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gtest-death-test.cc
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gtest-death-test.cc
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			// Copyright 2005, Google Inc.
			// All rights reserved.
			//
			// Redistribution and use in source and binary forms, with or without
			// modification, are permitted provided that the following conditions are
			// met:
			//
			// * Redistributions of source code must retain the above copyright
			// notice, this list of conditions and the following disclaimer.
			// * Redistributions in binary form must reproduce the above
			// copyright notice, this list of conditions and the following disclaimer
			// in the documentation and/or other materials provided with the
			// distribution.
			// * Neither the name of Google Inc. nor the names of its
			// contributors may be used to endorse or promote products derived from
			// this software without specific prior written permission.
			//
			// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
			// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
			// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
			// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
			// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
			// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
			// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
			// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
			// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
			// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
			// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

			//
			// This file implements death tests.

			#include "gtest/gtest-death-test.h"

			#include <utility>

			#include "gtest/internal/gtest-port.h"
			#include "gtest/internal/custom/gtest.h"

			#if GTEST_HAS_DEATH_TEST

			# if GTEST_OS_MAC
			# include <crt_externs.h>
			# endif // GTEST_OS_MAC

			# include <errno.h>
			# include <fcntl.h>
			# include <limits.h>

			# if GTEST_OS_LINUX
			# include <signal.h>
			# endif // GTEST_OS_LINUX

			# include <stdarg.h>

			# if GTEST_OS_WINDOWS
			# include <windows.h>
			# else
			# include <sys/mman.h>
			# include <sys/wait.h>
			# endif // GTEST_OS_WINDOWS

			# if GTEST_OS_QNX
			# include <spawn.h>
			# endif // GTEST_OS_QNX

			# if GTEST_OS_FUCHSIA
			# include <lib/fdio/io.h>
			# include <lib/fdio/spawn.h>
			# include <lib/fdio/util.h>
			# include <lib/zx/socket.h>
			# include <lib/zx/port.h>
			# include <lib/zx/process.h>
			# include <zircon/processargs.h>
			# include <zircon/syscalls.h>
			# include <zircon/syscalls/policy.h>
			# include <zircon/syscalls/port.h>
			# endif // GTEST_OS_FUCHSIA

			#endif // GTEST_HAS_DEATH_TEST

			#include "gtest/gtest-message.h"
			#include "gtest/internal/gtest-string.h"
			#include "src/gtest-internal-inl.h"

			namespace testing {

			// Constants.

			// The default death test style.
			//
			// This is defined in internal/gtest-port.h as "fast", but can be overridden by
			// a definition in internal/custom/gtest-port.h. The recommended value, which is
			// used internally at Google, is "threadsafe".
			static const char kDefaultDeathTestStyle[] = GTEST_DEFAULT_DEATH_TEST_STYLE;

			GTEST_DEFINE_string_(
			death_test_style,
			internal::StringFromGTestEnv("death_test_style", kDefaultDeathTestStyle),
			"Indicates how to run a death test in a forked child process: "
			"\"threadsafe\" (child process re-executes the test binary "
			"from the beginning, running only the specific death test) or "
			"\"fast\" (child process runs the death test immediately "
			"after forking).");

			GTEST_DEFINE_bool_(
			death_test_use_fork,
			internal::BoolFromGTestEnv("death_test_use_fork", false),
			"Instructs to use fork()/_exit() instead of clone() in death tests. "
			"Ignored and always uses fork() on POSIX systems where clone() is not "
			"implemented. Useful when running under valgrind or similar tools if "
			"those do not support clone(). Valgrind 3.3.1 will just fail if "
			"it sees an unsupported combination of clone() flags. "
			"It is not recommended to use this flag w/o valgrind though it will "
			"work in 99% of the cases. Once valgrind is fixed, this flag will "
			"most likely be removed.");

			namespace internal {
			GTEST_DEFINE_string_(
			internal_run_death_test, "",
			"Indicates the file, line number, temporal index of "
			"the single death test to run, and a file descriptor to "
			"which a success code may be sent, all separated by "
			"the '\|' characters. This flag is specified if and only if the current "
			"process is a sub-process launched for running a thread-safe "
			"death test. FOR INTERNAL USE ONLY.");
			} // namespace internal

			#if GTEST_HAS_DEATH_TEST

			namespace internal {

			// Valid only for fast death tests. Indicates the code is running in the
			// child process of a fast style death test.
			# if !GTEST_OS_WINDOWS && !GTEST_OS_FUCHSIA
			static bool g_in_fast_death_test_child = false;
			# endif

			// Returns a Boolean value indicating whether the caller is currently
			// executing in the context of the death test child process. Tools such as
			// Valgrind heap checkers may need this to modify their behavior in death
			// tests. IMPORTANT: This is an internal utility. Using it may break the
			// implementation of death tests. User code MUST NOT use it.
			bool InDeathTestChild() {
			# if GTEST_OS_WINDOWS \|\| GTEST_OS_FUCHSIA

			// On Windows and Fuchsia, death tests are thread-safe regardless of the value
			// of the death_test_style flag.
			return !GTEST_FLAG(internal_run_death_test).empty();

			# else

			if (GTEST_FLAG(death_test_style) == "threadsafe")
			return !GTEST_FLAG(internal_run_death_test).empty();
			else
			return g_in_fast_death_test_child;
			#endif
			}

			} // namespace internal

			// ExitedWithCode constructor.
			ExitedWithCode::ExitedWithCode(int exit_code) : exit_code_(exit_code) {
			}

			// ExitedWithCode function-call operator.
			bool ExitedWithCode::operator()(int exit_status) const {
			# if GTEST_OS_WINDOWS \|\| GTEST_OS_FUCHSIA

			return exit_status == exit_code_;

			# else

			return WIFEXITED(exit_status) && WEXITSTATUS(exit_status) == exit_code_;

			# endif // GTEST_OS_WINDOWS \|\| GTEST_OS_FUCHSIA
			}

			# if !GTEST_OS_WINDOWS && !GTEST_OS_FUCHSIA
			// KilledBySignal constructor.
			KilledBySignal::KilledBySignal(int signum) : signum_(signum) {
			}

			// KilledBySignal function-call operator.
			bool KilledBySignal::operator()(int exit_status) const {
			# if defined(GTEST_KILLED_BY_SIGNAL_OVERRIDE_)
			{
			bool result;
			if (GTEST_KILLED_BY_SIGNAL_OVERRIDE_(signum_, exit_status, &result)) {
			return result;
			}
			}
			# endif // defined(GTEST_KILLED_BY_SIGNAL_OVERRIDE_)
			return WIFSIGNALED(exit_status) && WTERMSIG(exit_status) == signum_;
			}
			# endif // !GTEST_OS_WINDOWS && !GTEST_OS_FUCHSIA

			namespace internal {

			// Utilities needed for death tests.

			// Generates a textual description of a given exit code, in the format
			// specified by wait(2).
			static std::string ExitSummary(int exit_code) {
			Message m;

			# if GTEST_OS_WINDOWS \|\| GTEST_OS_FUCHSIA

			m << "Exited with exit status " << exit_code;

			# else

			if (WIFEXITED(exit_code)) {
			m << "Exited with exit status " << WEXITSTATUS(exit_code);
			} else if (WIFSIGNALED(exit_code)) {
			m << "Terminated by signal " << WTERMSIG(exit_code);
			}
			# ifdef WCOREDUMP
			if (WCOREDUMP(exit_code)) {
			m << " (core dumped)";
			}
			# endif
			# endif // GTEST_OS_WINDOWS \|\| GTEST_OS_FUCHSIA

			return m.GetString();
			}

			// Returns true if exit_status describes a process that was terminated
			// by a signal, or exited normally with a nonzero exit code.
			bool ExitedUnsuccessfully(int exit_status) {
			return !ExitedWithCode(0)(exit_status);
			}

