let list_is_singleton() return false for an empty list (#1075415)

elinks-0.12pre6-list_is_singleton.patch

@@ -0,0 +1,38 @@
+From 701b16e0ee6f159cbf8498f4569022005dfdebbd Mon Sep 17 00:00:00 2001
+From: Kamil Dudka <kdudka@redhat.com>
+Date: Wed, 19 Mar 2014 11:48:34 +0100
+Subject: [PATCH] lists.h: list_is_singleton() now returns false for empty list
+
+We have a crash report of ELinks 0.12pre6 with backtrace going through
+bookmark_all_terminals().  I believe it is caused by list_is_singleton()
+returning true for an empty list.  Consequently, bookmark_terminal()
+attempts to access a list item that does not exist.
+
+While it would be possible to fix bookmark_all_terminals() to explicitly
+check the list for emptiness, I propose to fix list_is_singleton() such
+that it does not return true for an empty list.  I checked the other
+uses of list_is_singleton() and the proposed change should not introduce
+any change in the behavior elsewhere.
+
+Bug: https://bugzilla.redhat.com/1075415
+---
+ src/util/lists.h | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/src/util/lists.h b/src/util/lists.h
+index b577c9f..9da38ae 100644
+--- a/src/util/lists.h
++++ b/src/util/lists.h
+@@ -146,7 +146,8 @@ do { \
+ #define list_empty(x) (list_magic_chkbool(x, "list_empty") && (x).next == &(x))
+ 
+ #define list_is_singleton(x) \
+-	(list_magic_chkbool(x, "list_is_singleton") && (x).next == (x).prev)
++	(list_magic_chkbool(x, "list_is_singleton") && (x).next == (x).prev \
++	&& !list_empty(x))
+ 
+ #define list_has_prev(l,p) \
+ 	(list_magic_chkbool(l, "list_has_prev") && (p)->prev !=  (void *) &(l))
+-- 
+1.8.3.1
+

elinks.spec

@@ -3,7 +3,7 @@
 Name:      elinks
 Summary:   A text-mode Web browser
 Version:   0.12
-Release:   0.37.%{prerel}%{?dist}
+Release:   0.38.%{prerel}%{?dist}
 License:   GPLv2
 URL:       http://elinks.or.cz
 Group:     Applications/Internet
@@ -42,6 +42,7 @@ Patch11: elinks-0.12pre5-js185.patch
 Patch12: elinks-0.12pre5-ddg-search.patch
 Patch13: elinks-0.12pre6-autoconf.patch
 Patch14: elinks-0.12pre6-ssl-hostname.patch
+Patch15: elinks-0.12pre6-list_is_singleton.patch
 
 %description
 Elinks is a text-based Web browser. Elinks does not display any images,
@@ -91,6 +92,9 @@ quickly and swiftly displays Web pages.
 # verify server certificate hostname with nss_compat_ossl (#881411)
 %patch14 -p1
 
+# let list_is_singleton() return false for an empty list (#1075415)
+%patch15 -p1
+
 # remove bogus serial numbers
 sed -i 's/^# *serial [AM0-9]*$//' acinclude.m4 config/m4/*.m4
 
@@ -159,6 +163,9 @@ exit 0
 %{_mandir}/man5/*
 
 %changelog
+* Tue Apr 29 2014 Kamil Dudka <kdudka@redhat.com> - 0.12-0.38.pre6
+- let list_is_singleton() return false for an empty list (#1075415)
+
 * Wed Sep 18 2013 Kamil Dudka <kdudka@redhat.com> - 0.12-0.37.pre6
 - verify server certificate hostname with nss_compat_ossl (#881411)