hesiod: Always use thread-local resolver state [BZ #19573]

The Hesiod implementation imported into glibc was enhanced
to support caller-supplied resolver states.  But its only
consumer is nss_hesiod, and it supplies the thread-local
resolver state.  Therefore, this commit changes the Hesiod
implementation to use the thread-local resolver state (_res)
directly.  This fixes bug 19573 because the Hesiod
implementation no longer has to initialize and free any
resolver state.

To avoid any risk of interposition of ABI-incompatible Hesiod
function implementations, this commit marks the Hesiod functions
as hidden.  (They were already hidden using a linker version
script.)

1 files changed, 17 insertions, 5 deletions

diff --git a/hesiod/hesiod_p.h b/hesiod/hesiod_p.h
index 0c00c58538..859a8df082 100644
--- a/hesiod/hesiod_p.h
+++ b/hesiod/hesiod_p.h
@@ -1,3 +1,20 @@
+/* Copyright (C) 1997-2016 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, see
+   <http://www.gnu.org/licenses/>.  */
+
 /*
  * Copyright (c) 1996,1999 by Internet Software Consortium.
  *
@@ -31,11 +48,6 @@
 struct hesiod_p {
 	char *		LHS;		/* normally ".ns" */
 	char *		RHS;		/* AKA the default hesiod domain */
-	struct __res_state * res;	/* resolver context */
-	void		(*free_res)(void *);
-	void		(*res_set)(struct hesiod_p *, struct __res_state *,
-				   void (*)(void *));
-	struct __res_state * (*res_get)(struct hesiod_p *);
 	int		classes[2];	/* The class search order. */
 };