loader: move ctypes hooks into a module

Move the ctypes hooks from bootstrap script into separate module
(pymod04_ctypes). The main motivation for this is to prevent the
modifications to global namespace from affecting the ctypes hooks
code. Specifically, if user decides to use `sys` or `os` as
variables in the global namespace, that should not effect the
ctypes hook function _frozen_name(), which treats `sys` and `os`
as names of modules (which were bound to those names when the
bootstrap script was executed).

Fixes #5797.

This commit is a cleaned-up and modernized version of corresponding
commit from #3038 (daf60a6).

Co-authored-by: Hartmut Goebel <h.goebel@crazy-compilers.com>

PyInstaller/depend/analysis.py

@@ -847,6 +847,7 @@ def get_bootstrap_modules():
         ('pyimod01_os_path', os.path.join(loaderpath, 'pyimod01_os_path.pyc'), 'PYMODULE'),
         ('pyimod02_archive',  os.path.join(loaderpath, 'pyimod02_archive.pyc'), 'PYMODULE'),
         ('pyimod03_importers',  os.path.join(loaderpath, 'pyimod03_importers.pyc'), 'PYMODULE'),
+        ('pyimod04_ctypes',  os.path.join(loaderpath, 'pyimod04_ctypes.pyc'), 'PYMODULE'),  # noqa: E501
         ('pyiboot01_bootstrap', os.path.join(loaderpath, 'pyiboot01_bootstrap.py'), 'PYSOURCE'),
     ]
     return loader_mods

PyInstaller/loader/pyiboot01_bootstrap.py

@@ -118,86 +118,9 @@ def isatty(self):
 if sys.warnoptions:
     import warnings
 
-try:
-    import ctypes
-    import os
-    from ctypes import LibraryLoader, DEFAULT_MODE
-
-    def _frozen_name(name):
-        if name:
-            frozen_name = os.path.join(sys._MEIPASS, os.path.basename(name))
-            if os.path.exists(frozen_name) and not os.path.isdir(frozen_name):
-                name = frozen_name
-        return name
-
-    class PyInstallerImportError(OSError):
-        def __init__(self, name):
-            self.msg = ("Failed to load dynlib/dll %r. "
-                        "Most probably this dynlib/dll was not found "
-                        "when the application was frozen.") % name
-            self.args = (self.msg,)
-
-    class PyInstallerCDLL(ctypes.CDLL):
-        def __init__(self, name, *args, **kwargs):
-            name = _frozen_name(name)
-            try:
-                super(PyInstallerCDLL, self).__init__(name, *args, **kwargs)
-            except Exception as base_error:
-                raise PyInstallerImportError(name) from base_error
-
-    ctypes.CDLL = PyInstallerCDLL
-    ctypes.cdll = LibraryLoader(PyInstallerCDLL)
-
-    class PyInstallerPyDLL(ctypes.PyDLL):
-        def __init__(self, name, *args, **kwargs):
-            name = _frozen_name(name)
-            try:
-                super(PyInstallerPyDLL, self).__init__(name, *args, **kwargs)
-            except Exception as base_error:
-                raise PyInstallerImportError(name) from base_error
-
-    ctypes.PyDLL = PyInstallerPyDLL
-    ctypes.pydll = LibraryLoader(PyInstallerPyDLL)
-
-    if sys.platform.startswith('win'):
-        class PyInstallerWinDLL(ctypes.WinDLL):
-            def __init__(self, name,*args, **kwargs):
-                name = _frozen_name(name)
-                try:
-                    super(PyInstallerWinDLL, self).__init__(name, *args, **kwargs)
-                except Exception as base_error:
-                    raise PyInstallerImportError(name) from base_error
-
-        ctypes.WinDLL = PyInstallerWinDLL
-        ctypes.windll = LibraryLoader(PyInstallerWinDLL)
-
-        class PyInstallerOleDLL(ctypes.OleDLL):
-            def __init__(self, name,*args, **kwargs):
-                name = _frozen_name(name)
-                try:
-                    super(PyInstallerOleDLL, self).__init__(name, *args, **kwargs)
-                except Exception as base_error:
-                    raise PyInstallerImportError(name) from base_error
-
-        ctypes.OleDLL = PyInstallerOleDLL
-        ctypes.oledll = LibraryLoader(PyInstallerOleDLL)
-except ImportError:
-    pass
-
-# On Mac OS X insert sys._MEIPASS in the first position of the list of paths
-# that ctypes uses to search for libraries.
-#
-# Note: 'ctypes' module will NOT be bundled with every app because code in this
-#       module is not scanned for module dependencies. It is safe to wrap
-#       'ctypes' module into 'try/except ImportError' block.
-if sys.platform.startswith('darwin'):
-    try:
-        from ctypes.macholib import dyld
-        dyld.DEFAULT_LIBRARY_FALLBACK.insert(0, sys._MEIPASS)
-    except ImportError:
-        # Do nothing when module 'ctypes' is not available.
-        pass
-
+# Install the hooks for ctypes
+import pyimod04_ctypes  # noqa: E402
+pyimod04_ctypes.install()
 
