Unifying ChildProcessLauncher across platforms.

content/browser/child_process_launcher_helper.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_BROWSER_CHILD_PROCESS_LAUNCHER_HELPER_H_
+#define CONTENT_BROWSER_CHILD_PROCESS_LAUNCHER_HELPER_H_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/process/kill.h"
+#include "base/process/process.h"
+#include "build/build_config.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/common/result_codes.h"
+#include "mojo/edk/embedder/embedder.h"
+#include "mojo/edk/embedder/scoped_platform_handle.h"
+
+#if defined(OS_WIN)
+#include "sandbox/win/src/sandbox_types.h"
+#else
+#include "content/public/browser/file_descriptor_info.h"
+#endif
+
+#if defined(OS_LINUX)
+#include "content/public/common/zygote_handle.h"
+#endif
+
+namespace base {
+class CommandLine;
+}
+
+namespace content {
+
+class ChildProcessLauncher;
+class FileDescriptorInfo;
+class SandboxedProcessLauncherDelegate;
+
+namespace internal {
+
+
+#if defined(OS_WIN)
+using FileMappedForLaunch = base::HandlesToInheritVector;
+#else
+using FileMappedForLaunch = FileDescriptorInfo;
+#endif
+
+// ChildProcessLauncherHelper is used by ChildProcessLauncher to start a
+// process. Since ChildProcessLauncher can be deleted by its client at any time,
+// this class is used to keep state as the process is started asynchronously.
+// It also contains the platform specific pieces.
+class ChildProcessLauncherHelper :
+    public base::RefCountedThreadSafe<ChildProcessLauncherHelper> {
+ public:
+  // Abstraction around a process required to deal in a platform independent way
+  // between Linux (which can use zygotes) and the other platforms.
+  struct Process {
+    Process() {}
+    Process(Process&& other);
+    ~Process() {}
+    Process& operator=(Process&& other);
+
+    base::Process process;
+
+#if defined(OS_LINUX)
+    ZygoteHandle zygote = nullptr;
+#endif
+  };
+
+  ChildProcessLauncherHelper(
+      int child_process_id,
+      BrowserThread::ID client_thread_id,
+      std::unique_ptr<base::CommandLine> command_line,
+      std::unique_ptr<SandboxedProcessLauncherDelegate> delegate,
+      const base::WeakPtr<ChildProcessLauncher>& child_process_launcher,
+      bool terminate_on_shutdown);
+
+  // The methods below are defined in the order they are called.
+
+  // Starts the flow of launching the process.
+  void StartLaunchOnClientThread();
+
+  // Platform specific.
+  void BeforeLaunchOnClientThread();
+
+  // Called in to give implementors a chance at creating a server pipe.
+  // Platform specific.
+  mojo::edk::ScopedPlatformHandle PrepareMojoPipeHandlesOnClientThread();
+
+  // Returns the list of files that should be mapped in the child process.
+  // Platform specific.
+  std::unique_ptr<FileMappedForLaunch> GetFilesToMap();
+
+  // Platform specific.
+  void BeforeLaunchOnLauncherThread(
+      const FileMappedForLaunch& files_to_register,
+      base::LaunchOptions* options);
+
+  // Does the actual starting of the process.
+  // |is_synchronous_launch| is set to false if the starting of the process is
+  // asynchonous (this is the case on Android), in which case the returned
+  // Process is not valid (and PostLaunchOnLauncherThread() will provide the
+  // process once it is available).
+  // Platform specific.
+  ChildProcessLauncherHelper::Process LaunchProcessOnLauncherThread(
+      const base::LaunchOptions& options,
+      std::unique_ptr<FileMappedForLaunch> files_to_register,
+      bool* is_synchronous_launch,
+      int* launch_result);
+
+  // Called right after the process has been launched, whether it was created
+  // yet or not.
+  // Platform specific.
+  void AfterLaunchOnLauncherThread(
+      const ChildProcessLauncherHelper::Process& process,
+      const base::LaunchOptions& options);
+
+  // Called once the process has been created, successfully or not.
+  // If |post_launch_on_client_thread_called| is false,
+  // this calls PostLaunchOnClientThread on the client thread.
+  void PostLaunchOnLauncherThread(ChildProcessLauncherHelper::Process process,
+                                  int launch_result,
+                                  bool post_launch_on_client_thread_called);
+
+  // Note that this could be called before PostLaunchOnLauncherThread() is
+  // called.
+  void PostLaunchOnClientThread(ChildProcessLauncherHelper::Process process,
+                                int error_code);
+
+  int client_thread_id() const { return client_thread_id_; }
+
+  // Returns the termination status and sets |exit_code| if non null.
+  // See ChildProcessLauncher::GetChildTerminationStatus for more info.
+  static base::TerminationStatus GetTerminationStatus(
+      const ChildProcessLauncherHelper::Process& process,
+      bool known_dead,
+      int* exit_code);
+
+  // Terminates |process|.
+  // Returns true if the process was stopped, false if the process had not been
+  // started yet or could not be stopped.
+  // Note that |exit_code| and |wait| are not used on Android.
+  static bool TerminateProcess(const base::Process& process,
+                               int exit_code,
+                               bool wait);
+
+  // Terminates the process with the normal exit code and ensures it has been
+  // stopped. By returning a normal exit code this ensures UMA won't treat this
+  // as a crash.
+  // Returns immediately and perform the work on the launcher thread.
+  static void ForceNormalProcessTerminationAsync(
+      ChildProcessLauncherHelper::Process process);
+
+  static void SetProcessBackgroundedOnLauncherThread(
+      base::Process process, bool background);
+
+ private:
+  friend class base::RefCountedThreadSafe<ChildProcessLauncherHelper>;
+
+  ~ChildProcessLauncherHelper();
+
+  void LaunchOnLauncherThread();
+
+  const mojo::edk::PlatformHandle& mojo_client_handle() const {
+    return mojo_client_handle_.get();
+  }
+  base::CommandLine* command_line() { return command_line_.get(); }
+  int child_process_id() const { return child_process_id_; }
+
+  std::string GetProcessType();
+
+  static void ForceNormalProcessTerminationSync(
+      ChildProcessLauncherHelper::Process process);
+
+  const int child_process_id_;
+  const BrowserThread::ID client_thread_id_;
+  base::TimeTicks begin_launch_time_;
+  std::unique_ptr<base::CommandLine> command_line_;
+  std::unique_ptr<SandboxedProcessLauncherDelegate> delegate_;
+  base::WeakPtr<ChildProcessLauncher> child_process_launcher_;
+  mojo::edk::ScopedPlatformHandle mojo_client_handle_;
+  mojo::edk::ScopedPlatformHandle mojo_server_handle_;
+  bool terminate_on_shutdown_;
+};
+
+}  // namespace internal
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_CHILD_PROCESS_LAUNCHER_HELPER_H_