root/chrome/common/service_process_util_win.cc

DEFINITIONS

1. GetServiceProcessReadyEventName
2. GetServiceProcessTerminateEventName
3. GetServiceProcessAutoRunKey
4. GetObsoleteServiceProcessAutoRunKey
5. Start
6. OnObjectSignaled
7. GetServiceProcessChannel
8. ForceServiceProcessShutdown
9. CheckServiceProcessReady
10. CreateState
11. TakeSingletonLock
12. SignalReady
13. AddToAutoRun
14. RemoveFromAutoRun
15. TearDownState

// Copyright (c) 2011 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 "chrome/common/service_process_util.h"

#include "base/callback.h"
#include "base/command_line.h"
#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "base/path_service.h"
#include "base/strings/string16.h"
#include "base/strings/utf_string_conversions.h"
#include "base/win/object_watcher.h"
#include "base/win/scoped_handle.h"
#include "base/win/win_util.h"
#include "chrome/common/chrome_paths.h"
#include "chrome/common/chrome_switches.h"

namespace {

const char* kTerminateEventSuffix = "_service_terminate_evt";

base::string16 GetServiceProcessReadyEventName() {
  return base::UTF8ToWide(
      GetServiceProcessScopedVersionedName("_service_ready"));
}

base::string16 GetServiceProcessTerminateEventName() {
  return base::UTF8ToWide(
      GetServiceProcessScopedVersionedName(kTerminateEventSuffix));
}

std::string GetServiceProcessAutoRunKey() {
  return GetServiceProcessScopedName("_service_run");
}

// Returns the name of the autotun reg value that we used to use for older
// versions of Chrome.
std::string GetObsoleteServiceProcessAutoRunKey() {
  base::FilePath user_data_dir;
  PathService::Get(chrome::DIR_USER_DATA, &user_data_dir);
  std::string scoped_name = base::WideToUTF8(user_data_dir.value());
  std::replace(scoped_name.begin(), scoped_name.end(), '\\', '!');
  std::replace(scoped_name.begin(), scoped_name.end(), '/', '!');
  scoped_name.append("_service_run");
  return scoped_name;
}

class ServiceProcessTerminateMonitor
    : public base::win::ObjectWatcher::Delegate {
 public:
  explicit ServiceProcessTerminateMonitor(const base::Closure& terminate_task)
      : terminate_task_(terminate_task) {
  }
  void Start() {
    base::string16 event_name = GetServiceProcessTerminateEventName();
    DCHECK(event_name.length() <= MAX_PATH);
    terminate_event_.Set(CreateEvent(NULL, TRUE, FALSE, event_name.c_str()));
    watcher_.StartWatching(terminate_event_.Get(), this);
  }

  // base::ObjectWatcher::Delegate implementation.
  virtual void OnObjectSignaled(HANDLE object) {
    if (!terminate_task_.is_null()) {
      terminate_task_.Run();
      terminate_task_.Reset();
    }
  }

 private:
  base::win::ScopedHandle terminate_event_;
  base::win::ObjectWatcher watcher_;
  base::Closure terminate_task_;
};

}  // namespace

// Gets the name of the service process IPC channel.
IPC::ChannelHandle GetServiceProcessChannel() {
  return GetServiceProcessScopedVersionedName("_service_ipc");
}

bool ForceServiceProcessShutdown(const std::string& version,
                                 base::ProcessId process_id) {
  base::win::ScopedHandle terminate_event;
  std::string versioned_name = version;
  versioned_name.append(kTerminateEventSuffix);
  base::string16 event_name =
      base::UTF8ToWide(GetServiceProcessScopedName(versioned_name));
  terminate_event.Set(OpenEvent(EVENT_MODIFY_STATE, FALSE, event_name.c_str()));
  if (!terminate_event.IsValid())
    return false;
  SetEvent(terminate_event.Get());
  return true;
}

bool CheckServiceProcessReady() {
  base::string16 event_name = GetServiceProcessReadyEventName();
  base::win::ScopedHandle event(
      OpenEvent(SYNCHRONIZE | READ_CONTROL, false, event_name.c_str()));
  if (!event.IsValid())
    return false;
  // Check if the event is signaled.
  return WaitForSingleObject(event, 0) == WAIT_OBJECT_0;
}

struct ServiceProcessState::StateData {
  // An event that is signaled when a service process is ready.
  base::win::ScopedHandle ready_event;
  scoped_ptr<ServiceProcessTerminateMonitor> terminate_monitor;
};

void ServiceProcessState::CreateState() {
  DCHECK(!state_);
  state_ = new StateData;
}

bool ServiceProcessState::TakeSingletonLock() {
  DCHECK(state_);
  base::string16 event_name = GetServiceProcessReadyEventName();
  DCHECK(event_name.length() <= MAX_PATH);
  base::win::ScopedHandle service_process_ready_event;
  service_process_ready_event.Set(
      CreateEvent(NULL, TRUE, FALSE, event_name.c_str()));
  DWORD error = GetLastError();
  if ((error == ERROR_ALREADY_EXISTS) || (error == ERROR_ACCESS_DENIED))
    return false;
  DCHECK(service_process_ready_event.IsValid());
  state_->ready_event.Set(service_process_ready_event.Take());
  return true;
}

bool ServiceProcessState::SignalReady(
    base::MessageLoopProxy* message_loop_proxy,
    const base::Closure& terminate_task) {
  DCHECK(state_);
  DCHECK(state_->ready_event.IsValid());
  if (!SetEvent(state_->ready_event.Get())) {
    return false;
  }
  if (!terminate_task.is_null()) {
    state_->terminate_monitor.reset(
        new ServiceProcessTerminateMonitor(terminate_task));
    state_->terminate_monitor->Start();
  }
  return true;
}

bool ServiceProcessState::AddToAutoRun() {
  DCHECK(autorun_command_line_.get());
  // Remove the old autorun value first because we changed the naming scheme
  // for the autorun value name.
  base::win::RemoveCommandFromAutoRun(
      HKEY_CURRENT_USER,
      base::UTF8ToWide(GetObsoleteServiceProcessAutoRunKey()));
  return base::win::AddCommandToAutoRun(
      HKEY_CURRENT_USER,
      base::UTF8ToWide(GetServiceProcessAutoRunKey()),
      autorun_command_line_->GetCommandLineString());
}

bool ServiceProcessState::RemoveFromAutoRun() {
  // Remove the old autorun value first because we changed the naming scheme
  // for the autorun value name.
  base::win::RemoveCommandFromAutoRun(
      HKEY_CURRENT_USER,
      base::UTF8ToWide(GetObsoleteServiceProcessAutoRunKey()));
  return base::win::RemoveCommandFromAutoRun(
      HKEY_CURRENT_USER, base::UTF8ToWide(GetServiceProcessAutoRunKey()));
}

void ServiceProcessState::TearDownState() {
  delete state_;
  state_ = NULL;
}