Re: problem in unpack-trees.c

From: Junio C Hamano <junkio@cox.net>
Date: Dec 4, 2006, 10:00 UTC
Message-ID: <7vhcwcq8u7.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <7vodqkq956.fsf@assigned-by-dhcp.cox.net>

Junio C Hamano <junkio@cox.net> writes:

> If the alignment requirement of the platform is smaller, we may
> be overstepping the struct when we access its name[] member.

Would this help?

I do not think we need a separate identity for df_conflict_entry per invocation of unpack_trees(), so this allocates one such entry with NUL name at the first call to the function and reuses it from the variable.

diff --git a/unpack-trees.c b/unpack-trees.c
index 7cfd628..47aa804 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -370,7 +370,7 @@ int unpack_trees(struct object_list *trees, struct unpack_trees_options *o)
 	int i;
 	struct object_list *posn = trees;
 	struct tree_entry_list df_conflict_list;
-	struct cache_entry df_conflict_entry;
+	static struct cache_entry *dfc;
 
 	memset(&df_conflict_list, 0, sizeof(df_conflict_list));
 	df_conflict_list.next = &df_conflict_list;
@@ -381,8 +381,10 @@ int unpack_trees(struct object_list *trees, struct unpack_trees_options *o)
 	state.refresh_cache = 1;
 
 	o->merge_size = len;
-	memset(&df_conflict_entry, 0, sizeof(df_conflict_entry));
-	o->df_conflict_entry = &df_conflict_entry;
+
+	if (!dfc)
+		dfc = xcalloc(1, sizeof(struct cache_entry) + 1);
+	o->df_conflict_entry = dfc;
 
 	if (len) {
 		posns = xmalloc(len * sizeof(struct tree_entry_list *));