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-rw-r--r--security/sandbox/chromium/base/at_exit.cc114
1 files changed, 114 insertions, 0 deletions
diff --git a/security/sandbox/chromium/base/at_exit.cc b/security/sandbox/chromium/base/at_exit.cc
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index 0000000000..eb7d26cdc7
--- /dev/null
+++ b/security/sandbox/chromium/base/at_exit.cc
@@ -0,0 +1,114 @@
+// Copyright (c) 2011 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/at_exit.h"
+
+#include <stddef.h>
+#include <ostream>
+#include <utility>
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/logging.h"
+
+namespace base {
+
+// Keep a stack of registered AtExitManagers. We always operate on the most
+// recent, and we should never have more than one outside of testing (for a
+// statically linked version of this library). Testing may use the shadow
+// version of the constructor, and if we are building a dynamic library we may
+// end up with multiple AtExitManagers on the same process. We don't protect
+// this for thread-safe access, since it will only be modified in testing.
+static AtExitManager* g_top_manager = nullptr;
+
+static bool g_disable_managers = false;
+
+AtExitManager::AtExitManager() : next_manager_(g_top_manager) {
+// If multiple modules instantiate AtExitManagers they'll end up living in this
+// module... they have to coexist.
+#if !defined(COMPONENT_BUILD)
+ DCHECK(!g_top_manager);
+#endif
+ g_top_manager = this;
+}
+
+AtExitManager::~AtExitManager() {
+ if (!g_top_manager) {
+ NOTREACHED() << "Tried to ~AtExitManager without an AtExitManager";
+ return;
+ }
+ DCHECK_EQ(this, g_top_manager);
+
+ if (!g_disable_managers)
+ ProcessCallbacksNow();
+ g_top_manager = next_manager_;
+}
+
+// static
+void AtExitManager::RegisterCallback(AtExitCallbackType func, void* param) {
+ DCHECK(func);
+ RegisterTask(base::BindOnce(func, param));
+}
+
+// static
+void AtExitManager::RegisterTask(base::OnceClosure task) {
+ if (!g_top_manager) {
+ NOTREACHED() << "Tried to RegisterCallback without an AtExitManager";
+ return;
+ }
+
+ AutoLock lock(g_top_manager->lock_);
+#if DCHECK_IS_ON()
+ DCHECK(!g_top_manager->processing_callbacks_);
+#endif
+ g_top_manager->stack_.push(std::move(task));
+}
+
+// static
+void AtExitManager::ProcessCallbacksNow() {
+ if (!g_top_manager) {
+ NOTREACHED() << "Tried to ProcessCallbacksNow without an AtExitManager";
+ return;
+ }
+
+ // Callbacks may try to add new callbacks, so run them without holding
+ // |lock_|. This is an error and caught by the DCHECK in RegisterTask(), but
+ // handle it gracefully in release builds so we don't deadlock.
+ base::stack<base::OnceClosure> tasks;
+ {
+ AutoLock lock(g_top_manager->lock_);
+ tasks.swap(g_top_manager->stack_);
+#if DCHECK_IS_ON()
+ g_top_manager->processing_callbacks_ = true;
+#endif
+ }
+
+ // Relax the cross-thread access restriction to non-thread-safe RefCount.
+ // It's safe since all other threads should be terminated at this point.
+ ScopedAllowCrossThreadRefCountAccess allow_cross_thread_ref_count_access;
+
+ while (!tasks.empty()) {
+ std::move(tasks.top()).Run();
+ tasks.pop();
+ }
+
+#if DCHECK_IS_ON()
+ AutoLock lock(g_top_manager->lock_);
+ // Expect that all callbacks have been run.
+ DCHECK(g_top_manager->stack_.empty());
+ g_top_manager->processing_callbacks_ = false;
+#endif
+}
+
+void AtExitManager::DisableAllAtExitManagers() {
+ AutoLock lock(g_top_manager->lock_);
+ g_disable_managers = true;
+}
+
+AtExitManager::AtExitManager(bool shadow) : next_manager_(g_top_manager) {
+ DCHECK(shadow || !g_top_manager);
+ g_top_manager = this;
+}
+
+} // namespace base