components/crash/content/browser/child_exit_observer_android.h

// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_CRASH_CONTENT_BROWSER_CHILD_EXIT_OBSERVER_ANDROID_H_
#define COMPONENTS_CRASH_CONTENT_BROWSER_CHILD_EXIT_OBSERVER_ANDROID_H_

#include <map>
#include <memory>
#include <vector>

#include "base/android/application_status_listener.h"
#include "base/android/child_process_binding_types.h"
#include "base/process/process.h"
#include "base/scoped_multi_source_observation.h"
#include "base/scoped_observation.h"
#include "base/synchronization/lock.h"
#include "components/crash/content/browser/crash_handler_host_linux.h"
#include "content/public/browser/browser_child_process_observer.h"
#include "content/public/browser/child_process_host.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_process_host_creation_observer.h"
#include "content/public/browser/render_process_host_observer.h"
#include "content/public/common/process_type.h"
#include "third_party/blink/public/common/oom_intervention/oom_intervention_types.h"

namespace content {
struct ChildProcessTerminationInfo;
}

namespace crash_reporter {

// This class centralises the observation of child processes for the
// purpose of reacting to child process crashes.
// The ChildExitObserver instance exists on the browser main thread.
class ChildExitObserver : public content::BrowserChildProcessObserver,
                          public content::RenderProcessHostCreationObserver,
                          public content::RenderProcessHostObserver,
                          public crashpad::CrashHandlerHost::Observer {
 public:
  struct TerminationInfo {
    // Used to indicate the child did not receive a crash signal.
    static constexpr int kInvalidSigno = -1;

    TerminationInfo();
    TerminationInfo(const TerminationInfo& other);
    TerminationInfo& operator=(const TerminationInfo& other);

    bool is_crashed() const {
      return crash_signo != kInvalidSigno || threw_exception_during_init;
    }

    int process_host_id = content::ChildProcessHost::kInvalidUniqueID;
    // |pid| may not be valid if termination happens before the process has
    // finished launching.
    base::ProcessHandle pid = base::kNullProcessHandle;
    content::ProcessType process_type = content::PROCESS_TYPE_UNKNOWN;
    base::android::ApplicationState app_state =
        base::android::APPLICATION_STATE_UNKNOWN;

    // The crash signal the child process received before it exited.
    int crash_signo = kInvalidSigno;

    // True if this is intentional shutdown of the child process, e.g. when a
    // tab is closed. Some fields below may not be populated if this is true.
    bool normal_termination = false;

    // Renderer process shutdown started by RenderProcessHost::Shutdown.
    bool renderer_shutdown_requested = false;

    // Values from ChildProcessTerminationInfo.
    // Note base::TerminationStatus and exit_code are missing intentionally
    // because those fields hold no useful information on Android.
    base::android::ChildBindingState binding_state =
        base::android::ChildBindingState::UNBOUND;
    bool threw_exception_during_init = false;
    bool was_killed_intentionally_by_browser = false;

    // Applies to renderer process only. Generally means renderer is hosting
    // one or more visible tabs.
    bool renderer_has_visible_clients = false;

    // Applies to renderer process only. Generally true indicates that there
    // is no main frame being hosted in this renderer process. Note there are
    // edge cases, eg if an invisible main frame and a visible sub frame from
    // different tabs are sharing the same renderer, then this is false.
    bool renderer_was_subframe = false;

    // Applies to renderer process only. This metrics contains the information
    // about virtual address space OOM situation, private memory footprint,
    // swap size, vm size and the estimation of blink memory usage.
    blink::OomInterventionMetrics blink_oom_metrics;

    // Applies to renderer process only. Whether the killed process is a
    // spare renderer.
    bool is_spare_renderer = false;

    // Applies to renderer process only. Whether there is any spare renderer
    // in the browser when the process is killed. Always true if the killed
    // process is a spare renderer.
    bool has_spare_renderer = false;
  };

  // ChildExitObserver client interface.
  // Client methods will be called synchronously in the order in which
  // clients were registered. It is the implementer's responsibility
  // to post tasks to the appropriate threads if required (and be
  // aware that this may break ordering guarantees).
  //
  // Note, callbacks are generated for both "child processes" which are hosted
  // by BrowserChildProcessHosts, and "render processes" which are hosted by
  // RenderProcessHosts. The unique ids correspond to either the
  // ChildProcessData::id, or the RenderProcessHost::ID, depending on the
  // process type.
  class Client {
   public:
    // OnChildExit is called on the UI thread.
    // OnChildExit may be called twice for the same process.
    virtual void OnChildExit(const TerminationInfo& info) = 0;

    virtual ~Client() = default;
  };
  ChildExitObserver();
  ~ChildExitObserver() override;

  ChildExitObserver(const ChildExitObserver&) = delete;
  ChildExitObserver& operator=(const ChildExitObserver&) = delete;

  void RegisterClient(std::unique_ptr<Client> client);

  // crashpad::CrashHandlerHost::Observer
  void ChildReceivedCrashSignal(base::ProcessId pid, int signo) override;

  // content::RenderProcessHostCreationObserver implementation.
  void OnRenderProcessHostCreated(content::RenderProcessHost* host) override;

 private:
  // content::BrowserChildProcessObserver implementation:
  void BrowserChildProcessHostDisconnected(
      const content::ChildProcessData& data) override;
  void BrowserChildProcessKilled(
      const content::ChildProcessData& data,
      const content::ChildProcessTerminationInfo& info) override;

  // RenderProcessHostObserver implementation.
  // RenderProcessHostDestroyed() corresponds to death of an underlying
  // RenderProcess. RenderProcessExited() corresponds to when the
  // RenderProcessHost's lifetime is ending. Ideally, we'd only listen to the
  // former, but if the RenderProcessHost is destroyed before the RenderProcess,
  // then the former is never observed.
  void RenderProcessExited(
      content::RenderProcessHost* host,
      const content::ChildProcessTerminationInfo& info) override;
  void RenderProcessHostDestroyed(content::RenderProcessHost* host) override;

  // Processes RenderProcessHost exited and destroyed events. |content_info| is
  // expected to be null for destroyed events.
  void ProcessRenderProcessHostLifetimeEndEvent(
      content::RenderProcessHost* rph,
      const content::ChildProcessTerminationInfo* content_info);

  // Called on child process exit (including crash).
  void OnChildExit(TerminationInfo* info);

  base::Lock registered_clients_lock_;
  std::vector<std::unique_ptr<Client>> registered_clients_;

  // process_host_id to process id. Only accessed on the UI thread.
  std::map<int, base::ProcessHandle> process_host_id_to_pid_;

  // Key is process_host_id. Only used for BrowserChildProcessHost. Only
  // accessed on the UI thread.
  std::map<int, TerminationInfo> browser_child_process_info_;

  base::ScopedMultiSourceObservation<content::RenderProcessHost,
                                     content::RenderProcessHostObserver>
      render_process_host_observation_{this};

  base::Lock crash_signals_lock_;
  std::map<base::ProcessId, int> child_pid_to_crash_signal_;
  base::ScopedObservation<crashpad::CrashHandlerHost,
                          crashpad::CrashHandlerHost::Observer>
      scoped_crash_handler_host_observation_{this};
};

}  // namespace crash_reporter

#endif  // COMPONENTS_CRASH_CONTENT_BROWSER_CHILD_EXIT_OBSERVER_ANDROID_H_