			# if !GTEST_OS_WINDOWS && !GTEST_OS_FUCHSIA
			// Generates a textual failure message when a death test finds more than
			// one thread running, or cannot determine the number of threads, prior
			// to executing the given statement. It is the responsibility of the
			// caller not to pass a thread_count of 1.
			static std::string DeathTestThreadWarning(size_t thread_count) {
			Message msg;
			msg << "Death tests use fork(), which is unsafe particularly"
			<< " in a threaded context. For this test, " << GTEST_NAME_ << " ";
			if (thread_count == 0) {
			msg << "couldn't detect the number of threads.";
			} else {
			msg << "detected " << thread_count << " threads.";
			}
			msg << " See "
			"https://github.com/abseil/googletest/blob/master/googletest/docs/"
			"advanced.md#death-tests-and-threads"
			<< " for more explanation and suggested solutions, especially if"
			<< " this is the last message you see before your test times out.";
			return msg.GetString();
			}
			# endif // !GTEST_OS_WINDOWS && !GTEST_OS_FUCHSIA

			// Flag characters for reporting a death test that did not die.
			static const char kDeathTestLived = 'L';
			static const char kDeathTestReturned = 'R';
			static const char kDeathTestThrew = 'T';
			static const char kDeathTestInternalError = 'I';

			#if GTEST_OS_FUCHSIA

			// File descriptor used for the pipe in the child process.
			static const int kFuchsiaReadPipeFd = 3;

			#endif

			// An enumeration describing all of the possible ways that a death test can
			// conclude. DIED means that the process died while executing the test
			// code; LIVED means that process lived beyond the end of the test code;
			// RETURNED means that the test statement attempted to execute a return
			// statement, which is not allowed; THREW means that the test statement
			// returned control by throwing an exception. IN_PROGRESS means the test
			// has not yet concluded.
			// FIXME: Unify names and possibly values for
			// AbortReason, DeathTestOutcome, and flag characters above.
			enum DeathTestOutcome { IN_PROGRESS, DIED, LIVED, RETURNED, THREW };

			// Routine for aborting the program which is safe to call from an
			// exec-style death test child process, in which case the error
			// message is propagated back to the parent process. Otherwise, the
			// message is simply printed to stderr. In either case, the program
			// then exits with status 1.
			static void DeathTestAbort(const std::string& message) {
			// On a POSIX system, this function may be called from a threadsafe-style
			// death test child process, which operates on a very small stack. Use
			// the heap for any additional non-minuscule memory requirements.
			const InternalRunDeathTestFlag* const flag =
			GetUnitTestImpl()->internal_run_death_test_flag();
			if (flag != nullptr) {
			FILE* parent = posix::FDOpen(flag->write_fd(), "w");
			fputc(kDeathTestInternalError, parent);
			fprintf(parent, "%s", message.c_str());
			fflush(parent);
			_exit(1);
			} else {
			fprintf(stderr, "%s", message.c_str());
			fflush(stderr);
			posix::Abort();
			}
			}

			// A replacement for CHECK that calls DeathTestAbort if the assertion
			// fails.
			# define GTEST_DEATH_TEST_CHECK_(expression) \
			do { \
			if (!::testing::internal::IsTrue(expression)) { \
			DeathTestAbort( \
			::std::string("CHECK failed: File ") + __FILE__ + ", line " \
			+ ::testing::internal::StreamableToString(__LINE__) + ": " \
			+ #expression); \
			} \
			} while (::testing::internal::AlwaysFalse())

			// This macro is similar to GTEST_DEATH_TEST_CHECK_, but it is meant for
			// evaluating any system call that fulfills two conditions: it must return
			// -1 on failure, and set errno to EINTR when it is interrupted and
			// should be tried again. The macro expands to a loop that repeatedly
			// evaluates the expression as long as it evaluates to -1 and sets
			// errno to EINTR. If the expression evaluates to -1 but errno is
			// something other than EINTR, DeathTestAbort is called.
			# define GTEST_DEATH_TEST_CHECK_SYSCALL_(expression) \
			do { \
			int gtest_retval; \
			do { \
			gtest_retval = (expression); \
			} while (gtest_retval == -1 && errno == EINTR); \
			if (gtest_retval == -1) { \
			DeathTestAbort( \
			::std::string("CHECK failed: File ") + __FILE__ + ", line " \
			+ ::testing::internal::StreamableToString(__LINE__) + ": " \
			+ #expression + " != -1"); \
			} \
			} while (::testing::internal::AlwaysFalse())

			// Returns the message describing the last system error in errno.
			std::string GetLastErrnoDescription() {
			return errno == 0 ? "" : posix::StrError(errno);
			}

			// This is called from a death test parent process to read a failure
			// message from the death test child process and log it with the FATAL
			// severity. On Windows, the message is read from a pipe handle. On other
			// platforms, it is read from a file descriptor.
			static void FailFromInternalError(int fd) {
			Message error;
			char buffer[256];
			int num_read;

			do {
			while ((num_read = posix::Read(fd, buffer, 255)) > 0) {
			buffer[num_read] = '\0';
			error << buffer;
			}
			} while (num_read == -1 && errno == EINTR);

			if (num_read == 0) {
			GTEST_LOG_(FATAL) << error.GetString();
			} else {
			const int last_error = errno;
			GTEST_LOG_(FATAL) << "Error while reading death test internal: "
			<< GetLastErrnoDescription() << " [" << last_error << "]";
			}
			}

			// Death test constructor. Increments the running death test count
			// for the current test.
			DeathTest::DeathTest() {
			TestInfo* const info = GetUnitTestImpl()->current_test_info();
			if (info == nullptr) {
			DeathTestAbort("Cannot run a death test outside of a TEST or "
			"TEST_F construct");
			}
			}

			// Creates and returns a death test by dispatching to the current
			// death test factory.
			bool DeathTest::Create(const char* statement,
			Matcher<const std::string&> matcher, const char* file,
			int line, DeathTest** test) {
			return GetUnitTestImpl()->death_test_factory()->Create(
			statement, std::move(matcher), file, line, test);
			}

			const char* DeathTest::LastMessage() {
			return last_death_test_message_.c_str();
			}

			void DeathTest::set_last_death_test_message(const std::string& message) {
			last_death_test_message_ = message;
			}

			std::string DeathTest::last_death_test_message_;

			// Provides cross platform implementation for some death functionality.
			class DeathTestImpl : public DeathTest {
			protected:
			DeathTestImpl(const char* a_statement, Matcher<const std::string&> matcher)
			: statement_(a_statement),
			matcher_(std::move(matcher)),
			spawned_(false),
			status_(-1),
			outcome_(IN_PROGRESS),
			read_fd_(-1),
			write_fd_(-1) {}

			// read_fd_ is expected to be closed and cleared by a derived class.
			~DeathTestImpl() override { GTEST_DEATH_TEST_CHECK_(read_fd_ == -1); }

			void Abort(AbortReason reason) override;
			bool Passed(bool status_ok) override;

			const char* statement() const { return statement_; }
			bool spawned() const { return spawned_; }
			void set_spawned(bool is_spawned) { spawned_ = is_spawned; }
			int status() const { return status_; }
			void set_status(int a_status) { status_ = a_status; }
			DeathTestOutcome outcome() const { return outcome_; }
			void set_outcome(DeathTestOutcome an_outcome) { outcome_ = an_outcome; }
			int read_fd() const { return read_fd_; }
			void set_read_fd(int fd) { read_fd_ = fd; }
			int write_fd() const { return write_fd_; }
			void set_write_fd(int fd) { write_fd_ = fd; }

			// Called in the parent process only. Reads the result code of the death
			// test child process via a pipe, interprets it to set the outcome_
			// member, and closes read_fd_. Outputs diagnostics and terminates in
			// case of unexpected codes.
			void ReadAndInterpretStatusByte();

