Pass fd to faulthandler to avoid ResourceWarning.

rst/installation.rst

@@ -41,7 +41,7 @@ that is not the case.
 * `SQLite <http://www.sqlite.org/>`_ version 3.7.0 or newer. SQLite
   has to be installed as a *shared library* with development headers.
 
-* `Python <http://www.python.org/>`_ 3.3.0 or newer. Make sure to also
+* `Python <http://www.python.org/>`_ 3.5.0 or newer. Make sure to also
   install the development headers.
 
 * The following Python modules:

src/s3ql/mount.py

@@ -185,10 +185,10 @@ def unmount():
         else:
             if stdout_log_handler:
                 logging.getLogger().removeHandler(stdout_log_handler)
-            global crit_log_fh
-            crit_log_fh = open(os.path.join(options.cachedir, 'mount.s3ql_crit.log'), 'a')
-            faulthandler.enable(crit_log_fh)
-            faulthandler.register(signal.SIGUSR1, file=crit_log_fh)
+            crit_log_fd = os.open(os.path.join(options.cachedir, 'mount.s3ql_crit.log'),
+                                  flags=os.O_APPEND|os.O_CREAT|os.O_WRONLY, mode=0o644)
+            faulthandler.enable(crit_log_fd)
+            faulthandler.register(signal.SIGUSR1, file=crit_log_fd)
             daemonize(options.cachedir)
 
         mark_metadata_dirty(backend, cachepath, param)

tests/conftest.py

@@ -93,10 +93,10 @@ def pytest_configure(config):
         warnings.simplefilter('default')
 
     # Enable faulthandler
-    global faultlog_fh
-    faultlog_fh = open(os.path.join(basedir, 'tests', 'test_crit.log'), 'a')
-    faulthandler.enable(faultlog_fh)
-    faulthandler.register(signal.SIGUSR1, file=faultlog_fh)
+    faultlog_fd = os.open(os.path.join(basedir, 'test_crit.log'),
+                          flags=os.O_APPEND|os.O_CREAT|os.O_WRONLY, mode=0o644)
+    faulthandler.enable(faultlog_fd)
+    faulthandler.register(signal.SIGUSR1, file=faultlog_fd)
 
     # Configure logging. We don't set a default handler but rely on
     # the catchlog pytest plugin.