bool
GeckoChildProcessHost::PerformAsyncLaunchInternal(std::vector<std::string>& aExtraOpts, base::ProcessArchitecture arch)
{
  // We rely on the fact that InitializeChannel() has already been processed
  // on the IO thread before this point is reached.
  if (!GetChannel()) {
    return false;
  }

  base::ProcessHandle process = 0;

  // send the child the PID so that it can open a ProcessHandle back to us.
  // probably don't want to do this in the long run
  char pidstring[32];
  PR_snprintf(pidstring, sizeof(pidstring) - 1,
	      "%ld", base::Process::Current().pid());

  const char* const childProcessType =
      XRE_ChildProcessTypeToString(mProcessType);

//--------------------------------------------------
#if defined(OS_POSIX)
  // For POSIX, we have to be extremely anal about *not* using
  // std::wstring in code compiled with Mozilla's -fshort-wchar
  // configuration, because chromium is compiled with -fno-short-wchar
  // and passing wstrings from one config to the other is unsafe.  So
  // we split the logic here.

#if defined(OS_LINUX) || defined(OS_MACOSX) || defined(OS_BSD)
  base::environment_map newEnvVars;
  ChildPrivileges privs = mPrivileges;
  if (privs == base::PRIVILEGES_DEFAULT) {
    privs = DefaultChildPrivileges();
  }
  // XPCOM may not be initialized in some subprocesses.  We don't want
  // to initialize XPCOM just for the directory service, especially
  // since LD_LIBRARY_PATH is already set correctly in subprocesses
  // (meaning that we don't need to set that up in the environment).
  if (ShouldHaveDirectoryService()) {
    MOZ_ASSERT(gGREBinPath);
    nsCString path;
    NS_CopyUnicodeToNative(nsDependentString(gGREBinPath), path);
# if defined(OS_LINUX) || defined(OS_BSD)
#  if defined(MOZ_WIDGET_ANDROID)
    path += "/lib";
#  endif  // MOZ_WIDGET_ANDROID
    const char *ld_library_path = PR_GetEnv("LD_LIBRARY_PATH");
    nsCString new_ld_lib_path;
    if (ld_library_path && *ld_library_path) {
      new_ld_lib_path.Assign(path.get());
      new_ld_lib_path.Append(':');
      new_ld_lib_path.Append(ld_library_path);
      newEnvVars["LD_LIBRARY_PATH"] = new_ld_lib_path.get();
    } else {
      newEnvVars["LD_LIBRARY_PATH"] = path.get();
    }

#  if (MOZ_WIDGET_GTK == 3)
    if (mProcessType == GeckoProcessType_Plugin) {
      const char *ld_preload = PR_GetEnv("LD_PRELOAD");
      nsCString new_ld_preload;

      new_ld_preload.Assign(path.get());
      new_ld_preload.AppendLiteral("/" DLL_PREFIX "mozgtk2" DLL_SUFFIX);

      if (ld_preload && *ld_preload) {
        new_ld_preload.AppendLiteral(":");
        new_ld_preload.Append(ld_preload);
      }
      newEnvVars["LD_PRELOAD"] = new_ld_preload.get();
    }
#  endif // MOZ_WIDGET_GTK


# elif OS_MACOSX
    newEnvVars["DYLD_LIBRARY_PATH"] = path.get();
    // XXX DYLD_INSERT_LIBRARIES should only be set when launching a plugin
    //     process, and has no effect on other subprocesses (the hooks in
    //     libplugin_child_interpose.dylib become noops).  But currently it
    //     gets set when launching any kind of subprocess.
    //
    // Trigger "dyld interposing" for the dylib that contains
    // plugin_child_interpose.mm.  This allows us to hook OS calls in the
    // plugin process (ones that don't work correctly in a background
    // process).  Don't break any other "dyld interposing" that has already
    // been set up by whatever may have launched the browser.
    const char* prevInterpose = PR_GetEnv("DYLD_INSERT_LIBRARIES");
    nsCString interpose;
    if (prevInterpose) {
      interpose.Assign(prevInterpose);
      interpose.Append(':');
    }
    interpose.Append(path.get());
    interpose.AppendLiteral("/libplugin_child_interpose.dylib");
    newEnvVars["DYLD_INSERT_LIBRARIES"] = interpose.get();
# endif  // OS_LINUX
  }
#endif  // OS_LINUX || OS_MACOSX

  FilePath exePath;
  GetPathToBinary(exePath);

#ifdef MOZ_WIDGET_ANDROID
  // The java wrapper unpacks this for us but can't make it executable
  chmod(exePath.value().c_str(), 0700);
#endif  // MOZ_WIDGET_ANDROID

#ifdef ANDROID
  // Remap the Android property workspace to a well-known int,
  // and update the environment to reflect the new value for the
  // child process.
  const char *apws = getenv("ANDROID_PROPERTY_WORKSPACE");
  if (apws) {
    int fd = atoi(apws);
    mFileMap.push_back(std::pair<int, int>(fd, kMagicAndroidSystemPropFd));

    char buf[32];
    char *szptr = strchr(apws, ',');

    snprintf(buf, sizeof(buf), "%d%s", kMagicAndroidSystemPropFd, szptr);
    newEnvVars["ANDROID_PROPERTY_WORKSPACE"] = buf;
  }
#endif  // ANDROID

#ifdef MOZ_WIDGET_GONK
  if (const char *ldPreloadPath = getenv("LD_PRELOAD")) {
    newEnvVars["LD_PRELOAD"] = ldPreloadPath;
  }
#endif // MOZ_WIDGET_GONK

  // remap the IPC socket fd to a well-known int, as the OS does for
  // STDOUT_FILENO, for example
  int srcChannelFd, dstChannelFd;
  channel().GetClientFileDescriptorMapping(&srcChannelFd, &dstChannelFd);
  mFileMap.push_back(std::pair<int,int>(srcChannelFd, dstChannelFd));

  // no need for kProcessChannelID, the child process inherits the
  // other end of the socketpair() from us

  std::vector<std::string> childArgv;

  childArgv.push_back(exePath.value());

  childArgv.insert(childArgv.end(), aExtraOpts.begin(), aExtraOpts.end());

  if (Omnijar::IsInitialized()) {
    // Make sure that child processes can find the omnijar
    // See XRE_InitCommandLine in nsAppRunner.cpp
    nsAutoCString path;
    nsCOMPtr<nsIFile> file = Omnijar::GetPath(Omnijar::GRE);
    if (file && NS_SUCCEEDED(file->GetNativePath(path))) {
      childArgv.push_back("-greomni");
      childArgv.push_back(path.get());
    }
    file = Omnijar::GetPath(Omnijar::APP);
    if (file && NS_SUCCEEDED(file->GetNativePath(path))) {
      childArgv.push_back("-appomni");
      childArgv.push_back(path.get());
    }
  }

