symbol.map

@@ -0,0 +1,18 @@
+# $FreeBSD$
+
+FBSD_1.0 {
+    _rtld_error;
+    dlclose;
+    dlerror;
+    dlopen;
+    dlsym;
+    dlvsym;
+    dladdr;
+    dllockinit;
+    dlinfo;
+    dl_iterate_phdr;
+    _rtld_thread_init;
+    _rtld_allocate_tls;
+    _rtld_free_tls;
+    __tls_get_addr;
+};

libexec/rtld-elf/Versions.def

@@ -0,0 +1,4 @@
+# $FreeBSD$
+
+FBSD_1.0 {
+};

libexec/rtld-elf/i386/Symbol.map

@@ -0,0 +1,12 @@
+# $FreeBSD$
+
+FBSD_1.0 {
+    ___tls_get_addr;
+};
+
+# This is our private namespace.  Any global interfaces that are
+# strictly for use only by other FreeBSD applications and libraries
+# are listed here.  We use a separate namespace so we can write
+# simple ABI-checking tools.
+FBSDprivate {
+};