			// Returns stderr output from the child process.
			virtual std::string GetErrorLogs();

			private:
			// The textual content of the code this object is testing. This class
			// doesn't own this string and should not attempt to delete it.
			const char* const statement_;
			// A matcher that's expected to match the stderr output by the child process.
			Matcher<const std::string&> matcher_;
			// True if the death test child process has been successfully spawned.
			bool spawned_;
			// The exit status of the child process.
			int status_;
			// How the death test concluded.
			DeathTestOutcome outcome_;
			// Descriptor to the read end of the pipe to the child process. It is
			// always -1 in the child process. The child keeps its write end of the
			// pipe in write_fd_.
			int read_fd_;
			// Descriptor to the child's write end of the pipe to the parent process.
			// It is always -1 in the parent process. The parent keeps its end of the
			// pipe in read_fd_.
			int write_fd_;
			};

			// Called in the parent process only. Reads the result code of the death
			// test child process via a pipe, interprets it to set the outcome_
			// member, and closes read_fd_. Outputs diagnostics and terminates in
			// case of unexpected codes.
			void DeathTestImpl::ReadAndInterpretStatusByte() {
			char flag;
			int bytes_read;

			// The read() here blocks until data is available (signifying the
			// failure of the death test) or until the pipe is closed (signifying
			// its success), so it's okay to call this in the parent before
			// the child process has exited.
			do {
			bytes_read = posix::Read(read_fd(), &flag, 1);
			} while (bytes_read == -1 && errno == EINTR);

			if (bytes_read == 0) {
			set_outcome(DIED);
			} else if (bytes_read == 1) {
			switch (flag) {
			case kDeathTestReturned:
			set_outcome(RETURNED);
			break;
			case kDeathTestThrew:
			set_outcome(THREW);
			break;
			case kDeathTestLived:
			set_outcome(LIVED);
			break;
			case kDeathTestInternalError:
			FailFromInternalError(read_fd()); // Does not return.
			break;
			default:
			GTEST_LOG_(FATAL) << "Death test child process reported "
			<< "unexpected status byte ("
			<< static_cast<unsigned int>(flag) << ")";
			}
			} else {
			GTEST_LOG_(FATAL) << "Read from death test child process failed: "
			<< GetLastErrnoDescription();
			}
			GTEST_DEATH_TEST_CHECK_SYSCALL_(posix::Close(read_fd()));
			set_read_fd(-1);
			}

			std::string DeathTestImpl::GetErrorLogs() {
			return GetCapturedStderr();
			}

			// Signals that the death test code which should have exited, didn't.
			// Should be called only in a death test child process.
			// Writes a status byte to the child's status file descriptor, then
			// calls _exit(1).
			void DeathTestImpl::Abort(AbortReason reason) {
			// The parent process considers the death test to be a failure if
			// it finds any data in our pipe. So, here we write a single flag byte
			// to the pipe, then exit.
			const char status_ch =
			reason == TEST_DID_NOT_DIE ? kDeathTestLived :
			reason == TEST_THREW_EXCEPTION ? kDeathTestThrew : kDeathTestReturned;

			GTEST_DEATH_TEST_CHECK_SYSCALL_(posix::Write(write_fd(), &status_ch, 1));
			// We are leaking the descriptor here because on some platforms (i.e.,
			// when built as Windows DLL), destructors of global objects will still
			// run after calling _exit(). On such systems, write_fd_ will be
			// indirectly closed from the destructor of UnitTestImpl, causing double
			// close if it is also closed here. On debug configurations, double close
			// may assert. As there are no in-process buffers to flush here, we are
			// relying on the OS to close the descriptor after the process terminates
			// when the destructors are not run.
			_exit(1); // Exits w/o any normal exit hooks (we were supposed to crash)
			}

			// Returns an indented copy of stderr output for a death test.
			// This makes distinguishing death test output lines from regular log lines
			// much easier.
			static ::std::string FormatDeathTestOutput(const ::std::string& output) {
			::std::string ret;
			for (size_t at = 0; ; ) {
			const size_t line_end = output.find('\n', at);
			ret += "[ DEATH ] ";
			if (line_end == ::std::string::npos) {
			ret += output.substr(at);
			break;
			}
			ret += output.substr(at, line_end + 1 - at);
			at = line_end + 1;
			}
			return ret;
			}

			// Assesses the success or failure of a death test, using both private
			// members which have previously been set, and one argument:
			//
			// Private data members:
			// outcome: An enumeration describing how the death test
			// concluded: DIED, LIVED, THREW, or RETURNED. The death test
			// fails in the latter three cases.
			// status: The exit status of the child process. On *nix, it is in the
			// in the format specified by wait(2). On Windows, this is the
			// value supplied to the ExitProcess() API or a numeric code
			// of the exception that terminated the program.
			// matcher_: A matcher that's expected to match the stderr output by the child
			// process.
			//
			// Argument:
			// status_ok: true if exit_status is acceptable in the context of
			// this particular death test, which fails if it is false
			//
			// Returns true iff all of the above conditions are met. Otherwise, the
			// first failing condition, in the order given above, is the one that is
			// reported. Also sets the last death test message string.
			bool DeathTestImpl::Passed(bool status_ok) {
			if (!spawned())
			return false;

			const std::string error_message = GetErrorLogs();

			bool success = false;
			Message buffer;

			buffer << "Death test: " << statement() << "\n";
			switch (outcome()) {
			case LIVED:
			buffer << " Result: failed to die.\n"
			<< " Error msg:\n" << FormatDeathTestOutput(error_message);
			break;
			case THREW:
			buffer << " Result: threw an exception.\n"
			<< " Error msg:\n" << FormatDeathTestOutput(error_message);
			break;
			case RETURNED:
			buffer << " Result: illegal return in test statement.\n"
			<< " Error msg:\n" << FormatDeathTestOutput(error_message);
			break;
			case DIED:
			if (status_ok) {
			if (matcher_.Matches(error_message)) {
			success = true;
			} else {
			std::ostringstream stream;
			matcher_.DescribeTo(&stream);
			buffer << " Result: died but not with expected error.\n"
			<< " Expected: " << stream.str() << "\n"
			<< "Actual msg:\n"
			<< FormatDeathTestOutput(error_message);
			}
			} else {
			buffer << " Result: died but not with expected exit code:\n"
			<< " " << ExitSummary(status()) << "\n"
			<< "Actual msg:\n" << FormatDeathTestOutput(error_message);
			}
			break;
			case IN_PROGRESS:
			default:
			GTEST_LOG_(FATAL)
			<< "DeathTest::Passed somehow called before conclusion of test";
			}

			DeathTest::set_last_death_test_message(buffer.GetString());
			return success;
			}

			# if GTEST_OS_WINDOWS
			// WindowsDeathTest implements death tests on Windows. Due to the
			// specifics of starting new processes on Windows, death tests there are
			// always threadsafe, and Google Test considers the
			// --gtest_death_test_style=fast setting to be equivalent to
			// --gtest_death_test_style=threadsafe there.
			//
			// A few implementation notes: Like the Linux version, the Windows
			// implementation uses pipes for child-to-parent communication. But due to
			// the specifics of pipes on Windows, some extra steps are required:
			//
			// 1. The parent creates a communication pipe and stores handles to both
			// ends of it.
			// 2. The parent starts the child and provides it with the information
			// necessary to acquire the handle to the write end of the pipe.
			// 3. The child acquires the write end of the pipe and signals the parent
			// using a Windows event.
			// 4. Now the parent can release the write end of the pipe on its side. If
			// this is done before step 3, the object's reference count goes down to
			// 0 and it is destroyed, preventing the child from acquiring it. The
			// parent now has to release it, or read operations on the read end of
			// the pipe will not return when the child terminates.
			// 5. The parent reads child's output through the pipe (outcome code and
			// any possible error messages) from the pipe, and its stderr and then
			// determines whether to fail the test.
			//
			// Note: to distinguish Win32 API calls from the local method and function
			// calls, the former are explicitly resolved in the global namespace.
			//
			class WindowsDeathTest : public DeathTestImpl {
			public:
			WindowsDeathTest(const char* a_statement, Matcher<const std::string&> matcher,
			const char* file, int line)
			: DeathTestImpl(a_statement, std::move(matcher)),
			file_(file),
			line_(line) {}

