Only read magic-folder config from config reader

Also, fix the umask feature which was completely broken previously due
to failure to parse the umask string into an integer.

src/allmydata/client.py

@@ -606,7 +606,7 @@ class _Client(node.Node, pollmixin.PollMixin):
                     collective_dircap=mf_config["collective_dircap"],
                     local_path_u=abspath_expanduser_unicode(local_dir_config, base=self.basedir),
                     dbfile=abspath_expanduser_unicode(db_filename),
-                    umask=self.get_config("magic_folder", "download.umask", 0077),
+                    umask=mf_config["umask"],
                     name=name,
                     downloader_delay=poll_interval,
                 )

src/allmydata/frontends/magic_folder.py

@@ -30,6 +30,9 @@ from allmydata.immutable.upload import FileName, Data
 from allmydata import magicfolderdb, magicpath
 
 
+# Mask off all non-owner permissions for magic-folders files by default.
+_DEFAULT_DOWNLOAD_UMASK = 0o077
+
 IN_EXCL_UNLINK = 0x04000000L
 
 def get_inotify_module():
@@ -157,11 +160,17 @@ def load_magic_folders(node_directory):
                     )
                 )
 
+            if config.has_option("magic_folder", "download.umask"):
+                umask = int(config.get("magic_folder", "download.umask"), 8)
+            else:
+                umask = _DEFAULT_DOWNLOAD_UMASK
+
             folders[u"default"] = {
                 u"directory": directory,
                 u"upload_dircap": fileutil.read(up_fname),
                 u"collective_dircap": fileutil.read(coll_fname),
                 u"poll_interval": interval,
+                u"umask": umask,
             }
         else:
             # without any YAML file AND no local.directory option it's
@@ -213,6 +222,12 @@ def load_magic_folders(node_directory):
             if isinstance(mf_config[k], unicode):
                 mf_config[k] = mf_config[k].encode('ascii')
 
+        if not isinstance(
+            mf_config.setdefault(u"umask", _DEFAULT_DOWNLOAD_UMASK),
+            int,
+        ):
+            raise Exception("magic-folder download umask must be an integer")
+
     return folders
 
 

src/allmydata/test/test_magic_folder.py

@@ -65,6 +65,7 @@ class NewConfigUtilTests(unittest.TestCase):
     def test_load(self):
         folders = magic_folder.load_magic_folders(self.basedir)
         self.assertEqual(['default'], list(folders.keys()))
+        self.assertEqual(folders['default'][u'umask'], 0o077)
 
     def test_both_styles_of_config(self):
         os.unlink(join(self.basedir, u"private", u"magic_folders.yaml"))
@@ -115,6 +116,23 @@ class NewConfigUtilTests(unittest.TestCase):
             str(ctx.exception)
         )
 
+    def test_wrong_umask_obj(self):
+        """
+        If a umask is given for a magic-folder that is not an integer, an
+        exception is raised.
+        """
+        self.folders[u"default"][u"umask"] = "0077"
+        yaml_fname = join(self.basedir, u"private", u"magic_folders.yaml")
+        with open(yaml_fname, "w") as f:
+            f.write(yamlutil.safe_dump({u"magic-folders": self.folders}))
+
+        with self.assertRaises(Exception) as ctx:
+            magic_folder.load_magic_folders(self.basedir)
+        self.assertIn(
+            "umask must be an integer",
+            str(ctx.exception)
+        )
+
     def test_wrong_sub_obj(self):
         yaml_fname = join(self.basedir, u"private", u"magic_folders.yaml")
         with open(yaml_fname, "w") as f: