// Copyright (c) 2012 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 "content/browser/utility_process_host_impl.h"

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/command_line.h"
#include "base/lazy_instance.h"
#include "base/message_loop/message_loop.h"
#include "base/run_loop.h"
#include "base/sequenced_task_runner.h"
#include "base/strings/utf_string_conversions.h"
#include "base/synchronization/lock.h"
#include "base/synchronization/waitable_event.h"
#include "content/browser/browser_child_process_host_impl.h"
#include "content/browser/renderer_host/render_process_host_impl.h"
#include "content/child/child_process.h"
#include "content/common/child_process_host_impl.h"
#include "content/common/utility_messages.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/content_browser_client.h"
#include "content/public/browser/utility_process_host_client.h"
#include "content/public/common/content_switches.h"
#include "content/public/common/process_type.h"
#include "content/utility/utility_thread_impl.h"
#include "ipc/ipc_switches.h"
#include "ui/base/ui_base_switches.h"

#if defined(OS_WIN)
#include "content/public/common/sandboxed_process_launcher_delegate.h"
#endif

namespace content {

#if defined(OS_WIN)
// NOTE: changes to this class need to be reviewed by the security team.
class UtilitySandboxedProcessLauncherDelegate
    : public SandboxedProcessLauncherDelegate {
 public:
  explicit UtilitySandboxedProcessLauncherDelegate(
    const base::FilePath& exposed_dir) : exposed_dir_(exposed_dir) {}
  virtual ~UtilitySandboxedProcessLauncherDelegate() {}

  virtual void PreSandbox(bool* disable_default_policy,
                          base::FilePath* exposed_dir) OVERRIDE {
    *exposed_dir = exposed_dir_;
  }

private:
  base::FilePath exposed_dir_;
};
#endif

// We want to ensure there's only one utility thread running at a time, as there
// are many globals used in the utility process.
static base::LazyInstance<base::Lock> g_one_utility_thread_lock;

// Single process not supported in multiple dll mode currently.
#if !defined(CHROME_MULTIPLE_DLL)
class UtilityMainThread : public base::Thread {
 public:
  UtilityMainThread(const std::string& channel_id)
      : Thread("Chrome_InProcUtilityThread"),
        channel_id_(channel_id) {
  }

  virtual ~UtilityMainThread() {
    Stop();
  }

 private:
  // base::Thread implementation:
  virtual void Init() OVERRIDE {
    // We need to return right away or else the main thread that started us will
    // hang.
    base::MessageLoop::current()->PostTask(
        FROM_HERE,
        base::Bind(&UtilityMainThread::InitInternal, base::Unretained(this)));
  }

  virtual void CleanUp() OVERRIDE {
    child_process_.reset();

    // See comment in RendererMainThread.
    SetThreadWasQuitProperly(true);
    g_one_utility_thread_lock.Get().Release();
  }

  void InitInternal() {
    g_one_utility_thread_lock.Get().Acquire();
    child_process_.reset(new ChildProcess());
    child_process_->set_main_thread(new UtilityThreadImpl(channel_id_));
  }

  std::string channel_id_;
  scoped_ptr<ChildProcess> child_process_;

  DISALLOW_COPY_AND_ASSIGN(UtilityMainThread);
};
#endif  // !CHROME_MULTIPLE_DLL

UtilityProcessHost* UtilityProcessHost::Create(
    UtilityProcessHostClient* client,
    base::SequencedTaskRunner* client_task_runner) {
  return new UtilityProcessHostImpl(client, client_task_runner);
}

UtilityProcessHostImpl::UtilityProcessHostImpl(
    UtilityProcessHostClient* client,
    base::SequencedTaskRunner* client_task_runner)
    : client_(client),
      client_task_runner_(client_task_runner),
      is_batch_mode_(false),
      is_mdns_enabled_(false),
      no_sandbox_(false),
#if defined(OS_LINUX)
      child_flags_(ChildProcessHost::CHILD_ALLOW_SELF),
#else
      child_flags_(ChildProcessHost::CHILD_NORMAL),
#endif
      use_linux_zygote_(false),
      started_(false) {
}

UtilityProcessHostImpl::~UtilityProcessHostImpl() {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  if (is_batch_mode_)
    EndBatchMode();
}

bool UtilityProcessHostImpl::Send(IPC::Message* message) {
  if (!StartProcess())
    return false;

  return process_->Send(message);
}

bool UtilityProcessHostImpl::StartBatchMode()  {
  CHECK(!is_batch_mode_);
  is_batch_mode_ = StartProcess();
  Send(new UtilityMsg_BatchMode_Started());
  return is_batch_mode_;
}

void UtilityProcessHostImpl::EndBatchMode()  {
  CHECK(is_batch_mode_);
  is_batch_mode_ = false;
  Send(new UtilityMsg_BatchMode_Finished());
}

void UtilityProcessHostImpl::SetExposedDir(const base::FilePath& dir) {
  exposed_dir_ = dir;
}

void UtilityProcessHostImpl::EnableMDns() {
  is_mdns_enabled_ = true;
}

void UtilityProcessHostImpl::DisableSandbox() {
  no_sandbox_ = true;
}

void UtilityProcessHostImpl::EnableZygote() {
  use_linux_zygote_ = true;
}

const ChildProcessData& UtilityProcessHostImpl::GetData() {
  return process_->GetData();
}