  // Add the application directory path (-appdir path)
  AddAppDirToCommandLine(childArgv);

  childArgv.push_back(pidstring);

#if defined(MOZ_CRASHREPORTER)
#  if defined(OS_LINUX) || defined(OS_BSD)
  int childCrashFd, childCrashRemapFd;
  if (!CrashReporter::CreateNotificationPipeForChild(
        &childCrashFd, &childCrashRemapFd))
    return false;
  if (0 <= childCrashFd) {
    mFileMap.push_back(std::pair<int,int>(childCrashFd, childCrashRemapFd));
    // "true" == crash reporting enabled
    childArgv.push_back("true");
  }
  else {
    // "false" == crash reporting disabled
    childArgv.push_back("false");
  }
#  elif defined(MOZ_WIDGET_COCOA)
  childArgv.push_back(CrashReporter::GetChildNotificationPipe());
#  endif  // OS_LINUX
#endif

#ifdef MOZ_WIDGET_COCOA
  // Add a mach port to the command line so the child can communicate its
  // 'task_t' back to the parent.
  //
  // Put a random number into the channel name, so that a compromised renderer
  // can't pretend being the child that's forked off.
  std::string mach_connection_name = StringPrintf("org.mozilla.machname.%d",
                                                  base::RandInt(0, std::numeric_limits<int>::max()));
  childArgv.push_back(mach_connection_name.c_str());
#endif

  childArgv.push_back(childProcessType);

  base::LaunchApp(childArgv, mFileMap,
#if defined(OS_LINUX) || defined(OS_MACOSX) || defined(OS_BSD)
                  newEnvVars, privs,
#endif
                  false, &process, arch);

  // We're in the parent and the child was launched. Close the child FD in the
  // parent as soon as possible, which will allow the parent to detect when the
  // child closes its FD (either due to normal exit or due to crash).
  GetChannel()->CloseClientFileDescriptor();

#ifdef MOZ_WIDGET_COCOA
  // Wait for the child process to send us its 'task_t' data.
  const int kTimeoutMs = 10000;

  MachReceiveMessage child_message;
  ReceivePort parent_recv_port(mach_connection_name.c_str());
  kern_return_t err = parent_recv_port.WaitForMessage(&child_message, kTimeoutMs);
  if (err != KERN_SUCCESS) {
    std::string errString = StringPrintf("0x%x %s", err, mach_error_string(err));
    CHROMIUM_LOG(ERROR) << "parent WaitForMessage() failed: " << errString;
    return false;
  }

  task_t child_task = child_message.GetTranslatedPort(0);
  if (child_task == MACH_PORT_NULL) {
    CHROMIUM_LOG(ERROR) << "parent GetTranslatedPort(0) failed.";
    return false;
  }

  if (child_message.GetTranslatedPort(1) == MACH_PORT_NULL) {
    CHROMIUM_LOG(ERROR) << "parent GetTranslatedPort(1) failed.";
    return false;
  }
  MachPortSender parent_sender(child_message.GetTranslatedPort(1));

  MachSendMessage parent_message(/* id= */0);
  if (!parent_message.AddDescriptor(MachMsgPortDescriptor(bootstrap_port))) {
    CHROMIUM_LOG(ERROR) << "parent AddDescriptor(" << bootstrap_port << ") failed.";
    return false;
  }

  err = parent_sender.SendMessage(parent_message, kTimeoutMs);
  if (err != KERN_SUCCESS) {
    std::string errString = StringPrintf("0x%x %s", err, mach_error_string(err));
    CHROMIUM_LOG(ERROR) << "parent SendMessage() failed: " << errString;
    return false;
  }
#endif

//--------------------------------------------------
#elif defined(OS_WIN)

  FilePath exePath;
  GetPathToBinary(exePath);

  CommandLine cmdLine(exePath.ToWStringHack());
  cmdLine.AppendSwitchWithValue(switches::kProcessChannelID, channel_id());

  for (std::vector<std::string>::iterator it = aExtraOpts.begin();
       it != aExtraOpts.end();
       ++it) {
      cmdLine.AppendLooseValue(UTF8ToWide(*it));
  }

  if (Omnijar::IsInitialized()) {
    // Make sure the child process can find the omnijar
    // See XRE_InitCommandLine in nsAppRunner.cpp
    nsAutoString path;
    nsCOMPtr<nsIFile> file = Omnijar::GetPath(Omnijar::GRE);
    if (file && NS_SUCCEEDED(file->GetPath(path))) {
      cmdLine.AppendLooseValue(UTF8ToWide("-greomni"));
      cmdLine.AppendLooseValue(path.get());
    }
    file = Omnijar::GetPath(Omnijar::APP);
    if (file && NS_SUCCEEDED(file->GetPath(path))) {
      cmdLine.AppendLooseValue(UTF8ToWide("-appomni"));
      cmdLine.AppendLooseValue(path.get());
    }
  }

#if defined(XP_WIN)
  bool shouldSandboxCurrentProcess = false;
  switch (mProcessType) {
    case GeckoProcessType_Content:
#if defined(MOZ_CONTENT_SANDBOX)
      if (!PR_GetEnv("MOZ_DISABLE_CONTENT_SANDBOX")) {
        mSandboxBroker.SetSecurityLevelForContentProcess();
        cmdLine.AppendLooseValue(UTF8ToWide("-sandbox"));
        shouldSandboxCurrentProcess = true;
      }
#endif // MOZ_CONTENT_SANDBOX
      break;
    case GeckoProcessType_Plugin:
      // XXX: We don't sandbox this process type yet
      // mSandboxBroker.SetSecurityLevelForPluginProcess();
      // cmdLine.AppendLooseValue(UTF8ToWide("-sandbox"));
      // shouldSandboxCurrentProcess = true;
      break;
    case GeckoProcessType_IPDLUnitTest:
      // XXX: We don't sandbox this process type yet
      // mSandboxBroker.SetSecurityLevelForIPDLUnitTestProcess();
      // cmdLine.AppendLooseValue(UTF8ToWide("-sandbox"));
      // shouldSandboxCurrentProcess = true;
      break;
    case GeckoProcessType_GMPlugin:
#ifdef MOZ_SANDBOX
      if (!PR_GetEnv("MOZ_DISABLE_GMP_SANDBOX")) {
        mSandboxBroker.SetSecurityLevelForGMPlugin();
        cmdLine.AppendLooseValue(UTF8ToWide("-sandbox"));
        shouldSandboxCurrentProcess = true;
      }
#endif
      break;
    case GeckoProcessType_Default:
    default:
      MOZ_CRASH("Bad process type in GeckoChildProcessHost");
      break;
  };

  if (shouldSandboxCurrentProcess) {
    for (auto it = mAllowedFilesRead.begin();
         it != mAllowedFilesRead.end();
         ++it) {
      mSandboxBroker.AllowReadFile(it->c_str());
    }
  }

#endif // XP_WIN

  // Add the application directory path (-appdir path)
  AddAppDirToCommandLine(cmdLine);

  // XXX Command line params past this point are expected to be at
  // the end of the command line string, and in a specific order.
  // See XRE_InitChildProcess in nsEmbedFunction.

