Unifying ChildProcessLauncher across platforms.

content/browser/child_process_launcher_linux.cc

+// Copyright 2016 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.
+
+#include "base/posix/global_descriptors.h"
+#include "content/browser/child_process_launcher.h"
+#include "content/browser/child_process_launcher_posix.h"
+#include "content/browser/renderer_host/render_sandbox_host_linux.h"
+#include "content/browser/zygote_host/zygote_communication_linux.h"
+#include "content/browser/zygote_host/zygote_host_impl_linux.h"
+#include "content/common/child_process_sandbox_support_impl_linux.h"
+#include "content/public/browser/content_browser_client.h"
+#include "content/public/browser/zygote_handle_linux.h"
+#include "content/public/common/content_client.h"
+#include "content/public/common/content_switches.h"
+#include "content/public/common/result_codes.h"
+#include "content/public/common/sandboxed_process_launcher_delegate.h"
+#include "gin/v8_initializer.h"
+
+namespace content {
+
+mojo::edk::ScopedPlatformHandle
+ChildProcessLauncher::Helper::PrepareMojoPipeHandlesOnClientThread() {
+  DCHECK_CURRENTLY_ON(client_thread_id_);
+  return mojo::edk::ScopedPlatformHandle();
+}
+
+void ChildProcessLauncher::Helper::BeforeLaunchOnClientThread() {
+  DCHECK_CURRENTLY_ON(client_thread_id_);
+}
+
+bool ChildProcessLauncher::Helper::ShouldForkAsZygote() {
+    return !base::CommandLine::ForCurrentProcess()->HasSwitch(
+        switches::kNoZygote) && delegate_->GetZygote() != nullptr;
+}
+
+ZygoteHandle ChildProcessLauncher::Helper::ForkAsZygote(
+        std::unique_ptr<FileDescriptorInfo> files_to_register,
+        base::Process* process) {
+  ZygoteHandle* zygote_handle = delegate_->GetZygote();
+  DCHECK(zygote_handle);  // This should only be called when ZygoteSuppported()
+                          // returned true.
+
+  // This code runs on the PROCESS_LAUNCHER thread so race conditions are not
+  // an issue with the lazy initialization.
+  if (*zygote_handle == nullptr) {
+    *zygote_handle = CreateZygote();
+  }
+  base::ProcessHandle handle = (*zygote_handle)->ForkRequest(
+      command_line()->argv(),
+      std::move(files_to_register),
+      GetProcessType());
+  *process = base::Process(handle);
+
+  return *zygote_handle;
+}
+
+std::unique_ptr<FileDescriptorInfo>
+ChildProcessLauncher::Helper::GetFilesToMap() {
+  DCHECK_CURRENTLY_ON(BrowserThread::PROCESS_LAUNCHER);
+
+  std::unique_ptr<FileDescriptorInfo> files_to_register =
+      CreateDefaultPosixFilesToMap(*command_line(), child_process_id(),
+                                   mojo_client_handle());
+
+#if defined(V8_USE_EXTERNAL_STARTUP_DATA)
+  bool snapshot_loaded = false;
+  base::MemoryMappedFile::Region unused_region;
+  base::PlatformFile natives_pf =
+      gin::V8Initializer::GetOpenNativesFileForChildProcesses(&unused_region);
+  DCHECK_GE(natives_pf, 0);
+  files_to_register->Share(kV8NativesDataDescriptor, natives_pf);
+
+  base::MemoryMappedFile::Region snapshot_region;
+  base::PlatformFile snapshot_pf =
+      gin::V8Initializer::GetOpenSnapshotFileForChildProcesses(
+          &snapshot_region);
+  // Failure to load the V8 snapshot is not necessarily an error. V8 can start
+  // up (slower) without the snapshot.
