| msg278963 - (view) |
Author: Kelvin You (Kelvin You) |
Date: 2016-10-19 07:28 |
| // callproc.c static PyObject *format_error(PyObject *self, PyObject *args) { PyObject *result; wchar_t *lpMsgBuf; DWORD code = 0; if (!PyArg_ParseTuple(args, "|i:FormatError", &code)) ^ Here the format string should be " |
I:FormatError" return NULL; if (code == 0) code = GetLastError(); lpMsgBuf = FormatError(code); if (lpMsgBuf) { result = PyUnicode_FromWideChar(lpMsgBuf, wcslen(lpMsgBuf)); LocalFree(lpMsgBuf); } else { result = PyUnicode_FromString(""); } return result; } |
|
| msg279005 - (view) |
Author: Josh Rosenberg (josh.r) *  |
Date: 2016-10-20 01:16 |
| You can't use I as a format code safely; it silently ignores/wraps overflow on the conversion, where i raises on overflow. The unsigned converters are basically useless for resilient code in 99% of cases. I *think* I remember some private utility functions for doing this using O& though, not sure if they're available in callproc.c... |
|
|
| msg279008 - (view) |
Author: Kelvin You (Kelvin You) |
Date: 2016-10-20 03:35 |
| I report this issue because the function WlanScan(https://msdn.microsoft.com/zh-cn/library/windows/desktop/ms706783(v=vs.85).aspx) returns a error code 0x80342002 when the WLAN is disabled on Windows 10. ctypes.WinError() raise an exception of 'Python int too large to convert to C long' when handle this error code. |
|
|
| msg279009 - (view) |
Author: Kelvin You (Kelvin You) |
Date: 2016-10-20 03:53 |
| Here is the full list of windows error code: https://msdn.microsoft.com/en-us/library/cc231196.aspx You can see a lot of error codes is above 0x80000000. |
|
|
| msg279033 - (view) |
Author: Steve Dower (steve.dower) *  |
Date: 2016-10-20 14:15 |
| All HRESULT values are, since the topmost bit indicates that it's an error, but all the others should be 16-bit positive integers IIRC. I don't think this function is meant to work with HRESULTs, but I could be wrong - fairly sure it's meant for Win32 error codes, though I'd have to dig into the format function it calls. What function are you calling that produces an HRESULT from GetLastError? |
|
|
| msg279047 - (view) |
Author: Eryk Sun (eryksun) * |
Date: 2016-10-20 16:48 |
| Kelvin is calling WlanScan [1], which returns an error code that apparently can include HRESULT (signed) values cast as DWORD (unsigned) values, including 0x80342002 (ERROR_NDIS_DOT11_POWER_STATE_INVALID). ctypes.FormatError calls FormatMessage [2] with the flag FORMAT_MESSAGE_FROM_SYSTEM. About half of the system error codes defined in winerror.h consist of COM HRESULT codes. But, to clarify Kelvin's link [3], this does not include NTSTATUS values from kernel-mode system calls. NTSTATUS values require the ntdll.dll message table. [1]: https://msdn.microsoft.com/en-us/library/ms706783 [2]: https://msdn.microsoft.com/en-us/library/ms679351 [3]: https://msdn.microsoft.com/en-us/library/cc231196 A workaround in this case is to use the default c_int restype to return the error as a signed integer: >>> ctypes.FormatError(0x80342002 - 2**32) "The wireless local area network interface is powered down and doesn't support the requested operation." A similar workaround works for setting the exit code to an HRESULT or NTSTATUS error code: >>> hex(subprocess.call('python -c "import os; os._exit(0xC0000001)"')) Traceback (most recent call last): File "", line 1, in OverflowError: Python int too large to convert to C long '0x1' >>> hex(subprocess.call('python -c "import sys; sys.exit(0xC0000001)"')) '0xffffffff' >>> hex(subprocess.call('python -c "import os; os._exit(0xC0000001 - 2**32)"')) '0xc0000001' >>> hex(subprocess.call('python -c "import sys; sys.exit(0xC0000001 - 2**32)"')) '0xc0000001' |
|
|
| msg387744 - (view) |
Author: Eryk Sun (eryksun) * |
Date: 2021-02-26 20:32 |
| format_error() can use format "L" (long long) and then check for a value in the accepted range `value >= LONG_MIN && value <= ULONG_MAX`. If the value is out of range, raise OverflowError. Otherwise assign the value to DWORD `code`. |
|
|
| msg400134 - (view) |
Author: Adam Meily (meilyadam) * |
Date: 2021-08-23 13:22 |
| I can potentially take a stab at writing up a PR for this. I've also seen this affecting other locations that eventually call FormatMessage, including: - ctypes.format_error() - this original issue - os.strerror() - OSError(winerror=X) I will most likely look into fixing all three. |
|
|