content/renderer/renderer_main.cc

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <stddef.h>

#include <optional>
#include <utility>

#include "base/allocator/partition_alloc_support.h"
#include "base/base_switches.h"
#include "base/command_line.h"
#include "base/debug/debugger.h"
#include "base/debug/leak_annotations.h"
#include "base/feature_list.h"
#include "base/i18n/rtl.h"
#include "base/message_loop/message_pump.h"
#include "base/message_loop/message_pump_type.h"
#include "base/metrics/histogram_functions.h"
#include "base/pending_task.h"
#include "base/process/current_process.h"
#include "base/run_loop.h"
#include "base/strings/string_number_conversions.h"
#include "base/system/sys_info.h"
#include "base/task/sequence_manager/sequence_manager.h"
#include "base/task/thread_pool.h"
#include "base/threading/hang_watcher.h"
#include "base/threading/platform_thread.h"
#include "base/threading/platform_thread_metrics.h"
#include "base/time/time.h"
#include "base/timer/hi_res_timer_manager.h"
#include "base/trace_event/trace_event.h"
#include "build/build_config.h"
#include "components/performance_manager/scenario_api/performance_scenario_memory.h"
#include "content/child/memory_coordinator/child_memory_coordinator.h"
#include "content/common/content_constants_internal.h"
#include "content/common/content_switches_internal.h"
#include "content/common/features.h"
#include "content/common/skia_utils.h"
#include "content/public/common/content_switches.h"
#include "content/public/common/main_function_params.h"
#include "content/public/renderer/content_renderer_client.h"
#include "content/public/renderer/render_thread.h"
#include "content/renderer/memory_coordinator/last_resort_gc_policy.h"
#include "content/renderer/render_process_impl.h"
#include "content/renderer/render_thread_impl.h"
#include "content/renderer/renderer_main_platform_delegate.h"
#include "media/media_buildflags.h"
#include "mojo/public/cpp/bindings/direct_receiver.h"
#include "mojo/public/cpp/bindings/interface_endpoint_client.h"
#include "mojo/public/cpp/bindings/mojo_buildflags.h"
#include "sandbox/policy/switches.h"
#include "services/tracing/public/cpp/trace_startup.h"
#include "skia/ext/font_utils.h"
#include "third_party/blink/public/common/features.h"
#include "third_party/blink/public/platform/platform.h"
#include "third_party/blink/public/platform/scheduler/web_thread_scheduler.h"
#include "third_party/skia/include/core/SkFontMgr.h"
#include "third_party/webrtc_overrides/init_webrtc.h"  // nogncheck
#include "ui/base/ui_base_switches.h"

#if BUILDFLAG(IS_WIN)
#include "components/startup_metric_utils/renderer/startup_metric_utils.h"
#endif  // BUILDFLAG(IS_WIN)

#if BUILDFLAG(IS_ANDROID)
#include "base/android/library_loader/library_loader_hooks.h"
#endif  // BUILDFLAG(IS_ANDROID)

#if BUILDFLAG(IS_MAC)
#include <Carbon/Carbon.h>
#include <signal.h>
#include <unistd.h>

#include "base/apple/scoped_nsautorelease_pool.h"
#include "base/message_loop/message_pump_apple.h"
#include "third_party/blink/public/web/web_view.h"
#endif  // BUILDFLAG(IS_MAC)

#if BUILDFLAG(IS_CHROMEOS)
#include "chromeos/system/core_scheduling.h"
#endif  // BUILDFLAG(IS_CHROMEOS)

#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
#include "content/child/sandboxed_process_thread_type_handler.h"
#endif

#if BUILDFLAG(MOJO_RANDOM_DELAYS_ENABLED)
#include "mojo/public/cpp/bindings/lib/test_random_mojo_delays.h"
#endif

namespace content {
namespace {

// This function provides some ways to test crash and assertion handling
// behavior of the renderer.
void HandleRendererErrorTestParameters(const base::CommandLine& command_line) {
  if (command_line.HasSwitch(switches::kWaitForDebugger))
    base::debug::WaitForDebugger(60, true);

  if (command_line.HasSwitch(switches::kRendererStartupDialog))
    WaitForDebugger("Renderer");
}

std::unique_ptr<base::MessagePump> CreateMainThreadMessagePump() {
  std::unique_ptr<base::MessagePump> message_pump;
#if BUILDFLAG(IS_FUCHSIA)
  // Allow FIDL APIs on renderer main thread.
  message_pump = base::MessagePump::Create(base::MessagePumpType::IO);
#else
  message_pump = base::MessagePump::Create(base::MessagePumpType::DEFAULT);
#endif
  return message_pump;
}

void LogTimeToStartRunLoop(const base::CommandLine& command_line,
                           base::TimeTicks run_loop_start_time) {
#if BUILDFLAG(IS_WIN)
  startup_metric_utils::GetRenderer().RecordRunLoopStart(run_loop_start_time);
#endif