+  if (snapshot_pf != -1) {
+    snapshot_loaded = true;
+    files_to_register->Share(kV8SnapshotDataDescriptor, snapshot_pf);
+  }
+  if (GetProcessType() != switches::kZygoteProcess) {
+    command_line()->AppendSwitch(::switches::kV8NativesPassedByFD);
+    if (snapshot_loaded) {
+      command_line()->AppendSwitch(::switches::kV8SnapshotPassedByFD);
+    }
+  }
+#endif  // defined(V8_USE_EXTERNAL_STARTUP_DATA)
+
+  return files_to_register;
+}
+
+void ChildProcessLauncher::Helper::BeforeLaunchOnLauncherThread(
+    const FileDescriptorInfo& files_to_register,
+    base::LaunchOptions* options) {
+  // Convert FD mapping to FileHandleMappingVector
+  std::unique_ptr<base::FileHandleMappingVector> fds_to_map =
+      files_to_register.GetMappingWithIDAdjustment(
+          base::GlobalDescriptors::kBaseDescriptor);
+
+  if (GetProcessType() == switches::kRendererProcess) {
+    const int sandbox_fd =
+        RenderSandboxHostLinux::GetInstance()->GetRendererSocket();
+    fds_to_map->push_back(std::make_pair(sandbox_fd, GetSandboxFD()));
+  }
+
+  options->environ = delegate_->GetEnvironment();
+  // fds_to_remap will de deleted in AfterLaunchOnLauncherThread() below.
+  options->fds_to_remap = fds_to_map.release();
+}
+
+base::Process ChildProcessLauncher::Helper::LaunchProcessOnLauncherThread(
+    const base::LaunchOptions& options,
+    FileDescriptorInfo* files_to_register,
+    bool* is_synchronous_launch,
+    int* launch_result) {
+  *is_synchronous_launch = true;
+  base::Process process = base::LaunchProcess(*command_line(), options);
+  *launch_result = process.IsValid() ? LAUNCH_RESULT_SUCCESS
+                                     : LAUNCH_RESULT_FAILURE;
+  return process;
+}
+
+void ChildProcessLauncher::Helper::AfterLaunchOnLauncherThread(
+    const base::Process& process,
+    const base::LaunchOptions& options) {
+  delete options.fds_to_remap;
+}
+
+void ChildProcessLauncher::UpdateTerminationStatus(bool known_dead) {
+  DCHECK(CalledOnValidThread());
+  if (zygote_) {
+    termination_status_ = zygote_->GetTerminationStatus(
+        process_.Handle(), known_dead, &exit_code_);
+  } else if (known_dead) {
+    termination_status_ =
+        base::GetKnownDeadTerminationStatus(process_.Handle(), &exit_code_);
+  } else {
+    termination_status_ =
+      base::GetTerminationStatus(process_.Handle(), &exit_code_);
+  }
+}
+
+// static
+bool ChildProcessLauncher::TerminateProcess(
+    const base::Process& process, int exit_code, bool wait) {
+  return process.Terminate(exit_code, wait);
+}
+
+// static
+void ChildProcessLauncher::TerminateOnLauncherThread(
+    ZygoteHandle zygote, base::Process process) {
+  DCHECK_CURRENTLY_ON(BrowserThread::PROCESS_LAUNCHER);
+  // Client has gone away, so just kill the process.  Using exit code 0
+  // means that UMA won't treat this as a crash.
+  process.Terminate(RESULT_CODE_NORMAL_EXIT, false);
+  // On POSIX, we must additionally reap the child.
+  if (zygote) {
+    // If the renderer was created via a zygote, we have to proxy the reaping
+    // through the zygote process.
+    zygote->EnsureProcessTerminated(process.Handle());
+  } else {
+    base::EnsureProcessTerminated(std::move(process));
+  }
+}
+
+// static
+void ChildProcessLauncher::SetProcessBackgroundedOnLauncherThread(
+      base::Process process, bool background) {
+  DCHECK_CURRENTLY_ON(BrowserThread::PROCESS_LAUNCHER);
+  if (process.CanBackgroundProcesses())
+    process.SetProcessBackgrounded(background);
+}
+
+}  // namespace content