Loading...
src/frozen_malloc.c /dev/null libmalloc-140.50.6
--- /dev/null
+++ libmalloc/libmalloc-140.50.6/src/frozen_malloc.c
@@ -0,0 +1,178 @@
+/*
+ * Copyright (c) 2015 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@
+ */
+
+#include "internal.h"
+
+/********* Support code for emacs unexec ************/
+
+/* History of freezedry version numbers:
+ *
+ * 1) Old malloc (before the scalable malloc implementation in this file
+ *    existed).
+ * 2) Original freezedrying code for scalable malloc.  This code was apparently
+ *    based on the old freezedrying code and was fundamentally flawed in its
+ *    assumption that tracking allocated memory regions was adequate to fake
+ *    operations on freezedried memory.  This doesn't work, since scalable
+ *    malloc does not store flags in front of large page-aligned allocations.
+ * 3) Original szone-based freezedrying code.
+ * 4) Fresher malloc with tiny zone
+ * 5) 32/64bit compatible malloc
+ * 6) Metadata within 1MB and 8MB region for tiny and small
+ *
+ * No version backward compatibility is provided, but the version number does
+ * make it possible for malloc_jumpstart() to return an error if the application
+ * was freezedried with an older version of malloc.
+ */
+#define MALLOC_FREEZEDRY_VERSION 6
+
+typedef struct {
+	unsigned version;
+	unsigned nszones;
+	szone_t *szones;
+} malloc_frozen;
+
+static void *
+frozen_malloc(szone_t *zone, size_t new_size)
+{
+	return malloc(new_size);
+}
+
+static void *
+frozen_calloc(szone_t *zone, size_t num_items, size_t size)
+{
+	return calloc(num_items, size);
+}
+
+static void *
+frozen_valloc(szone_t *zone, size_t new_size)
+{
+	return valloc(new_size);
+}
+
+static void *
+frozen_realloc(szone_t *zone, void *ptr, size_t new_size)
+{
+	size_t old_size = szone_size(zone, ptr);
+	void *new_ptr;
+
+	if (new_size <= old_size) {
+		return ptr;
+	}
+	new_ptr = malloc(new_size);
+	if (old_size > 0) {
+		memcpy(new_ptr, ptr, old_size);
+	}
+	return new_ptr;
+}
+
+static void
+frozen_free(szone_t *zone, void *ptr)
+{
+}
+
+static void
+frozen_destroy(szone_t *zone)
+{
+}
+
+/********* Pseudo-private API for emacs unexec ************/
+
+/*
+ * malloc_freezedry() records all of the szones in use, so that they can be
+ * partially reconstituted by malloc_jumpstart().  Due to the differences
+ * between reconstituted memory regions and those created by the szone code,
+ * care is taken not to reallocate from the freezedried memory, except in the
+ * case of a non-growing realloc().
+ *
+ * Due to the flexibility provided by the zone registration mechanism, it is
+ * impossible to implement generic freezedrying for any zone type.  This code
+ * only handles applications that use the szone allocator, so malloc_freezedry()
+ * returns 0 (error) if any non-szone zones are encountered.
+ */
+
+uintptr_t
+malloc_freezedry(void)
+{
+	extern unsigned malloc_num_zones;
+	extern malloc_zone_t **malloc_zones;
+	malloc_frozen *data;
+	unsigned i;
+
+	/* Allocate space in which to store the freezedry state. */
+	data = (malloc_frozen *)malloc(sizeof(malloc_frozen));
+
+	/* Set freezedry version number so that malloc_jumpstart() can check for compatibility. */
+	data->version = MALLOC_FREEZEDRY_VERSION;
+
+	/* Allocate the array of szone pointers. */
+	data->nszones = malloc_num_zones;
+	data->szones = (szone_t *)calloc(malloc_num_zones, sizeof(szone_t));
+
+	/*
+	 * Fill in the array of szone structures.  They are copied rather than
+	 * referenced, since the originals are likely to be clobbered during malloc
+	 * initialization.
+	 */
+	for (i = 0; i < malloc_num_zones; i++) {
+		if (strcmp(malloc_zones[i]->zone_name, "DefaultMallocZone")) {
+			/* Unknown zone type. */
+			free(data->szones);
+			free(data);
+			return 0;
+		}
+		memcpy(&data->szones[i], malloc_zones[i], sizeof(szone_t));
+	}
+
+	return ((uintptr_t)data);
+}
+
+int
+malloc_jumpstart(uintptr_t cookie)
+{
+	malloc_frozen *data = (malloc_frozen *)cookie;
+	unsigned i;
+
+	if (data->version != MALLOC_FREEZEDRY_VERSION) {
+		/* Unsupported freezedry version. */
+		return 1;
+	}
+
+	for (i = 0; i < data->nszones; i++) {
+		/* Set function pointers.  Even the functions that stay the same must be
+		 * set, since there are no guarantees that they will be mapped to the
+		 * same addresses. */
+		data->szones[i].basic_zone.size = (void *)szone_size;
+		data->szones[i].basic_zone.malloc = (void *)frozen_malloc;
+		data->szones[i].basic_zone.calloc = (void *)frozen_calloc;
+		data->szones[i].basic_zone.valloc = (void *)frozen_valloc;
+		data->szones[i].basic_zone.free = (void *)frozen_free;
+		data->szones[i].basic_zone.realloc = (void *)frozen_realloc;
+		data->szones[i].basic_zone.destroy = (void *)frozen_destroy;
+		data->szones[i].basic_zone.introspect = (struct malloc_introspection_t *)&szone_introspect;
+
+		/* Register the freezedried zone. */
+		malloc_zone_register(&data->szones[i].basic_zone);
+	}
+
+	return 0;
+}