--- /dev/null
+++ libmalloc/libmalloc-715.100.22/src/msl_lite_support.c
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2018 Apple Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+/*
+ * Support for stack logging lite in the malloc stack logging library. This code
+ * will go away when MSL lite no longer requires its own zone.
+ */
+#ifndef MALLOC_ENABLE_MSL_LITE_SPI
+#define MALLOC_ENABLE_MSL_LITE_SPI 1
+#endif // MALLOC_ENABLE_MSL_LITE_SPI
+
+#include "internal.h"
+
+// These definitions are here and not in a header file because all of this code
+// is intended to go away very soon.
+extern malloc_zone_t **malloc_zones;
+extern malloc_zone_t* lite_zone;
+extern boolean_t has_default_zone0(void);
+
+static void
+insert_msl_lite_zone(malloc_zone_t *zone)
+{
+	lite_zone = zone;
+	malloc_slowpath_update();
+}
+
+static malloc_zone_t *
+get_global_helper_zone(void)
+{
+	return malloc_zones[0];  // TODO: this is broken
+}
+
+// This struct contains many more function pointers than the ones given here. MSL previously used
+// those when it called into libmalloc to create a lite zone.
+// Now that MSL creates a lite zone itself, we don't need to provide those other function pointers.
+static struct _malloc_msl_lite_hooks_s malloc_msl_lite_hooks = {
+	.has_default_zone0      = &has_default_zone0,
+	.insert_msl_lite_zone   = &insert_msl_lite_zone,
+	.get_global_helper_zone = &get_global_helper_zone,
+};
+
+/*
+ * Copies the malloc library's _malloc_msl_lite_hooks_t structure to a given
+ * location. We pass the structure size to allow the structure to
+ * grow. Since this is a temporary arrangement, we don't need to worry about
+ * pointer authentication here or in the _malloc_msl_lite_hooks_t structure itself.
+ */
+MALLOC_NOEXPORT
+void
+set_msl_lite_hooks(set_msl_lite_hooks_callout_t callout)
+{
+	callout(&malloc_msl_lite_hooks, sizeof(malloc_msl_lite_hooks));
+}