From b64c89bd7abf05baad517b50cef7bc7de7b4eb74 Mon Sep 17 00:00:00 2001 From: Brian Curtin Date: Tue, 25 May 2010 15:06:15 +0000 Subject: 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 | 136 ++++++++++++++++++++++++++++++++++++------------ 3 files changed, 159 insertions(+), 33 deletions(-) diff --git a/Lib/test/test_winreg.py b/Lib/test/test_winreg.py index 753be74..da3a918 100644 --- a/Lib/test/test_winreg.py +++ b/Lib/test/test_winreg.py @@ -4,6 +4,7 @@ import os, sys import unittest from test import test_support +threading = test_support.import_module("threading") from platform import machine # Do this first so test will be skipped if module doesn't exist @@ -231,6 +232,58 @@ class LocalWinregTests(BaseWinregTests): 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, None) + # 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 7b74743..9d69378 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -63,6 +63,9 @@ 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 #8674: Fixed a number of incorrect or undefined-behaviour-inducing overflow checks in the ``audioop`` module. diff --git a/PC/_winreg.c b/PC/_winreg.c index 6872603..d3c39f9 100644 --- a/PC/_winreg.c +++ b/PC/_winreg.c @@ -1153,7 +1153,14 @@ PyEnumKey(PyObject *self, PyObject *args) int index; long rc; PyObject *retStr; - char 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. */ + char tmpbuf[257]; DWORD len = sizeof(tmpbuf); /* includes NULL terminator */ if (!PyArg_ParseTuple(args, "Oi:EnumKey", &obKey, &index)) @@ -1180,8 +1187,8 @@ PyEnumValue(PyObject *self, PyObject *args) long rc; char *retValueBuf; char *retDataBuf; - DWORD retValueSize; - DWORD retDataSize; + DWORD retValueSize, bufValueSize; + DWORD retDataSize, bufDataSize; DWORD typ; PyObject *obData; PyObject *retVal; @@ -1199,6 +1206,8 @@ PyEnumValue(PyObject *self, PyObject *args) "RegQueryInfoKey"); ++retValueSize; /* include null terminators */ ++retDataSize; + bufDataSize = retDataSize; + bufValueSize = retValueSize; retValueBuf = (char *)PyMem_Malloc(retValueSize); if (retValueBuf == NULL) return PyErr_NoMemory(); @@ -1208,16 +1217,33 @@ PyEnumValue(PyObject *self, PyObject *args) return PyErr_NoMemory(); } - Py_BEGIN_ALLOW_THREADS - rc = RegEnumValue(hKey, - index, - retValueBuf, - &retValueSize, - NULL, - &typ, - (BYTE *)retDataBuf, - &retDataSize); - Py_END_ALLOW_THREADS + while (1) { + char *tmp; + Py_BEGIN_ALLOW_THREADS + rc = RegEnumValue(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, @@ -1374,28 +1400,56 @@ PyQueryValue(PyObject *self, PyObject *args) long rc; PyObject *retStr; char *retBuf; - long bufSize = 0; + DWORD bufSize = 0; + DWORD retSize = 0; + char *tmp; if (!PyArg_ParseTuple(args, "Oz:QueryValue", &obKey, &subKey)) return NULL; if (!PyHKEY_AsHKEY(obKey, &hKey, FALSE)) return NULL; - if ((rc = RegQueryValue(hKey, subKey, NULL, &bufSize)) - != ERROR_SUCCESS) + + rc = RegQueryValue(hKey, subKey, NULL, &retSize); + if (rc == ERROR_MORE_DATA) + retSize = 256; + else if (rc != ERROR_SUCCESS) return PyErr_SetFromWindowsErrWithFunction(rc, "RegQueryValue"); - retStr = PyString_FromStringAndSize(NULL, bufSize); - if (retStr == NULL) - return NULL; - retBuf = PyString_AS_STRING(retStr); - if ((rc = RegQueryValue(hKey, subKey, retBuf, &bufSize)) - != ERROR_SUCCESS) { - Py_DECREF(retStr); + + bufSize = retSize; + retBuf = (char *) PyMem_Malloc(bufSize); + if (retBuf == NULL) + return PyErr_NoMemory(); + + while (1) { + retSize = bufSize; + rc = RegQueryValue(hKey, subKey, 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, "RegQueryValue"); } - _PyString_Resize(&retStr, strlen(retBuf)); + + if (retBuf[retSize-1] == '\x00') + retSize--; + retStr = PyString_FromStringAndSize(retBuf, retSize); + if (retStr == NULL) { + PyMem_Free(retBuf); + return NULL; + } return retStr; } @@ -1407,8 +1461,8 @@ PyQueryValueEx(PyObject *self, PyObject *args) char *valueName; long rc; - char *retBuf; - DWORD bufSize = 0; + char *retBuf, *tmp; + DWORD bufSize = 0, retSize; DWORD typ; PyObject *obData; PyObject *result; @@ -1418,18 +1472,34 @@ PyQueryValueEx(PyObject *self, PyObject *args) if (!PyHKEY_AsHKEY(obKey, &hKey, FALSE)) return NULL; - if ((rc = RegQueryValueEx(hKey, valueName, - NULL, NULL, NULL, - &bufSize)) - != ERROR_SUCCESS) + + rc = RegQueryValueEx(hKey, valueName, NULL, NULL, NULL, &bufSize); + if (rc == ERROR_MORE_DATA) + bufSize = 256; + else if (rc != ERROR_SUCCESS) return PyErr_SetFromWindowsErrWithFunction(rc, "RegQueryValueEx"); retBuf = (char *)PyMem_Malloc(bufSize); if (retBuf == NULL) return PyErr_NoMemory(); - if ((rc = RegQueryValueEx(hKey, valueName, NULL, - &typ, (BYTE *)retBuf, &bufSize)) - != ERROR_SUCCESS) { + + while (1) { + retSize = bufSize; + rc = RegQueryValueEx(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"); -- cgit v0.12