Initial import.

src/gtest-death-test.cc

@@ -0,0 +1,751 @@
+// 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.
+//
+// Author: wan@google.com (Zhanyong Wan)
+//
+// This file implements death tests.
+
+#include <gtest/gtest-death-test.h>
+#include <gtest/internal/gtest-port.h>
+
+#include <errno.h>
+#include <limits.h>
+#include <stdarg.h>
+
+#include <gtest/gtest-message.h>
+#include <gtest/internal/gtest-string.h>
+
+// Indicates that this translation unit is part of Google Test's
+// implementation.  It must come before gtest-internal-inl.h is
+// included, or there will be a compiler error.  This trick is to
+// prevent a user from accidentally including gtest-internal-inl.h in
+// his code.
+#define GTEST_IMPLEMENTATION
+#include "gtest-internal-inl.h"
+#undef GTEST_IMPLEMENTATION
+
+namespace testing {
+
+// Constants.
+
+// The default death test style.
+static const char kDefaultDeathTestStyle[] = "fast";
+
+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).");
+
+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 "
+    "colons.  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
+
+#ifdef GTEST_HAS_DEATH_TEST
+
+// ExitedWithCode constructor.
+ExitedWithCode::ExitedWithCode(int exit_code) : exit_code_(exit_code) {
+}
+
+// ExitedWithCode function-call operator.
+bool ExitedWithCode::operator()(int exit_status) const {
+  return WIFEXITED(exit_status) && WEXITSTATUS(exit_status) == exit_code_;
+}
+
+// KilledBySignal constructor.
+KilledBySignal::KilledBySignal(int signum) : signum_(signum) {
+}
+
+// KilledBySignal function-call operator.
+bool KilledBySignal::operator()(int exit_status) const {
+  return WIFSIGNALED(exit_status) && WTERMSIG(exit_status) == signum_;
+}
+
+namespace internal {
+
+// Utilities needed for death tests.
+
+// Generates a textual description of a given exit code, in the format
+// specified by wait(2).
+static String ExitSummary(int exit_code) {
+  Message m;
+  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
+  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);
+}
+
+// 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 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.";
+  return msg.GetString();
+}
+
+// Static string containing a description of the outcome of the
+// last death test.
+static String last_death_test_message;
+
+// Flag characters for reporting a death test that did not die.
+static const char kDeathTestLived = 'L';
+static const char kDeathTestReturned = 'R';
+static const char kDeathTestInternalError = 'I';
+
+// 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; and RETURNED means that the test statement attempted a "return,"
+// which is not allowed.  IN_PROGRESS means the test has not yet
+// concluded.
+enum DeathTestOutcome { IN_PROGRESS, DIED, LIVED, RETURNED };
+
+// Routine for aborting the program which is safe to call from an
+// exec-style death test child process, in which case the 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.
+void DeathTestAbort(const char* format, ...) {
+  // 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-miniscule memory requirements.
+  const InternalRunDeathTestFlag* const flag =
+      GetUnitTestImpl()->internal_run_death_test_flag();
+  va_list args;
+  va_start(args, format);
+
+  if (flag != NULL) {
+    FILE* parent = fdopen(flag->status_fd, "w");
+    fputc(kDeathTestInternalError, parent);
+    vfprintf(parent, format, args);
+    fclose(parent);
+    va_end(args);
+    _exit(1);
+  } else {
+    vfprintf(stderr, format, args);
+    va_end(args);
+    abort();
+  }
+}
+
+// A replacement for CHECK that calls DeathTestAbort if the assertion
+// fails.
+#define GTEST_DEATH_TEST_CHECK(expression) \
+  do { \
+    if (!(expression)) { \
+      DeathTestAbort("CHECK failed: File %s, line %d: %s", \
+                     __FILE__, __LINE__, #expression); \
+    } \
+  } while (0)
+
+// 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 retval; \
+    do { \
+      retval = (expression); \
+    } while (retval == -1 && errno == EINTR); \
+    if (retval == -1) { \
+      DeathTestAbort("CHECK failed: File %s, line %d: %s != -1", \
+                     __FILE__, __LINE__, #expression); \
+    } \
+  } while (0)
+
+// Death test constructor.  Increments the running death test count
+// for the current test.
+DeathTest::DeathTest() {
+  TestInfo* const info = GetUnitTestImpl()->current_test_info();
+  if (info == NULL) {
+    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, const RE* regex,
+                       const char* file, int line, DeathTest** test) {
+  return GetUnitTestImpl()->death_test_factory()->Create(
+      statement, regex, file, line, test);
+}
+
+const char* DeathTest::LastMessage() {
+  return last_death_test_message.c_str();
+}
+
+// ForkingDeathTest provides implementations for most of the abstract
+// methods of the DeathTest interface.  Only the AssumeRole method is
+// left undefined.
