Reorganize Multiprocess and implement for Windows

util/test/multiprocess_exec.cc

-// Copyright 2014 The Crashpad Authors. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#include "util/test/multiprocess_exec.h"
-
-#include <fcntl.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "base/posix/eintr_wrapper.h"
-#include "gtest/gtest.h"
-#include "util/misc/scoped_forbid_return.h"
-#include "util/posix/close_multiple.h"
-#include "util/test/errors.h"
-
-namespace crashpad {
-namespace test {
-
-MultiprocessExec::MultiprocessExec()
-    : Multiprocess(),
-      command_(),
-      arguments_(),
-      argv_() {
-}
-
-void MultiprocessExec::SetChildCommand(
-    const std::string& command, const std::vector<std::string>* arguments) {
-  command_ = command;
-  if (arguments) {
-    arguments_ = *arguments;
-  } else {
-    arguments_.clear();
-  }
-}
-
-MultiprocessExec::~MultiprocessExec() {
-}
-
-void MultiprocessExec::PreFork() {
-  ASSERT_NO_FATAL_FAILURE(Multiprocess::PreFork());
-
-  ASSERT_FALSE(command_.empty());
-
-  // Build up the argv vector. This is done in PreFork() instead of
-  // MultiprocessChild() because although the result is only needed in the child
-  // process, building it is a hazardous operation in that process.
-  ASSERT_TRUE(argv_.empty());
-
-  argv_.push_back(command_.c_str());
-  for (const std::string& argument : arguments_) {
-    argv_.push_back(argument.c_str());
-  }
-  argv_.push_back(nullptr);
-}
-
-void MultiprocessExec::MultiprocessChild() {
-  // Make sure that stdin, stdout, and stderr are FDs 0, 1, and 2, respectively.
-  // All FDs above this will be closed.
-  static_assert(STDIN_FILENO == 0, "stdin must be fd 0");
-  static_assert(STDOUT_FILENO == 1, "stdout must be fd 1");
-  static_assert(STDERR_FILENO == 2, "stderr must be fd 2");
-
-  // Move the read pipe to stdin.
-  int read_fd = ReadPipeFD();
-  ASSERT_NE(read_fd, STDIN_FILENO);
-  ASSERT_NE(read_fd, STDOUT_FILENO);
-  ASSERT_EQ(STDIN_FILENO, fileno(stdin));
-
-  int rv = fpurge(stdin);
-  ASSERT_EQ(0, rv) << ErrnoMessage("fpurge");
-
-  rv = HANDLE_EINTR(dup2(read_fd, STDIN_FILENO));
-  ASSERT_EQ(STDIN_FILENO, rv) << ErrnoMessage("dup2");
-
-  // Move the write pipe to stdout.
-  int write_fd = WritePipeFD();
-  ASSERT_NE(write_fd, STDIN_FILENO);
-  ASSERT_NE(write_fd, STDOUT_FILENO);
-  ASSERT_EQ(STDOUT_FILENO, fileno(stdout));
-
-  // Make a copy of the original stdout file descriptor so that in case there’s
-  // an execv() failure, the original stdout can be restored so that gtest
-  // messages directed to stdout go to the right place. Mark it as
-  // close-on-exec, so that the child won’t see it after a successful exec(),
-  // but it will still be available in this process after an unsuccessful
-  // exec().
-  int dup_orig_stdout_fd = dup(STDOUT_FILENO);
-  ASSERT_GE(dup_orig_stdout_fd, 0) << ErrnoMessage("dup");
-
-  rv = fcntl(dup_orig_stdout_fd, F_SETFD, FD_CLOEXEC);
-  ASSERT_NE(rv, -1) << ErrnoMessage("fcntl");
-
-  rv = HANDLE_EINTR(fflush(stdout));
-  ASSERT_EQ(0, rv) << ErrnoMessage("fflush");
-
-  rv = HANDLE_EINTR(dup2(write_fd, STDOUT_FILENO));
-  ASSERT_EQ(STDOUT_FILENO, rv) << ErrnoMessage("dup2");
-
-  CloseMultipleNowOrOnExec(STDERR_FILENO + 1, dup_orig_stdout_fd);
-
-  // Start the new program, replacing this one. execv() has a weird declaration
-  // where its argv argument is declared as char* const*. In reality, the
-  // implementation behaves as if the argument were const char* const*, and this
-  // behavior is required by the standard. See
-  // http://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html
-  // (search for “constant”).
-  execv(argv_[0], const_cast<char* const*>(&argv_[0]));
-
-  // This should not normally be reached. Getting here means that execv()
-  // failed.
-
-  // Be sure not to return until FAIL() is reached.
-  ScopedForbidReturn forbid_return;
-
-  // Put the original stdout back. Close the copy of the write pipe FD that’s
-  // currently on stdout first, so that in case the dup2() that restores the
-  // original stdout fails, stdout isn’t left attached to the pipe when the
-  // FAIL() statement executes.
-  HANDLE_EINTR(fflush(stdout));
-  IGNORE_EINTR(close(STDOUT_FILENO));
-  HANDLE_EINTR(dup2(dup_orig_stdout_fd, STDOUT_FILENO));
-  IGNORE_EINTR(close(dup_orig_stdout_fd));
-
-  forbid_return.Disarm();
-  FAIL() << ErrnoMessage("execv") << ": " << argv_[0];
-}
-
-}  // namespace test
-}  // namespace crashpad