Per discussion with Joakim Tjernlund, all the horrible weak declarations junk

in libdl pointing to the local 'foobar' function is garbage.  This cleans all
that up and makes the code much less horrible.  Now it is only really really
ugly (which is a marked improvement),

ldso/libdl/libdl.c

@@ -1,70 +1,82 @@
+/* vi: set sw=4 ts=4: */
 /*
- * libdl.c
- * 
- * Functions required for dlopen et. al.
+ * Program to load an ELF binary on a linux system, and run it
+ * after resolving ELF shared library symbols
+ *
+ * Copyright (C) 2000-2004 by Erik Andersen <andersen@codpoet.org>
+ * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
+ *				David Engel, Hongjiu Lu and Mitch D'Souza
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. The name of the above contributors may not be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
  */
 
-#include <ldso.h>
-
 
-/* The public interfaces */
-void *dlopen(const char *, int) __attribute__ ((__weak__, __alias__ ("_dlopen")));
-int dlclose(void *) __attribute__ ((__weak__, __alias__ ("_dlclose")));
-void *dlsym(void *, const char *) __attribute__ ((__weak__, __alias__ ("_dlsym")));
-const char *dlerror(void) __attribute__ ((__weak__, __alias__ ("_dlerror")));
-int dladdr(void *, Dl_info *) __attribute__ ((__weak__, __alias__ ("_dladdr")));
-void _dlinfo(void);
+#include <ldso.h>
 
 
 #if defined (__LIBDL_SHARED__)
-/* This is a real hack.  We need access to the dynamic linker, but we
-also need to make it possible to link against this library without any
-unresolved externals.  We provide these weak symbols to make the link
-possible, but at run time the normal symbols are accessed. */
-static void __attribute__ ((unused)) foobar(void)
-{
-	const char msg[]="libdl library not correctly linked\n";
-	_dl_write(2, msg, _dl_strlen(msg));
-	_dl_exit(1);
-}
 
