diff options
| -rw-r--r-- | src/mongo/SConscript | 1 | ||||
| -rw-r--r-- | src/mongo/db/db.cpp | 5 | ||||
| -rw-r--r-- | src/mongo/stdx/SConscript | 11 | ||||
| -rw-r--r-- | src/mongo/stdx/thread.h | 2 | ||||
| -rw-r--r-- | src/mongo/transport/service_entry_point_utils.cpp | 2 | ||||
| -rw-r--r-- | src/mongo/util/SConscript | 10 | ||||
| -rw-r--r-- | src/mongo/util/thread_safety_context.cpp | 59 | ||||
| -rw-r--r-- | src/mongo/util/thread_safety_context.h | 87 | ||||
| -rw-r--r-- | src/mongo/util/thread_safety_context_test.cpp | 103 |
9 files changed, 275 insertions, 5 deletions
diff --git a/src/mongo/SConscript b/src/mongo/SConscript index f0ef13a95e7..fdc017efb8b 100644 --- a/src/mongo/SConscript +++ b/src/mongo/SConscript @@ -164,6 +164,7 @@ baseEnv.Library( 'util/system_clock_source.cpp', 'util/system_tick_source.cpp', 'util/text.cpp', + 'util/thread_safety_context.cpp', 'util/time_support.cpp', 'util/timer.cpp', 'util/uuid.cpp', diff --git a/src/mongo/db/db.cpp b/src/mongo/db/db.cpp index e79178ed28c..ac10b378700 100644 --- a/src/mongo/db/db.cpp +++ b/src/mongo/db/db.cpp @@ -1228,6 +1228,8 @@ void shutdownTask(const ShutdownTaskArgs& shutdownArgs) { } int mongoDbMain(int argc, char* argv[], char** envp) { + ThreadSafetyContext::getThreadSafetyContext()->forbidMultiThreading(); + registerShutdownTask(shutdownTask); setupSignalHandlers(); @@ -1277,6 +1279,9 @@ int mongoDbMain(int argc, char* argv[], char** envp) { if (!initializeServerSecurityGlobalState(service)) quickExit(EXIT_FAILURE); + // There is no single-threaded guarantee beyond this point. + ThreadSafetyContext::getThreadSafetyContext()->allowMultiThreading(); + // Per SERVER-7434, startSignalProcessingThread must run after any forks (i.e. // initializeServerGlobalState) and before the creation of any other threads startSignalProcessingThread(); diff --git a/src/mongo/stdx/SConscript b/src/mongo/stdx/SConscript index 02af02ec6f3..fc70228475e 100644 --- a/src/mongo/stdx/SConscript +++ b/src/mongo/stdx/SConscript @@ -10,6 +10,7 @@ env.Benchmark( 'condition_variable_bm.cpp', ], LIBDEPS=[ + '$BUILD_DIR/mongo/base', ], ) @@ -44,7 +45,7 @@ env.CppUnitTest( 'sigaltstack_location_test.cpp', ], LIBDEPS=[ - 'stdx', + '$BUILD_DIR/mongo/base', ], UNITTEST_HAS_CUSTOM_MAINLINE=True, ) @@ -64,7 +65,7 @@ env.CppUnitTest( 'set_terminate_dispatch_test.cpp', ], LIBDEPS=[ - 'stdx', + '$BUILD_DIR/mongo/base', ], UNITTEST_HAS_CUSTOM_MAINLINE=True, ) @@ -76,7 +77,7 @@ env.CppUnitTest( 'set_terminate_from_main_die_in_thread_test.cpp', ], LIBDEPS=[ - 'stdx', + '$BUILD_DIR/mongo/base', ], UNITTEST_HAS_CUSTOM_MAINLINE=True, ) @@ -88,7 +89,7 @@ env.CppUnitTest( 'set_terminate_from_thread_die_in_main_test.cpp', ], LIBDEPS=[ - 'stdx', + '$BUILD_DIR/mongo/base', ], UNITTEST_HAS_CUSTOM_MAINLINE=True, ) @@ -100,7 +101,7 @@ env.CppUnitTest( 'set_terminate_from_thread_die_in_thread_test.cpp', ], LIBDEPS=[ - 'stdx', + '$BUILD_DIR/mongo/base', ], UNITTEST_HAS_CUSTOM_MAINLINE=True, ) diff --git a/src/mongo/stdx/thread.h b/src/mongo/stdx/thread.h index e072de0cc72..f8058279e34 100644 --- a/src/mongo/stdx/thread.h +++ b/src/mongo/stdx/thread.h @@ -39,6 +39,7 @@ #include <type_traits> #include "mongo/stdx/exception.h" +#include "mongo/util/thread_safety_context.h" #if defined(__linux__) || defined(__FreeBSD__) #define MONGO_HAS_SIGALTSTACK 1 @@ -180,6 +181,7 @@ public: ::std::set_terminate( // NOLINT ::mongo::stdx::TerminateHandlerDetailsInterface::dispatch); #endif + ThreadSafetyContext::getThreadSafetyContext()->onThreadCreate(); auto sigAltStackGuard = sigAltStackController.makeInstallGuard(); return