  // Win app model id
  cmdLine.AppendLooseValue(mGroupId.get());

  // Process id
  cmdLine.AppendLooseValue(UTF8ToWide(pidstring));

#if defined(MOZ_CRASHREPORTER)
  cmdLine.AppendLooseValue(
    UTF8ToWide(CrashReporter::GetChildNotificationPipe()));
#endif

  // Process type
  cmdLine.AppendLooseValue(UTF8ToWide(childProcessType));

#if defined(XP_WIN) && defined(MOZ_SANDBOX)
  if (shouldSandboxCurrentProcess) {
    mSandboxBroker.LaunchApp(cmdLine.program().c_str(),
                             cmdLine.command_line_string().c_str(),
                             &process);
  } else
#endif
  {
    base::LaunchApp(cmdLine, false, false, &process);
  }

#else
#  error Sorry
#endif

  if (!process) {
    MonitorAutoLock lock(mMonitor);
    mProcessState = PROCESS_ERROR;
    lock.Notify();
    return false;
  }
  // NB: on OS X, we block much longer than we need to in order to
  // reach this call, waiting for the child process's task_t.  The
  // best way to fix that is to refactor this file, hard.
  SetHandle(process);
#if defined(MOZ_WIDGET_COCOA)
  mChildTask = child_task;
#endif

  OpenPrivilegedHandle(base::GetProcId(process));
  {
    MonitorAutoLock lock(mMonitor);
    mProcessState = PROCESS_CREATED;
    lock.Notify();
  }

  return true;
}
bool
GeckoChildProcessHost::PerformAsyncLaunchInternal(std::vector<std::string>& aExtraOpts, base::ProcessArchitecture arch)
{
  // We rely on the fact that InitializeChannel() has already been processed
  // on the IO thread before this point is reached.
  if (!GetChannel()) {
    return false;
  }

  base::ProcessHandle process;

  // send the child the PID so that it can open a ProcessHandle back to us.
  // probably don't want to do this in the long run
  char pidstring[32];
  PR_snprintf(pidstring, sizeof(pidstring) - 1,
	      "%ld", base::Process::Current().pid());

  const char* const childProcessType =
      XRE_ChildProcessTypeToString(mProcessType);

//--------------------------------------------------
#if defined(OS_POSIX)
  // For POSIX, we have to be extremely anal about *not* using
  // std::wstring in code compiled with Mozilla's -fshort-wchar
  // configuration, because chromium is compiled with -fno-short-wchar
  // and passing wstrings from one config to the other is unsafe.  So
  // we split the logic here.

#if defined(OS_LINUX) || defined(OS_MACOSX) || defined(OS_BSD)
  base::environment_map newEnvVars;
  ChildPrivileges privs = mPrivileges;
  if (privs == base::PRIVILEGES_DEFAULT) {
    privs = kLowRightsSubprocesses ?
            base::PRIVILEGES_UNPRIVILEGED : base::PRIVILEGES_INHERIT;
  }
  // XPCOM may not be initialized in some subprocesses.  We don't want
  // to initialize XPCOM just for the directory service, especially
  // since LD_LIBRARY_PATH is already set correctly in subprocesses
  // (meaning that we don't need to set that up in the environment).
  if (ShouldHaveDirectoryService()) {
    nsCOMPtr<nsIProperties> directoryService(do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID));
    NS_ASSERTION(directoryService, "Expected XPCOM to be available");
    if (directoryService) {
      nsCOMPtr<nsIFile> greDir;
      nsresult rv = directoryService->Get(NS_GRE_DIR, NS_GET_IID(nsIFile), getter_AddRefs(greDir));
      if (NS_SUCCEEDED(rv)) {
        nsCString path;
        greDir->GetNativePath(path);
# if defined(OS_LINUX) || defined(OS_BSD)
#  if defined(MOZ_WIDGET_ANDROID) || defined(OS_BSD)
        path += "/lib";
#  endif  // MOZ_WIDGET_ANDROID
        const char *ld_library_path = PR_GetEnv("LD_LIBRARY_PATH");
        nsCString new_ld_lib_path;
        if (ld_library_path && *ld_library_path) {
            new_ld_lib_path.Assign(path.get());
            new_ld_lib_path.AppendLiteral(":");
            new_ld_lib_path.Append(ld_library_path);
            newEnvVars["LD_LIBRARY_PATH"] = new_ld_lib_path.get();
        } else {
            newEnvVars["LD_LIBRARY_PATH"] = path.get();
        }
# elif OS_MACOSX
        newEnvVars["DYLD_LIBRARY_PATH"] = path.get();
        // XXX DYLD_INSERT_LIBRARIES should only be set when launching a plugin
        //     process, and has no effect on other subprocesses (the hooks in
        //     libplugin_child_interpose.dylib become noops).  But currently it
        //     gets set when launching any kind of subprocess.
        //
        // Trigger "dyld interposing" for the dylib that contains
        // plugin_child_interpose.mm.  This allows us to hook OS calls in the
        // plugin process (ones that don't work correctly in a background
        // process).  Don't break any other "dyld interposing" that has already
        // been set up by whatever may have launched the browser.
        const char* prevInterpose = PR_GetEnv("DYLD_INSERT_LIBRARIES");
        nsCString interpose;
        if (prevInterpose) {
          interpose.Assign(prevInterpose);
          interpose.AppendLiteral(":");
        }
        interpose.Append(path.get());
        interpose.AppendLiteral("/libplugin_child_interpose.dylib");
        newEnvVars["DYLD_INSERT_LIBRARIES"] = interpose.get();
# endif  // OS_LINUX
      }
    }
  }
#endif  // OS_LINUX || OS_MACOSX

  FilePath exePath;
  GetPathToBinary(exePath);