+class ForkingDeathTest : public DeathTest {
+ public:
+  ForkingDeathTest(const char* statement, const RE* regex);
+
+  // All of these virtual functions are inherited from DeathTest.
+  virtual int Wait();
+  virtual bool Passed(bool status_ok);
+  virtual void Abort(AbortReason reason);
+
+ protected:
+  void set_forked(bool forked) { forked_ = forked; }
+  void set_child_pid(pid_t child_pid) { child_pid_ = child_pid; }
+  void set_read_fd(int fd) { read_fd_ = fd; }
+  void set_write_fd(int fd) { write_fd_ = fd; }
+
+ private:
+  // The textual content of the code this object is testing.
+  const char* const statement_;
+  // The regular expression which test output must match.
+  const RE* const regex_;
+  // True if the death test successfully forked.
+  bool forked_;
+  // PID of child process during death test; 0 in the child process itself.
+  pid_t child_pid_;
+  // File descriptors for communicating the death test's status byte.
+  int read_fd_;   // Always -1 in the child process.
+  int write_fd_;  // Always -1 in the parent process.
+  // The exit status of the child process.
+  int status_;
+  // How the death test concluded.
+  DeathTestOutcome outcome_;
+};
+
+// Constructs a ForkingDeathTest.
+ForkingDeathTest::ForkingDeathTest(const char* statement, const RE* regex)
+    : DeathTest(),
+      statement_(statement),
+      regex_(regex),
+      forked_(false),
+      child_pid_(-1),
+      read_fd_(-1),
+      write_fd_(-1),
+      status_(-1),
+      outcome_(IN_PROGRESS) {
+}
+
+// Reads an internal failure message from a file descriptor, then calls
+// LOG(FATAL) with that message.  Called from a death test parent process
+// to read a failure message from the death test child process.
+static void FailFromInternalError(int fd) {
+  Message error;
+  char buffer[256];
+  ssize_t num_read;
+
+  do {
+    while ((num_read = read(fd, buffer, 255)) > 0) {
+      buffer[num_read] = '\0';
+      error << buffer;
+    }
+  } while (num_read == -1 && errno == EINTR);
+
+  // TODO(smcafee):  Maybe just FAIL the test instead?
+  if (num_read == 0) {
+    GTEST_LOG(FATAL, error);
+  } else {
+    GTEST_LOG(FATAL,
+              Message() << "Error while reading death test internal: "
+              << strerror(errno) << " [" << errno << "]");
+  }
+}
+
+// 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 (!forked_)
+    return 0;
+
+  // 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.
+  char flag;
+  ssize_t bytes_read;
+
+  do {
+    bytes_read = read(read_fd_, &flag, 1);
+  } while (bytes_read == -1 && errno == EINTR);
+
+  if (bytes_read == 0) {
+    outcome_ = DIED;
+  } else if (bytes_read == 1) {
+    switch (flag) {
+      case kDeathTestReturned:
+        outcome_ = RETURNED;
+        break;
+      case kDeathTestLived:
+        outcome_ = LIVED;
+        break;
+      case kDeathTestInternalError:
+        FailFromInternalError(read_fd_);  // Does not return.
+        break;
+      default:
+        GTEST_LOG(FATAL,
+                  Message() << "Death test child process reported unexpected "
+                  << "status byte (" << static_cast<unsigned int>(flag)
+                  << ")");
+    }
+  } else {
+    GTEST_LOG(FATAL,
+              Message() << "Read from death test child process failed: "
+              << strerror(errno));
+  }
+
+  GTEST_DEATH_TEST_CHECK_SYSCALL(close(read_fd_));
+  GTEST_DEATH_TEST_CHECK_SYSCALL(waitpid(child_pid_, &status_, 0));
+  return status_;
+}
+
+// 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, or RETURNED.  The death test fails
+//             in the latter two cases
+//   status:   the exit status of the child process, in the format
+//             specified by wait(2)
+//   regex:    a regular expression object to be applied to
+//             the test's captured standard error output; the death test
+//             fails if it does not match
+//
+// 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 static variable last_death_test_message.