#if defined(OS_POSIX)

void UtilityProcessHostImpl::SetEnv(const base::EnvironmentVector& env) {
  env_ = env;
}

#endif  // OS_POSIX

bool UtilityProcessHostImpl::StartProcess() {
  if (started_)
    return true;
  started_ = true;

  if (is_batch_mode_)
    return true;

  // Name must be set or metrics_service will crash in any test which
  // launches a UtilityProcessHost.
  process_.reset(new BrowserChildProcessHostImpl(PROCESS_TYPE_UTILITY, this));
  process_->SetName(ASCIIToUTF16("utility process"));

  std::string channel_id = process_->GetHost()->CreateChannel();
  if (channel_id.empty())
    return false;

  // Single process not supported in multiple dll mode currently.
#if !defined(CHROME_MULTIPLE_DLL)
  if (RenderProcessHost::run_renderer_in_process()) {
    // See comment in RenderProcessHostImpl::Init() for the background on why we
    // support single process mode this way.
    in_process_thread_.reset(new UtilityMainThread(channel_id));
    in_process_thread_->Start();
  } else
#endif  // !CHROME_MULTIPLE_DLL
  {
    const CommandLine& browser_command_line = *CommandLine::ForCurrentProcess();
    int child_flags = child_flags_;

#if defined(OS_POSIX)
    bool has_cmd_prefix = browser_command_line.HasSwitch(
        switches::kUtilityCmdPrefix);

    // When running under gdb, forking /proc/self/exe ends up forking the gdb
    // executable instead of Chromium. It is almost safe to assume that no
    // updates will happen while a developer is running with
    // |switches::kUtilityCmdPrefix|. See ChildProcessHost::GetChildPath() for
    // a similar case with Valgrind.
    if (has_cmd_prefix)
      child_flags = ChildProcessHost::CHILD_NORMAL;
#endif

    base::FilePath exe_path = ChildProcessHost::GetChildPath(child_flags);
    if (exe_path.empty()) {
      NOTREACHED() << "Unable to get utility process binary name.";
      return false;
    }

    CommandLine* cmd_line = new CommandLine(exe_path);
    cmd_line->AppendSwitchASCII(switches::kProcessType,
                                switches::kUtilityProcess);
    cmd_line->AppendSwitchASCII(switches::kProcessChannelID, channel_id);
    std::string locale = GetContentClient()->browser()->GetApplicationLocale();
    cmd_line->AppendSwitchASCII(switches::kLang, locale);

    if (no_sandbox_ || browser_command_line.HasSwitch(switches::kNoSandbox))
      cmd_line->AppendSwitch(switches::kNoSandbox);
#if defined(OS_MACOSX)
    if (browser_command_line.HasSwitch(switches::kEnableSandboxLogging))
      cmd_line->AppendSwitch(switches::kEnableSandboxLogging);
#endif
    if (browser_command_line.HasSwitch(switches::kDebugPluginLoading))
      cmd_line->AppendSwitch(switches::kDebugPluginLoading);

#if defined(OS_POSIX)
    // TODO(port): Sandbox this on Linux.  Also, zygote this to work with
    // Linux updating.
    if (has_cmd_prefix) {
      // launch the utility child process with some prefix (usually "xterm -e gdb
      // --args").
      cmd_line->PrependWrapper(browser_command_line.GetSwitchValueNative(
          switches::kUtilityCmdPrefix));
    }

    cmd_line->AppendSwitchPath(switches::kUtilityProcessAllowedDir, exposed_dir_);
#endif

    if (is_mdns_enabled_)
      cmd_line->AppendSwitch(switches::kUtilityProcessEnableMDns);

    bool use_zygote = false;

#if defined(OS_LINUX)
    use_zygote = !no_sandbox_ && use_linux_zygote_;
#endif

    process_->Launch(
#if defined(OS_WIN)
        new UtilitySandboxedProcessLauncherDelegate(exposed_dir_),
#elif defined(OS_POSIX)
        use_zygote,
        env_,
#endif
        cmd_line);
  }

  return true;
}

bool UtilityProcessHostImpl::OnMessageReceived(const IPC::Message& message) {
  client_task_runner_->PostTask(
      FROM_HERE,
      base::Bind(base::IgnoreResult(
          &UtilityProcessHostClient::OnMessageReceived), client_.get(),
          message));
  return true;
}

void UtilityProcessHostImpl::OnProcessCrashed(int exit_code) {
  client_task_runner_->PostTask(
      FROM_HERE,
      base::Bind(&UtilityProcessHostClient::OnProcessCrashed, client_.get(),
            exit_code));
}

}  // namespace content