-static int __attribute__ ((unused)) foobar1 = (int) foobar;	/* Use as pointer */
-extern void _dl_dprintf(int, const char *, ...) __attribute__ ((__weak__, __alias__ ("foobar")));
+/* When libdl is loaded as a shared library, we need to load in
+ * and use a pile of symbols from ldso... */
+
+extern void _dl_dprintf(int, const char *, ...) __attribute__ ((__weak__));
 extern char *_dl_find_hash(const char *, struct dyn_elf *, int)
-	__attribute__ ((__weak__, __alias__ ("foobar")));
-extern struct elf_resolve * _dl_load_shared_library(int, struct dyn_elf **, struct elf_resolve *, char *, int)
-	__attribute__ ((__weak__, __alias__ ("foobar")));
+	__attribute__ ((__weak__));
+extern struct elf_resolve * _dl_load_shared_library(int, struct dyn_elf **,
+	struct elf_resolve *, char *, int) __attribute__ ((__weak__));
 extern struct elf_resolve * _dl_check_if_named_library_is_loaded(const char *, int)
-	__attribute__ ((__weak__, __alias__ ("foobar")));
+	__attribute__ ((__weak__));
 extern int _dl_fixup(struct dyn_elf *rpnt, int lazy)
-	 __attribute__ ((__weak__, __alias__ ("foobar")));
+	 __attribute__ ((__weak__));
+extern struct dyn_elf *_dl_symbol_tables __attribute__ ((__weak__));
+extern struct dyn_elf *_dl_handles __attribute__ ((__weak__));
+extern struct elf_resolve *_dl_loaded_modules __attribute__ ((__weak__));
+extern struct r_debug *_dl_debug_addr __attribute__ ((__weak__));
+extern unsigned long _dl_error_number __attribute__ ((__weak__));
+extern void *(*_dl_malloc_function)(size_t) __attribute__ ((__weak__));
+#ifdef USE_CACHE
+int _dl_map_cache(void) __attribute__ ((__weak__));
+int _dl_unmap_cache(void) __attribute__ ((__weak__));
+#endif
 #ifdef __mips__
 extern void _dl_perform_mips_global_got_relocations(struct elf_resolve *tpnt)
-	__attribute__ ((__weak__, __alias__ ("foobar")));
+	__attribute__ ((__weak__));
 #endif
-#ifdef USE_CACHE
-int _dl_map_cache(void) __attribute__ ((__weak__, __alias__ ("foobar")));
-int _dl_unmap_cache(void) __attribute__ ((__weak__, __alias__ ("foobar")));
-#endif	
-
-extern struct dyn_elf *_dl_symbol_tables __attribute__ ((__weak__, __alias__ ("foobar1")));
-extern struct dyn_elf *_dl_handles __attribute__ ((__weak__, __alias__ ("foobar1")));
-extern struct elf_resolve *_dl_loaded_modules __attribute__ ((__weak__, __alias__ ("foobar1")));
-extern struct r_debug *_dl_debug_addr __attribute__ ((__weak__, __alias__ ("foobar1")));
-extern unsigned long _dl_error_number __attribute__ ((__weak__, __alias__ ("foobar1")));
-extern void *(*_dl_malloc_function)(size_t) __attribute__ ((__weak__, __alias__ ("foobar1")));
 #ifdef __SUPPORT_LD_DEBUG__
-extern char *_dl_debug __attribute__ ((__weak__, __alias__ ("foobar1")));
-extern char *_dl_debug_symbols __attribute__ ((__weak__, __alias__ ("foobar1")));
-extern char *_dl_debug_move __attribute__ ((__weak__, __alias__ ("foobar1")));
-extern char *_dl_debug_reloc __attribute__ ((__weak__, __alias__ ("foobar1")));
-extern char *_dl_debug_detail __attribute__ ((__weak__, __alias__ ("foobar1")));
-extern char *_dl_debug_nofixups __attribute__ ((__weak__, __alias__ ("foobar1")));
-extern char *_dl_debug_bindings __attribute__ ((__weak__, __alias__ ("foobar1")));
-extern int   _dl_debug_file __attribute__ ((__weak__, __alias__ ("foobar1")));
+extern char *_dl_debug __attribute__ ((__weak__));
+extern char *_dl_debug_symbols __attribute__ ((__weak__));
+extern char *_dl_debug_move __attribute__ ((__weak__));
+extern char *_dl_debug_reloc __attribute__ ((__weak__));
+extern char *_dl_debug_detail __attribute__ ((__weak__));
+extern char *_dl_debug_nofixups __attribute__ ((__weak__));
+extern char *_dl_debug_bindings __attribute__ ((__weak__));
+extern int   _dl_debug_file __attribute__ ((__weak__));
 #endif
 
-#else	/* __LIBDL_SHARED__ */
+
+#else /* __LIBDL_SHARED__ */
+
+/* When libdl is linked as a static library, we need to replace all
+ * the symbols that otherwise would have been loaded in from ldso... */
 
 #ifdef __SUPPORT_LD_DEBUG__
 char *_dl_debug  = 0;
@@ -80,12 +92,12 @@ char *_dl_library_path = 0;
 char *_dl_ldsopath = 0;
 struct r_debug *_dl_debug_addr = NULL;
 static unsigned char *_dl_malloc_addr, *_dl_mmap_zero;
+void *(*_dl_malloc_function) (size_t size);
+int _dl_fixup(struct dyn_elf *rpnt, int lazy);
 #include "../ldso/dl-progname.h"               /* Pull in the name of ld.so */
 #include "../ldso/dl-hash.c"
 #define _dl_trace_loaded_objects    0
 #include "../ldso/dl-elf.c"
-void *(*_dl_malloc_function) (size_t size);
-int _dl_fixup(struct dyn_elf *rpnt, int lazy);
 #endif
 
 static int do_dlclose(void *, int need_fini);
@@ -176,7 +188,7 @@ void *_dlopen(const char *libname, int flag)
 
 	/* Try to load the specified library */
 #ifdef __SUPPORT_LD_DEBUG__
-	if(_dl_debug) 
+	if(_dl_debug)
 	_dl_dprintf(_dl_debug_file, "Trying to dlopen '%s'\n", (char*)libname);
 #endif
 	if (!(tpnt = _dl_check_if_named_library_is_loaded((char *)libname, 0)))
@@ -205,7 +217,7 @@ void *_dlopen(const char *libname, int flag)
 
 
 #ifdef __SUPPORT_LD_DEBUG__
-	if(_dl_debug) 
+	if(_dl_debug)
 	_dl_dprintf(_dl_debug_file, "Looking for needed libraries\n");
 #endif
 
