[New-bugs-announce] [issue41862] can not open file in system folder

Christopher Reilly report at bugs.python.org
Fri Sep 25 08:48:03 EDT 2020


New submission from Christopher Reilly <reilly.christopher at gmail.com>:

I am trying to load a Windows dll "ibfs64.dll" located in the C:\Windows\System32 folder:

    ctypes.windll.LoadLibrary('ibfs64.dll')

When I attempt this call with Python 3.8.5 downloaded from python.org, the call fails with 

> FileNotFoundError: Could not find module 'ibfs64.dll' (or one of its dependencies). Try using the full path with constructor syntax.

The function call, however, succeeds in Python 3.7.9 (downloaded from python.org). This behavior (3.7.9 works, 3.8.5 does not), has been duplicated by another user on two different Windows 10 machines (my machine is also Windows 10).

Another piece of information is that this function call also succeeds in anaconda environments running Python 3.7.9 and Python 3.8.5.

When I use the dll-diagnostics tracing utility (https://pypi.org/project/dll-diagnostics/) with the anaconda-managed Python 3.8.5 installation, it succeeds:

> DLL Diagnostic Tools version 0.0.3
> Copyright (c) 2019 Adam Rehn
> 
> Parsing module header and detecting architecture... done.
> 
> Identifying the module's delay-loaded dependencies... done.
> 
> Parsed module details: Module:          C:\Windows\System32\ibfs64.dll
> Type:            Dynamic-Link Library Architecture:    x64
> 
> The module imports 0 delay-loaded dependencies:
> 
> 
> Performing LoadLibrary() trace for C:\Windows\System32\ibfs64.dll...
> Done.
> 
> Summary of LdrLoadDll calls: C:\Windows\System32\ibfs64.dll    Loaded
> successfully
> 
> Summary of LdrpLoadDllInternal calls: C:\Windows\System32\ibfs64.dll  
> Loaded successfully NTDLL.DLL                         Loaded
> successfully
> 
> Summary of LdrpMinimalMapModule calls:
> C:\Windows\System32\ADVAPI32.dll                                      
> Mapped successfully C:\Windows\System32\ibfs64.dll                    
> Mapped successfully C:\Windows\System32\msvcrt.dll                    
> Mapped successfully C:\Windows\System32\RPCRT4.dll                    
> Mapped successfully C:\Windows\System32\sechost.dll                   
> Mapped successfully
> C:\Windows\WinSxS\amd64_microsoft.vc80.crt_1fc8b3b9a1e18e3b_8.0.50727.9672_none_88e266cb2fac7c0d\MSVCR80.dll
> Mapped successfully
> 
> Summary of LdrpResolveDllName calls: ibfs64.dll    
> C:\Windows\System32\ibfs64.dll MSVCR80.dll   
> C:\Windows\WinSxS\amd64_microsoft.vc80.crt_1fc8b3b9a1e18e3b_8.0.50727.9672_none_88e266cb2fac7c0d\MSVCR80.dll

But when I try it with the Python 3.8.5 installed from python.org, it fails:

> DLL Diagnostic Tools version 0.0.3
> Copyright (c) 2019 Adam Rehn
> 
> Parsing module header and detecting architecture... Traceback (most recent call last):
> 
> File "c:\users\chris\appdata\local\programs\python\python38-32\lib\runpy.py", line 194, in _run_module_as_main
> 
> return _run_code(code, main_globals, None,
> 		       
> File "c:\users\chris\appdata\local\programs\python\python38-32\lib\runpy.py", line 87, in _run_code
> 
> exec(code, run_globals)
> 
> File "C:\Users\Chris\AppData\Local\Programs\Python\Python38-32\Scripts\dlldiag.exe\__main__.py", line 7, in <module>
> 
> File "c:\users\chris\appdata\local\programs\python\python38-32\lib\site-packages\dlldiag\main.py", line 29, in main
> 
> subcommands[subcommand]['function']()
> 
> File "c:\users\chris\appdata\local\programs\python\python38-32\lib\site-packages\dlldiag\subcommands\trace.py", line 188, in trace
> 
> header = ModuleHeader(args.module)
> 
> File "c:\users\chris\appdata\local\programs\python\python38-32\lib\site-packages\dlldiag\common\ModuleHeader.py", line 14, in __init__
> 
> self._pe = pefile.PE(module, fast_load=True)
> 
> File "c:\users\chris\appdata\local\programs\python\python38-32\lib\site-packages\pefile.py", line 1754, in __init__
> 
> self.__parse__(name, data, fast_load)
> 
> File "c:\users\chris\appdata\local\programs\python\python38-32\lib\site-packages\pefile.py", line 1797, in __parse__
> 
> stat = os.stat(fname)
> 
> FileNotFoundError: [WinError 2] The system cannot find the file specified: 'C:\\Windows\\system32\\ibfs64.dll'

In fact, I can not even open the file in the python.org installation of Python 3.8.5, while I can in the python.org installation of Python 3.7.9. In other words, the command

    open(r'C:\Windows\System32\ibfs64.dll','r')

succeeds with the python.org installation of Python 3.7.9, but fails (same FileNotFoundError) with version Python 3.8.5. 

What is the anaconda-managed installation doing differently? Why is the Python 3.7.9 installation from python.org successful while the 3.8.5 installation is not?

----------
components: IO, Installation, Windows, ctypes
messages: 377489
nosy: paul.moore, reilly.christopher, steve.dower, tim.golden, zach.ware
priority: normal
severity: normal
status: open
title: can not open file in system folder
type: behavior
versions: Python 3.8

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue41862>
_______________________________________


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