#ifdef MOZ_WIDGET_ANDROID
  // The java wrapper unpacks this for us but can't make it executable
  chmod(exePath.value().c_str(), 0700);
  int cacheCount = 0;
  const struct lib_cache_info * cache = getLibraryCache();
  nsCString cacheStr;
  while (cache &&
         cacheCount++ < MAX_LIB_CACHE_ENTRIES &&
         strlen(cache->name)) {
    mFileMap.push_back(std::pair<int,int>(cache->fd, cache->fd));
    cacheStr.Append(cache->name);
    cacheStr.AppendPrintf(":%d;", cache->fd);
    cache++;
  }
  // fill the last arg with something if there's no cache
  if (cacheStr.IsEmpty())
    cacheStr.AppendLiteral("-");
#endif  // MOZ_WIDGET_ANDROID

#ifdef ANDROID
  // Remap the Android property workspace to a well-known int,
  // and update the environment to reflect the new value for the
  // child process.
  const char *apws = getenv("ANDROID_PROPERTY_WORKSPACE");
  if (apws) {
    int fd = atoi(apws);
    mFileMap.push_back(std::pair<int, int>(fd, kMagicAndroidSystemPropFd));

    char buf[32];
    char *szptr = strchr(apws, ',');

    snprintf(buf, sizeof(buf), "%d%s", kMagicAndroidSystemPropFd, szptr);
    newEnvVars["ANDROID_PROPERTY_WORKSPACE"] = buf;
  }
#endif  // ANDROID

#ifdef MOZ_WIDGET_GONK
  if (const char *ldPreloadPath = getenv("LD_PRELOAD")) {
    newEnvVars["LD_PRELOAD"] = ldPreloadPath;
  }
#endif // MOZ_WIDGET_GONK

  // remap the IPC socket fd to a well-known int, as the OS does for
  // STDOUT_FILENO, for example
  int srcChannelFd, dstChannelFd;
  channel().GetClientFileDescriptorMapping(&srcChannelFd, &dstChannelFd);
  mFileMap.push_back(std::pair<int,int>(srcChannelFd, dstChannelFd));

  // no need for kProcessChannelID, the child process inherits the
  // other end of the socketpair() from us

  std::vector<std::string> childArgv;

  childArgv.push_back(exePath.value());

  childArgv.insert(childArgv.end(), aExtraOpts.begin(), aExtraOpts.end());

  if (Omnijar::IsInitialized()) {
    // Make sure that child processes can find the omnijar
    // See XRE_InitCommandLine in nsAppRunner.cpp
    nsAutoCString path;
    nsCOMPtr<nsIFile> file = Omnijar::GetPath(Omnijar::GRE);
    if (file && NS_SUCCEEDED(file->GetNativePath(path))) {
      childArgv.push_back("-greomni");
      childArgv.push_back(path.get());
    }
    file = Omnijar::GetPath(Omnijar::APP);
    if (file && NS_SUCCEEDED(file->GetNativePath(path))) {
      childArgv.push_back("-appomni");
      childArgv.push_back(path.get());
    }
  }

  childArgv.push_back(pidstring);

#if defined(MOZ_CRASHREPORTER)
#  if defined(OS_LINUX) || defined(OS_BSD)
  int childCrashFd, childCrashRemapFd;
  if (!CrashReporter::CreateNotificationPipeForChild(
        &childCrashFd, &childCrashRemapFd))
    return false;
  if (0 <= childCrashFd) {
    mFileMap.push_back(std::pair<int,int>(childCrashFd, childCrashRemapFd));
    // "true" == crash reporting enabled
    childArgv.push_back("true");
  }
  else {
    // "false" == crash reporting disabled
    childArgv.push_back("false");
  }
#  elif defined(MOZ_WIDGET_COCOA)
  childArgv.push_back(CrashReporter::GetChildNotificationPipe());
#  endif  // OS_LINUX
#endif

#ifdef MOZ_WIDGET_COCOA
  // Add a mach port to the command line so the child can communicate its
  // 'task_t' back to the parent.
  //
  // Put a random number into the channel name, so that a compromised renderer
  // can't pretend being the child that's forked off.
  std::string mach_connection_name = StringPrintf("org.mozilla.machname.%d",
                                                  base::RandInt(0, std::numeric_limits<int>::max()));
  childArgv.push_back(mach_connection_name.c_str());
#endif

  childArgv.push_back(childProcessType);

#ifdef MOZ_WIDGET_ANDROID
  childArgv.push_back(cacheStr.get());
#endif

  base::LaunchApp(childArgv, mFileMap,
#if defined(OS_LINUX) || defined(OS_MACOSX) || defined(OS_BSD)
                  newEnvVars, privs,
#endif
                  false, &process, arch);

#ifdef MOZ_WIDGET_COCOA
  // Wait for the child process to send us its 'task_t' data.
  const int kTimeoutMs = 10000;

  MachReceiveMessage child_message;
  ReceivePort parent_recv_port(mach_connection_name.c_str());
  kern_return_t err = parent_recv_port.WaitForMessage(&child_message, kTimeoutMs);
  if (err != KERN_SUCCESS) {
    std::string errString = StringPrintf("0x%x %s", err, mach_error_string(err));
    LOG(ERROR) << "parent WaitForMessage() failed: " << errString;
    return false;
  }

  task_t child_task = child_message.GetTranslatedPort(0);
  if (child_task == MACH_PORT_NULL) {
    LOG(ERROR) << "parent GetTranslatedPort(0) failed.";
    return false;
  }

  if (child_message.GetTranslatedPort(1) == MACH_PORT_NULL) {
    LOG(ERROR) << "parent GetTranslatedPort(1) failed.";
    return false;
  }
  MachPortSender parent_sender(child_message.GetTranslatedPort(1));

  MachSendMessage parent_message(/* id= */0);
  if (!parent_message.AddDescriptor(bootstrap_port)) {
    LOG(ERROR) << "parent AddDescriptor(" << bootstrap_port << ") failed.";
    return false;
  }

  err = parent_sender.SendMessage(parent_message, kTimeoutMs);
  if (err != KERN_SUCCESS) {
    std::string errString = StringPrintf("0x%x %s", err, mach_error_string(err));
    LOG(ERROR) << "parent SendMessage() failed: " << errString;
    return false;
  }
#endif

//--------------------------------------------------
#elif defined(OS_WIN)

  FilePath exePath;
  GetPathToBinary(exePath);

  CommandLine cmdLine(exePath.ToWStringHack());
  cmdLine.AppendSwitchWithValue(switches::kProcessChannelID, channel_id());

  for (std::vector<std::string>::iterator it = aExtraOpts.begin();
       it != aExtraOpts.end();
       ++it) {
      cmdLine.AppendLooseValue(UTF8ToWide(*it));
  }

  cmdLine.AppendLooseValue(std::wstring(mGroupId.get()));

  if (Omnijar::IsInitialized()) {
    // Make sure the child process can find the omnijar
    // See XRE_InitCommandLine in nsAppRunner.cpp
    nsAutoString path;
    nsCOMPtr<nsIFile> file = Omnijar::GetPath(Omnijar::GRE);
    if (file && NS_SUCCEEDED(file->GetPath(path))) {
      cmdLine.AppendLooseValue(UTF8ToWide("-greomni"));
      cmdLine.AppendLooseValue(path.get());
    }
    file = Omnijar::GetPath(Omnijar::APP);
    if (file && NS_SUCCEEDED(file->GetPath(path))) {
      cmdLine.AppendLooseValue(UTF8ToWide("-appomni"));
      cmdLine.AppendLooseValue(path.get());
    }
  }

  cmdLine.AppendLooseValue(UTF8ToWide(pidstring));

#if defined(MOZ_CRASHREPORTER)
  cmdLine.AppendLooseValue(
    UTF8ToWide(CrashReporter::GetChildNotificationPipe()));
#endif

  cmdLine.AppendLooseValue(UTF8ToWide(childProcessType));

  base::LaunchApp(cmdLine, false, false, &process);

#else
#  error Sorry
#endif

  if (!process) {
    MonitorAutoLock lock(mMonitor);
    mProcessState = PROCESS_ERROR;
    lock.Notify();
    return false;
  }
  // NB: on OS X, we block much longer than we need to in order to
  // reach this call, waiting for the child process's task_t.  The
  // best way to fix that is to refactor this file, hard.
  SetHandle(process);
#if defined(MOZ_WIDGET_COCOA)
  mChildTask = child_task;
#endif

  OpenPrivilegedHandle(base::GetProcId(process));
  {
    MonitorAutoLock lock(mMonitor);
    mProcessState = PROCESS_CREATED;
    lock.Notify();
  }

  return true;
}
bool
GeckoChildProcessHost::PerformAsyncLaunchInternal(std::vector<std::string>& aExtraOpts, base::ProcessArchitecture arch)
{
  // We rely on the fact that InitializeChannel() has already been processed
  // on the IO thread before this point is reached.
  if (!GetChannel()) {
    return false;
  }

  base::ProcessHandle process = 0;

  // send the child the PID so that it can open a ProcessHandle back to us.
  // probably don't want to do this in the long run
  char pidstring[32];
  SprintfLiteral(pidstring,"%d", base::Process::Current().pid());

  const char* const childProcessType =
      XRE_ChildProcessTypeToString(mProcessType);

//--------------------------------------------------
#if defined(OS_POSIX)
  // For POSIX, we have to be extremely anal about *not* using
  // std::wstring in code compiled with Mozilla's -fshort-wchar
  // configuration, because chromium is compiled with -fno-short-wchar
  // and passing wstrings from one config to the other is unsafe.  So
  // we split the logic here.

#if defined(OS_LINUX) || defined(OS_MACOSX) || defined(OS_BSD) || defined(OS_SOLARIS)
  base::environment_map newEnvVars;
  ChildPrivileges privs = mPrivileges;
  if (privs == base::PRIVILEGES_DEFAULT ||
      privs == base::PRIVILEGES_FILEREAD) {
    privs = DefaultChildPrivileges();
  }

#if defined(MOZ_WIDGET_GTK)
  if (mProcessType == GeckoProcessType_Content) {
    // disable IM module to avoid sandbox violation
    newEnvVars["GTK_IM_MODULE"] = "gtk-im-context-simple";

    // Disable ATK accessibility code in content processes because it conflicts
    // with the sandbox, and we proxy that information through the main process
    // anyway.
    newEnvVars["NO_AT_BRIDGE"] = "1";
  }
#endif

  // XPCOM may not be initialized in some subprocesses.  We don't want
  // to initialize XPCOM just for the directory service, especially
  // since LD_LIBRARY_PATH is already set correctly in subprocesses
  // (meaning that we don't need to set that up in the environment).
  if (ShouldHaveDirectoryService()) {
    MOZ_ASSERT(gGREBinPath);
    nsCString path;
    NS_CopyUnicodeToNative(nsDependentString(gGREBinPath), path);
# if defined(OS_LINUX) || defined(OS_BSD)
    const char *ld_library_path = PR_GetEnv("LD_LIBRARY_PATH");
    nsCString new_ld_lib_path(path.get());

#  if (MOZ_WIDGET_GTK == 3)
    if (mProcessType == GeckoProcessType_Plugin) {
      new_ld_lib_path.Append("/gtk2:");
      new_ld_lib_path.Append(path.get());
    }
#endif
    if (ld_library_path && *ld_library_path) {
      new_ld_lib_path.Append(':');
      new_ld_lib_path.Append(ld_library_path);
    }
    newEnvVars["LD_LIBRARY_PATH"] = new_ld_lib_path.get();

# elif OS_MACOSX
    newEnvVars["DYLD_LIBRARY_PATH"] = path.get();
    // XXX DYLD_INSERT_LIBRARIES should only be set when launching a plugin
    //     process, and has no effect on other subprocesses (the hooks in
    //     libplugin_child_interpose.dylib become noops).  But currently it
    //     gets set when launching any kind of subprocess.
    //
    // Trigger "dyld interposing" for the dylib that contains
    // plugin_child_interpose.mm.  This allows us to hook OS calls in the
    // plugin process (ones that don't work correctly in a background
    // process).  Don't break any other "dyld interposing" that has already
    // been set up by whatever may have launched the browser.
    const char* prevInterpose = PR_GetEnv("DYLD_INSERT_LIBRARIES");
    nsCString interpose;
    if (prevInterpose && strlen(prevInterpose) > 0) {
      interpose.Assign(prevInterpose);
      interpose.Append(':');
    }
    interpose.Append(path.get());
    interpose.AppendLiteral("/libplugin_child_interpose.dylib");
    newEnvVars["DYLD_INSERT_LIBRARIES"] = interpose.get();
# endif  // OS_LINUX
  }
#endif  // OS_LINUX || OS_MACOSX

  FilePath exePath;
  BinaryPathType pathType = GetPathToBinary(exePath, mProcessType);

#ifdef MOZ_WIDGET_GONK
  if (const char *ldPreloadPath = getenv("LD_PRELOAD")) {
    newEnvVars["LD_PRELOAD"] = ldPreloadPath;
  }
#endif // MOZ_WIDGET_GONK

#if defined(XP_LINUX) && defined(MOZ_SANDBOX)
  // Preload libmozsandbox.so so that sandbox-related interpositions
  // can be defined there instead of in the executable.
  // (This could be made conditional on intent to use sandboxing, but
  // it's harmless for non-sandboxed processes.)
  {
    nsAutoCString preload;
    // Prepend this, because people can and do preload libpthread.
    // (See bug 1222500.)
    preload.AssignLiteral("libmozsandbox.so");
    if (const char* oldPreload = PR_GetEnv("LD_PRELOAD")) {
      // Doesn't matter if oldPreload is ""; extra separators are ignored.
      preload.Append(' ');
      preload.Append(oldPreload);
    }
    // Explicitly construct the std::string to make it clear that this
    // isn't retaining a pointer to the nsCString's buffer.
    newEnvVars["LD_PRELOAD"] = std::string(preload.get());
  }
#endif

