[Qemu-devel] [PATCH 2/7] qom: handle registration of new types when initializing the first ones

[Hervé Poussineau]

When initializing all types in object_class_foreach, called by 
object_class_get_list,
some new types may be registered. Those will change the type internal hashtable 
which
is currently enumerated, and may crash QEMU.

Fix it, by adding a second hash table which contains all the non-initialized 
types,
merged to the main one before each round of initializations.

Bug has been detected when registering dynamic types containing an interface.

Signed-off-by: Hervé Poussineau <address@hidden>
---
 qom/object.c |   45 +++++++++++++++++++++++++++++++++++++--------
 1 file changed, 37 insertions(+), 8 deletions(-)

diff --git a/qom/object.c b/qom/object.c
index 75e6aac..e0a24dc 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -65,25 +65,39 @@ struct TypeImpl
 
 static Type type_interface;
 
+static GHashTable *type_table_to_initialize;
+static GHashTable *type_table_initialized;
+
 static GHashTable *type_table_get(void)
 {
-    static GHashTable *type_table;
-
-    if (type_table == NULL) {
-        type_table = g_hash_table_new(g_str_hash, g_str_equal);
+    if (!type_table_initialized) {
+        type_table_initialized = g_hash_table_new(g_str_hash, g_str_equal);
     }
 
-    return type_table;
+    return type_table_initialized;
 }
 
 static void type_table_add(TypeImpl *ti)
 {
-    g_hash_table_insert(type_table_get(), (void *)ti->name, ti);
+    GHashTable **type_table;
+    if (ti->class) {
+        type_table = &type_table_initialized;
+    } else {
+        type_table = &type_table_to_initialize;
+    }
+    if (!*type_table) {
+        *type_table = g_hash_table_new(g_str_hash, g_str_equal);
+    }
+    g_hash_table_insert(*type_table, (void *)ti->name, ti);
 }
 
 static TypeImpl *type_table_lookup(const char *name)
 {
-    return g_hash_table_lookup(type_table_get(), name);
+    TypeImpl *ret = g_hash_table_lookup(type_table_get(), name);
+    if (!ret && type_table_to_initialize) {
+        ret = g_hash_table_lookup(type_table_to_initialize, name);
+    }
+    return ret;
 }
 
 static TypeImpl *type_register_internal(const TypeInfo *info)
@@ -573,13 +587,28 @@ static void object_class_foreach_tramp(gpointer key, 
gpointer value,
     data->fn(k, data->opaque);
 }
 
+static void object_class_merge(gpointer key, gpointer value,
+                               gpointer opaque)
+{
+    g_hash_table_insert(type_table_get(), key, value);
+}
+
 void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
                           const char *implements_type, bool include_abstract,
                           void *opaque)
 {
     OCFData data = { fn, implements_type, include_abstract, opaque };
 
-    g_hash_table_foreach(type_table_get(), object_class_foreach_tramp, &data);
+    while (type_table_to_initialize &&
+           g_hash_table_size(type_table_to_initialize) > 0) {
+        g_hash_table_foreach(type_table_to_initialize, object_class_merge,
+                             NULL);
+        g_hash_table_destroy(type_table_to_initialize);
+        type_table_to_initialize = NULL;
+
+        g_hash_table_foreach(type_table_get(), object_class_foreach_tramp,
+                             &data);
+    }
 }
 
 int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
-- 
1.7.10.4