			// All of these virtual functions are inherited from DeathTest.
			virtual int Wait();
			virtual TestRole AssumeRole();

			private:
			// The name of the file in which the death test is located.
			const char* const file_;
			// The line number on which the death test is located.
			const int line_;
			// Handle to the write end of the pipe to the child process.
			AutoHandle write_handle_;
			// Child process handle.
			AutoHandle child_handle_;
			// Event the child process uses to signal the parent that it has
			// acquired the handle to the write end of the pipe. After seeing this
			// event the parent can release its own handles to make sure its
			// ReadFile() calls return when the child terminates.
			AutoHandle event_handle_;
			};

			// Waits for the child in a death test to exit, returning its exit
			// status, or 0 if no child process exists. As a side effect, sets the
			// outcome data member.
			int WindowsDeathTest::Wait() {
			if (!spawned())
			return 0;

			// Wait until the child either signals that it has acquired the write end
			// of the pipe or it dies.
			const HANDLE wait_handles[2] = { child_handle_.Get(), event_handle_.Get() };
			switch (::WaitForMultipleObjects(2,
			wait_handles,
			FALSE, // Waits for any of the handles.
			INFINITE)) {
			case WAIT_OBJECT_0:
			case WAIT_OBJECT_0 + 1:
			break;
			default:
			GTEST_DEATH_TEST_CHECK_(false); // Should not get here.
			}

			// The child has acquired the write end of the pipe or exited.
			// We release the handle on our side and continue.
			write_handle_.Reset();
			event_handle_.Reset();

			ReadAndInterpretStatusByte();

			// Waits for the child process to exit if it haven't already. This
			// returns immediately if the child has already exited, regardless of
			// whether previous calls to WaitForMultipleObjects synchronized on this
			// handle or not.
			GTEST_DEATH_TEST_CHECK_(
			WAIT_OBJECT_0 == ::WaitForSingleObject(child_handle_.Get(),
			INFINITE));
			DWORD status_code;
			GTEST_DEATH_TEST_CHECK_(
			::GetExitCodeProcess(child_handle_.Get(), &status_code) != FALSE);
			child_handle_.Reset();
			set_status(static_cast<int>(status_code));
			return status();
			}

			// The AssumeRole process for a Windows death test. It creates a child
			// process with the same executable as the current process to run the
			// death test. The child process is given the --gtest_filter and
			// --gtest_internal_run_death_test flags such that it knows to run the
			// current death test only.
			DeathTest::TestRole WindowsDeathTest::AssumeRole() {
			const UnitTestImpl* const impl = GetUnitTestImpl();
			const InternalRunDeathTestFlag* const flag =
			impl->internal_run_death_test_flag();
			const TestInfo* const info = impl->current_test_info();
			const int death_test_index = info->result()->death_test_count();

			if (flag != nullptr) {
			// ParseInternalRunDeathTestFlag() has performed all the necessary
			// processing.
			set_write_fd(flag->write_fd());
			return EXECUTE_TEST;
			}

			// WindowsDeathTest uses an anonymous pipe to communicate results of
			// a death test.
			SECURITY_ATTRIBUTES handles_are_inheritable = {sizeof(SECURITY_ATTRIBUTES),
			nullptr, TRUE};
			HANDLE read_handle, write_handle;
			GTEST_DEATH_TEST_CHECK_(
			::CreatePipe(&read_handle, &write_handle, &handles_are_inheritable,
			0) // Default buffer size.
			!= FALSE);
			set_read_fd(::_open_osfhandle(reinterpret_cast<intptr_t>(read_handle),
			O_RDONLY));
			write_handle_.Reset(write_handle);
			event_handle_.Reset(::CreateEvent(
			&handles_are_inheritable,
			TRUE, // The event will automatically reset to non-signaled state.
			FALSE, // The initial state is non-signalled.
			nullptr)); // The even is unnamed.
			GTEST_DEATH_TEST_CHECK_(event_handle_.Get() != nullptr);
			const std::string filter_flag =
			std::string("--") + GTEST_FLAG_PREFIX_ + kFilterFlag + "=" +
			info->test_case_name() + "." + info->name();
			const std::string internal_flag =
			std::string("--") + GTEST_FLAG_PREFIX_ + kInternalRunDeathTestFlag +
			"=" + file_ + "\|" + StreamableToString(line_) + "\|" +
			StreamableToString(death_test_index) + "\|" +
			StreamableToString(static_cast<unsigned int>(::GetCurrentProcessId())) +
			// size_t has the same width as pointers on both 32-bit and 64-bit
			// Windows platforms.
			// See http://msdn.microsoft.com/en-us/library/tcxf1dw6.aspx.
			"\|" + StreamableToString(reinterpret_cast<size_t>(write_handle)) +
			"\|" + StreamableToString(reinterpret_cast<size_t>(event_handle_.Get()));

			char executable_path[_MAX_PATH + 1]; // NOLINT
			GTEST_DEATH_TEST_CHECK_(_MAX_PATH + 1 != ::GetModuleFileNameA(nullptr,
			executable_path,
			_MAX_PATH));

			std::string command_line =
			std::string(::GetCommandLineA()) + " " + filter_flag + " \"" +
			internal_flag + "\"";

			DeathTest::set_last_death_test_message("");

			CaptureStderr();
			// Flush the log buffers since the log streams are shared with the child.
			FlushInfoLog();

			// The child process will share the standard handles with the parent.
			STARTUPINFOA startup_info;
			memset(&startup_info, 0, sizeof(STARTUPINFO));
			startup_info.dwFlags = STARTF_USESTDHANDLES;
			startup_info.hStdInput = ::GetStdHandle(STD_INPUT_HANDLE);
			startup_info.hStdOutput = ::GetStdHandle(STD_OUTPUT_HANDLE);
			startup_info.hStdError = ::GetStdHandle(STD_ERROR_HANDLE);

			PROCESS_INFORMATION process_info;
			GTEST_DEATH_TEST_CHECK_(
			::CreateProcessA(
			executable_path, const_cast<char*>(command_line.c_str()),
			nullptr, // Retuned process handle is not inheritable.
			nullptr, // Retuned thread handle is not inheritable.
			TRUE, // Child inherits all inheritable handles (for write_handle_).
			0x0, // Default creation flags.
			nullptr, // Inherit the parent's environment.
			UnitTest::GetInstance()->original_working_dir(), &startup_info,
			&process_info) != FALSE);
			child_handle_.Reset(process_info.hProcess);
			::CloseHandle(process_info.hThread);
			set_spawned(true);
			return OVERSEE_TEST;
			}

			# elif GTEST_OS_FUCHSIA

			class FuchsiaDeathTest : public DeathTestImpl {
			public:
			FuchsiaDeathTest(const char* a_statement, Matcher<const std::string&> matcher,
			const char* file, int line)
			: DeathTestImpl(a_statement, std::move(matcher)),
			file_(file),
			line_(line) {}

			// All of these virtual functions are inherited from DeathTest.
			int Wait() override;
			TestRole AssumeRole() override;
			std::string GetErrorLogs() override;

			private:
			// The name of the file in which the death test is located.
			const char* const file_;
			// The line number on which the death test is located.
			const int line_;
			// The stderr data captured by the child process.
			std::string captured_stderr_;

			zx::process child_process_;
			zx::port port_;
			zx::socket stderr_socket_;
			};

			// Utility class for accumulating command-line arguments.
			class Arguments {
			public:
			Arguments() { args_.push_back(nullptr); }

			~Arguments() {
			for (std::vector<char*>::iterator i = args_.begin(); i != args_.end();
			++i) {
			free(*i);
			}
			}
			void AddArgument(const char* argument) {
			args_.insert(args_.end() - 1, posix::StrDup(argument));
			}

			template <typename Str>
			void AddArguments(const ::std::vector<Str>& arguments) {
			for (typename ::std::vector<Str>::const_iterator i = arguments.begin();
			i != arguments.end();
			++i) {
			args_.insert(args_.end() - 1, posix::StrDup(i->c_str()));
			}
			}
			char* const* Argv() {
			return &args_[0];
			}

			int size() {
			return args_.size() - 1;
			}

			private:
			std::vector<char*> args_;
			};