@@ -217,7 +229,7 @@ void *_dlopen(const char *libname, int flag)
 			if (dpnt->d_tag == DT_NEEDED) {
 
 				char *name;
-				lpntstr = (char*) (tcurr->loadaddr + tcurr->dynamic_info[DT_STRTAB] + 
+				lpntstr = (char*) (tcurr->loadaddr + tcurr->dynamic_info[DT_STRTAB] +
 					dpnt->d_un.d_val);
 				name = _dl_get_last_path_component(lpntstr);
 
@@ -225,8 +237,8 @@ void *_dlopen(const char *libname, int flag)
 					continue;
 
 #ifdef __SUPPORT_LD_DEBUG__
-				if(_dl_debug) 
-				_dl_dprintf(_dl_debug_file, "Trying to load '%s', needed by '%s'\n", 
+				if(_dl_debug)
+				_dl_dprintf(_dl_debug_file, "Trying to load '%s', needed by '%s'\n",
 						lpntstr, tcurr->libname);
 #endif
 
@@ -258,7 +270,7 @@ void *_dlopen(const char *libname, int flag)
 #endif
 
 #ifdef __SUPPORT_LD_DEBUG__
-	if(_dl_debug) 
+	if(_dl_debug)
 	_dl_dprintf(_dl_debug_file, "Beginning dlopen relocation fixups\n");
 #endif
 	/*
@@ -285,7 +297,7 @@ void *_dlopen(const char *libname, int flag)
 	}
 
 #if 0 //def __SUPPORT_LD_DEBUG__
-	if(_dl_debug) 
+	if(_dl_debug)
 	_dlinfo();
 #endif
 
@@ -313,7 +325,7 @@ void *_dlopen(const char *libname, int flag)
 		    dl_elf_func = (void (*)(void)) (tpnt->loadaddr + tpnt->dynamic_info[DT_INIT]);
 		    if (dl_elf_func && *dl_elf_func != NULL) {
 #ifdef __SUPPORT_LD_DEBUG__
-			if(_dl_debug) 
+			if(_dl_debug)
 			_dl_dprintf(2, "running ctors for library %s at '%x'\n", tpnt->libname, dl_elf_func);
 #endif
 			(*dl_elf_func) ();
@@ -324,7 +336,7 @@ void *_dlopen(const char *libname, int flag)
 		    dl_elf_func = (void (*)(void)) (tpnt->loadaddr + tpnt->dynamic_info[DT_FINI]);
 		    if (dl_elf_func && *dl_elf_func != NULL) {
 #ifdef __SUPPORT_LD_DEBUG__
-			if(_dl_debug) 
+			if(_dl_debug)
 			_dl_dprintf(2, "setting up dtors for library %s at '%x'\n", tpnt->libname, dl_elf_func);
 #endif
 			atexit(dl_elf_func);
@@ -340,6 +352,7 @@ oops:
 	do_dlclose(dyn_chain, 0);
 	return NULL;
 }
+weak_alias(_dlopen, dlopen);
 
 void *_dlsym(void *vhandle, const char *name)
 {
@@ -394,11 +407,7 @@ void *_dlsym(void *vhandle, const char *name)
 		_dl_error_number = LD_NO_SYMBOL;
 	return ret;
 }
-
-int _dlclose(void *vhandle)
-{
-	return do_dlclose(vhandle, 1);
-}
+weak_alias(_dlsym, dlsym);
 
 static int do_dlclose(void *vhandle, int need_fini)
 {
@@ -432,7 +441,7 @@ static int do_dlclose(void *vhandle, int need_fini)
 	for (; spnt; spnt = spnt1) {
 		spnt1 = spnt->next;
 
-		/* We appended the module list to the end - when we get back here, 
+		/* We appended the module list to the end - when we get back here,
 		   quit. The access counts were not adjusted to account for being here. */
 		if (spnt == _dl_symbol_tables)
 			break;
@@ -444,7 +453,7 @@ static int do_dlclose(void *vhandle, int need_fini)
 			 */
 
 			if (tpnt->dynamic_info[DT_FINI]) {
-				dl_elf_fini = (int (*)(void)) (tpnt->loadaddr + 
+				dl_elf_fini = (int (*)(void)) (tpnt->loadaddr +
 					tpnt->dynamic_info[DT_FINI]);
 				(*dl_elf_fini) ();
 			}
@@ -459,7 +468,7 @@ static int do_dlclose(void *vhandle, int need_fini)
 	for (rpnt = handle; rpnt; rpnt = rpnt1) {
 		rpnt1 = rpnt->next;
 