  if (!command_line.HasSwitch(switches::kRendererProcessLaunchTimeTicks)) {
    return;
  }

  const std::string launch_time_delta_micro_as_string =
      command_line.GetSwitchValueASCII(
          switches::kRendererProcessLaunchTimeTicks);
  int64_t launch_time_delta_micro;
  if (!base::StringToInt64(launch_time_delta_micro_as_string,
                           &launch_time_delta_micro)) {
    return;
  }
  const base::TimeDelta delta = run_loop_start_time.since_origin() -
                                base::Microseconds(launch_time_delta_micro);
  base::UmaHistogramTimes("Renderer.BrowserLaunchToRunLoopStart", delta);
}

}  // namespace

// mainline routine for running as the Renderer process
int RendererMain(MainFunctionParams parameters) {
  // Don't use the TRACE_EVENT0 macro because the tracing infrastructure doesn't
  // expect synchronous events around the main loop of a thread.
  TRACE_EVENT_INSTANT("startup", "RendererMain");

#if BUILDFLAG(IS_MAC)
  // Declare that this process has CPU security mitigations enabled (see
  // RendererSandboxedProcessLauncherDelegate::EnableCpuSecurityMitigations).
  // This must be done before the first call to
  // base::SysInfo::NumberOfProcessors().
  base::SysInfo::SetCpuSecurityMitigationsEnabled();
#endif

  base::CurrentProcess::GetInstance().SetProcessType(
      base::CurrentProcessType::PROCESS_RENDERER);

  const base::CommandLine& command_line = *parameters.command_line;

#if BUILDFLAG(IS_MAC)
  base::apple::ScopedNSAutoreleasePool* pool = parameters.autorelease_pool;
#endif  // BUILDFLAG(IS_MAC)

#if BUILDFLAG(IS_CHROMEOS)
  // As the Zygote process starts up earlier than the browser process, it gets
  // its own locale (at login time for Chrome OS). So we have to set the ICU
  // default locale for the renderer process here.
  // ICU locale will be used for fallback font selection, etc.
  if (command_line.HasSwitch(switches::kLang)) {
    const std::string locale =
        command_line.GetSwitchValueASCII(switches::kLang);
    base::i18n::SetICUDefaultLocale(locale);
  }

  // When we start the renderer on ChromeOS if the system has core scheduling
  // available we want to turn it on.
  chromeos::system::EnableCoreSchedulingIfAvailable();
#endif  // BUILDFLAG(IS_CHROMEOS)

  InitializeSkia();

#if !BUILDFLAG(IS_WIN) && !BUILDFLAG(IS_LINUX) && !BUILDFLAG(IS_CHROMEOS)
  // On Linux, Windows, and ChromeOS, the font manager is overridden or
  // specially handled in RendererBlinkPlatformImpl(). On other platforms,
  // initialise the default one on a thread pool, to avoid blocking on it later.
  base::ThreadPool::PostTask(FROM_HERE,
                             base::BindOnce([] { skia::DefaultFontMgr(); }));
#endif

  // This function allows pausing execution using the --renderer-startup-dialog
  // flag allowing us to attach a debugger.
  // Do not move this function down since that would mean we can't easily debug
  // whatever occurs before it.
  HandleRendererErrorTestParameters(command_line);

  RendererMainPlatformDelegate platform(parameters);

  base::PlatformThread::SetName("CrRendererMain");
  mojo::InterfaceEndpointClient::SetThreadNameSuffixForMetrics("RendererMain");

  // Force main thread initialization. When the implementation is based on a
  // better means of determining which is the main thread, remove.
  RenderThread::IsMainThread();

  // This must be created before `main_thread_scheduler` because the scheduler
  // can install observers.
  performance_scenarios::ScopedScenarioObserverList scenario_observer_list;

  // This scope is used to reduce the number of stack frames needed to be
  // scanned during conservative stack scanning in cppgc. It allows us to skip
  // scanning the caller frames of this function.
  cppgc::StackStartMarker cppgc_stack_start_marker;
  blink::Platform::InitializeBlink(std::move(cppgc_stack_start_marker));
  std::unique_ptr<blink::scheduler::WebThreadScheduler> main_thread_scheduler =
      blink::scheduler::WebThreadScheduler::CreateMainThreadScheduler(
          CreateMainThreadMessagePump());
  platform.PlatformInitialize();

  // Initialize WebRTC before engaging the sandbox.
  // NOTE: On linux, this call could already have been made from
  // zygote_main_linux.cc.  However, calling multiple times from the same thread
  // is OK.
  InitializeWebRtcModuleBeforeSandbox();

  std::optional<LastResortGCPolicy> last_resort_gc_policy;
  if (base::FeatureList::IsEnabled(kMemoryCoordinatorLastResortGC)) {
    last_resort_gc_policy.emplace(ChildMemoryCoordinator::Get());
  }