  // remap the IPC socket fd to a well-known int, as the OS does for
  // STDOUT_FILENO, for example
  int srcChannelFd, dstChannelFd;
  channel().GetClientFileDescriptorMapping(&srcChannelFd, &dstChannelFd);
  mFileMap.push_back(std::pair<int,int>(srcChannelFd, dstChannelFd));

  // no need for kProcessChannelID, the child process inherits the
  // other end of the socketpair() from us

  std::vector<std::string> childArgv;

  childArgv.push_back(exePath.value());

  if (pathType == BinaryPathType::Self) {
    childArgv.push_back("-contentproc");
  }

  childArgv.insert(childArgv.end(), aExtraOpts.begin(), aExtraOpts.end());

  if (Omnijar::IsInitialized()) {
    // Make sure that child processes can find the omnijar
    // See XRE_InitCommandLine in nsAppRunner.cpp
    nsAutoCString path;
    nsCOMPtr<nsIFile> file = Omnijar::GetPath(Omnijar::GRE);
    if (file && NS_SUCCEEDED(file->GetNativePath(path))) {
      childArgv.push_back("-greomni");
      childArgv.push_back(path.get());
    }
    file = Omnijar::GetPath(Omnijar::APP);
    if (file && NS_SUCCEEDED(file->GetNativePath(path))) {
      childArgv.push_back("-appomni");
      childArgv.push_back(path.get());
    }
  }

  // Add the application directory path (-appdir path)
  AddAppDirToCommandLine(childArgv);

  childArgv.push_back(pidstring);

#if defined(MOZ_CRASHREPORTER)
#  if defined(OS_LINUX) || defined(OS_BSD) || defined(OS_SOLARIS)
  int childCrashFd, childCrashRemapFd;
  if (!CrashReporter::CreateNotificationPipeForChild(
        &childCrashFd, &childCrashRemapFd))
    return false;
  if (0 <= childCrashFd) {
    mFileMap.push_back(std::pair<int,int>(childCrashFd, childCrashRemapFd));
    // "true" == crash reporting enabled
    childArgv.push_back("true");
  }
  else {
    // "false" == crash reporting disabled
    childArgv.push_back("false");
  }
#  elif defined(MOZ_WIDGET_COCOA)
  childArgv.push_back(CrashReporter::GetChildNotificationPipe());
#  endif  // OS_LINUX || OS_BSD || OS_SOLARIS
#endif

#if defined(XP_LINUX) && defined(MOZ_SANDBOX)
  {
    int srcFd, dstFd;
    SandboxReporter::Singleton()
      ->GetClientFileDescriptorMapping(&srcFd, &dstFd);
    mFileMap.push_back(std::make_pair(srcFd, dstFd));
  }
#endif

#ifdef MOZ_WIDGET_COCOA
  // Add a mach port to the command line so the child can communicate its
  // 'task_t' back to the parent.
  //
  // Put a random number into the channel name, so that a compromised renderer
  // can't pretend being the child that's forked off.
  std::string mach_connection_name = StringPrintf("org.mozilla.machname.%d",
                                                  base::RandInt(0, std::numeric_limits<int>::max()));
  childArgv.push_back(mach_connection_name.c_str());
#endif

  childArgv.push_back(childProcessType);

#if defined(MOZ_WIDGET_ANDROID)
  LaunchAndroidService(childProcessType, childArgv, mFileMap, &process);
#else
  base::LaunchApp(childArgv, mFileMap,
#if defined(OS_LINUX) || defined(OS_MACOSX) || defined(OS_BSD) || defined(OS_SOLARIS)
                  newEnvVars, privs,
#endif
                  false, &process, arch);
#endif // defined(MOZ_WIDGET_ANDROID)

  // We're in the parent and the child was launched. Close the child FD in the
  // parent as soon as possible, which will allow the parent to detect when the
  // child closes its FD (either due to normal exit or due to crash).
  GetChannel()->CloseClientFileDescriptor();

#ifdef MOZ_WIDGET_COCOA
  // Wait for the child process to send us its 'task_t' data.
  const int kTimeoutMs = 10000;

  MachReceiveMessage child_message;
  ReceivePort parent_recv_port(mach_connection_name.c_str());
  kern_return_t err = parent_recv_port.WaitForMessage(&child_message, kTimeoutMs);
  if (err != KERN_SUCCESS) {
    std::string errString = StringPrintf("0x%x %s", err, mach_error_string(err));
    CHROMIUM_LOG(ERROR) << "parent WaitForMessage() failed: " << errString;
    return false;
  }

  task_t child_task = child_message.GetTranslatedPort(0);
  if (child_task == MACH_PORT_NULL) {
    CHROMIUM_LOG(ERROR) << "parent GetTranslatedPort(0) failed.";
    return false;
  }

  if (child_message.GetTranslatedPort(1) == MACH_PORT_NULL) {
    CHROMIUM_LOG(ERROR) << "parent GetTranslatedPort(1) failed.";
    return false;
  }
  MachPortSender parent_sender(child_message.GetTranslatedPort(1));

  if (child_message.GetTranslatedPort(2) == MACH_PORT_NULL) {
    CHROMIUM_LOG(ERROR) << "parent GetTranslatedPort(2) failed.";
  }
  auto* parent_recv_port_memory_ack = new MachPortSender(child_message.GetTranslatedPort(2));

  if (child_message.GetTranslatedPort(3) == MACH_PORT_NULL) {
    CHROMIUM_LOG(ERROR) << "parent GetTranslatedPort(3) failed.";
  }
  auto* parent_send_port_memory = new MachPortSender(child_message.GetTranslatedPort(3));

