content/browser/browser_child_process_host_impl.h

// 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.

#ifndef CONTENT_BROWSER_BROWSER_CHILD_PROCESS_HOST_IMPL_H_
#define CONTENT_BROWSER_BROWSER_CHILD_PROCESS_HOST_IMPL_H_

#include <stdint.h>

#include <list>
#include <memory>

#include "base/memory/raw_ptr.h"
#include "base/memory/ref_counted.h"
#include "base/memory/unsafe_shared_memory_region.h"
#include "base/memory/weak_ptr.h"
#include "base/process/process.h"
#include "base/synchronization/waitable_event_watcher.h"
#include "base/task/single_thread_task_runner.h"
#include "build/build_config.h"
#include "components/metrics/histogram_child_process.h"
#include "content/browser/child_process_host_impl.h"
#include "content/browser/child_process_launcher.h"
#include "content/browser/tracing/tracing_service_controller.h"
#include "content/common/buildflags.h"
#include "content/common/child_process.mojom.h"
#include "content/public/browser/browser_child_process_host.h"
#include "content/public/browser/child_process_data.h"
#include "content/public/browser/child_process_host.h"
#include "content/public/browser/child_process_host_delegate.h"
#include "mojo/public/cpp/bindings/binder_map.h"
#include "mojo/public/cpp/system/invitation.h"
#include "services/resource_coordinator/public/mojom/memory_instrumentation/memory_instrumentation.mojom.h"

#if BUILDFLAG(IS_WIN)
#include "base/win/object_watcher.h"
#endif

#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
#include "content/browser/child_thread_type_switcher_linux.h"
#endif  // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)

namespace base {
class CommandLine;
}

namespace tracing {
class SystemTracingService;
}

namespace content {

class BrowserChildProcessHostIterator;
class BrowserChildProcessObserver;
class BrowserMessageFilter;

// Plugins/workers and other child processes that live on the IO thread use this
// class. RenderProcessHostImpl is the main exception that doesn't use this
/// class because it lives on the UI thread.
class BrowserChildProcessHostImpl
    : public BrowserChildProcessHost,
      public ChildProcessHostDelegate,
      public metrics::HistogramChildProcess,
#if BUILDFLAG(IS_WIN)
      public base::win::ObjectWatcher::Delegate,
#endif
      public ChildProcessLauncher::Client,
      public memory_instrumentation::mojom::CoordinatorConnector {
 public:
  // Constructs a process host with |ipc_mode| determining how IPC is done.
  BrowserChildProcessHostImpl(content::ProcessType process_type,
                              BrowserChildProcessHostDelegate* delegate,
                              ChildProcessHost::IpcMode ipc_mode);

  ~BrowserChildProcessHostImpl() override;

  // Terminates all child processes and deletes each BrowserChildProcessHost
  // instance.
  static void TerminateAll();

  // BrowserChildProcessHost implementation:
  bool Send(IPC::Message* message) override;
  void Launch(std::unique_ptr<SandboxedProcessLauncherDelegate> delegate,
              std::unique_ptr<base::CommandLine> cmd_line,
              bool terminate_on_shutdown) override;
  const ChildProcessData& GetData() override;
  ChildProcessHost* GetHost() override;
  ChildProcessTerminationInfo GetTerminationInfo(bool known_dead) override;
  std::unique_ptr<base::PersistentMemoryAllocator> TakeMetricsAllocator()
      override;
  void SetName(const std::u16string& name) override;
  void SetMetricsName(const std::string& metrics_name) override;
  void SetProcess(base::Process process) override;

  // ChildProcessHostDelegate implementation:
  void OnChannelInitialized(IPC::Channel* channel) override;
  void OnChildDisconnected() override;
  const base::Process& GetProcess() override;
  void BindHostReceiver(mojo::GenericPendingReceiver receiver) override;
  bool OnMessageReceived(const IPC::Message& message) override;
  void OnChannelConnected(int32_t peer_pid) override;
  void OnChannelError() override;
  void OnBadMessageReceived(const IPC::Message& message) override;