			// Waits for the child in a death test to exit, returning its exit
			// status, or 0 if no child process exists. As a side effect, sets the
			// outcome data member.
			int FuchsiaDeathTest::Wait() {
			const int kProcessKey = 0;
			const int kSocketKey = 1;

			if (!spawned())
			return 0;

			// Register to wait for the child process to terminate.
			zx_status_t status_zx;
			status_zx = child_process_.wait_async(
			port_, kProcessKey, ZX_PROCESS_TERMINATED, ZX_WAIT_ASYNC_ONCE);
			GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);
			// Register to wait for the socket to be readable or closed.
			status_zx = stderr_socket_.wait_async(
			port_, kSocketKey, ZX_SOCKET_READABLE \| ZX_SOCKET_PEER_CLOSED,
			ZX_WAIT_ASYNC_REPEATING);
			GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);

			bool process_terminated = false;
			bool socket_closed = false;
			do {
			zx_port_packet_t packet = {};
			status_zx = port_.wait(zx::time::infinite(), &packet);
			GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);

			if (packet.key == kProcessKey) {
			if (ZX_PKT_IS_EXCEPTION(packet.type)) {
			// Process encountered an exception. Kill it directly rather than
			// letting other handlers process the event. We will get a second
			// kProcessKey event when the process actually terminates.
			status_zx = child_process_.kill();
			GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);
			} else {
			// Process terminated.
			GTEST_DEATH_TEST_CHECK_(ZX_PKT_IS_SIGNAL_ONE(packet.type));
			GTEST_DEATH_TEST_CHECK_(packet.signal.observed & ZX_PROCESS_TERMINATED);
			process_terminated = true;
			}
			} else if (packet.key == kSocketKey) {
			GTEST_DEATH_TEST_CHECK_(ZX_PKT_IS_SIGNAL_REP(packet.type));
			if (packet.signal.observed & ZX_SOCKET_READABLE) {
			// Read data from the socket.
			constexpr size_t kBufferSize = 1024;
			do {
			size_t old_length = captured_stderr_.length();
			size_t bytes_read = 0;
			captured_stderr_.resize(old_length + kBufferSize);
			status_zx = stderr_socket_.read(
			0, &captured_stderr_.front() + old_length, kBufferSize,
			&bytes_read);
			captured_stderr_.resize(old_length + bytes_read);
			} while (status_zx == ZX_OK);
			if (status_zx == ZX_ERR_PEER_CLOSED) {
			socket_closed = true;
			} else {
			GTEST_DEATH_TEST_CHECK_(status_zx == ZX_ERR_SHOULD_WAIT);
			}
			} else {
			GTEST_DEATH_TEST_CHECK_(packet.signal.observed & ZX_SOCKET_PEER_CLOSED);
			socket_closed = true;
			}
			}
			} while (!process_terminated && !socket_closed);

			ReadAndInterpretStatusByte();

			zx_info_process_t buffer;
			status_zx = child_process_.get_info(
			ZX_INFO_PROCESS, &buffer, sizeof(buffer), nullptr, nullptr);
			GTEST_DEATH_TEST_CHECK_(status_zx == ZX_OK);

			GTEST_DEATH_TEST_CHECK_(buffer.exited);
			set_status(buffer.return_code);
			return status();
			}

			// The AssumeRole process for a Fuchsia death test. It creates a child
			// process with the same executable as the current process to run the
			// death test. The child process is given the --gtest_filter and
			// --gtest_internal_run_death_test flags such that it knows to run the
			// current death test only.
			DeathTest::TestRole FuchsiaDeathTest::AssumeRole() {
			const UnitTestImpl* const impl = GetUnitTestImpl();
			const InternalRunDeathTestFlag* const flag =
			impl->internal_run_death_test_flag();
			const TestInfo* const info = impl->current_test_info();
			const int death_test_index = info->result()->death_test_count();

			if (flag != nullptr) {
			// ParseInternalRunDeathTestFlag() has performed all the necessary
			// processing.
			set_write_fd(kFuchsiaReadPipeFd);
			return EXECUTE_TEST;
			}

			// Flush the log buffers since the log streams are shared with the child.
			FlushInfoLog();

			// Build the child process command line.
			const std::string filter_flag =
			std::string("--") + GTEST_FLAG_PREFIX_ + kFilterFlag + "="
			+ info->test_case_name() + "." + info->name();
			const std::string internal_flag =
			std::string("--") + GTEST_FLAG_PREFIX_ + kInternalRunDeathTestFlag + "="
			+ file_ + "\|"
			+ StreamableToString(line_) + "\|"
			+ StreamableToString(death_test_index);
			Arguments args;
			args.AddArguments(GetInjectableArgvs());
			args.AddArgument(filter_flag.c_str());
			args.AddArgument(internal_flag.c_str());

			// Build the pipe for communication with the child.
			zx_status_t status;
			zx_handle_t child_pipe_handle;
			uint32_t type;
			status = fdio_pipe_half(&child_pipe_handle, &type);
			GTEST_DEATH_TEST_CHECK_(status >= 0);
			set_read_fd(status);

			// Set the pipe handle for the child.
			fdio_spawn_action_t spawn_actions[2] = {};
			fdio_spawn_action_t* add_handle_action = &spawn_actions[0];
			add_handle_action->action = FDIO_SPAWN_ACTION_ADD_HANDLE;
			add_handle_action->h.id = PA_HND(type, kFuchsiaReadPipeFd);
			add_handle_action->h.handle = child_pipe_handle;

			// Create a socket pair will be used to receive the child process' stderr.
			zx::socket stderr_producer_socket;
			status =
			zx::socket::create(0, &stderr_producer_socket, &stderr_socket_);
			GTEST_DEATH_TEST_CHECK_(status >= 0);
			int stderr_producer_fd = -1;
			zx_handle_t producer_handle[1] = { stderr_producer_socket.release() };
			uint32_t producer_handle_type[1] = { PA_FDIO_SOCKET };
			status = fdio_create_fd(
			producer_handle, producer_handle_type, 1, &stderr_producer_fd);
			GTEST_DEATH_TEST_CHECK_(status >= 0);

			// Make the stderr socket nonblocking.
			GTEST_DEATH_TEST_CHECK_(fcntl(stderr_producer_fd, F_SETFL, 0) == 0);

			fdio_spawn_action_t* add_stderr_action = &spawn_actions[1];
			add_stderr_action->action = FDIO_SPAWN_ACTION_CLONE_FD;
			add_stderr_action->fd.local_fd = stderr_producer_fd;
			add_stderr_action->fd.target_fd = STDERR_FILENO;

			// Create a child job.
			zx_handle_t child_job = ZX_HANDLE_INVALID;
			status = zx_job_create(zx_job_default(), 0, & child_job);
			GTEST_DEATH_TEST_CHECK_(status == ZX_OK);
			zx_policy_basic_t policy;
			policy.condition = ZX_POL_NEW_ANY;
			policy.policy = ZX_POL_ACTION_ALLOW;
			status = zx_job_set_policy(
			child_job, ZX_JOB_POL_RELATIVE, ZX_JOB_POL_BASIC, &policy, 1);
			GTEST_DEATH_TEST_CHECK_(status == ZX_OK);

			// Create an exception port and attach it to the \|child_job\|, to allow
			// us to suppress the system default exception handler from firing.
			status = zx::port::create(0, &port_);
			GTEST_DEATH_TEST_CHECK_(status == ZX_OK);
			status = zx_task_bind_exception_port(
			child_job, port_.get(), 0 /* key /, 0 /options */);
			GTEST_DEATH_TEST_CHECK_(status == ZX_OK);

			// Spawn the child process.
			status = fdio_spawn_etc(
			child_job, FDIO_SPAWN_CLONE_ALL, args.Argv()[0], args.Argv(), nullptr,
			2, spawn_actions, child_process_.reset_and_get_address(), nullptr);
			GTEST_DEATH_TEST_CHECK_(status == ZX_OK);

			set_spawned(true);
			return OVERSEE_TEST;
			}

			std::string FuchsiaDeathTest::GetErrorLogs() {
			return captured_stderr_;
			}

			#else // We are neither on Windows, nor on Fuchsia.

