1 files changed, 85 insertions, 0 deletions
diff --git a/elf/dl-caller.c b/elf/dl-caller.c
new file mode 100644
index 0000000000..ddabbd0f2d
--- /dev/null
+++ b/elf/dl-caller.c
@@ -0,0 +1,85 @@
+/* Check whether caller comes from the right place.
+   Copyright (C) 2004 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
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <assert.h>
+#include <ldsodefs.h>
+#include <stddef.h>
+#include <caller.h>
+#include <gnu/lib-names.h>
+
+
+int
+attribute_hidden
+_dl_check_caller (const void *caller, enum allowmask mask)
+{
+  static const char expected1[] = LIBC_SO;
+  static const char expected2[] = LIBDL_SO;
+#ifdef LIBPTHREAD_SO
+  static const char expected3[] = LIBPTHREAD_SO;
+#endif
+  static const char expected4[] = LD_SO;
+
+  for (struct link_map *l = GL(dl_loaded); l != NULL; l = l->l_next)
+    if (caller >= (const void *) l->l_map_start
+	&& caller < (const void *) l->l_text_end)
+      {
+	/* The address falls into this DSO's address range.  Check the
+	   name.  */
+	if ((mask & allow_libc) && strcmp (expected1, l->l_name) == 0)
+	  return 0;
+	if ((mask & allow_libdl) && strcmp (expected2, l->l_name) == 0)
+	  return 0;
+#ifdef LIBPTHREAD_SO
+	if ((mask & allow_libpthread) && strcmp (expected3, l->l_name) == 0)
+	  return 0;
+#endif
+	if ((mask & allow_ldso) && strcmp (expected4, l->l_name) == 0)
+	  return 0;
+
+	struct libname_list *runp = l->l_libname;
+
+	while (runp != NULL)
+	  {
+	    if ((mask & allow_libc) && strcmp (expected1, runp->name) == 0)
+		  return 0;
+	    if ((mask & allow_libdl) && strcmp (expected2, runp->name) == 0)
+	      return 0;
+#ifdef LIBPTHREAD_SO
+	    if ((mask & allow_libpthread)
+		&& strcmp (expected3, runp->name) == 0)
+	      return 0;
+#endif
+	    if ((mask & allow_ldso) && strcmp (expected4, runp->name) == 0)
+	      return 0;
+
+	    runp = runp->next;
+	  }
+
+	break;
+      }
+
+  /* Maybe the dynamic linker is not yet on the list.  */
+  if ((mask & allow_ldso) != 0
+      && caller >= (const void *) GL(dl_rtld_map).l_map_start
+      && caller < (const void *) GL(dl_rtld_map).l_text_end)
+    return 0;
+
+  /* No valid caller.  */
+  return 1;
+}