  MachSendMessage parent_message(/* id= */0);
  if (!parent_message.AddDescriptor(MachMsgPortDescriptor(bootstrap_port))) {
    CHROMIUM_LOG(ERROR) << "parent AddDescriptor(" << bootstrap_port << ") failed.";
    return false;
  }

  auto* parent_recv_port_memory = new ReceivePort();
  if (!parent_message.AddDescriptor(MachMsgPortDescriptor(parent_recv_port_memory->GetPort()))) {
    CHROMIUM_LOG(ERROR) << "parent AddDescriptor(" << parent_recv_port_memory->GetPort() << ") failed.";
    return false;
  }

  auto* parent_send_port_memory_ack = new ReceivePort();
  if (!parent_message.AddDescriptor(MachMsgPortDescriptor(parent_send_port_memory_ack->GetPort()))) {
    CHROMIUM_LOG(ERROR) << "parent AddDescriptor(" << parent_send_port_memory_ack->GetPort() << ") failed.";
    return false;
  }

  err = parent_sender.SendMessage(parent_message, kTimeoutMs);
  if (err != KERN_SUCCESS) {
    std::string errString = StringPrintf("0x%x %s", err, mach_error_string(err));
    CHROMIUM_LOG(ERROR) << "parent SendMessage() failed: " << errString;
    return false;
  }

  SharedMemoryBasic::SetupMachMemory(process, parent_recv_port_memory, parent_recv_port_memory_ack,
                                     parent_send_port_memory, parent_send_port_memory_ack, false);

#endif

//--------------------------------------------------
#elif defined(OS_WIN)

  FilePath exePath;
  BinaryPathType pathType = GetPathToBinary(exePath, mProcessType);

  CommandLine cmdLine(exePath.ToWStringHack());

  if (pathType == BinaryPathType::Self) {
    cmdLine.AppendLooseValue(UTF8ToWide("-contentproc"));
  }

  cmdLine.AppendSwitchWithValue(switches::kProcessChannelID, channel_id());

  for (std::vector<std::string>::iterator it = aExtraOpts.begin();
       it != aExtraOpts.end();
       ++it) {
      cmdLine.AppendLooseValue(UTF8ToWide(*it));
  }

  if (Omnijar::IsInitialized()) {
    // Make sure the child process can find the omnijar
    // See XRE_InitCommandLine in nsAppRunner.cpp
    nsAutoString path;
    nsCOMPtr<nsIFile> file = Omnijar::GetPath(Omnijar::GRE);
    if (file && NS_SUCCEEDED(file->GetPath(path))) {
      cmdLine.AppendLooseValue(UTF8ToWide("-greomni"));
      cmdLine.AppendLooseValue(path.get());
    }
    file = Omnijar::GetPath(Omnijar::APP);
    if (file && NS_SUCCEEDED(file->GetPath(path))) {
      cmdLine.AppendLooseValue(UTF8ToWide("-appomni"));
      cmdLine.AppendLooseValue(path.get());
    }
  }

#if defined(XP_WIN) && defined(MOZ_SANDBOX)
  bool shouldSandboxCurrentProcess = false;

  // XXX: Bug 1124167: We should get rid of the process specific logic for
  // sandboxing in this class at some point. Unfortunately it will take a bit
  // of reorganizing so I don't think this patch is the right time.
  switch (mProcessType) {
    case GeckoProcessType_Content:
#if defined(MOZ_CONTENT_SANDBOX)
      if (mSandboxLevel > 0 &&
          !PR_GetEnv("MOZ_DISABLE_CONTENT_SANDBOX")) {
        // For now we treat every failure as fatal in SetSecurityLevelForContentProcess
        // and just crash there right away. Should this change in the future then we
        // should also handle the error here.
        mSandboxBroker.SetSecurityLevelForContentProcess(mSandboxLevel,
                                                         mPrivileges);
        shouldSandboxCurrentProcess = true;
      }
#endif // MOZ_CONTENT_SANDBOX
      break;
    case GeckoProcessType_Plugin:
      if (mSandboxLevel > 0 &&
          !PR_GetEnv("MOZ_DISABLE_NPAPI_SANDBOX")) {
        bool ok = mSandboxBroker.SetSecurityLevelForPluginProcess(mSandboxLevel);
        if (!ok) {
          return false;
        }
        shouldSandboxCurrentProcess = true;
      }
      break;
    case GeckoProcessType_IPDLUnitTest:
      // XXX: We don't sandbox this process type yet
      break;
    case GeckoProcessType_GMPlugin:
      if (!PR_GetEnv("MOZ_DISABLE_GMP_SANDBOX")) {
        // The Widevine CDM on Windows can only load at USER_RESTRICTED,
        // not at USER_LOCKDOWN. So look in the command line arguments
        // to see if we're loading the path to the Widevine CDM, and if
        // so use sandbox level USER_RESTRICTED instead of USER_LOCKDOWN.
        bool isWidevine = std::any_of(aExtraOpts.begin(), aExtraOpts.end(),
          [](const std::string arg) { return arg.find("gmp-widevinecdm") != std::string::npos; });
        auto level = isWidevine ? SandboxBroker::Restricted : SandboxBroker::LockDown;
        bool ok = mSandboxBroker.SetSecurityLevelForGMPlugin(level);
        if (!ok) {
          return false;
        }
        shouldSandboxCurrentProcess = true;
      }
      break;
    case GeckoProcessType_GPU:
      if (mSandboxLevel > 0 && !PR_GetEnv("MOZ_DISABLE_GPU_SANDBOX")) {
        // For now we treat every failure as fatal in SetSecurityLevelForGPUProcess
        // and just crash there right away. Should this change in the future then we
        // should also handle the error here.
        mSandboxBroker.SetSecurityLevelForGPUProcess(mSandboxLevel);
        shouldSandboxCurrentProcess = true;
      }
      break;
    case GeckoProcessType_Default:
    default:
      MOZ_CRASH("Bad process type in GeckoChildProcessHost");
      break;
  };

  if (shouldSandboxCurrentProcess) {
    for (auto it = mAllowedFilesRead.begin();
         it != mAllowedFilesRead.end();
         ++it) {
      mSandboxBroker.AllowReadFile(it->c_str());
    }

    for (auto it = mAllowedFilesReadWrite.begin();
         it != mAllowedFilesReadWrite.end();
         ++it) {
      mSandboxBroker.AllowReadWriteFile(it->c_str());
    }

    for (auto it = mAllowedDirectories.begin();
         it != mAllowedDirectories.end();
         ++it) {
      mSandboxBroker.AllowDirectory(it->c_str());
    }
  }
#endif // XP_WIN && MOZ_SANDBOX

  // Add the application directory path (-appdir path)
  AddAppDirToCommandLine(cmdLine);

  // XXX Command line params past this point are expected to be at
  // the end of the command line string, and in a specific order.
  // See XRE_InitChildProcess in nsEmbedFunction.