std::apply(std::move(f), std::move(pack)); }) { diff --git a/src/mongo/transport/service_entry_point_utils.cpp b/src/mongo/transport/service_entry_point_utils.cpp index f4e894e1168..aab92e246c3 100644 --- a/src/mongo/transport/service_entry_point_utils.cpp +++ b/src/mongo/transport/service_entry_point_utils.cpp @@ -40,6 +40,7 @@ #include "mongo/stdx/thread.h" #include "mongo/util/assert_util.h" #include "mongo/util/debug_util.h" +#include "mongo/util/thread_safety_context.h" #if !defined(_WIN32) #include <sys/resource.h> @@ -101,6 +102,7 @@ Status launchServiceWorkerThread(std::function<void()> task) { pthread_t thread; auto ctx = std::make_unique<std::function<void()>>(std::move(task)); + ThreadSafetyContext::getThreadSafetyContext()->onThreadCreate(); int failed = pthread_create(&thread, &attrs, runFunc, ctx.get()); pthread_attr_destroy(&attrs); diff --git a/src/mongo/util/SConscript b/src/mongo/util/SConscript index 50b413173dd..46fa8aec9b1 100644 --- a/src/mongo/util/SConscript +++ b/src/mongo/util/SConscript @@ -213,6 +213,16 @@ env.Library( ] ) +env.CppUnitTest( + target='thread_safety_context_test', + source=[ + 'thread_safety_context_test.cpp', + ], + LIBDEPS=[ + '$BUILD_DIR/mongo/base', + ], +) + if env['MONGO_ALLOCATOR'] in ['tcmalloc', 'tcmalloc-experimental']: tcmspEnv = env.Clone() diff --git a/src/mongo/util/thread_safety_context.cpp b/src/mongo/util/thread_safety_context.cpp new file mode 100644 index 00000000000..1b40c2746c5 --- /dev/null +++ b/src/mongo/util/thread_safety_context.cpp @@ -0,0 +1,59 @@ +/** + * Copyright (C) 2020-present MongoDB, Inc. + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the Server Side Public License, version 1, + * as published by MongoDB, Inc. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * Server Side Public License for more details. + * + * You should have received a copy of the Server Side Public License + * along with this program. If not, see + * <http://www.mongodb.com/licensing/server-side-public-license>. + * + * As a special exception, the copyright holders give permission to link the + * code of portions of this program with the OpenSSL library under certain + * conditions as described in each individual source file and distribute + * linked combinations including the program with the OpenSSL library. You + * must comply with the Server Side Public License in all respects for + * all of the code used other than as permitted herein. If you modify file(s) + * with this exception, you may extend this exception to your version of the + * file(s), but you are not obligated to do so. If you do not wish to do so, + * delete this exception statement from your version. If you delete this + * exception statement from all source files in the program, then also delete + * it in the license file. + */ + +#include "mongo/util/thread_safety_context.h" + +#include "mongo/platform/compiler.h" +#include "mongo/util/assert_util.h" + +namespace mongo { + +ThreadSafetyContext* ThreadSafetyContext::getThreadSafetyContext() noexcept { + static auto safetyContext = new ThreadSafetyContext(); // Intentionally leaked + return safetyContext; +} + +void ThreadSafetyContext::forbidMultiThreading() noexcept { + invariant(_isSingleThreaded.load()); + invariant(_safeToCreateThreads.swap(false)); +} + +void ThreadSafetyContext::allowMultiThreading() noexcept { + invariant(_isSingleThreaded.load()); + invariant(!