			// ForkingDeathTest provides implementations for most of the abstract
			// methods of the DeathTest interface. Only the AssumeRole method is
			// left undefined.
			class ForkingDeathTest : public DeathTestImpl {
			public:
			ForkingDeathTest(const char* statement, Matcher<const std::string&> matcher);

			// All of these virtual functions are inherited from DeathTest.
			int Wait() override;

			protected:
			void set_child_pid(pid_t child_pid) { child_pid_ = child_pid; }

			private:
			// PID of child process during death test; 0 in the child process itself.
			pid_t child_pid_;
			};

			// Constructs a ForkingDeathTest.
			ForkingDeathTest::ForkingDeathTest(const char* a_statement,
			Matcher<const std::string&> matcher)
			: DeathTestImpl(a_statement, std::move(matcher)), child_pid_(-1) {}

			// Waits for the child in a death test to exit, returning its exit
			// status, or 0 if no child process exists. As a side effect, sets the
			// outcome data member.
			int ForkingDeathTest::Wait() {
			if (!spawned())
			return 0;

			ReadAndInterpretStatusByte();

			int status_value;
			GTEST_DEATH_TEST_CHECK_SYSCALL_(waitpid(child_pid_, &status_value, 0));
			set_status(status_value);
			return status_value;
			}

			// A concrete death test class that forks, then immediately runs the test
			// in the child process.
			class NoExecDeathTest : public ForkingDeathTest {
			public:
			NoExecDeathTest(const char* a_statement, Matcher<const std::string&> matcher)
			: ForkingDeathTest(a_statement, std::move(matcher)) {}
			TestRole AssumeRole() override;
			};

			// The AssumeRole process for a fork-and-run death test. It implements a
			// straightforward fork, with a simple pipe to transmit the status byte.
			DeathTest::TestRole NoExecDeathTest::AssumeRole() {
			const size_t thread_count = GetThreadCount();
			if (thread_count != 1) {
			GTEST_LOG_(WARNING) << DeathTestThreadWarning(thread_count);
			}

			int pipe_fd[2];
			GTEST_DEATH_TEST_CHECK_(pipe(pipe_fd) != -1);

			DeathTest::set_last_death_test_message("");
			CaptureStderr();
			// When we fork the process below, the log file buffers are copied, but the
			// file descriptors are shared. We flush all log files here so that closing
			// the file descriptors in the child process doesn't throw off the
			// synchronization between descriptors and buffers in the parent process.
			// This is as close to the fork as possible to avoid a race condition in case
			// there are multiple threads running before the death test, and another
			// thread writes to the log file.
			FlushInfoLog();

			const pid_t child_pid = fork();
			GTEST_DEATH_TEST_CHECK_(child_pid != -1);
			set_child_pid(child_pid);
			if (child_pid == 0) {
			GTEST_DEATH_TEST_CHECK_SYSCALL_(close(pipe_fd[0]));
			set_write_fd(pipe_fd[1]);
			// Redirects all logging to stderr in the child process to prevent
			// concurrent writes to the log files. We capture stderr in the parent
			// process and append the child process' output to a log.
			LogToStderr();
			// Event forwarding to the listeners of event listener API mush be shut
			// down in death test subprocesses.
			GetUnitTestImpl()->listeners()->SuppressEventForwarding();
			g_in_fast_death_test_child = true;
			return EXECUTE_TEST;
			} else {
			GTEST_DEATH_TEST_CHECK_SYSCALL_(close(pipe_fd[1]));
			set_read_fd(pipe_fd[0]);
			set_spawned(true);
			return OVERSEE_TEST;
			}
			}

			// A concrete death test class that forks and re-executes the main
			// program from the beginning, with command-line flags set that cause
			// only this specific death test to be run.
			class ExecDeathTest : public ForkingDeathTest {
			public:
			ExecDeathTest(const char* a_statement, Matcher<const std::string&> matcher,
			const char* file, int line)
			: ForkingDeathTest(a_statement, std::move(matcher)),
			file_(file),
			line_(line) {}
			TestRole AssumeRole() override;

			private:
			static ::std::vector<std::string> GetArgvsForDeathTestChildProcess() {
			::std::vector<std::string> args = GetInjectableArgvs();
			# if defined(GTEST_EXTRA_DEATH_TEST_COMMAND_LINE_ARGS_)
			::std::vector<std::string> extra_args =
			GTEST_EXTRA_DEATH_TEST_COMMAND_LINE_ARGS_();
			args.insert(args.end(), extra_args.begin(), extra_args.end());
			# endif // defined(GTEST_EXTRA_DEATH_TEST_COMMAND_LINE_ARGS_)
			return args;
			}
			// The name of the file in which the death test is located.
			const char* const file_;
			// The line number on which the death test is located.
			const int line_;
			};

			// Utility class for accumulating command-line arguments.
			class Arguments {
			public:
			Arguments() { args_.push_back(nullptr); }

			~Arguments() {
			for (std::vector<char*>::iterator i = args_.begin(); i != args_.end();
			++i) {
			free(*i);
			}
			}
			void AddArgument(const char* argument) {
			args_.insert(args_.end() - 1, posix::StrDup(argument));
			}

			template <typename Str>
			void AddArguments(const ::std::vector<Str>& arguments) {
			for (typename ::std::vector<Str>::const_iterator i = arguments.begin();
			i != arguments.end();
			++i) {
			args_.insert(args_.end() - 1, posix::StrDup(i->c_str()));
			}
			}
			char* const* Argv() {
			return &args_[0];
			}

			private:
			std::vector<char*> args_;
			};

			// A struct that encompasses the arguments to the child process of a
			// threadsafe-style death test process.
			struct ExecDeathTestArgs {
			char* const* argv; // Command-line arguments for the child's call to exec
			int close_fd; // File descriptor to close; the read end of a pipe
			};

			# if GTEST_OS_MAC
			inline char** GetEnviron() {
			// When Google Test is built as a framework on MacOS X, the environ variable
			// is unavailable. Apple's documentation (man environ) recommends using
			// _NSGetEnviron() instead.
			return *_NSGetEnviron();
			}
			# else
			// Some POSIX platforms expect you to declare environ. extern "C" makes
			// it reside in the global namespace.
			extern "C" char** environ;
			inline char** GetEnviron() { return environ; }
			# endif // GTEST_OS_MAC

			# if !GTEST_OS_QNX
			// The main function for a threadsafe-style death test child process.
			// This function is called in a clone()-ed process and thus must avoid
			// any potentially unsafe operations like malloc or libc functions.
			static int ExecDeathTestChildMain(void* child_arg) {
			ExecDeathTestArgs* const args = static_cast<ExecDeathTestArgs*>(child_arg);
			GTEST_DEATH_TEST_CHECK_SYSCALL_(close(args->close_fd));

			// We need to execute the test program in the same environment where
			// it was originally invoked. Therefore we change to the original
			// working directory first.
			const char* const original_dir =
			UnitTest::GetInstance()->original_working_dir();
			// We can safely call chdir() as it's a direct system call.
			if (chdir(original_dir) != 0) {
			DeathTestAbort(std::string("chdir(\"") + original_dir + "\") failed: " +
			GetLastErrnoDescription());
			return EXIT_FAILURE;
			}

			// We can safely call execve() as it's a direct system call. We
			// cannot use execvp() as it's a libc function and thus potentially
			// unsafe. Since execve() doesn't search the PATH, the user must
			// invoke the test program via a valid path that contains at least
			// one path separator.
			execve(args->argv[0], args->argv, GetEnviron());
			DeathTestAbort(std::string("execve(") + args->argv[0] + ", ...) in " +
			original_dir + " failed: " +
			GetLastErrnoDescription());
			return EXIT_FAILURE;
			}
			# endif // !GTEST_OS_QNX

