mac: Periodically shim new malloc zones immediately after startup.

base/allocator/allocator_interception_mac.mm

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file contains all the logic necessary to intercept allocations on
 // macOS. "malloc zones" are an abstraction that allows the process to intercept
 // all malloc-related functions.  There is no good mechanism [short of
 // interposition] to determine new malloc zones are added, so there's no clean
 // mechanism to intercept all malloc zones. This file contains logic to
 // intercept the default and purgeable zones, which always exist. A cursory
@@ skipping 11 matching lines @@
 #include <errno.h>
 #include <mach/mach.h>
 #include <mach/mach_vm.h>
 #import <objc/runtime.h>
 #include <stddef.h>
 
 #include <new>
 
 #include "base/allocator/features.h"
 #include "base/allocator/malloc_zone_functions_mac.h"
+#include "base/bind.h"
 #include "base/logging.h"
 #include "base/mac/mac_util.h"
 #include "base/mac/mach_logging.h"
 #include "base/process/memory.h"
 #include "base/scoped_clear_errno.h"
+#include "base/threading/sequenced_task_runner_handle.h"
 #include "build/build_config.h"
 #include "third_party/apple_apsl/CFBase.h"
 
 namespace base {
 namespace allocator {
 
 bool g_replaced_default_zone = false;
 
 namespace {
 
@@ skipping 209 matching lines @@
 typedef id (*allocWithZone_t)(id, SEL, NSZone*);
 allocWithZone_t g_old_allocWithZone;
 
 id oom_killer_allocWithZone(id self, SEL _cmd, NSZone* zone) {
   id result = g_old_allocWithZone(self, _cmd, zone);
   if (!result)
     TerminateBecauseOutOfMemory(0);
   return result;
 }
 
-void ReplaceZoneFunctions(ChromeMallocZone* zone,
-                          const MallocZoneFunctions* functions) {
-  // Remove protection.
-  mach_vm_address_t reprotection_start = 0;
-  mach_vm_size_t reprotection_length = 0;
-  vm_prot_t reprotection_value = VM_PROT_NONE;
-  DeprotectMallocZone(zone, &reprotection_start, &reprotection_length,
-                      &reprotection_value);
-
-  CHECK(functions->malloc && functions->calloc && functions->valloc &&
-        functions->free && functions->realloc);
-  zone->malloc = functions->malloc;
-  zone->calloc = functions->calloc;
-  zone->valloc = functions->valloc;
-  zone->free = functions->free;
-  zone->realloc = functions->realloc;
-  if (functions->batch_malloc)
-    zone->batch_malloc = functions->batch_malloc;
-  if (functions->batch_free)
-    zone->batch_free = functions->batch_free;
-  if (functions->size)
-    zone->size = functions->size;
-  if (zone->version >= 5 && functions->memalign) {
-    zone->memalign = functions->memalign;
-  }
-  if (zone->version >= 6 && functions->free_definite_size) {
-    zone->free_definite_size = functions->free_definite_size;
-  }
-
-  // Restore protection if it was active.
-  if (reprotection_start) {
-    kern_return_t result =
-        mach_vm_protect(mach_task_self(), reprotection_start,
-                        reprotection_length, false, reprotection_value);
-    MACH_CHECK(result == KERN_SUCCESS, result) << "mach_vm_protect";
-  }
-}
-
 void UninterceptMallocZoneForTesting(struct _malloc_zone_t* zone) {
   ChromeMallocZone* chrome_zone = reinterpret_cast<ChromeMallocZone*>(zone);
   if (!IsMallocZoneAlreadyStored(chrome_zone))
     return;
   MallocZoneFunctions& functions = GetFunctionsForZone(zone);
   ReplaceZoneFunctions(chrome_zone, &functions);
 }
 
 }  // namespace
 
@@ skipping 203 matching lines @@
   kern_return_t kr = malloc_get_all_zones(mach_task_self(), 0, &zones, &count);
   CHECK(kr == KERN_SUCCESS);
   for (unsigned int i = 0; i < count; ++i) {
     UninterceptMallocZoneForTesting(
         reinterpret_cast<struct _malloc_zone_t*>(zones[i]));
   }
 
   ClearAllMallocZonesForTesting();
 }
 
+namespace {
+
+void ShimNewMallocZonesAndReschedule(base::Time end_time,
+                                     base::TimeDelta delay) {
+  ShimNewMallocZones();
+
+  if (base::Time::Now() > end_time)
+    return;
+
+  base::TimeDelta next_delay = delay * 2;
+  SequencedTaskRunnerHandle::Get()->PostDelayedTask(
+      FROM_HERE,
+      base::Bind(&ShimNewMallocZonesAndReschedule, end_time, next_delay),
+      delay);
+}
+
+}  // namespace
+
+void PeriodicallyShimNewMallocZones() {
+  base::Time end_time = base::Time::Now() + base::TimeDelta::FromMinutes(1);
+  base::TimeDelta initial_delay = base::TimeDelta::FromSeconds(1);
+  ShimNewMallocZonesAndReschedule(end_time, initial_delay);
+}
+
+void ShimNewMallocZones() {
+  StoreFunctionsForAllZones();
+
+  // Use the functions for the default zone as a template to replace those
+  // new zones.
+  ChromeMallocZone* default_zone =
+      reinterpret_cast<ChromeMallocZone*>(malloc_default_zone());
+  DCHECK(IsMallocZoneAlreadyStored(default_zone));
+
+  MallocZoneFunctions new_functions;
+  StoreZoneFunctions(default_zone, &new_functions);
+  ReplaceFunctionsForStoredZones(&new_functions);
+}
+
+void ReplaceZoneFunctions(ChromeMallocZone* zone,
+                          const MallocZoneFunctions* functions) {
+  // Remove protection.
+  mach_vm_address_t reprotection_start = 0;
+  mach_vm_size_t reprotection_length = 0;
+  vm_prot_t reprotection_value = VM_PROT_NONE;
+  DeprotectMallocZone(zone, &reprotection_start, &reprotection_length,
+                      &reprotection_value);
+
+  CHECK(functions->malloc && functions->calloc && functions->valloc &&
+        functions->free && functions->realloc);
+  zone->malloc = functions->malloc;
+  zone->calloc = functions->calloc;
+  zone->valloc = functions->valloc;
+  zone->free = functions->free;
+  zone->realloc = functions->realloc;
+  if (functions->batch_malloc)
+    zone->batch_malloc = functions->batch_malloc;
+  if (functions->batch_free)
+    zone->batch_free = functions->batch_free;
+  if (functions->size)
+    zone->size = functions->size;
+  if (zone->version >= 5 && functions->memalign) {
+    zone->memalign = functions->memalign;
+  }
+  if (zone->version >= 6 && functions->free_definite_size) {
+    zone->free_definite_size = functions->free_definite_size;
+  }
+
+  // Restore protection if it was active.
+  if (reprotection_start) {
+    kern_return_t result =
+        mach_vm_protect(mach_task_self(), reprotection_start,
+                        reprotection_length, false, reprotection_value);
+    MACH_CHECK(result == KERN_SUCCESS, result) << "mach_vm_protect";
+  }
+}
+
 }  // namespace allocator
 }  // namespace base