wallet backup function for kivy/android

electrum/gui/kivy/main_window.py

@@ -1199,6 +1199,21 @@ class ElectrumWindow(App):
                                    on_success=on_success, on_failure=on_failure, is_change=1)
         self._password_dialog.open()
 
+    def save_backup(self):
+        from .uix.dialogs.password_dialog import PasswordDialog
+        from electrum.util import get_backup_dir
+        if self._password_dialog is None:
+            self._password_dialog = PasswordDialog()
+        message = _("Create backup.") + '\n' + _("Enter your current PIN:")
+        def on_success(old_password, new_password):
+            new_path = os.path.join(get_backup_dir(self.electrum_config), self.wallet.basename() + '.backup')
+            self.wallet.save_backup(new_path, old_password=old_password, new_password=new_password)
+            self.show_info(_("Backup saved:") + f"\n{new_path}")
+        on_failure = lambda: self.show_error(_("PIN codes do not match"))
+        self._password_dialog.init(self, wallet=self.wallet, msg=message,
+                                   on_success=on_success, on_failure=on_failure, is_change=1, is_backup=True)
+        self._password_dialog.open()
+
     def export_private_keys(self, pk_label, addr):
         if self.wallet.is_watching_only():
             self.show_info(_('This is a watching-only wallet. It does not contain private keys.'))

electrum/gui/kivy/tools/buildozer.spec

@@ -67,7 +67,7 @@ fullscreen = False
 #
 
 # (list) Permissions
-android.permissions = INTERNET, CAMERA
+android.permissions = INTERNET, CAMERA, WRITE_EXTERNAL_STORAGE
 
 # (int) Android API to use
 android.api = 28

electrum/gui/kivy/uix/dialogs/password_dialog.py

@@ -19,6 +19,7 @@ Builder.load_string('''
 
 <PasswordDialog@Popup>
     id: popup
+    is_generic: False
     title: 'Electrum'
     message: ''
     BoxLayout:
@@ -26,31 +27,17 @@ Builder.load_string('''
         orientation: 'vertical'
         Widget:
             size_hint: 1, 0.05
-        BoxLayout:
+        Label:
-            size_hint: 1, None
+            size_hint: 0.70, None
-            orientation: 'horizontal'
+            font_size: '20dp'
-            Label:
+            text: root.message
-                size_hint: 0.70, None
+            text_size: self.width, None
-                font_size: '20dp'
-                text: root.message
-                text_size: self.width, None
-            Label:
-                size_hint: 0.23, None
-                font_size: '9dp'
-                text: _('Generic password')
-            CheckBox:
-                size_hint: 0.07, None
-                id: cb_generic_password
-                on_active:
-                    box_generic_password.visible = self.active
-                    kb.disabled = box_generic_password.visible
-                    textinput_generic_password.focus = box_generic_password.visible
         Widget:
             size_hint: 1, 0.05
         BoxLayout:
             orientation: 'horizontal'
             id: box_generic_password
-            visible: False
+            visible: root.is_generic
             size_hint_y: 0.05
             opacity: 1 if self.visible else 0
             disabled: not self.visible
@@ -59,10 +46,11 @@ Builder.load_string('''
                 valign: 'center'
                 multiline: False
                 on_text_validate:
-                    popup.on_password(self.text, is_generic=True)
+                    popup.on_password(self.text)
                 password: True
                 size_hint: 0.9, None
                 unfocus_on_touch: False
+                focus: root.is_generic
             Button:
                 size_hint: 0.1, None
                 valign: 'center'
@@ -75,7 +63,7 @@ Builder.load_string('''
                     textinput_generic_password.password = False if textinput_generic_password.password else True
         Label:
             id: label_pin
-            visible: not box_generic_password.visible
+            visible: not root.is_generic
             size_hint_y: 0.05
             opacity: 1 if self.visible else 0
             disabled: not self.visible
@@ -86,6 +74,7 @@ Builder.load_string('''
             size_hint: 1, 0.05
         GridLayout:
             id: kb
+            disabled: root.is_generic
             size_hint: 1, None
             height: self.minimum_height
             update_amount: popup.update_password
@@ -125,8 +114,9 @@ class PasswordDialog(Factory.Popup):
     def init(self, app: 'ElectrumWindow', *,
              wallet: Union['Abstract_Wallet', 'WalletStorage'] = None,
              msg: str, on_success: Callable = None, on_failure: Callable = None,
-             is_change: int = 0):
+             is_change: int = 0, is_backup: bool = False):
         self.app = app
+        self.is_backup = is_backup
         self.wallet = wallet
         self.message = msg
         self.on_success = on_success
@@ -138,7 +128,7 @@ class PasswordDialog(Factory.Popup):
         self.pw = None
         self.new_password = None
         self.title = 'Electrum' + ('  -  ' + self.wallet.basename() if self.wallet else '')
-        self.ids.cb_generic_password.active = False
+        #self.ids.cb_generic_password.active = False
 
     def check_password(self, password):
         if self.is_change > 1:
@@ -172,8 +162,8 @@ class PasswordDialog(Factory.Popup):
             text += c
         kb.password = text
 
