elf: Split _dl_lookup_map, _dl_map_new_object from _dl_map_object

So that they can eventually be called separately from dlopen.

elf/dl-load.c

@@ -1887,24 +1887,14 @@ open_path (const char *name, size_t namelen, int mode,
   return -1;
 }
 
-/* Map in the shared object file NAME.  */
-
 struct link_map *
-_dl_map_object (struct link_map *loader, const char *name,
+_dl_lookup_map (Lmid_t nsid, const char *name)
-		int type, int trace_mode, int mode, Lmid_t nsid)
 {
-  int fd;
-  const char *origname = NULL;
-  char *realname;
-  char *name_copy;
-  struct link_map *l;
-  struct filebuf fb;
-
   assert (nsid >= 0);
   assert (nsid < GL(dl_nns));
 
   /* Look for this name among those already loaded.  */
-  for (l = GL(dl_ns)[nsid]._ns_loaded; l; l = l->l_next)
+  for (struct link_map *l = GL(dl_ns)[nsid]._ns_loaded; l; l = l->l_next)
     {
       /* If the requested name matches the soname of a loaded object,
 	 use that object.  Elide this check for names that have not
@@ -1933,6 +1923,22 @@ _dl_map_object (struct link_map *loader, const char *name,
       return l;
     }
 
+  return NULL;
+}
+
+/* Map in the shared object file NAME.  */
+
+struct link_map *
+_dl_map_new_object (struct link_map *loader, const char *name,
+		    int type, int trace_mode, int mode, Lmid_t nsid)
+{
+  int fd;
+  const char *origname = NULL;
+  char *realname;
+  char *name_copy;
+  struct link_map *l;
+  struct filebuf fb;
+
   /* Display information if we are debugging.  */
   if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)
       && loader != NULL)
@@ -2183,6 +2189,17 @@ _dl_map_object (struct link_map *loader, const char *name,
 				 type, mode, &stack_end, nsid);
 }
 
+struct link_map *
+_dl_map_object (struct link_map *loader, const char *name,
+		int type, int trace_mode, int mode, Lmid_t nsid)
+{
+  struct link_map *l = _dl_lookup_map (nsid, name);
+  if (l != NULL)
+    return l;
+  return _dl_map_new_object (loader, name, type, trace_mode, mode, nsid);
+}
+
+
 struct add_path_state
 {
   bool counting;

sysdeps/generic/ldsodefs.h

@@ -885,6 +885,11 @@ int _dl_catch_exception (struct dl_exception *exception,
 			 void (*operate) (void *), void *args);
 rtld_hidden_proto (_dl_catch_exception)
 
+/* Search NSID for a map with NAME.  If no such map is already loaded,
+   return NULL.  */
+struct link_map *_dl_lookup_map (Lmid_t nsid, const char *name)
+   attribute_hidden;
+
 /* Open the shared object NAME and map in its segments.
    LOADER's DT_RPATH is used in searching for NAME.
    If the object is already opened, returns its existing map.  */
@@ -893,6 +898,14 @@ extern struct link_map *_dl_map_object (struct link_map *loader,
 					int type, int trace_mode, int mode,
 					Lmid_t nsid) attribute_hidden;
 
+/* Like _dl_map_object, but assumes that NAME has not been loaded yet
+   (_dl_lookup_map returned NULL).  */
+struct link_map *_dl_map_new_object (struct link_map *loader,
+				     const char *name,
+				     int type, int trace_mode, int mode,
+					     Lmid_t nsid) attribute_hidden;
+
+
 /* Call _dl_map_object on the dependencies of MAP, and set up
    MAP->l_searchlist.  PRELOADS points to a vector of NPRELOADS previously
    loaded objects that will be inserted into MAP->l_searchlist after MAP