  {
    content::ContentRendererClient* client = GetContentClient()->renderer();
    bool should_run_loop = true;
    bool need_sandbox =
        !command_line.HasSwitch(sandbox::policy::switches::kNoSandbox);

    if (!need_sandbox) {
      // The post-sandbox actions still need to happen at some point.
      if (client) {
        client->PostSandboxInitialized();
      }
    }

#if !BUILDFLAG(IS_WIN) && !BUILDFLAG(IS_MAC)
    // Sandbox is enabled before RenderProcess initialization on all platforms,
    // except Windows and Mac.
    // TODO(markus): Check if it is OK to remove ifdefs for Windows and Mac.
    if (need_sandbox) {
      should_run_loop = platform.EnableSandbox();
      need_sandbox = false;
      if (client) {
        client->PostSandboxInitialized();
      }
    }
#endif

#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
    // Thread type delegate of the process should be registered before
    // first thread type change in ChildProcess constructor.
    // It also needs to be registered before the process has multiple threads,
    // which may race with application of the sandbox.
    SandboxedProcessThreadTypeHandler::Create();
#endif

    // Startup tracing creates a tracing thread, which is incompatible on
    // platforms that require single-threaded sandbox initialization. In these
    // cases, startup tracing is initialized right after sandbox initialization.
    if (parameters.needs_startup_tracing_after_sandbox_init) {
      tracing::InitTracingPostFeatureList(/*enable_consumer=*/false,
                                          /*will_trace_thread_restart=*/false);
      TRACE_EVENT_INSTANT("startup", "RendererMain",
                          "needs_startup_tracing_after_sandbox_init", true);
    }

    std::unique_ptr<RenderProcess> render_process = RenderProcessImpl::Create();
    // It's not a memory leak since RenderThread has the same lifetime
    // as a renderer process.
    base::RunLoop run_loop;
    new RenderThreadImpl(run_loop.QuitClosure(),
                         std::move(main_thread_scheduler));

#if BUILDFLAG(IS_WIN)
    // Now that Mojo is initialized, but before the sandbox is enabled, set up
    // DirectReceiver.
    if (base::FeatureList::IsEnabled(
            blink::features::kDirectCompositorThreadIpc)) {
      // Pre-initialize a transport since a feature that will use it is enabled.
      mojo::CreateDirectReceiverTransportBeforeSandbox();
    }
#endif  // BUILDFLAG(IS_WIN)

    if (need_sandbox) {
      should_run_loop = platform.EnableSandbox();
      if (client) {
        client->PostSandboxInitialized();
      }
    }

    // Start the HangWatcher now that the sandbox is engaged, if it hasn't
    // already been started.
    if (base::HangWatcher::IsEnabled() &&
        !base::HangWatcher::GetInstance()->IsStarted()) {
      DCHECK(parameters.hang_watcher_not_started_time.has_value());
      base::TimeDelta uncovered_hang_watcher_time =
          base::TimeTicks::Now() -
          parameters.hang_watcher_not_started_time.value();
      base::UmaHistogramTimes(
          "HangWatcher.RendererProcess.UncoveredStartupTime",
          uncovered_hang_watcher_time);
      base::HangWatcher::GetInstance()->Start();
    }

#if BUILDFLAG(IS_ANDROID)
    base::PlatformThreadPriorityMonitor::Get().RegisterCurrentThread(
        "RendererMain");
    base::PlatformThreadPriorityMonitor::Get().Start();
#endif  // BUILDFLAG(IS_ANDROID)

#if BUILDFLAG(MOJO_RANDOM_DELAYS_ENABLED)
    mojo::BeginRandomMojoDelays();
#endif

    base::allocator::PartitionAllocSupport::Get()
        ->ReconfigureAfterTaskRunnerInit(switches::kRendererProcess);

    base::HighResolutionTimerManager hi_res_timer_manager;

    if (should_run_loop) {
#if BUILDFLAG(IS_MAC)
      if (pool)
        pool->Recycle();
#endif
      TRACE_EVENT_INSTANT("toplevel", "RendererMain.START_MSG_LOOP");
      const base::TimeTicks run_loop_start_time = base::TimeTicks::Now();
      RenderThreadImpl::current()->set_run_loop_start_time(run_loop_start_time);
      LogTimeToStartRunLoop(command_line, run_loop_start_time);
      run_loop.Run();
    }

#if defined(LEAK_SANITIZER)
    // Run leak detection before RenderProcessImpl goes out of scope. This helps
    // ignore shutdown-only leaks.
    __lsan_do_leak_check();
#endif
  }
  platform.PlatformUninitialize();
  return 0;
}

}  // namespace content