  // HistogramChildProcess implementation:
  void BindChildHistogramFetcherFactory(
      mojo::PendingReceiver<metrics::mojom::ChildHistogramFetcherFactory>
          factory) override;

  // Terminates the process and logs a stack trace after a bad message was
  // received from the child process.
  void TerminateOnBadMessageReceived(const std::string& error);

  // Removes this host from the host list. Calls ChildProcessHost::ForceShutdown
  void ForceShutdown();

#if BUILDFLAG(CONTENT_ENABLE_LEGACY_IPC)
  // Adds an IPC message filter.
  void AddFilter(BrowserMessageFilter* filter);
#endif

  // Same as Launch(), but the process is launched with preloaded files and file
  // descriptors containing in `file_data`.
  void LaunchWithFileData(
      std::unique_ptr<SandboxedProcessLauncherDelegate> delegate,
      std::unique_ptr<base::CommandLine> cmd_line,
      std::unique_ptr<ChildProcessLauncherFileData> file_data,
      bool terminate_on_shutdown);

  // Unlike Launch(), AppendExtraCommandLineSwitches will not be called
  // in this function. If AppendExtraCommandLineSwitches has been called before
  // reaching launch, call this function instead so the command line switches
  // won't be appended twice
  void LaunchWithoutExtraCommandLineSwitches(
      std::unique_ptr<SandboxedProcessLauncherDelegate> delegate,
      std::unique_ptr<base::CommandLine> cmd_line,
      std::unique_ptr<ChildProcessLauncherFileData> file_data,
      bool terminate_on_shutdown);

#if !BUILDFLAG(IS_ANDROID)
  void SetProcessPriority(base::Process::Priority priority);
#endif  // !BUILDFLAG(IS_ANDROID)

#if BUILDFLAG(IS_ANDROID)
  void EnableWarmUpConnection();
  void DumpProcessStack();
#endif

  BrowserChildProcessHostDelegate* delegate() const { return delegate_; }

  mojo::OutgoingInvitation* GetInProcessMojoInvitation() {
    in_process_ = true;
    return &child_process_host_->GetMojoInvitation().value();
  }

  mojom::ChildProcess* child_process() const {
    return static_cast<ChildProcessHostImpl*>(child_process_host_.get())
        ->child_process();
  }

  typedef std::list<raw_ptr<BrowserChildProcessHostImpl, CtnExperimental>>
      BrowserChildProcessList;

 private:
  friend class BrowserChildProcessHostIterator;
  friend class BrowserChildProcessObserver;

  void OnProcessConnected();

  static BrowserChildProcessList* GetIterator();

  static void AddObserver(BrowserChildProcessObserver* observer);
  static void RemoveObserver(BrowserChildProcessObserver* observer);

  // Creates the |metrics_allocator_|.
  void CreateMetricsAllocator();

  // Passes the |metrics_allocator_|, if any, to the managed process. This
  // requires the process to have been launched and the IPC channel to be
  // available.
  void ShareMetricsAllocatorToProcess();

  // ChildProcessLauncher::Client implementation.
  void OnProcessLaunched() override;
  void OnProcessLaunchFailed(int error_code) override;
#if BUILDFLAG(IS_ANDROID)
  bool CanUseWarmUpConnection() override;
#endif

  // memory_instrumentation::mojom::CoordinatorConnector implementation:
  void RegisterCoordinatorClient(
      mojo::PendingReceiver<memory_instrumentation::mojom::Coordinator>
          receiver,
      mojo::PendingRemote<memory_instrumentation::mojom::ClientProcess>
          client_process) override;

  // Returns true if the process has successfully launched. Must only be called
  // on the IO thread.
  bool IsProcessLaunched() const;

  static void OnMojoError(
      base::WeakPtr<BrowserChildProcessHostImpl> process,
      scoped_refptr<base::SingleThreadTaskRunner> task_runner,
      const std::string& error);
  static void TerminateProcessForBadMessage(
      base::WeakPtr<BrowserChildProcessHostImpl> process,
      const std::string& error);

