New submission from Eryk Sun <eryk...@gmail.com>:
In Windows, os.device_encoding() is hard coded to map file descriptor 0 and descriptors 1 and 2 respectively to the console's input and output code page if isatty(fd) is true. But isatty() is true for any character device, such as "NUL". Also any fd might be a console, by way of dup(), dup2() -- or open() with the device names "CON", "CONIN$", and "CONOUT$". The correct device encoding of a console file is needed for use with os.read() and os.write(). It's also necessary for io.TextIOWrapper() if PYTHONLEGACYWINDOWSSTDIO is set. _Py_device_encoding() in Python/fileutils.c should use _get_osfhandle() to get the OS handle, and, if it's a character-device file, determine the code page to return, if any, depending on whether it's an input or output console file. For example: PyObject * _Py_device_encoding(int fd) { #if defined(MS_WINDOWS) HANDLE handle; DWORD temp; UINT cp = 0; _Py_BEGIN_SUPPRESS_IPH handle = (HANDLE)_get_osfhandle(fd); _Py_END_SUPPRESS_IPH if (handle == INVALID_HANDLE_VALUE || GetFileType(handle) != FILE_TYPE_CHAR) Py_RETURN_NONE; Py_BEGIN_ALLOW_THREADS /* GetConsoleMode requires a console handle. */ if (!GetConsoleMode(handle, &temp)) { /* Assume access denied implies output. */ if (GetLastError() == ERROR_ACCESS_DENIED) cp = GetConsoleOutputCP(); } else { if (GetNumberOfConsoleInputEvents(handle, &temp)) { cp = GetConsoleCP(); } else { cp = GetConsoleOutputCP(); } } Py_END_ALLOW_THREADS if (cp == CP_UTF8) { return PyUnicode_FromString("UTF-8"); } else if (cp != 0) { return PyUnicode_FromFormat("cp%u", (unsigned int)cp); } else { Py_RETURN_NONE; } #else if (isatty(fd)) { return _Py_GetLocaleEncodingObject(); } else { Py_RETURN_NONE; } #endif /* defined(MS_WINDOWS) */ } ---------- components: Extension Modules, IO, Interpreter Core, Windows messages: 388201 nosy: eryksun, paul.moore, steve.dower, tim.golden, zach.ware priority: normal severity: normal status: open title: os.device_encoding(fd) should support any console fd in Windows type: behavior versions: Python 3.10, Python 3.8, Python 3.9 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue43421> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com