-    def on_password(self, pw: str, *, is_generic=False):
+    def on_password(self, pw: str):
-        if is_generic:
+        if self.is_generic:
             if len(pw) < 6:
                 self.app.show_error(_('Password is too short (min {} characters)').format(6))
                 return
@@ -186,18 +176,20 @@ class PasswordDialog(Factory.Popup):
                     self.dismiss()
                 elif self.is_change == 1:
                     self.pw = pw
-                    self.message = _('Enter new PIN')
+                    self.message = _('Enter a strong password for your backup') if self.is_backup else _('Enter new PIN')
                     self.ids.kb.password = ''
                     self.ids.textinput_generic_password.text = ''
                     self.is_change = 2
+                    self.is_generic = self.is_backup
                 elif self.is_change == 2:
                     self.new_password = pw
-                    self.message = _('Confirm new PIN')
+                    self.message = _('Confirm backup password') if self.is_backup else _('Confirm new PIN')
                     self.ids.kb.password = ''
                     self.ids.textinput_generic_password.text = ''
                     self.is_change = 3
                 elif self.is_change == 3:
                     self.success = pw == self.new_password
+                    self.is_generic = False
                     self.dismiss()
             else:
                 self.app.show_error(_('Wrong PIN'))

electrum/gui/kivy/uix/ui_screens/status.kv

@@ -83,13 +83,14 @@ Popup:
             Button:
                 size_hint: 0.5, None
                 height: '48dp'
-                text: _('Disable LN') if app.wallet.has_lightning() else _('Enable LN')
+                text: _('Save Backup')
                 on_release:
                     root.dismiss()
-                    app.toggle_lightning()
+                    app.save_backup()
             Button:
                 size_hint: 0.5, None
                 height: '48dp'
-                text: _('Close')
+                text: _('Disable LN') if app.wallet.has_lightning() else _('Enable LN')
                 on_release:
                     root.dismiss()
+                    app.toggle_lightning()

electrum/util.py

@@ -425,11 +425,25 @@ def profiler(func):
     return lambda *args, **kw_args: do_profile(args, kw_args)
 
 
+def android_ext_dir():
+    import jnius
+    env = jnius.autoclass('android.os.Environment')
+    return env.getExternalStorageDirectory().getPath()
+
+def android_backup_dir():
+    d = android_ext_dir() + '/org.electrum.electrum'
+    if not os.path.exists(d):
+        os.mkdir(d)
+    return d
+
 def android_data_dir():
     import jnius
     PythonActivity = jnius.autoclass('org.kivy.android.PythonActivity')
     return PythonActivity.mActivity.getFilesDir().getPath() + '/data'
 
+def get_backup_dir(config):
+    return android_backup_dir() if 'ANDROID_DATA' in os.environ else config.path
+
 
 def ensure_sparse_file(filename):
     # On modern Linux, no need to do anything.

electrum/wallet.py

@@ -263,12 +263,16 @@ class Abstract_Wallet(AddressSynchronizer, ABC):
         if self.storage:
             self.db.write(self.storage)
 
-    def save_backup(self, path):
+    def save_backup(self, path, *, old_password=None, new_password=None):
-        # fixme: we need to change password...
+        new_db = WalletDB(self.storage.read(), manual_upgrades=False)
+        new_db.put('is_backup', True)
         new_storage = WalletStorage(path)
-        self.db.put('is_backup', True)
+        #new_storage._encryption_version = self.storage.get_encryption_version()
-        self.db.write(new_storage)
+        new_storage._encryption_version = StorageEncryptionVersion.PLAINTEXT
-        self.db.put('is_backup', None)
+        w2 = Wallet(new_db, new_storage, config=self.config)
+        if new_password:
+            w2.update_password(old_password, new_password, encrypt_storage=True)
+        w2.save_db()
 
     def has_lightning(self):
         return bool(self.lnworker)