+bool ForkingDeathTest::Passed(bool status_ok) {
+  if (!forked_)
+    return false;
+
+#if GTEST_HAS_GLOBAL_STRING
+  const ::string error_message = GetCapturedStderr();
+#else
+  const ::std::string error_message = GetCapturedStderr();
+#endif  // GTEST_HAS_GLOBAL_STRING
+
+  bool success = false;
+  Message buffer;
+
+  buffer << "Death test: " << statement_ << "\n";
+  switch (outcome_) {
+    case LIVED:
+      buffer << "    Result: failed to die.\n"
+             << " Error msg: " << error_message;
+      break;
+    case RETURNED:
+      buffer << "    Result: illegal return in test statement.\n"
+             << " Error msg: " << error_message;
+      break;
+    case DIED:
+      if (status_ok) {
+        if (RE::PartialMatch(error_message, *regex_)) {
+          success = true;
+        } else {
+          buffer << "    Result: died but not with expected error.\n"
+                 << "  Expected: " << regex_->pattern() << "\n"
+                 << "Actual msg: " << error_message;
+        }
+      } else {
+        buffer << "    Result: died but not with expected exit code:\n"
+               << "            " << ExitSummary(status_) << "\n";
+      }
+      break;
+    default:
+      GTEST_LOG(FATAL,
+                "DeathTest::Passed somehow called before conclusion of test");
+  }
+
+  last_death_test_message = buffer.GetString();
+  return success;
+}
+
+// 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 desriptor, then
+// calls _exit(1).
+void ForkingDeathTest::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 flag =
+      reason == TEST_DID_NOT_DIE ? kDeathTestLived : kDeathTestReturned;
+  GTEST_DEATH_TEST_CHECK_SYSCALL(write(write_fd_, &flag, 1));
+  GTEST_DEATH_TEST_CHECK_SYSCALL(close(write_fd_));
+  _exit(1);  // Exits w/o any normal exit hooks (we were supposed to crash)
+}
+
+// A concrete death test class that forks, then immediately runs the test
+// in the child process.
+class NoExecDeathTest : public ForkingDeathTest {
+ public:
+  NoExecDeathTest(const char* statement, const RE* regex) :
+      ForkingDeathTest(statement, regex) { }
+  virtual TestRole AssumeRole();
+};
+
+// 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);
+
+  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();
+    return EXECUTE_TEST;
+  } else {
+    GTEST_DEATH_TEST_CHECK_SYSCALL(close(pipe_fd[1]));
+    set_read_fd(pipe_fd[0]);
+    set_forked(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* statement, const RE* regex,
+                const char* file, int line) :
+      ForkingDeathTest(statement, regex), file_(file), line_(line) { }
+  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_;
+};
+
+// Utility class for accumulating command-line arguments.
+class Arguments {
+ public:
+  Arguments() {
+    args_.push_back(NULL);
+  }
+  ~Arguments() {
+    for (std::vector<char*>::iterator i = args_.begin();
+         i + 1 != args_.end();
+         ++i) {
+      free(*i);
+    }
+  }
+  void AddArgument(const char* argument) {
+    args_.insert(args_.end() - 1, 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, 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
+};
+
+// The main function for a threadsafe-style death test child process.
+static int ExecDeathTestChildMain(void* child_arg) {
+  ExecDeathTestArgs* const args = static_cast<ExecDeathTestArgs*>(child_arg);
+  GTEST_DEATH_TEST_CHECK_SYSCALL(close(args->close_fd));
+  execve(args->argv[0], args->argv, environ);
+  DeathTestAbort("execve failed: %s", strerror(errno));
+  return EXIT_FAILURE;
+}
+
+// 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.
+static bool StackLowerThanAddress(const void* ptr) {
+  int dummy;
+  return &dummy < ptr;
+}
+
+static bool StackGrowsDown() {
+  int dummy;
+  return StackLowerThanAddress(&dummy);
+}
+
+// A threadsafe implementation of fork(2) for threadsafe-style death tests
+// that uses clone(2).  It dies with an error message if anything goes
+// wrong.
+static pid_t ExecDeathTestFork(char* const* argv, int close_fd) {
+  static const bool stack_grows_down = StackGrowsDown();
+  const size_t stack_size = getpagesize();
+  void* const stack = mmap(NULL, stack_size, PROT_READ | PROT_WRITE,
+                           MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+  GTEST_DEATH_TEST_CHECK(stack != MAP_FAILED);
+  void* const stack_top =
+      static_cast<char*>(stack) + (stack_grows_down ? stack_size : 0);
+  ExecDeathTestArgs args = { argv, close_fd };
+  const pid_t child_pid = clone(&ExecDeathTestChildMain, stack_top,
+                                SIGCHLD, &args);
+  GTEST_DEATH_TEST_CHECK(child_pid != -1);
+  GTEST_DEATH_TEST_CHECK(munmap(stack, stack_size) != -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 != NULL) {
+    set_write_fd(flag->status_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 String filter_flag =
+      String::Format("--%s%s=%s.%s",
+                     GTEST_FLAG_PREFIX, kFilterFlag,
+                     info->test_case_name(), info->name());
+  const String internal_flag =
+      String::Format("--%s%s=%s:%d:%d:%d",
+                     GTEST_FLAG_PREFIX, kInternalRunDeathTestFlag, file_, line_,
+                     death_test_index, pipe_fd[1]);
+  Arguments args;
+  args.AddArguments(GetArgvs());
+  args.AddArgument("--logtostderr");
+  args.AddArgument(filter_flag.c_str());
+  args.AddArgument(internal_flag.c_str());
+
+  last_death_test_message = "";
+
+  CaptureStderr();
+  // See the comment in NoExecDeathTest::AssumeRole for why the next line
+  // is necessary.
