imprecise mark and sweep native memory leak detector
libmemunreachable uses an imprecise mark and sweep pass over all memory
allocated by jemalloc in order to find unreachable allocations.
Change-Id: Ia70bbf31f5b40ff71dab28cfd6cd06c5ef01a2d4
diff --git a/libmemunreachable/ScopedDisableMalloc.h b/libmemunreachable/ScopedDisableMalloc.h
new file mode 100644
index 0000000..4f96376
--- /dev/null
+++ b/libmemunreachable/ScopedDisableMalloc.h
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LIBMEMUNREACHABLE_SCOPED_DISABLE_MALLOC_H_
+#define LIBMEMUNREACHABLE_SCOPED_DISABLE_MALLOC_H_
+
+#include <memory>
+
+#include "android-base/macros.h"
+
+#include "bionic.h"
+#include "log.h"
+#include "ScopedAlarm.h"
+
+class DisableMallocGuard{
+ public:
+ DisableMallocGuard() : disabled_(false){}
+ ~DisableMallocGuard() {
+ Enable();
+ }
+
+ void Disable() {
+ if (!disabled_) {
+ malloc_disable();
+ disabled_ = true;
+ }
+ }
+
+ void Enable() {
+ if (disabled_) {
+ malloc_enable();
+ disabled_ = false;
+ }
+ }
+ private:
+ DISALLOW_COPY_AND_ASSIGN(DisableMallocGuard);
+ bool disabled_;
+};
+
+// Any calls to malloc or free from this thread will deadlock as long as this
+// object is in scope. Calls to malloc from other threads may succeed (for
+// example if the allocation is satisfied out of the thread's tcache), or may
+// block until the object is destroyed.
+//
+// Don't call fork() while malloc is disabled, it needs the same locks held
+// here.
+class ScopedDisableMalloc {
+ public:
+ ScopedDisableMalloc() {
+ disable_malloc_.Disable();
+ }
+
+ ~ScopedDisableMalloc() {
+ disable_malloc_.Enable();
+ }
+
+ private:
+ DISALLOW_COPY_AND_ASSIGN(ScopedDisableMalloc);
+ DisableMallocGuard disable_malloc_;
+};
+
+class ScopedDisableMallocTimeout {
+ public:
+ ScopedDisableMallocTimeout(std::chrono::milliseconds timeout = std::chrono::milliseconds(2000)) :
+ timeout_(timeout), timed_out_(false), disable_malloc_() {
+ Disable();
+ }
+
+ ~ScopedDisableMallocTimeout() {
+ Enable();
+ }
+
+ bool timed_out() {
+ return timed_out_;
+ }
+
+ void Enable() {
+ disable_malloc_.Enable();
+ alarm_ = nullptr;
+ }
+
+ void Disable() {
+ // set up the alarm before disabling malloc so unique_ptr can be used
+ alarm_ = std::make_unique<ScopedAlarm>(timeout_, [&]() {
+ disable_malloc_.Enable();
+ timed_out_ = true;
+ });
+
+ disable_malloc_.Disable();
+ }
+
+ private:
+ DISALLOW_COPY_AND_ASSIGN(ScopedDisableMallocTimeout);
+ std::chrono::milliseconds timeout_;
+ bool timed_out_;
+ std::unique_ptr<ScopedAlarm> alarm_;
+ DisableMallocGuard disable_malloc_;
+};
+
+#endif // LIBMEMUNREACHABLE_SCOPED_DISABLE_MALLOC_H_