_safeToCreateThreads.swap(true)); +} + +void ThreadSafetyContext::onThreadCreate() noexcept { + invariant(_safeToCreateThreads.load()); + if (MONGO_unlikely(_isSingleThreaded.load())) { + _isSingleThreaded.store(false); + } +} + +} // namespace mongo diff --git a/src/mongo/util/thread_safety_context.h b/src/mongo/util/thread_safety_context.h new file mode 100644 index 00000000000..cbf3f153efd --- /dev/null +++ b/src/mongo/util/thread_safety_context.h @@ -0,0 +1,87 @@ +/** + * Copyright (C) 2020-present MongoDB, Inc. + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the Server Side Public License, version 1, + * as published by MongoDB, Inc. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * Server Side Public License for more details. + * + * You should have received a copy of the Server Side Public License + * along with this program. If not, see + * <http://www.mongodb.com/licensing/server-side-public-license>. + * + * As a special exception, the copyright holders give permission to link the + * code of portions of this program with the OpenSSL library under certain + * conditions as described in each individual source file and distribute + * linked combinations including the program with the OpenSSL library. You + * must comply with the Server Side Public License in all respects for + * all of the code used other than as permitted herein. If you modify file(s) + * with this exception, you may extend this exception to your version of the + * file(s), but you are not obligated to do so. If you do not wish to do so, + * delete this exception statement from your version. If you delete this + * exception statement from all source files in the program, then also delete + * it in the license file. + */ + +#pragma once + +#include "mongo/platform/atomic_word.h" + +namespace mongo { + +class ThreadSafetyContextTest; + +/** + * Provides a singleton object that allows enforcing a single-threaded context at startup. + * + * This class, currently, intercepts `stdx::thread` creations and aborts the process if a single + * threaded context is expected. + * + * You should avoid using the interfaces that specify single-threaded context (i.e., + * `forbidMultiThreading()` and `allowMultiThreading()`) outside the main function. + * + * If using other APIs for spawning threads (e.g., `pthread_create()`), make sure to precede the + * API call with `onThreadCreate()`. + */ +class ThreadSafetyContext final { +public: + ThreadSafetyContext(const ThreadSafetyContext&) = delete; + + ThreadSafetyContext(ThreadSafetyContext&&) noexcept = delete; + + ThreadSafetyContext& operator=(const ThreadSafetyContext&) = delete; + + ThreadSafetyContext& operator=(ThreadSafetyContext&&) = delete; + + static ThreadSafetyContext* getThreadSafetyContext() noexcept; + + // Prevents a multi-threaded context -- aborts the process on thread creation. + // If the program is already multi-threaded, it will abort the program. + void forbidMultiThreading() noexcept; + + // Allows a multi-threaded context by lifting the limit enforced by `forbidMultiThreading()`. + void allowMultiThreading() noexcept; + + // Allows detecting thread creation, and thus a multi-threaded context. + // If not using `stdx::thread`, you must always call this method before spawning a new thread. + void onThreadCreate() noexcept; + + // Restricts the ability of resetting the context to the unit-test fixture. + friend class ThreadSafetyContextTest; + +private: + // Prevents creating any instance of the object (other than the singleton). + ThreadSafetyContext() = default; + + // An indicator on whether the program is single-threaded. + AtomicWord<bool> _isSingleThreaded{true}; + + // If set to "false", it will prevent creation of new threads. + AtomicWord<bool> _safeToCreateThreads{true}; +}; + +} // namespace mongo diff --git a/src/mongo/util/thread_safety_context_test.cpp b/src/mongo/util/thread_safety_context_test.cpp new file mode 100644 index 00000000000..4e27614b514 --- /dev/null +++ b/src/mongo/util/thread_safety_context_test.cpp @@ -0,0 +1,103 @@ +/** + * Copyright (C) 2020-present MongoDB, Inc. + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the Server Side Public License, version 1, + * as published by MongoDB, Inc. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * Server Side Public License for more details. + * + * You should have received a copy of the Server Side Public License + * along with this program. If not, see + * <http://www.mongodb.com/licensing/server-side-public-license>. + * + * As a special exception, the copyright holders give permission to link the + * code of portions of this program with the OpenSSL library under certain + * conditions as described in each individual source file and distribute + * linked combinations including the program with the OpenSSL library. You + * must comply with the Server Side Public License in all respects for + * all of the code used other than as permitted herein. If you modify file(s) + * with this exception, you may extend this exception to your version of the + * file(s), but you are not obligated to do so. If you do not wish to do so, + * delete this exception statement from your version. If you delete this + * exception statement from all source files in the program, then also delete + * it in the license file. + */ +#include <vector> + +#include "mongo/stdx/thread.h" +#include "mongo/unittest/death_test.h" +#include "mongo/unittest/unittest.h" +#include "mongo/util/thread_safety_context.h" +#include "mongo/util/time_support.h" + +namespace mongo { + +class ThreadSafetyContextTest : public unittest::Test { +public: + void setUp() override { + // Always start tests with a clean context + resetContext(); + } + + void tearDown() override { + // Clear the context for the next test + resetContext(); + } + +private: + void resetContext() { + auto context = ThreadSafetyContext::getThreadSafetyContext(); + context->_isSingleThreaded.store(true); + context->_safeToCreateThreads.store(true); + } +}; + +TEST_F(ThreadSafetyContextTest, CreateThreadsWithNoSafetyContext) { + constexpr auto threadCount = 16; + std::vector<stdx::thread> threads; + + for (auto i = 0; i < threadCount; i++) { + threads.emplace_back([] { sleepFor(Milliseconds(10)); }); + } + + for (auto i = 0; i < threadCount; i++) { + threads[i].join(); + } +} + +DEATH_TEST_F(ThreadSafetyContextTest, CreateThreadsAfterForbidingMultiThreading, "invariant") { + ThreadSafetyContext::getThreadSafetyContext()->forbidMultiThreading(); + auto thread = stdx::thread([] {}); + // Must never reach here or the test fails +} + +DEATH_TEST_F(ThreadSafetyContextTest, ForbidMultiThreadingAfterCreatingThreads, "invariant") { + auto thread = stdx::thread([] { sleepFor(Milliseconds(50)); }); + + ThreadSafetyContext::getThreadSafetyContext()->forbidMultiThreading(); + // Must never reach here or the test fails +} + +TEST_F(ThreadSafetyContextTest, CreateThreadsAfterSafetyContext) { + ThreadSafetyContext::getThreadSafetyContext()->forbidMultiThreading(); + // Do something inside the single-threaded context + sleepFor(Milliseconds(10)); + ThreadSafetyContext::getThreadSafetyContext()->allowMultiThreading(); + + constexpr auto threadCount = 16; + std::vector<stdx::thread> threads; + + for (auto i = 0; i < threadCount; i++) { + threads.emplace_back([] { sleepFor(Milliseconds(10)); }); + } + + for (auto i = 0; i < threadCount; i++) { + threads[i].join(); + } +} + +} // namespace mongo |