From 60853211da1d3c450b6371ebfaedade04a908f21 Mon Sep 17 00:00:00 2001 From: Brian Curtin Date: Wed, 26 May 2010 17:43:50 +0000 Subject: [PATCH] Fix #2810 - handle the case where some registry calls return ERROR_MORE_DATA, requiring another call to get the remaining data. Patch by Daniel Stutzbach --- Lib/test/test_winreg.py | 53 ++++++++++++++++++ Misc/NEWS | 3 + PC/winreg.c | 119 ++++++++++++++++++++++++++++++---------- 3 files changed, 147 insertions(+), 28 deletions(-) diff --git a/Lib/test/test_winreg.py b/Lib/test/test_winreg.py index e29a727ef89..c5ee846460c 100644 --- a/Lib/test/test_winreg.py +++ b/Lib/test/test_winreg.py @@ -5,6 +5,7 @@ import os, sys import unittest from test import support +threading = support.import_module("threading") from platform import machine # Do this first so test will be skipped if module doesn't exist @@ -227,6 +228,58 @@ def test_context_manager(self): except WindowsError: self.assertEqual(h.handle, 0) + def test_changing_value(self): + # Issue2810: A race condition in 2.6 and 3.1 may cause + # EnumValue or QueryValue to throw "WindowsError: More data is + # available" + done = False + + class VeryActiveThread(threading.Thread): + def run(self): + with CreateKey(HKEY_CURRENT_USER, test_key_name) as key: + use_short = True + long_string = 'x'*2000 + while not done: + s = 'x' if use_short else long_string + use_short = not use_short + SetValue(key, 'changing_value', REG_SZ, s) + + thread = VeryActiveThread() + thread.start() + try: + with CreateKey(HKEY_CURRENT_USER, + test_key_name+'\\changing_value') as key: + for _ in range(1000): + num_subkeys, num_values, t = QueryInfoKey(key) + for i in range(num_values): + name = EnumValue(key, i) + QueryValue(key, name[0]) + finally: + done = True + thread.join() + DeleteKey(HKEY_CURRENT_USER, test_key_name+'\\changing_value') + DeleteKey(HKEY_CURRENT_USER, test_key_name) + + def test_long_key(self): + # Issue2810, in 2.6 and 3.1 when the key name was exactly 256 + # characters, EnumKey threw "WindowsError: More data is + # available" + name = 'x'*256 + try: + with CreateKey(HKEY_CURRENT_USER, test_key_name) as key: + SetValue(key, name, REG_SZ, 'x') + num_subkeys, num_values, t = QueryInfoKey(key) + EnumKey(key, 0) + finally: + DeleteKey(HKEY_CURRENT_USER, '\\'.join((test_key_name, name))) + DeleteKey(HKEY_CURRENT_USER, test_key_name) + + def test_dynamic_key(self): + # Issue2810, when the value is dynamically generated, these + # throw "WindowsError: More data is available" in 2.6 and 3.1 + EnumValue(HKEY_PERFORMANCE_DATA, 0) + QueryValueEx(HKEY_PERFORMANCE_DATA, "") + # Reflection requires XP x64/Vista at a minimum. XP doesn't have this stuff # or DeleteKeyEx so make sure their use raises NotImplementedError @unittest.skipUnless(WIN_VER < (5, 2), "Requires Windows XP") diff --git a/Misc/NEWS b/Misc/NEWS index 2065bb6e3c1..22e8dc80a61 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -1220,6 +1220,9 @@ Library Extension Modules ----------------- +- Issue #2810: Fix cases where the Windows registry API returns + ERROR_MORE_DATA, requiring a re-try in order to get the complete result. + - Issue #8692: Optimize math.factorial: replace the previous naive algorithm with an improved 'binary-split' algorithm that uses fewer multiplications and allows many of the multiplications to be diff --git a/PC/winreg.c b/PC/winreg.c index 5dc5dde1ebb..8f89a003336 100644 --- a/PC/winreg.c +++ b/PC/winreg.c @@ -1096,7 +1096,14 @@ PyEnumKey(PyObject *self, PyObject *args) int index; long rc; PyObject *retStr; - wchar_t tmpbuf[256]; /* max key name length is 255 */ + + /* The Windows docs claim that the max key name length is 255 + * characters, plus a terminating nul character. However, + * empirical testing demonstrates that it is possible to + * create a 256 character key that is missing the terminating + * nul. RegEnumKeyEx requires a 257 character buffer to + * retrieve such a key name. */ + wchar_t tmpbuf[257]; DWORD len = sizeof(tmpbuf); /* includes NULL terminator */ if (!PyArg_ParseTuple(args, "Oi:EnumKey", &obKey, &index)) @@ -1123,8 +1130,8 @@ PyEnumValue(PyObject *self, PyObject *args) long rc; wchar_t *retValueBuf; BYTE *retDataBuf; - DWORD retValueSize; - DWORD retDataSize; + DWORD retValueSize, bufValueSize; + DWORD retDataSize, bufDataSize; DWORD typ; PyObject *obData; PyObject *retVal; @@ -1142,6 +1149,8 @@ PyEnumValue(PyObject *self, PyObject *args) "RegQueryInfoKey"); ++retValueSize; /* include null terminators */ ++retDataSize; + bufDataSize = retDataSize; + bufValueSize = retValueSize; retValueBuf = (wchar_t *)PyMem_Malloc(sizeof(wchar_t) * retValueSize); if (retValueBuf == NULL) return PyErr_NoMemory(); @@ -1151,16 +1160,33 @@ PyEnumValue(PyObject *self, PyObject *args) return PyErr_NoMemory(); } - Py_BEGIN_ALLOW_THREADS - rc = RegEnumValueW(hKey, - index, - retValueBuf, - &retValueSize, - NULL, - &typ, - retDataBuf, - &retDataSize); - Py_END_ALLOW_THREADS + while (1) { + wchar_t *tmp; + Py_BEGIN_ALLOW_THREADS + rc = RegEnumValueW(hKey, + index, + retValueBuf, + &retValueSize, + NULL, + &typ, + (BYTE *)retDataBuf, + &retDataSize); + Py_END_ALLOW_THREADS + + if (rc != ERROR_MORE_DATA) + break; + + bufDataSize *= 2; + tmp = (char *)PyMem_Realloc(retDataBuf, bufDataSize); + if (tmp == NULL) { + PyErr_NoMemory(); + retVal = NULL; + goto fail; + } + retDataBuf = tmp; + retDataSize = bufDataSize; + retValueSize = bufValueSize; + } if (rc != ERROR_SUCCESS) { retVal = PyErr_SetFromWindowsErrWithFunction(rc, @@ -1317,23 +1343,44 @@ PyQueryValue(PyObject *self, PyObject *args) long rc; PyObject *retStr; wchar_t *retBuf; - long bufSize = 0; + DWORD bufSize = 0; + DWORD retSize = 0; + wchar_t *tmp; if (!PyArg_ParseTuple(args, "OZ:QueryValue", &obKey, &subKey)) return NULL; if (!PyHKEY_AsHKEY(obKey, &hKey, FALSE)) return NULL; - if ((rc = RegQueryValueW(hKey, subKey, NULL, &bufSize)) - != ERROR_SUCCESS) + + rc = RegQueryValueW(hKey, subKey, NULL, &retSize); + if (rc == ERROR_MORE_DATA) + retSize = 256; + else if (rc != ERROR_SUCCESS) return PyErr_SetFromWindowsErrWithFunction(rc, "RegQueryValue"); - retBuf = (wchar_t *)PyMem_Malloc(bufSize); + + bufSize = retSize; + retBuf = (wchar_t *) PyMem_Malloc(bufSize); if (retBuf == NULL) return PyErr_NoMemory(); - if ((rc = RegQueryValueW(hKey, subKey, retBuf, &bufSize)) - != ERROR_SUCCESS) { + while (1) { + retSize = bufSize; + rc = RegQueryValueW(hKey, subKey, retBuf, &retSize); + if (rc != ERROR_MORE_DATA) + break; + + bufSize *= 2; + tmp = (wchar_t *) PyMem_Realloc(retBuf, bufSize); + if (tmp == NULL) { + PyMem_Free(retBuf); + return PyErr_NoMemory(); + } + retBuf = tmp; + } + + if (rc != ERROR_SUCCESS) { PyMem_Free(retBuf); return PyErr_SetFromWindowsErrWithFunction(rc, "RegQueryValue"); @@ -1352,8 +1399,8 @@ PyQueryValueEx(PyObject *self, PyObject *args) wchar_t *valueName; long rc; - BYTE *retBuf; - DWORD bufSize = 0; + BYTE *retBuf, *tmp; + DWORD bufSize = 0, retSize; DWORD typ; PyObject *obData; PyObject *result; @@ -1363,18 +1410,34 @@ PyQueryValueEx(PyObject *self, PyObject *args) if (!PyHKEY_AsHKEY(obKey, &hKey, FALSE)) return NULL; - if ((rc = RegQueryValueExW(hKey, valueName, - NULL, NULL, NULL, - &bufSize)) - != ERROR_SUCCESS) + + rc = RegQueryValueExW(hKey, valueName, NULL, NULL, NULL, &bufSize); + if (rc == ERROR_MORE_DATA) + bufSize = 256; + else if (rc != ERROR_SUCCESS) return PyErr_SetFromWindowsErrWithFunction(rc, "RegQueryValueEx"); retBuf = (BYTE *)PyMem_Malloc(bufSize); if (retBuf == NULL) return PyErr_NoMemory(); - if ((rc = RegQueryValueExW(hKey, valueName, NULL, - &typ, retBuf, &bufSize)) - != ERROR_SUCCESS) { + + while (1) { + retSize = bufSize; + rc = RegQueryValueExW(hKey, valueName, NULL, &typ, + (BYTE *)retBuf, &retSize); + if (rc != ERROR_MORE_DATA) + break; + + bufSize *= 2; + tmp = (char *) PyMem_Realloc(retBuf, bufSize); + if (tmp == NULL) { + PyMem_Free(retBuf); + return PyErr_NoMemory(); + } + retBuf = tmp; + } + + if (rc != ERROR_SUCCESS) { PyMem_Free(retBuf); return PyErr_SetFromWindowsErrWithFunction(rc, "RegQueryValueEx");