			# if GTEST_HAS_CLONE
			// Two utility routines that together determine the direction the stack
			// grows.
			// This could be accomplished more elegantly by a single recursive
			// function, but we want to guard against the unlikely possibility of
			// a smart compiler optimizing the recursion away.
			//
			// GTEST_NO_INLINE_ is required to prevent GCC 4.6 from inlining
			// StackLowerThanAddress into StackGrowsDown, which then doesn't give
			// correct answer.
			static void StackLowerThanAddress(const void* ptr,
			bool* result) GTEST_NO_INLINE_;
			static void StackLowerThanAddress(const void* ptr, bool* result) {
			int dummy;
			*result = (&dummy < ptr);
			}

			// Make sure AddressSanitizer does not tamper with the stack here.
			GTEST_ATTRIBUTE_NO_SANITIZE_ADDRESS_
			static bool StackGrowsDown() {
			int dummy;
			bool result;
			StackLowerThanAddress(&dummy, &result);
			return result;
			}
			# endif // GTEST_HAS_CLONE

			// Spawns a child process with the same executable as the current process in
			// a thread-safe manner and instructs it to run the death test. The
			// implementation uses fork(2) + exec. On systems where clone(2) is
			// available, it is used instead, being slightly more thread-safe. On QNX,
			// fork supports only single-threaded environments, so this function uses
			// spawn(2) there instead. The function dies with an error message if
			// anything goes wrong.
			static pid_t ExecDeathTestSpawnChild(char* const* argv, int close_fd) {
			ExecDeathTestArgs args = { argv, close_fd };
			pid_t child_pid = -1;

			# if GTEST_OS_QNX
			// Obtains the current directory and sets it to be closed in the child
			// process.
			const int cwd_fd = open(".", O_RDONLY);
			GTEST_DEATH_TEST_CHECK_(cwd_fd != -1);
			GTEST_DEATH_TEST_CHECK_SYSCALL_(fcntl(cwd_fd, F_SETFD, FD_CLOEXEC));
			// We need to execute the test program in the same environment where
			// it was originally invoked. Therefore we change to the original
			// working directory first.
			const char* const original_dir =
			UnitTest::GetInstance()->original_working_dir();
			// We can safely call chdir() as it's a direct system call.
			if (chdir(original_dir) != 0) {
			DeathTestAbort(std::string("chdir(\"") + original_dir + "\") failed: " +
			GetLastErrnoDescription());
			return EXIT_FAILURE;
			}

			int fd_flags;
			// Set close_fd to be closed after spawn.
			GTEST_DEATH_TEST_CHECK_SYSCALL_(fd_flags = fcntl(close_fd, F_GETFD));
			GTEST_DEATH_TEST_CHECK_SYSCALL_(fcntl(close_fd, F_SETFD,
			fd_flags \| FD_CLOEXEC));
			struct inheritance inherit = {0};
			// spawn is a system call.
			child_pid =
			spawn(args.argv[0], 0, nullptr, &inherit, args.argv, GetEnviron());
			// Restores the current working directory.
			GTEST_DEATH_TEST_CHECK_(fchdir(cwd_fd) != -1);
			GTEST_DEATH_TEST_CHECK_SYSCALL_(close(cwd_fd));

			# else // GTEST_OS_QNX
			# if GTEST_OS_LINUX
			// When a SIGPROF signal is received while fork() or clone() are executing,
			// the process may hang. To avoid this, we ignore SIGPROF here and re-enable
			// it after the call to fork()/clone() is complete.
			struct sigaction saved_sigprof_action;
			struct sigaction ignore_sigprof_action;
			memset(&ignore_sigprof_action, 0, sizeof(ignore_sigprof_action));
			sigemptyset(&ignore_sigprof_action.sa_mask);
			ignore_sigprof_action.sa_handler = SIG_IGN;
			GTEST_DEATH_TEST_CHECK_SYSCALL_(sigaction(
			SIGPROF, &ignore_sigprof_action, &saved_sigprof_action));
			# endif // GTEST_OS_LINUX

			# if GTEST_HAS_CLONE
			const bool use_fork = GTEST_FLAG(death_test_use_fork);

			if (!use_fork) {
			static const bool stack_grows_down = StackGrowsDown();
			const size_t stack_size = getpagesize();
			// MMAP_ANONYMOUS is not defined on Mac, so we use MAP_ANON instead.
			void* const stack = mmap(nullptr, stack_size, PROT_READ \| PROT_WRITE,
			MAP_ANON \| MAP_PRIVATE, -1, 0);
			GTEST_DEATH_TEST_CHECK_(stack != MAP_FAILED);

			// Maximum stack alignment in bytes: For a downward-growing stack, this
			// amount is subtracted from size of the stack space to get an address
			// that is within the stack space and is aligned on all systems we care
			// about. As far as I know there is no ABI with stack alignment greater
			// than 64. We assume stack and stack_size already have alignment of
			// kMaxStackAlignment.
			const size_t kMaxStackAlignment = 64;
			void* const stack_top =
			static_cast<char*>(stack) +
			(stack_grows_down ? stack_size - kMaxStackAlignment : 0);
			GTEST_DEATH_TEST_CHECK_(stack_size > kMaxStackAlignment &&
			reinterpret_cast<intptr_t>(stack_top) % kMaxStackAlignment == 0);

			child_pid = clone(&ExecDeathTestChildMain, stack_top, SIGCHLD, &args);

			GTEST_DEATH_TEST_CHECK_(munmap(stack, stack_size) != -1);
			}
			# else
			const bool use_fork = true;
			# endif // GTEST_HAS_CLONE

			if (use_fork && (child_pid = fork()) == 0) {
			ExecDeathTestChildMain(&args);
			_exit(0);
			}
			# endif // GTEST_OS_QNX
			# if GTEST_OS_LINUX
			GTEST_DEATH_TEST_CHECK_SYSCALL_(
			sigaction(SIGPROF, &saved_sigprof_action, nullptr));
			# endif // GTEST_OS_LINUX

			GTEST_DEATH_TEST_CHECK_(child_pid != -1);
			return child_pid;
			}

			// The AssumeRole process for a fork-and-exec death test. It re-executes the
			// main program from the beginning, setting the --gtest_filter
			// and --gtest_internal_run_death_test flags to cause only the current
			// death test to be re-run.
			DeathTest::TestRole ExecDeathTest::AssumeRole() {
			const UnitTestImpl* const impl = GetUnitTestImpl();
			const InternalRunDeathTestFlag* const flag =
			impl->internal_run_death_test_flag();
			const TestInfo* const info = impl->current_test_info();
			const int death_test_index = info->result()->death_test_count();

			if (flag != nullptr) {
			set_write_fd(flag->write_fd());
			return EXECUTE_TEST;
			}

			int pipe_fd[2];
			GTEST_DEATH_TEST_CHECK_(pipe(pipe_fd) != -1);
			// Clear the close-on-exec flag on the write end of the pipe, lest
			// it be closed when the child process does an exec:
			GTEST_DEATH_TEST_CHECK_(fcntl(pipe_fd[1], F_SETFD, 0) != -1);

			const std::string filter_flag =
			std::string("--") + GTEST_FLAG_PREFIX_ + kFilterFlag + "="
			+ info->test_case_name() + "." + info->name();
			const std::string internal_flag =
			std::string("--") + GTEST_FLAG_PREFIX_ + kInternalRunDeathTestFlag + "="
			+ file_ + "\|" + StreamableToString(line_) + "\|"
			+ StreamableToString(death_test_index) + "\|"
			+ StreamableToString(pipe_fd[1]);
			Arguments args;
			args.AddArguments(GetArgvsForDeathTestChildProcess());
			args.AddArgument(filter_flag.c_str());
			args.AddArgument(internal_flag.c_str());

			DeathTest::set_last_death_test_message("");

			CaptureStderr();
			// See the comment in NoExecDeathTest::AssumeRole for why the next line
			// is necessary.
			FlushInfoLog();

			const pid_t child_pid = ExecDeathTestSpawnChild(args.Argv(), pipe_fd[0]);
			GTEST_DEATH_TEST_CHECK_SYSCALL_(close(pipe_fd[1]));
			set_child_pid(child_pid);
			set_read_fd(pipe_fd[0]);
			set_spawned(true);
			return OVERSEE_TEST;
			}