-		/* We appended the module list to the end - when we get back here, 
+		/* We appended the module list to the end - when we get back here,
 		   quit. The access counts were not adjusted to account for being here. */
 		if (rpnt == _dl_symbol_tables)
 			break;
@@ -473,10 +482,10 @@ static int do_dlclose(void *vhandle, int need_fini)
 			 */
 #if 0
 
-			/* We have to do this above, before we start closing objects.  
-			 * Otherwise when the needed symbols for _fini handling are 
-			 * resolved a coredump would occur. Rob Ryan (robr@cmu.edu)*/ 
-			if (tpnt->dynamic_info[DT_FINI]) { 
+			/* We have to do this above, before we start closing objects.
+			 * Otherwise when the needed symbols for _fini handling are
+			 * resolved a coredump would occur. Rob Ryan (robr@cmu.edu)*/
+			if (tpnt->dynamic_info[DT_FINI]) {
 			    dl_elf_fini = (int (*)(void)) (tpnt->loadaddr + tpnt->dynamic_info[DT_FINI]);
 				(*dl_elf_fini) ();
 			}
@@ -524,6 +533,12 @@ static int do_dlclose(void *vhandle, int need_fini)
 	return 0;
 }
 
+int _dlclose(void *vhandle)
+{
+	return do_dlclose(vhandle, 1);
+}
+weak_alias(_dlclose, dlclose);
+
 const char *_dlerror(void)
 {
 	const char *retval;
@@ -534,6 +549,7 @@ const char *_dlerror(void)
 	_dl_error_number = 0;
 	return retval;
 }
+weak_alias(_dlerror, dlerror);
 
 /*
  * Dump information to stderrr about the current loaded modules
@@ -547,8 +563,8 @@ void _dlinfo(void)
 
 	_dl_dprintf(2, "List of loaded modules\n");
 	/* First start with a complete list of all of the loaded files. */
-	for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) { 
-		_dl_dprintf(2, "\t%x %x %x %s %d %s\n", 
+	for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
+		_dl_dprintf(2, "\t%x %x %x %s %d %s\n",
 			(unsigned) tpnt->loadaddr, (unsigned) tpnt,
 			(unsigned) tpnt->symbol_scope,
 			type[tpnt->libtype],
@@ -564,10 +580,11 @@ void _dlinfo(void)
 	for (hpnt = _dl_handles; hpnt; hpnt = hpnt->next_handle) {
 		_dl_dprintf(2, "Modules for handle %x\n", (unsigned) hpnt);
 		for (rpnt = hpnt; rpnt; rpnt = rpnt->next)
-			_dl_dprintf(2, "\t%x %s\n", (unsigned) rpnt->dyn, 
+			_dl_dprintf(2, "\t%x %s\n", (unsigned) rpnt->dyn,
 				rpnt->dyn->libname);
 	}
 }
+weak_alias(_dlinfo, dlinfo);
 
 int _dladdr(void *__address, Dl_info * __dlip)
 {
@@ -590,7 +607,7 @@ int _dladdr(void *__address, Dl_info * __dlip)
 
 		tpnt = rpnt;
 #if 0
-		_dl_dprintf(2, "Module \"%s\" at %x\n", 
+		_dl_dprintf(2, "Module \"%s\" at %x\n",
 			tpnt->libname, tpnt->loadaddr);
 #endif
 		if (tpnt->loadaddr < (ElfW(Addr)) __address
@@ -631,7 +648,7 @@ int _dladdr(void *__address, Dl_info * __dlip)
 					sf = 1;
 				}
 #if 0
-				_dl_dprintf(2, "Symbol \"%s\" at %x\n", 
+				_dl_dprintf(2, "Symbol \"%s\" at %x\n",
 					strtab + symtab[si].st_name, symbol_addr);
 #endif
 			}
@@ -646,3 +663,4 @@ int _dladdr(void *__address, Dl_info * __dlip)
 		return 1;
 	}
 }
+weak_alias(_dladdr, dladdr);