  // Win app model id
  cmdLine.AppendLooseValue(mGroupId.get());

  // Process id
  cmdLine.AppendLooseValue(UTF8ToWide(pidstring));

#if defined(MOZ_CRASHREPORTER)
  cmdLine.AppendLooseValue(
    UTF8ToWide(CrashReporter::GetChildNotificationPipe()));
#endif

  // Process type
  cmdLine.AppendLooseValue(UTF8ToWide(childProcessType));

#if defined(XP_WIN) && defined(MOZ_SANDBOX)
  if (shouldSandboxCurrentProcess) {
    if (mSandboxBroker.LaunchApp(cmdLine.program().c_str(),
                                 cmdLine.command_line_string().c_str(),
                                 mEnableSandboxLogging,
                                 &process)) {
      EnvironmentLog("MOZ_PROCESS_LOG").print(
        "==> process %d launched child process %d (%S)\n",
        base::GetCurrentProcId(), base::GetProcId(process),
        cmdLine.command_line_string().c_str());
    }
  } else
#endif
  {
    base::LaunchApp(cmdLine, false, false, &process);

#ifdef MOZ_SANDBOX
    // We need to be able to duplicate handles to some types of non-sandboxed
    // child processes.
    if (mProcessType == GeckoProcessType_Content ||
        mProcessType == GeckoProcessType_GPU ||
        mProcessType == GeckoProcessType_GMPlugin) {
      if (!mSandboxBroker.AddTargetPeer(process)) {
        NS_WARNING("Failed to add content process as target peer.");
      }
    }
#endif
  }

#else
#  error Sorry
#endif

  if (!process) {
    return false;
  }
  // NB: on OS X, we block much longer than we need to in order to
  // reach this call, waiting for the child process's task_t.  The
  // best way to fix that is to refactor this file, hard.
#if defined(MOZ_WIDGET_COCOA)
  mChildTask = child_task;
#endif

  if (!OpenPrivilegedHandle(base::GetProcId(process))
#ifdef XP_WIN
      // If we failed in opening the process handle, try harder by duplicating
      // one.
      && !::DuplicateHandle(::GetCurrentProcess(), process,
                            ::GetCurrentProcess(), &mChildProcessHandle,
                            PROCESS_DUP_HANDLE | PROCESS_TERMINATE |
                            PROCESS_QUERY_INFORMATION | PROCESS_VM_READ |
                            SYNCHRONIZE,
                            FALSE, 0)
#endif
     ) {
    MOZ_CRASH("cannot open handle to child process");
  }
  MonitorAutoLock lock(mMonitor);
  mProcessState = PROCESS_CREATED;
  lock.Notify();

  return true;
}
bool
GeckoChildProcessHost::PerformAsyncLaunch(std::vector<std::string> aExtraOpts)
{
  // FIXME/cjones: make this work from non-IO threads, too

  // We rely on the fact that InitializeChannel() has already been processed
  // on the IO thread before this point is reached.
  if (!GetChannel()) {
    return false;
  }

  base::ProcessHandle process;

  // send the child the PID so that it can open a ProcessHandle back to us.
  // probably don't want to do this in the long run
  char pidstring[32];
  PR_snprintf(pidstring, sizeof(pidstring) - 1,
	      "%ld", base::Process::Current().pid());

  const char* const childProcessType =
      XRE_ChildProcessTypeToString(mProcessType);

//--------------------------------------------------
#if defined(OS_POSIX)
  // For POSIX, we have to be extremely anal about *not* using
  // std::wstring in code compiled with Mozilla's -fshort-wchar
  // configuration, because chromium is compiled with -fno-short-wchar
  // and passing wstrings from one config to the other is unsafe.  So
  // we split the logic here.

  FilePath exePath;
#ifdef OS_LINUX
  base::environment_map newEnvVars;
#endif

  nsCOMPtr<nsIProperties> directoryService(do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID));
  nsCOMPtr<nsIFile> greDir;
  nsresult rv = directoryService->Get(NS_GRE_DIR, NS_GET_IID(nsIFile), getter_AddRefs(greDir));
  if (NS_SUCCEEDED(rv)) {
    nsCString path;
    greDir->GetNativePath(path);
    exePath = FilePath(path.get());
#ifdef OS_LINUX
    newEnvVars["LD_LIBRARY_PATH"] = path.get();
#endif
  }
  else {
    exePath = FilePath(CommandLine::ForCurrentProcess()->argv()[0]);
    exePath = exePath.DirName();
  }
  exePath = exePath.AppendASCII(MOZ_CHILD_PROCESS_NAME);

  // remap the IPC socket fd to a well-known int, as the OS does for
  // STDOUT_FILENO, for example
  int srcChannelFd, dstChannelFd;
  channel().GetClientFileDescriptorMapping(&srcChannelFd, &dstChannelFd);
  mFileMap.push_back(std::pair<int,int>(srcChannelFd, dstChannelFd));

  // no need for kProcessChannelID, the child process inherits the
  // other end of the socketpair() from us

  std::vector<std::string> childArgv;

  childArgv.push_back(exePath.value());

  childArgv.insert(childArgv.end(), aExtraOpts.begin(), aExtraOpts.end());

  childArgv.push_back(pidstring);
  childArgv.push_back(childProcessType);

#if defined(MOZ_CRASHREPORTER)
  int childCrashFd, childCrashRemapFd;
  if (!CrashReporter::CreateNotificationPipeForChild(
        &childCrashFd, &childCrashRemapFd))
    return false;
  if (0 <= childCrashFd) {
    mFileMap.push_back(std::pair<int,int>(childCrashFd, childCrashRemapFd));
    // "true" == crash reporting enabled
    childArgv.push_back("true");
  }
  else {
    // "false" == crash reporting disabled
    childArgv.push_back("false");
  }
#endif

  base::LaunchApp(childArgv, mFileMap,
#ifdef OS_LINUX
                  newEnvVars,
#endif
                  false, &process);

//--------------------------------------------------
#elif defined(OS_WIN)

  FilePath exePath =
    FilePath::FromWStringHack(CommandLine::ForCurrentProcess()->program());
  exePath = exePath.DirName();

  exePath = exePath.AppendASCII(MOZ_CHILD_PROCESS_NAME);

  CommandLine cmdLine(exePath.ToWStringHack());
  cmdLine.AppendSwitchWithValue(switches::kProcessChannelID, channel_id());

  for (std::vector<std::string>::iterator it = aExtraOpts.begin();
       it != aExtraOpts.end();
       ++it) {
      cmdLine.AppendLooseValue(UTF8ToWide(*it));
  }

  cmdLine.AppendLooseValue(UTF8ToWide(pidstring));
  cmdLine.AppendLooseValue(UTF8ToWide(childProcessType));
#if defined(MOZ_CRASHREPORTER)
  cmdLine.AppendLooseValue(
    UTF8ToWide(CrashReporter::GetChildNotificationPipe()));
#endif

  base::LaunchApp(cmdLine, false, false, &process);

#else
#  error Sorry
#endif

  if (!process) {
    return false;
  }
  SetHandle(process);

  return true;
}