#if BUILDFLAG(IS_WIN)
  // ObjectWatcher::Delegate implementation.
  void OnObjectSignaled(HANDLE object) override;
#endif

  ChildProcessData data_;
  std::string metrics_name_;
  raw_ptr<BrowserChildProcessHostDelegate> delegate_;
  std::unique_ptr<ChildProcessHost> child_process_host_;
  mojo::Receiver<memory_instrumentation::mojom::CoordinatorConnector>
      coordinator_connector_receiver_{this};
  mojo::BinderMapWithContext<BrowserChildProcessHost*> binder_map_;
  std::unique_ptr<ChildProcessLauncher> child_process_launcher_;

#if BUILDFLAG(IS_WIN)
  // Watches to see if the child process exits before the IPC channel has
  // been connected. Thereafter, its exit is determined by an error on the
  // IPC channel.
  base::win::ObjectWatcher early_exit_watcher_;
#endif

  // The memory allocator, if any, in which the process will write its metrics.
  std::unique_ptr<base::PersistentMemoryAllocator> metrics_allocator_;

  // The histogram shared memory region used to transmit metrics. The memory
  // region is allocated by the process host (this object) but ownership is
  // shared with the child process launcher/helper which runs, and is destroyed,
  // asynchronously. Depending on the feature configuration, either the host or
  // the launcher is responsible for passing the memory region to the child.
  // The destruction order of the host, launcher and child are indeterminate.
  scoped_refptr<base::RefCountedData<base::UnsafeSharedMemoryRegion>>
      metrics_shared_region_;

  // The tracing config memory region. Ownership of the memory region object is
  // shared with the child process launcher/helper which runs, and is destroyed,
  // asynchronously.
  scoped_refptr<base::RefCountedData<base::ReadOnlySharedMemoryRegion>>
      tracing_config_memory_region_;

  // The tracing output memory region to transmit traces. Ownership of the
  // memory region object is shared with the child process launcher/helper which
  // runs, and is destroyed, asynchronously.
  scoped_refptr<base::RefCountedData<base::UnsafeSharedMemoryRegion>>
      tracing_output_memory_region_;

  // Indicates if the main browser process is used instead of a dedicated child
  // process.
  bool in_process_ = false;

  // Indicates if legacy IPC is used to communicate with the child process. In
  // this mode, the BrowserChildProcessHost waits for OnChannelConnected() to be
  // called before sending the BrowserChildProcessLaunchedAndConnected
  // notification.
  bool has_legacy_ipc_channel_ = false;

  // Indicates if the IPC channel is connected. Always true when not using
  // legacy IPC.
  bool is_channel_connected_ = true;

  // Indicates if the BrowserChildProcessLaunchedAndConnected notification was
  // sent for this instance.
  bool launched_and_connected_ = false;

  // Whether the child process exited abnormally (killed or crashed).
  bool exited_abnormally_ = false;

#if BUILDFLAG(IS_ANDROID)
  // whether the child process can use pre-warmed up connection for better
  // performance.
  bool can_use_warm_up_connection_ = false;
#endif

  // Keeps this process registered with the tracing subsystem.
  std::unique_ptr<TracingServiceController::ClientRegistration>
      tracing_registration_;

#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_ANDROID)
  // For child process to connect to the system tracing service.
  std::unique_ptr<tracing::SystemTracingService> system_tracing_service_;
#endif

#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
  ChildThreadTypeSwitcher child_thread_type_switcher_;
#endif  // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)

  base::WeakPtrFactory<BrowserChildProcessHostImpl> weak_factory_{this};
};

}  // namespace content

#endif  // CONTENT_BROWSER_BROWSER_CHILD_PROCESS_HOST_IMPL_H_