+  FlushInfoLog();
+
+  const pid_t child_pid = ExecDeathTestFork(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_forked(true);
+  return OVERSEE_TEST;
+}
+
+// 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, const RE* regex,
+                                     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 != NULL) {
+    if (death_test_index > flag->index) {
+      last_death_test_message = String::Format(
+          "Death test count (%d) somehow exceeded expected maximum (%d)",
+          death_test_index, flag->index);
+      return false;
+    }
+
+    if (!(flag->file == file && flag->line == line &&
+          flag->index == death_test_index)) {
+      *test = NULL;
+      return true;
+    }
+  }
+
+  if (GTEST_FLAG(death_test_style) == "threadsafe") {
+    *test = new ExecDeathTest(statement, regex, file, line);
+  } else if (GTEST_FLAG(death_test_style) == "fast") {
+    *test = new NoExecDeathTest(statement, regex);
+  } else {
+    last_death_test_message = String::Format(
+        "Unknown death test style \"%s\" encountered",
+        GTEST_FLAG(death_test_style).c_str());
+    return false;
+  }
+
+  return true;
+}
+
+// Splits a given string on a given delimiter, populating a given
+// vector with the fields.  GTEST_HAS_DEATH_TEST implies that we have
+// ::std::string, so we can use it here.
+static void SplitString(const ::std::string& str, char delimiter,
+                        ::std::vector< ::std::string>* dest) {
+  ::std::vector< ::std::string> parsed;
+  ::std::string::size_type pos = 0;
+  while (true) {
+    const ::std::string::size_type colon = str.find(':', pos);
+    if (colon == ::std::string::npos) {
+      parsed.push_back(str.substr(pos));
+      break;
+    } else {
+      parsed.push_back(str.substr(pos, colon - pos));
+      pos = colon + 1;
+    }
+  }
+  dest->swap(parsed);
+}
+
+// Attempts to parse a string into a positive integer.  Returns true
+// if that is possible.  GTEST_HAS_DEATH_TEST implies that we have
+// ::std::string, so we can use it here.
+static bool ParsePositiveInt(const ::std::string& str, int* number) {
+  // Fail fast if the given string does not begin with a digit;
+  // this bypasses strtol's "optional leading whitespace and plus
+  // or minus sign" semantics, which are undesirable here.
+  if (str.empty() || !isdigit(str[0])) {
+    return false;
+  }
+  char* endptr;
+  const long parsed = strtol(str.c_str(), &endptr, 10);  // NOLINT
+  if (*endptr == '\0' && parsed <= INT_MAX) {
+    *number = static_cast<int>(parsed);
+    return true;
+  } else {
+    return false;
+  }
+}
+
+// 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 NULL;
+
+  InternalRunDeathTestFlag* const internal_run_death_test_flag =
+      new InternalRunDeathTestFlag;
+  // GTEST_HAS_DEATH_TEST implies that we have ::std::string, so we
+  // can use it here.
+  ::std::vector< ::std::string> fields;
+  SplitString(GTEST_FLAG(internal_run_death_test).c_str(), ':', &fields);
+  if (fields.size() != 4
+      || !ParsePositiveInt(fields[1], &internal_run_death_test_flag->line)
+      || !ParsePositiveInt(fields[2], &internal_run_death_test_flag->index)
+      || !ParsePositiveInt(fields[3],
+                           &internal_run_death_test_flag->status_fd)) {
+    DeathTestAbort("Bad --gtest_internal_run_death_test flag: %s",
+                   GTEST_FLAG(internal_run_death_test).c_str());
+  }
+  internal_run_death_test_flag->file = fields[0].c_str();
+  return internal_run_death_test_flag;
+}
+
+}  // namespace internal
+
+#endif  // GTEST_HAS_DEATH_TEST
+
+}  // namespace testing