From faab0349cbf2157f920df35ca982b96228204ae1 Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Mon, 5 Jun 2006 00:40:01 +0000
Subject: [PATCH] 2037.   [func]          When unlinking the first or last
 element in a list                         check that the list head points to
 the element to                         be unlinked. [RT #15959]

---
 CHANGES                     |  4 ++++
 lib/bind/include/isc/list.h |  8 ++++++--
 lib/isc/include/isc/list.h  | 10 +++++++---
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/CHANGES b/CHANGES
index 6305a7113d..3e032e8eda 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,7 @@
+2037.	[func]		When unlinking the first or last element in a list
+			check that the list head points to the element to
+			be unlinked. [RT #15959]
+
 2034.	[bug]		gcc: set -fno-strict-aliasing. [RT #16124]
 
 
diff --git a/lib/bind/include/isc/list.h b/lib/bind/include/isc/list.h
index ad574ac2b5..4e27eb19ba 100644
--- a/lib/bind/include/isc/list.h
+++ b/lib/bind/include/isc/list.h
@@ -66,12 +66,16 @@
 		INSIST(LINKED(elt, link));\
 		if ((elt)->link.next != NULL) \
 			(elt)->link.next->link.prev = (elt)->link.prev; \
-		else \
+		else { \
+			INSIST((list).tail == (elt)); \
 			(list).tail = (elt)->link.prev; \
+		} \
 		if ((elt)->link.prev != NULL) \
 			(elt)->link.prev->link.next = (elt)->link.next; \
-		else \
+		else { \
+			INSIST((list).head == (elt)); \
 			(list).head = (elt)->link.next; \
+		} \
 		INIT_LINK_TYPE(elt, link, type); \
 	} while (0)
 #define UNLINK(list, elt, link) \
diff --git a/lib/isc/include/isc/list.h b/lib/isc/include/isc/list.h
index cd5b2cf213..862c41e028 100644
--- a/lib/isc/include/isc/list.h
+++ b/lib/isc/include/isc/list.h
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: list.h,v 1.18.2.3 2004/03/09 06:11:57 marka Exp $ */
+/* $Id: list.h,v 1.18.2.4 2006/06/05 00:40:01 marka Exp $ */
 
 #ifndef ISC_LIST_H
 #define ISC_LIST_H 1
@@ -90,12 +90,16 @@
 	do { \
 		if ((elt)->link.next != NULL) \
 			(elt)->link.next->link.prev = (elt)->link.prev; \
-		else \
+		else { \
+			ISC_INSIST((list).tail == (elt)); \
 			(list).tail = (elt)->link.prev; \
+		} \
 		if ((elt)->link.prev != NULL) \
 			(elt)->link.prev->link.next = (elt)->link.next; \
-		else \
+		else { \
+			ISC_INSIST((list).head == (elt)); \
 			(list).head = (elt)->link.next; \
+		} \
 		(elt)->link.prev = (type *)(-1); \
 		(elt)->link.next = (type *)(-1); \
 	} while (0)