Refactor ChildProcess and related classes to create a framework outside of br...

base/mp/mp_child_process_launcher.cc

+// Copyright (c) 2009 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/mp/mp_child_process_launcher.h"
+
+#include "base/command_line.h"
+#include "base/logging.h"
+#include "base/scoped_ptr.h"
+#include "base/thread.h"
+
+#if defined(OS_POSIX)
+#include "base/global_descriptors_posix.h"
+#endif
+
+namespace base {
+
+// Having the functionality of MpChildProcessLauncher be in an internal
+// ref counted object allows us to automatically terminate the process when the
+// parent class destructs, while still holding on to state that we need.
+class MpChildProcessLauncher::Context
+    : public base::RefCountedThreadSafe<MpChildProcessLauncher::Context> {
+ public:
+  Context(MpChildProcessContext* process_context)
+      : process_context_(process_context),
+        starting_(true)
+#if defined(OS_LINUX)
+        , zygote_(false)
+#endif
+        {
+  }
+
+  void Launch(
+#if defined(OS_WIN)
+      const FilePath& exposed_dir,
+#elif defined(OS_POSIX)
+      bool use_zygote,
+      const base::environment_vector& environ,
+      int ipcfd,
+#endif
+      CommandLine* cmd_line,
+      Client* client) {
+    client_ = client;
+
+    CHECK(process_context_->GetCurrentThreadIdentifier(&client_thread_id_));
+
+    process_context_->PostProcessLauncherTask(
+        FROM_HERE,
+        NewRunnableMethod(
+            this,
+            &Context::LaunchInternal,
+#if defined(OS_WIN)
+            exposed_dir,
+#elif defined(POSIX)
+            use_zygote,
+            environ,
+            ipcfd,
+#endif
+            cmd_line));
+  }
+
+  void ResetClient() {
+    // No need for locking as this function gets called on the same thread that
+    // client_ would be used.
+    CHECK(process_context_->CurrentlyOnThread(client_thread_id_));
+    client_ = NULL;
+  }
+
+ private:
+  friend class base::RefCountedThreadSafe<MpChildProcessLauncher::Context>;
+  friend class MpChildProcessLauncher;
+
+  ~Context() {
+    Terminate();
+  }
+
+  void LaunchInternal(
+#if defined(OS_WIN)
+      const FilePath& exposed_dir,
+#elif defined(OS_POSIX)
+      bool use_zygote,
+      const base::environment_vector& env,
+      int ipcfd,
+#endif
+      CommandLine* cmd_line) {
+    scoped_ptr<CommandLine> cmd_line_deleter(cmd_line);
+    base::ProcessHandle handle = process_context_->StartProcess(
+#if defined(OS_WIN)
+      exposed_dir,
+#elif defined(OS_POSIX)
+      use_zygote,
+      cenv,
+      ipcfd,
+#endif
+      cmd_line);
+
+    process_context_->PostTask(
+        client_thread_id_,
+        FROM_HERE,
+        NewRunnableMethod(
+            this,
+            &MpChildProcessLauncher::Context::Notify,
+#if defined(OS_LINUX)
+            use_zygote,
+#endif
+            handle));
+  }
+
+  void Notify(
+#if defined(OS_LINUX)
+      bool zygote,
+#endif
+      base::ProcessHandle handle) {
+    starting_ = false;
+    process_.set_handle(handle);
+#if defined(OS_LINUX)
+    zygote_ = zygote;
+#endif
+    if (client_) {
+      client_->OnProcessLaunched();
+    } else {
+      Terminate();
+    }
+  }
+
+  void Terminate() {
+    if (!process_.handle())
+      return;
+
+    // On Posix, EnsureProcessTerminated can lead to 2 seconds of sleep!  So
+    // don't this on the UI/IO threads.
+    process_context_->PostProcessLauncherTask(
+        FROM_HERE,
+        NewRunnableFunction(
+            &MpChildProcessLauncher::Context::TerminateInternal,
+#if defined(OS_LINUX)
+            zygote_,
+#endif
+            process_context_,
+            process_.handle()));
+    process_.set_handle(base::kNullProcessHandle);
+  }
+
+  static void TerminateInternal(
+#if defined(OS_LINUX)
+      bool zygote,
+#endif
+      MpChildProcessContext* process_context,
+      base::ProcessHandle handle) {
+    base::Process process(handle);
+     // 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(process_context->GetNormalExitResultCode());
+    process_context->EnsureProcessTerminated(handle);
+    process.Close();
+  }
+
+  MpChildProcessContext* process_context_;
+  Client* client_;
+  int client_thread_id_;
+  base::Process process_;
+  bool starting_;
+
+#if defined(OS_LINUX)
+  bool zygote_;
+#endif
+};
+
+
+MpChildProcessLauncher::MpChildProcessLauncher(
+#if defined(OS_WIN)
+    const FilePath& exposed_dir,
+#elif defined(OS_POSIX)
+    bool use_zygote,
+    const base::environment_vector& environ,
+    int ipcfd,
+#endif
+    CommandLine* cmd_line,
+    MpChildProcessContext* context,
+    Client* client) : process_context_(context) {
+  context_ = new Context(process_context_);
+  context_->Launch(
+#if defined(OS_WIN)
+      exposed_dir,
+#elif defined(OS_POSIX)
+      use_zygote,
+      environ,
+      ipcfd,
+#endif
+      cmd_line,
+      client);
+}
+
+MpChildProcessLauncher::~MpChildProcessLauncher() {
+  context_->ResetClient();
+}
+
+bool MpChildProcessLauncher::IsStarting() {
+  return context_->starting_;
+}
+
+base::ProcessHandle MpChildProcessLauncher::GetHandle() {
+  DCHECK(!context_->starting_);
+  return context_->process_.handle();
+}
+
+bool MpChildProcessLauncher::DidProcessCrash() {
+  bool did_crash, child_exited;
+  base::ProcessHandle handle = context_->process_.handle();
+  did_crash = process_context_->CheckProcessCrash(
+      &child_exited,
+#if defined(OS_POSIX)
+      context_->zygote_,
+#endif
+      handle);
+
+  // POSIX: If the process crashed, then the kernel closed the socket for it
+  // and so the child has already died by the time we get here. Since
+  // DidProcessCrash called waitpid with WNOHANG, it'll reap the process.
+  // However, if DidProcessCrash didn't reap the child, we'll need to in
+  // Terminate via ProcessWatcher. So we can't close the handle here.
+  if (child_exited)
+    context_->process_.Close();
+
+  return did_crash;
+}
+
+void MpChildProcessLauncher::SetProcessBackgrounded(bool background) {
+  DCHECK(!context_->starting_);
+  context_->process_.SetProcessBackgrounded(background);
+}
+
+}  // namespace base