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/*
* 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 "ScopedAlarm.h"
#include "bionic.h"
#include "log.h"
namespace android {
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:
explicit 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_;
};
} // namespace android
#endif // LIBMEMUNREACHABLE_SCOPED_DISABLE_MALLOC_H_
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