 # Make .eggs and zipfiles available at runtime
 d = "eggs"

PyInstaller/loader/pyimod04_ctypes.py

@@ -0,0 +1,105 @@
+#-----------------------------------------------------------------------------
+# Copyright (c) 2005-2021, PyInstaller Development Team.
+#
+# Distributed under the terms of the GNU General Public License with exception
+# for distributing bootloader.
+#
+# The full license is in the file COPYING.txt, distributed with this software.
+#-----------------------------------------------------------------------------
+
+"""
+Hooks to make ctypes.CDLL, .PyDLL, etc. look in sys._MEIPASS first.
+"""
+
+import sys
+
+
+def install():
+    """Install the hooks.
+
+    This must be done from a function as opposed to at module-level,
+    because when the module is imported/executed, the import machinery
+    is not completely set up yet.
+    """
+
+    import os
+
+    try:
+        import ctypes
+    except ImportError:
+        # ctypes is not included in the frozen application
+        return
+
+    def _frozen_name(name):
+        if name:
+            frozen_name = os.path.join(sys._MEIPASS, os.path.basename(name))
+            if os.path.exists(frozen_name) and not os.path.isdir(frozen_name):
+                name = frozen_name
+        return name
+
+    class PyInstallerImportError(OSError):
+        def __init__(self, name):
+            self.msg = ("Failed to load dynlib/dll %r. "
+                        "Most probably this dynlib/dll was not found "
+                        "when the application was frozen.") % name
+            self.args = (self.msg,)
+
+    class PyInstallerCDLL(ctypes.CDLL):
+        def __init__(self, name, *args, **kwargs):
+            name = _frozen_name(name)
+            try:
+                super().__init__(name, *args, **kwargs)
+            except Exception as base_error:
+                raise PyInstallerImportError(name) from base_error
+
+    ctypes.CDLL = PyInstallerCDLL
+    ctypes.cdll = ctypes.LibraryLoader(PyInstallerCDLL)
+
+    class PyInstallerPyDLL(ctypes.PyDLL):
+        def __init__(self, name, *args, **kwargs):
+            name = _frozen_name(name)
+            try:
+                super().__init__(name, *args, **kwargs)
+            except Exception as base_error:
+                raise PyInstallerImportError(name) from base_error
+
+    ctypes.PyDLL = PyInstallerPyDLL
+    ctypes.pydll = ctypes.LibraryLoader(PyInstallerPyDLL)
+
+    if sys.platform.startswith('win'):
+        class PyInstallerWinDLL(ctypes.WinDLL):
+            def __init__(self, name, *args, **kwargs):
+                name = _frozen_name(name)
+                try:
+                    super().__init__(name, *args, **kwargs)
+                except Exception as base_error:
+                    raise PyInstallerImportError(name) from base_error
+
+        ctypes.WinDLL = PyInstallerWinDLL
+        ctypes.windll = ctypes.LibraryLoader(PyInstallerWinDLL)
+
+        class PyInstallerOleDLL(ctypes.OleDLL):
+            def __init__(self, name, *args, **kwargs):
+                name = _frozen_name(name)
+                try:
+                    super().__init__(name, *args, **kwargs)
+                except Exception as base_error:
+                    raise PyInstallerImportError(name) from base_error
+
+        ctypes.OleDLL = PyInstallerOleDLL
+        ctypes.oledll = ctypes.LibraryLoader(PyInstallerOleDLL)
+
+
+# On Mac OS X insert sys._MEIPASS in the first position of the list of paths
+# that ctypes uses to search for libraries.
+#
+# Note: 'ctypes' module will NOT be bundled with every app because code in this
+#       module is not scanned for module dependencies. It is safe to wrap
+#       'ctypes' module into 'try/except ImportError' block.
+if sys.platform.startswith('darwin'):
+    try:
+        from ctypes.macholib import dyld
+        dyld.DEFAULT_LIBRARY_FALLBACK.insert(0, sys._MEIPASS)
+    except ImportError:
+        # Do nothing when module 'ctypes' is not available.
+        pass

news/5797.bugfix.rst

@@ -0,0 +1,3 @@
+Prevent the use of ``sys`` or ``os`` as variables in the global namespace
+in frozen script from affecting the ``ctypes`` hooks thar are installed
+during bootstrap.