Add DeviceSettingsService.

chrome/browser/chromeos/login/device_settings_service.h

+// 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.
+
+#ifndef CHROME_BROWSER_CHROMEOS_LOGIN_DEVICE_SETTINGS_SERVICE_H_
+#define CHROME_BROWSER_CHROMEOS_LOGIN_DEVICE_SETTINGS_SERVICE_H_
+
+#include <deque>
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/observer_list.h"
+#include "base/synchronization/lock.h"
+#include "chrome/browser/policy/cloud_policy_validator.h"
+#include "chromeos/dbus/session_manager_client.h"
+
+namespace base {
+template <typename T> struct DefaultLazyInstanceTraits;
+}
+
+namespace crypto {
+class RSAPrivateKey;
+}
+
+namespace enterprise_management {
+class ChromeDeviceSettingsProto;
+class PolicyData;
+}
+
+namespace chromeos {
+
+class OwnerKeyUtil;
+class SessionManagerOperation;
+
+// Keeps the public and private halves of the owner key. Both may be missing,
+// but if the private key is present, the public half will be as well. This
+// class is immutable and refcounted in order to allow safe access from any
+// thread.
+class OwnerKey : public base::RefCountedThreadSafe<OwnerKey> {
+ public:
+  OwnerKey(scoped_ptr<std::vector<uint8> > public_key,
+           scoped_ptr<crypto::RSAPrivateKey> private_key);
+
+  const std::vector<uint8>* public_key() {
+    return public_key_.get();
+  }
+  crypto::RSAPrivateKey* private_key() {
+    return private_key_.get();
+  }
+
+ private:
+  friend class base::RefCountedThreadSafe<OwnerKey>;
+  ~OwnerKey();
+
+  scoped_ptr<std::vector<uint8> > public_key_;
+  scoped_ptr<crypto::RSAPrivateKey> private_key_;
+
+  DISALLOW_COPY_AND_ASSIGN(OwnerKey);
+};
+
+// Deals with the low-level interface to Chromium OS device settings. Device
+// settings are stored in a protobuf that's protected by a cryptographic
+// signature generated by a key in the device owner's possession. Key and
+// settings are brokered by the session_manager daemon.
+//
+// The purpose of DeviceSettingsService is to keep track of the current key and
+// settings blob. For reading and writing device settings, use CrosSettings
+// instead, which provides a high-level interface that allows for manipulation
+// of individual settings.
+//
+// DeviceSettingsService generates notifications for key and policy update
+// events so interested parties and reload state as appropriate.

[pastarmovj, 2012/07/30 12:19:19]

Hmm something is missing in this sentence.

[Mattias Nissler (ping if slow), 2012/07/31 13:02:15]

Done.

+class DeviceSettingsService : public SessionManagerClient::Observer {
+ public:
+  // Indicates ownership status of the device.
+  enum OwnershipStatus {
+    // Listed in upgrade order.
+    OWNERSHIP_UNKNOWN = 0,
+    OWNERSHIP_NONE,
+    OWNERSHIP_TAKEN
+  };
+
+  typedef base::Callback<void(OwnershipStatus, bool)> OwnershipStatusCallback;
+
+  // Status codes for Store().
+  enum Status {
+    STORE_SUCCESS,
+    STORE_KEY_UNAVAILABLE,   // Owner key not yet configured.
+    STORE_POLICY_ERROR,      // Failure constructing the settings blob.
+    STORE_OPERATION_FAILED,  // IPC to session_manager daemon failed.
+    STORE_NO_POLICY,         // No settings blob present.
+    STORE_INVALID_POLICY,    // Invalid settings blob.
+    STORE_VALIDATION_ERROR,  // Policy validation failure.
+  };
+
+  // Observer interface.
+  class Observer {
+   public:
+    virtual ~Observer();
+
+    // Indicates device ownership status changes.
+    virtual void OwnershipStatusChanged() = 0;
+
+    // Gets call after updates to the device settings.
+    virtual void DeviceSettingsUpdated() = 0;
+  };
+
+  // Creates a device settings service instance. This is meant for unit tests,
+  // production code uses the singleton returned by Get() below.
+  DeviceSettingsService();

[pastarmovj, 2012/07/30 12:19:19]

Isn't it better to create another static method like CreateInstanceForTests or
the like to make sure this constructor is not going to get called by
coincidence.

[Mattias Nissler (ping if slow), 2012/07/31 13:02:15]

How would you call a constructor by coincidence? CreateInstanceForTests would
require to use a pointer, so more noise in tests.

[pastarmovj, 2012/08/01 08:46:52]

What I meant by "coincidence" is somebody doing this :

DeviceSettingsService myservice;
myservice.callSomething();

instead of using the singleton.

I am fine with keeping it like that basically my concern was more for the user
facing classes like CrosSettings which you also changed this way in your second
CL.

+  ~DeviceSettingsService();
+
+  // Returns the singleton instance.
+  static DeviceSettingsService* Get();
+
+  // To be called on startup once threads are initialized and DBus is ready.
+  void Initialize(SessionManagerClient* session_manager_client,
+                  scoped_refptr<OwnerKeyUtil> owner_key_util);
+  void Shutdown();

[pastarmovj, 2012/07/30 12:19:19]

Please document with one line. Now it feels more like this is going to be called
on init too.

