Update.

1999-08-01  Ulrich Drepper  <drepper@cygnus.com>

	* elf/dl-sym.c (_dl_sym): Always determine module of the caller to
	pass it to _dl_lookup_symbol.

	* elf/dl-error.c (_dl_signal_error): Optimize string generation a
	bit.  Reword message.

	* dlfcn/dlerror.c: Make code thread-safe.

ChangeLog

@@ -1,3 +1,13 @@
+1999-08-01  Ulrich Drepper  <drepper@cygnus.com>
+
+	* elf/dl-sym.c (_dl_sym): Always determine module of the caller to
+	pass it to _dl_lookup_symbol.
+
+	* elf/dl-error.c (_dl_signal_error): Optimize string generation a
+	bit.  Reword message.
+
+	* dlfcn/dlerror.c: Make code thread-safe.
+
 1999-07-31  Roland McGrath  <roland@baalperazim.frob.com>
 
 	* hurd/intr-msg.c (_hurd_intr_rpc_mach_msg): Fix msgt_size member

dlfcn/dlerror.c

@@ -1,5 +1,5 @@
 /* Return error detail for failing <dlfcn.h> functions.
-   Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
+   Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -27,6 +27,7 @@
 struct dl_action_result
   {
     int errcode;
+    int returned;
     char *errstring;
   };
 static struct dl_action_result last_result;
@@ -44,38 +45,41 @@ static void free_key_mem (void *mem);
 char *
 dlerror (void)
 {
-  static char *buf;
+  char *buf;
   struct dl_action_result *result;
 
-  if (buf)
-    {
-      free (buf);
-      buf = NULL;
-    }
-
   /* Get error string.  */
   result = (struct dl_action_result *) __libc_getspecific (key);
   if (result == NULL)
     result = &last_result;
 
-  if (! result->errstring)
-    return NULL;
-
-  if (result->errcode == 0)
-    buf = result->errstring;
+  /* Test whether we already returned the string.  */
+  if (result->returned != 0)
+    {
+      /* We can now free the string.  */
+      if (result->errstring != NULL)
+	{
+	  free (result->errstring);
+	  result->errstring = NULL;
+	}
+      buf = NULL;
+    }
   else
     {
-      if (__asprintf (&buf, "%s: %s",
-		      result->errstring, strerror (result->errcode)) == -1)
-	buf = NULL;
+      buf = result->errstring;
+      if (result->errcode != 0
+	  && __asprintf (&buf, "%s: %s",
+			 result->errstring, strerror (result->errcode)) != -1)
+	{
+	  /* We don't need the error string anymore.  */
+	  free (result->errstring);
+	  result->errstring = buf;
+	}
 
-      /* We don't need the error string anymore.  */
-      free (result->errstring);
+      /* Mark the error as returned.  */
+      result->returned = 1;
     }
 
-  /* Reset the error indicator.  */
-  result->errstring = NULL;
-
   return buf;
 }
 
@@ -119,6 +123,9 @@ _dlerror_run (void (*operate) (void *), void *args)
 
   result->errcode = _dl_catch_error (&result->errstring, operate, args);
 
+  /* If no error we mark that no error string is available.  */
+  result->returned = result->errstring == NULL;
+
   return result->errstring != NULL;
 }
 

elf/dl-error.c

@@ -1,5 +1,5 @@
 /* Error handling for runtime dynamic linker.
-   Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
+   Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -75,12 +75,13 @@ _dl_signal_error (int errcode,
       lcatch->errstring = malloc (objname_len + errstring_len);
       if (lcatch->errstring != NULL)
 	{
+	  char *cp = lcatch->errstring;
 	  if (objname_len > 0)
 	    {
-	      memcpy (lcatch->errstring, objname, objname_len - 2);
-	      memcpy (lcatch->errstring + objname_len - 2, ": ", 2);
+	      cp = __mempcpy (cp, objname, objname_len - 2);
+	      cp = __mempcpy (cp, ": ", 2);
 	    }
-	  memcpy (lcatch->errstring + objname_len, errstring, errstring_len);
+	  memcpy (cp, errstring, errstring_len);
 	}
       longjmp (lcatch->env, errcode ?: -1);
     }
@@ -89,7 +90,7 @@ _dl_signal_error (int errcode,
       /* Lossage while resolving the program's own symbols is always fatal.  */
       char buffer[1024];
       _dl_sysdep_fatal (_dl_argv[0] ?: "<program name unknown>",
-			": error in loading shared libraries: ",
+			": error while loading shared libraries: ",
 			objname ?: "", objname && *objname ? ": " : "",
 			errstring, errcode ? ": " : "",
 			(errcode

elf/dl-sym.c

@@ -35,7 +35,7 @@ _dl_sym (void *handle, const char *name, void *who)
   if (handle == RTLD_DEFAULT)
     /* Search the global scope.  */
     loadbase = _dl_lookup_symbol (name, NULL, &ref, _dl_global_scope, 0);
-  else if (handle == RTLD_NEXT)
+  else
     {
       struct link_map *l, *match;
       ElfW(Addr) caller = (ElfW(Addr)) who;
@@ -46,22 +46,32 @@ _dl_sym (void *handle, const char *name, void *who)
 	if (caller >= l->l_addr && (!match || match->l_addr < l->l_addr))
 	  match = l;
 
-      if (! match)
-	_dl_signal_error (0, NULL, _("\
+      if (handle != RTLD_NEXT)
+	{
+	  /* Search the scope of the given object.  */
+	  struct link_map *map = handle;
+
+	  if (match == NULL)
+	    /* If the address is not recognized the call comes from the
+	       main program (we hope).  */
+	    match = _dl_loaded;
+
+	  loadbase = _dl_lookup_symbol (name, match, &ref, map->l_local_scope,
+					0);
+	}
+      else
+	{
+	  if (! match)
+	    _dl_signal_error (0, NULL, _("\
 RTLD_NEXT used in code not dynamically loaded"));
 
-      l = match;
-      while (l->l_loader)
-	l = l->l_loader;
+	  l = match;
+	  while (l->l_loader)
+	    l = l->l_loader;
 
-      loadbase = _dl_lookup_symbol_skip (name, l, &ref, l->l_local_scope,
-					 match);
-    }
-  else
-    {
-      /* Search the scope of the given object.  */
-      struct link_map *map = handle;
-      loadbase = _dl_lookup_symbol (name, map, &ref, map->l_local_scope, 0);
+	  loadbase = _dl_lookup_symbol_skip (name, l, &ref, l->l_local_scope,
+					     match);
+	}
     }
 
   if (loadbase)