arc: Abort booting ARC if the device is critically low on disk space.

chromeos/dbus/cryptohome_client.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 CHROMEOS_DBUS_CRYPTOHOME_CLIENT_H_
 #define CHROMEOS_DBUS_CRYPTOHOME_CLIENT_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 40 matching lines @@
                               bool return_status,
                               int return_code)>
       AsyncCallStatusHandler;
   // A callback to handle AsyncCallStatusWithData signals.
   typedef base::Callback<void(int async_id,
                               bool return_status,
                               const std::string& data)>
       AsyncCallStatusWithDataHandler;
   // A callback to handle responses of AsyncXXX methods.
   typedef base::Callback<void(int async_id)> AsyncMethodCallback;
+  // A callback for GetFreeDiskSpace().
+  typedef base::Callback<void(DBusMethodCallStatus call_status,
+                              uint64_t disk_free_bytes)>
+      GetFreeDiskSpaceCallback;
   // A callback for GetSystemSalt().
   typedef base::Callback<void(DBusMethodCallStatus call_status,
                               const std::vector<uint8_t>& system_salt)>
       GetSystemSaltCallback;
   // A callback to handle LowDiskSpace signals.
   typedef base::Callback<void(uint64_t disk_free_bytes)> LowDiskSpaceHandler;
   // A callback for WaitForServiceToBeAvailable().
   typedef base::Callback<void(bool service_is_ready)>
       WaitForServiceToBeAvailableCallback;
   // A callback to handle responses of Pkcs11GetTpmTokenInfo method.  The result
@@ skipping 75 matching lines @@
                            const AsyncMethodCallback& callback) = 0;
 
   // Calls RenameCryptohome method. |callback| is called after the method
   // call succeeds.
   virtual void RenameCryptohome(
       const cryptohome::Identification& cryptohome_id_from,
       const cryptohome::Identification& cryptohome_id_to,
       const ProtobufMethodCallback& callback) = 0;
 
   // Calls GetAccountDiskUsage method. |callback| is called after the method
-  // call succeeds
+  // call succeeds.
   virtual void GetAccountDiskUsage(const cryptohome::Identification& account_id,
                                    const ProtobufMethodCallback& callback) = 0;
 
+  // Calls GetFreeDiskSpace method. |callback| is called after the method
+  // call succeeds.
+  virtual void GetFreeDiskSpace(const GetFreeDiskSpaceCallback& callback) = 0;

[Junichi Uekawa, 2016/07/15 00:29:40]

Why do we need a DBus message to cryptohome to call statfs/statvfs ?
Is that somehow disallowed? It should also be possible to call that from I/O
thread?

+
   // Calls GetSystemSalt method.  |callback| is called after the method call
   // succeeds.
   virtual void GetSystemSalt(const GetSystemSaltCallback& callback) = 0;
 
   // Calls GetSanitizedUsername method.  |callback| is called after the method
   // call succeeds.
   virtual void GetSanitizedUsername(
       const cryptohome::Identification& cryptohome_id,
       const StringDBusMethodCallback& callback) = 0;
 
@@ skipping 389 matching lines @@
   // Create() should be used instead.
   CryptohomeClient();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CryptohomeClient);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_CRYPTOHOME_CLIENT_H_