[Mattias Nissler (ping if slow), 2012/07/31 13:02:15]

Done.

+
+  // Returns the currently active device settings. Returns NULL if the device
+  // settings have not yet been retrieved from session_manager yet.

[pastarmovj, 2012/07/30 12:19:19]

yet...yet. Please remove one of them.

[Mattias Nissler (ping if slow), 2012/07/31 13:02:15]

Done.

+  const enterprise_management::PolicyData* policy_data() {
+    return policy_data_.get();
+  }
+  const enterprise_management::ChromeDeviceSettingsProto*
+      device_settings() const {
+    return device_settings_.get();
+  }
+
+  // Returns the currently used owner key.
+  scoped_refptr<OwnerKey> GetOwnerKey();
+
+  // Returns the status generated by the last operation.
+  Status status() {
+    return store_status_;
+  }
+
+  // Triggers an attempt to pull the public half of the owner key from disk and
+  // load the device settings.
+  void Load();
+
+  // Signs |settings| with the private half of the owner key and sends the
+  // resulting policy blob to session manager for storage. The result of the
+  // operation is reported through |callback|. If successful, the updated device
+  // settings are present in policy_data() and device_settings() when the
+  // callback runs.
+  void SignAndStore(
+      scoped_ptr<enterprise_management::ChromeDeviceSettingsProto> settings,
+      const base::Closure& callback);
+
+  // Stores a policy blob to session_manager. The result of the operation is
+  // reported through |callback|. If successful, the updated device settings are
+  // present in policy_data() and device_settings() when the callback runs.
+  void Store(const std::string& policy_blob, const base::Closure& callback);
+
+  // This method can be run either on FILE or UI threads.  If |blocking| flag
+  // is specified then it is guaranteed to return either OWNERSHIP_NONE or
+  // OWNERSHIP_TAKEN (and not OWNERSHIP_UNKNOWN), however in this case it may
+  // occasionally block doing I/O.
+  //
+  // TODO(mnissler, pastarmovj): Remove the blocking flag and only allow this on
+  // the UI thread.

[pastarmovj, 2012/07/30 12:19:19]

FYI: I have an idea how we can get rid of the call to this one from the
DeviceSettingsProvider once you land this I will try to fix it. Maybe we'll be
able to get rid of it completely then.

[Mattias Nissler (ping if slow), 2012/07/31 13:02:15]

I've fixed DeviceSettingsProvider in the second patch set already :)

+  OwnershipStatus GetOwnershipStatus(bool blocking);
+
+  // Determines the ownership status and reports the result to |callback|. This
+  // is guaranteed to never return OWNERSHIP_UNKNOWN.
+  void GetOwnershipStatusAsync(const OwnershipStatusCallback& callback);
+
+  // Checks whether we have the private owner key.
+  bool HasPrivateOwnerKey();
+
+  // Sets the identity of the user that's interacting with the service. This is
+  // relevant only for writing settings through SignAndStore().
+  void SetUsername(const std::string& username);
+  const std::string& GetUsername() const;
+
+  // Adds an observer.
+  void AddObserver(Observer* observer);
+  // Removes and observer.
+  void RemoveObserver(Observer* observer);
+
+  // SessionManagerClient::Observer:
+  virtual void OwnerKeySet(bool success) OVERRIDE;
+  virtual void PropertyChangeComplete(bool success) OVERRIDE;
+
+ private:
+  // Enqueues a new operation. Takes ownership of |operation| and starts it
+  // right away if there is no active operation currently.
+  void Enqueue(SessionManagerOperation* operation);
+
+  // Enqueues a load operation.
+  void EnqueueLoad(bool force_key_load);
+
+  // Makes sure there's a reload operation so changes to the settings (and key,
+  // in case force_key_load is set) are getting picked up.
+  void EnsureReload(bool force_key_load);
+
+  // Runs the next pending operation.
+  void StartNextOperation();
+
+  // Updates status, policy data and owner key from a finished operation.
+  // Starts the next pending operation if available.
+  void HandleCompletedOperation(const base::Closure& callback,
+                                SessionManagerOperation* operation,
+                                Status status);
+
+  // Sets ownership status. May be called on either thread.
+  void SetOwnershipStatus(OwnershipStatus new_status);
+
+  SessionManagerClient* session_manager_client_;
+  scoped_refptr<OwnerKeyUtil> owner_key_util_;
+
+  base::WeakPtrFactory<DeviceSettingsService> weak_factory_;
+
+  Status store_status_;
+
+  OwnershipStatus ownership_status_;
+  base::Lock ownership_status_lock_;
+  std::vector<OwnershipStatusCallback> pending_ownership_status_callbacks_;
+
+  std::string username_;
+  scoped_refptr<OwnerKey> owner_key_;
+
+  scoped_ptr<enterprise_management::PolicyData> policy_data_;
+  scoped_ptr<enterprise_management::ChromeDeviceSettingsProto> device_settings_;
+
+  // The queue of pending operations. The first operation on the queue is
+  // currently active; it gets removed and destroyed once it completes.
+  std::deque<SessionManagerOperation*> pending_operations_;
+
+  ObserverList<Observer, true> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeviceSettingsService);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_LOGIN_DEVICE_SETTINGS_SERVICE_H_