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// Copyright (c) 2012 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.
#include "base/win/scoped_handle.h"
#include <unordered_map>
#include "base/debug/alias.h"
#include "base/hash.h"
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/synchronization/lock_impl.h"
namespace {
struct HandleHash {
size_t operator()(const HANDLE& handle) const {
char buffer[sizeof(handle)];
memcpy(buffer, &handle, sizeof(handle));
return base::Hash(buffer, sizeof(buffer));
}
};
struct Info {
const void* owner;
const void* pc1;
const void* pc2;
DWORD thread_id;
};
typedef std::unordered_map<HANDLE, Info, HandleHash> HandleMap;
// g_lock protects g_handle_map and g_closing.
typedef base::internal::LockImpl NativeLock;
base::LazyInstance<NativeLock>::Leaky g_lock = LAZY_INSTANCE_INITIALIZER;
base::LazyInstance<HandleMap>::Leaky g_handle_map = LAZY_INSTANCE_INITIALIZER;
bool g_closing = false;
// g_verifier_enabled is not protected by g_lock because that would require
// using the lock (hence, synchornizing multiple threads) even when the
// verifier is not in use. Note that this variable is initialized to track all
// handles, and it should only move to the disabled state, and never back to
// enabled, because that would crash when seeing handles created while the
// verifier was disabled. This also implies that it is OK if the value change is
// not propagated immediately to all CPUs (as would happen with a lock).
bool g_verifier_enabled = true;
bool CloseHandleWrapper(HANDLE handle) {
if (!::CloseHandle(handle))
CHECK(false);
return true;
}
// Simple automatic locking using a native critical section so it supports
// recursive locking.
class AutoNativeLock {
public:
explicit AutoNativeLock(NativeLock& lock) : lock_(lock) {
lock_.Lock();
}
~AutoNativeLock() {
lock_.Unlock();
}
private:
NativeLock& lock_;
DISALLOW_COPY_AND_ASSIGN(AutoNativeLock);
};
} // namespace
namespace base {
namespace win {
// Static.
bool HandleTraits::CloseHandle(HANDLE handle) {
if (!g_verifier_enabled)
return CloseHandleWrapper(handle);
AutoNativeLock lock(g_lock.Get());
g_closing = true;
CloseHandleWrapper(handle);
g_closing = false;
return true;
}
// Static.
void VerifierTraits::StartTracking(HANDLE handle, const void* owner,
const void* pc1, const void* pc2) {
if (!g_verifier_enabled)
return;
// Grab the thread id before the lock.
DWORD thread_id = GetCurrentThreadId();
AutoNativeLock lock(g_lock.Get());
Info handle_info = { owner, pc1, pc2, thread_id };
std::pair<HANDLE, Info> item(handle, handle_info);
std::pair<HandleMap::iterator, bool> result = g_handle_map.Get().insert(item);
if (!result.second) {
Info other = result.first->second;
debug::Alias(&other);
CHECK(false);
}
}
// Static.
void VerifierTraits::StopTracking(HANDLE handle, const void* owner,
const void* pc1, const void* pc2) {
if (!g_verifier_enabled)
return;
AutoNativeLock lock(g_lock.Get());
HandleMap::iterator i = g_handle_map.Get().find(handle);
if (i == g_handle_map.Get().end())
CHECK(false);
Info other = i->second;
if (other.owner != owner) {
debug::Alias(&other);
CHECK(false);
}
g_handle_map.Get().erase(i);
}
void DisableHandleVerifier() {
g_verifier_enabled = false;
}
void OnHandleBeingClosed(HANDLE handle) {
AutoNativeLock lock(g_lock.Get());
if (g_closing)
return;
HandleMap::iterator i = g_handle_map.Get().find(handle);
if (i == g_handle_map.Get().end())
return;
Info other = i->second;
debug::Alias(&other);
CHECK(false);
}
} // namespace win
} // namespace base
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