			# endif // !GTEST_OS_WINDOWS

			// Creates a concrete DeathTest-derived class that depends on the
			// --gtest_death_test_style flag, and sets the pointer pointed to
			// by the "test" argument to its address. If the test should be
			// skipped, sets that pointer to NULL. Returns true, unless the
			// flag is set to an invalid value.
			bool DefaultDeathTestFactory::Create(const char* statement,
			Matcher<const std::string&> matcher,
			const char* file, int line,
			DeathTest** test) {
			UnitTestImpl* const impl = GetUnitTestImpl();
			const InternalRunDeathTestFlag* const flag =
			impl->internal_run_death_test_flag();
			const int death_test_index = impl->current_test_info()
			->increment_death_test_count();

			if (flag != nullptr) {
			if (death_test_index > flag->index()) {
			DeathTest::set_last_death_test_message(
			"Death test count (" + StreamableToString(death_test_index)
			+ ") somehow exceeded expected maximum ("
			+ StreamableToString(flag->index()) + ")");
			return false;
			}

			if (!(flag->file() == file && flag->line() == line &&
			flag->index() == death_test_index)) {
			*test = nullptr;
			return true;
			}
			}

			# if GTEST_OS_WINDOWS

			if (GTEST_FLAG(death_test_style) == "threadsafe" \|\|
			GTEST_FLAG(death_test_style) == "fast") {
			*test = new WindowsDeathTest(statement, std::move(matcher), file, line);
			}

			# elif GTEST_OS_FUCHSIA

			if (GTEST_FLAG(death_test_style) == "threadsafe" \|\|
			GTEST_FLAG(death_test_style) == "fast") {
			*test = new FuchsiaDeathTest(statement, std::move(matcher), file, line);
			}

			# else

			if (GTEST_FLAG(death_test_style) == "threadsafe") {
			*test = new ExecDeathTest(statement, std::move(matcher), file, line);
			} else if (GTEST_FLAG(death_test_style) == "fast") {
			*test = new NoExecDeathTest(statement, std::move(matcher));
			}

			# endif // GTEST_OS_WINDOWS

			else { // NOLINT - this is more readable than unbalanced brackets inside #if.
			DeathTest::set_last_death_test_message(
			"Unknown death test style \"" + GTEST_FLAG(death_test_style)
			+ "\" encountered");
			return false;
			}

			return true;
			}

			# if GTEST_OS_WINDOWS
			// Recreates the pipe and event handles from the provided parameters,
			// signals the event, and returns a file descriptor wrapped around the pipe
			// handle. This function is called in the child process only.
			static int GetStatusFileDescriptor(unsigned int parent_process_id,
			size_t write_handle_as_size_t,
			size_t event_handle_as_size_t) {
			AutoHandle parent_process_handle(::OpenProcess(PROCESS_DUP_HANDLE,
			FALSE, // Non-inheritable.
			parent_process_id));
			if (parent_process_handle.Get() == INVALID_HANDLE_VALUE) {
			DeathTestAbort("Unable to open parent process " +
			StreamableToString(parent_process_id));
			}

			// FIXME: Replace the following check with a
			// compile-time assertion when available.
			GTEST_CHECK_(sizeof(HANDLE) <= sizeof(size_t));

			const HANDLE write_handle =
			reinterpret_cast<HANDLE>(write_handle_as_size_t);
			HANDLE dup_write_handle;

			// The newly initialized handle is accessible only in the parent
			// process. To obtain one accessible within the child, we need to use
			// DuplicateHandle.
			if (!::DuplicateHandle(parent_process_handle.Get(), write_handle,
			::GetCurrentProcess(), &dup_write_handle,
			0x0, // Requested privileges ignored since
			// DUPLICATE_SAME_ACCESS is used.
			FALSE, // Request non-inheritable handler.
			DUPLICATE_SAME_ACCESS)) {
			DeathTestAbort("Unable to duplicate the pipe handle " +
			StreamableToString(write_handle_as_size_t) +
			" from the parent process " +
			StreamableToString(parent_process_id));
			}

			const HANDLE event_handle = reinterpret_cast<HANDLE>(event_handle_as_size_t);
			HANDLE dup_event_handle;

			if (!::DuplicateHandle(parent_process_handle.Get(), event_handle,
			::GetCurrentProcess(), &dup_event_handle,
			0x0,
			FALSE,
			DUPLICATE_SAME_ACCESS)) {
			DeathTestAbort("Unable to duplicate the event handle " +
			StreamableToString(event_handle_as_size_t) +
			" from the parent process " +
			StreamableToString(parent_process_id));
			}

			const int write_fd =
			::_open_osfhandle(reinterpret_cast<intptr_t>(dup_write_handle), O_APPEND);
			if (write_fd == -1) {
			DeathTestAbort("Unable to convert pipe handle " +
			StreamableToString(write_handle_as_size_t) +
			" to a file descriptor");
			}

			// Signals the parent that the write end of the pipe has been acquired
			// so the parent can release its own write end.
			::SetEvent(dup_event_handle);

			return write_fd;
			}
			# endif // GTEST_OS_WINDOWS

			// Returns a newly created InternalRunDeathTestFlag object with fields
			// initialized from the GTEST_FLAG(internal_run_death_test) flag if
			// the flag is specified; otherwise returns NULL.
			InternalRunDeathTestFlag* ParseInternalRunDeathTestFlag() {
			if (GTEST_FLAG(internal_run_death_test) == "") return nullptr;

			// GTEST_HAS_DEATH_TEST implies that we have ::std::string, so we
			// can use it here.
			int line = -1;
			int index = -1;
			::std::vector< ::std::string> fields;
			SplitString(GTEST_FLAG(internal_run_death_test).c_str(), '\|', &fields);
			int write_fd = -1;

			# if GTEST_OS_WINDOWS

			unsigned int parent_process_id = 0;
			size_t write_handle_as_size_t = 0;
			size_t event_handle_as_size_t = 0;

			if (fields.size() != 6
			\|\| !ParseNaturalNumber(fields[1], &line)
			\|\| !ParseNaturalNumber(fields[2], &index)
			\|\| !ParseNaturalNumber(fields[3], &parent_process_id)
			\|\| !ParseNaturalNumber(fields[4], &write_handle_as_size_t)
			\|\| !ParseNaturalNumber(fields[5], &event_handle_as_size_t)) {
			DeathTestAbort("Bad --gtest_internal_run_death_test flag: " +
			GTEST_FLAG(internal_run_death_test));
			}
			write_fd = GetStatusFileDescriptor(parent_process_id,
			write_handle_as_size_t,
			event_handle_as_size_t);

			# elif GTEST_OS_FUCHSIA

			if (fields.size() != 3
			\|\| !ParseNaturalNumber(fields[1], &line)
			\|\| !ParseNaturalNumber(fields[2], &index)) {
			DeathTestAbort("Bad --gtest_internal_run_death_test flag: "
			+ GTEST_FLAG(internal_run_death_test));
			}

			# else

			if (fields.size() != 4
			\|\| !ParseNaturalNumber(fields[1], &line)
			\|\| !ParseNaturalNumber(fields[2], &index)
			\|\| !ParseNaturalNumber(fields[3], &write_fd)) {
			DeathTestAbort("Bad --gtest_internal_run_death_test flag: "
			+ GTEST_FLAG(internal_run_death_test));
			}

			# endif // GTEST_OS_WINDOWS

			return new InternalRunDeathTestFlag(fields[0], line, index, write_fd);
			}

			} // namespace internal

			#endif // GTEST_HAS_DEATH_TEST

			} // namespace testing

R9484/googletest/src/gtest-death-test.cc26743363be8fmaster

gtest-death-test.ccView Options

R9484/googletest/src/gtest-death-test.cc
26743363be8fmaster

gtest-death-test.cc
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