Resolve undefined weak references to a value of 0. This solves the

"__deregister_frame_info" problem that was seen when combining a
program linked using the old gcc with shared libraries that were
built using egcs.

1 files changed, 13 insertions, 1 deletions

diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c
index 837819c..f5bad83 100644
--- a/libexec/rtld-elf/rtld.c
+++ b/libexec/rtld-elf/rtld.c
@@ -22,7 +22,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- *      $Id: rtld.c,v 1.15 1999/03/24 23:47:29 nate Exp $
+ *      $Id: rtld.c,v 1.16 1999/04/04 06:01:09 peter Exp $
  */
 
 /*
@@ -133,10 +133,13 @@ static Obj_Entry **obj_tail;	/* Link field of last object in list */
 static Obj_Entry *obj_main;	/* The main program shared object */
 static Obj_Entry obj_rtld;	/* The dynamic linker shared object */
 
+static Elf_Sym sym_zero;	/* For resolving undefined weak refs. */
+
 #define GDB_STATE(s)	r_debug.r_state = s; r_debug_state();
 
 extern Elf_Dyn _DYNAMIC;
 
+
 /*
  * These are the functions the dynamic linker exports to application
  * programs.  They are the only symbols the dynamic linker is willing
@@ -272,6 +275,10 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
     obj_tail = &obj_main->next;
     obj_main->refcount++;
 
+    /* Initialize a fake symbol for resolving undefined weak references. */
+    sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
+    sym_zero.st_shndx = SHN_ABS;
+
     dbg("loading LD_PRELOAD libraries");
     if (load_preload_objects() == -1)
 	die();
@@ -759,6 +766,11 @@ find_symdef(unsigned long symnum, const Obj_Entry *refobj,
 	return weakdef;
     }
 
+    if (ELF_ST_BIND(ref->st_info) == STB_WEAK) {
+	*defobj_out = obj_main;
+	return &sym_zero;
+    }
+
     _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
     return NULL;
 }