diff -r 4d89d03690ef Modules/posixmodule.c
--- a/Modules/posixmodule.c	Sun Aug 31 15:48:55 2014 +0200
+++ b/Modules/posixmodule.c	Tue Sep 02 00:52:30 2014 +0200
@@ -784,6 +784,7 @@ typedef struct {
 
 static void
 path_cleanup(path_t *path) {
+    PyMem_Free(path->wide);
     if (path->cleanup) {
         Py_CLEAR(path->cleanup);
     }
@@ -809,6 +810,7 @@ path_converter(PyObject *o, void *p) {
     }
 
     /* ensure it's always safe to call path_cleanup() */
+    path->wide = NULL;
     path->cleanup = NULL;
 
     if (o == Py_None) {
@@ -830,13 +832,14 @@ path_converter(PyObject *o, void *p) {
 #ifdef MS_WINDOWS
         wchar_t *wide;
 
-        wide = PyUnicode_AsUnicodeAndSize(unicode, &length);
+        wide = PyUnicode_AsWideCharString(unicode, &length);
         if (!wide) {
             Py_DECREF(unicode);
             return 0;
         }
         if (length > 32767) {
             FORMAT_EXCEPTION(PyExc_ValueError, "%s too long for Windows");
+            PyMem_Free(wide);
             Py_DECREF(unicode);
             return 0;
         }
@@ -4754,7 +4757,7 @@ posix__getfullpathname(PyObject *self, P
         DWORD result;
         PyObject *v;
 
-        wpath = PyUnicode_AsUnicode(po);
+        wpath = PyUnicode_AsWideCharString(po, NULL);
         if (wpath == NULL)
             return NULL;
         result = GetFullPathNameW(wpath,
@@ -4762,10 +4765,13 @@ posix__getfullpathname(PyObject *self, P
                                   woutbuf, &wtemp);
         if (result > Py_ARRAY_LENGTH(woutbuf)) {
             woutbufp = PyMem_Malloc(result * sizeof(wchar_t));
-            if (!woutbufp)
+            if (!woutbufp) {
+                PyMem_Free(wpath);
                 return PyErr_NoMemory();
+            }
             result = GetFullPathNameW(wpath, result, woutbufp, &wtemp);
         }
+        PyMem_Free(wpath);
         if (result)
             v = PyUnicode_FromWideChar(woutbufp, wcslen(woutbufp));
         else
@@ -4844,10 +4850,6 @@ os__getfinalpathname_impl(PyModuleDef *m
     PyObject *result;
     wchar_t *path_wchar;
 
-    path_wchar = PyUnicode_AsUnicode(path);
-    if (path_wchar == NULL)
-        return NULL;
-
     if(!check_GetFinalPathNameByHandle()) {
         /* If the OS doesn't have GetFinalPathNameByHandle, return a
            NotImplementedError. */
@@ -4855,6 +4857,10 @@ os__getfinalpathname_impl(PyModuleDef *m
             "GetFinalPathNameByHandle not available on this platform");
     }
 
+    path_wchar = PyUnicode_AsWideCharString(path, NULL);
+    if (path_wchar == NULL)
+        return NULL;
+
     hFile = CreateFileW(
         path_wchar,
         0, /* desired access */
@@ -4865,6 +4871,8 @@ os__getfinalpathname_impl(PyModuleDef *m
         FILE_FLAG_BACKUP_SEMANTICS,
         NULL);
 
+    PyMem_Free(path_wchar);
+
     if(hFile == INVALID_HANDLE_VALUE)
         return win32_error_object("CreateFileW", path);
 
@@ -4905,11 +4913,12 @@ posix__isdir(PyObject *self, PyObject *a
     DWORD attributes;
 
     if (PyArg_ParseTuple(args, "U|:_isdir", &po)) {
-        wchar_t *wpath = PyUnicode_AsUnicode(po);
+        wchar_t *wpath = PyUnicode_AsWideCharString(po, NULL);
         if (wpath == NULL)
             return NULL;
 
         attributes = GetFileAttributesW(wpath);
+        PyMem_Free(wpath);
         if (attributes == INVALID_FILE_ATTRIBUTES)
             Py_RETURN_FALSE;
         goto check;
@@ -4980,7 +4989,7 @@ os__getvolumepathname_impl(PyModuleDef *
     size_t buflen;
     BOOL ret;
 
-    path_wchar = PyUnicode_AsUnicodeAndSize(path, &buflen);
+    path_wchar = PyUnicode_AsWideCharString(path, &buflen);
     if (path_wchar == NULL)
         return NULL;
     buflen += 1;
@@ -4990,12 +4999,14 @@ os__getvolumepathname_impl(PyModuleDef *
 
     if (buflen > DWORD_MAX) {
         PyErr_SetString(PyExc_OverflowError, "path too long");
-        return NULL;
+        goto exit;
     }
 
     mountpath = (wchar_t *)PyMem_Malloc(buflen * sizeof(wchar_t));
-    if (mountpath == NULL)
-        return PyErr_NoMemory();
+    if (mountpath == NULL) {
+        PyErr_NoMemory();
+        goto exit;
+    }
 
     Py_BEGIN_ALLOW_THREADS
     ret = GetVolumePathNameW(path_wchar, mountpath,
@@ -5010,6 +5021,7 @@ os__getvolumepathname_impl(PyModuleDef *
 
 exit:
     PyMem_Free(mountpath);
+    PyMem_Free(path_wchar);
     return result;
 }
 
@@ -10002,7 +10014,7 @@ win_readlink(PyObject *self, PyObject *a
                           ))
         return NULL;
 
-    path = PyUnicode_AsUnicode(po);
+    path = PyUnicode_AsWideCharString(po, NULL);
     if (path == NULL)
         return NULL;
 
@@ -10018,6 +10030,8 @@ win_readlink(PyObject *self, PyObject *a
         0);
     Py_END_ALLOW_THREADS
 
+    PyMem_Free(path);
+
     if (reparse_point_handle==INVALID_HANDLE_VALUE)
         return win32_error_object("readlink", po);
 
@@ -12930,13 +12944,15 @@ os_putenv_impl(PyModuleDef *module, PyOb
         goto error;
     }
 
-    env = PyUnicode_AsUnicode(unicode);
+    env = PyUnicode_AsWideCharString(unicode, NULL);
     if (env == NULL)
         goto error;
     if (_wputenv(env)) {
+        PyMem_Free(env);
         posix_error();
         goto error;
     }
+    PyMem_Free(env);
 
     posix_putenv_garbage_setitem(name, unicode);
     Py_RETURN_NONE;
@@ -15108,13 +15124,17 @@ win32_startfile(PyObject *self, PyObject
         }
     }
 
-    wpath = PyUnicode_AsUnicode(unipath);
-    if (wpath == NULL)
+    wpath = PyUnicode_AsWideCharString(unipath, NULL);
+    if (wpath == NULL) {
+        PyErr_Clear();
         goto normal;
+    }
     if (uoperation) {
-        woperation = PyUnicode_AsUnicode(uoperation);
-        if (woperation == NULL)
+        woperation = PyUnicode_AsWideCharString(uoperation, NULL);
+        if (woperation == NULL) {
+            PyMem_Free(wpath);
             goto normal;
+        }
     }
     else
         woperation = NULL;
@@ -15124,6 +15144,8 @@ win32_startfile(PyObject *self, PyObject
                        NULL, NULL, SW_SHOWNORMAL);
     Py_END_ALLOW_THREADS
 
+    PyMem_Free(wpath);
+
     Py_XDECREF(uoperation);
     if (rc <= (HINSTANCE)32) {
         win32_error_object("startfile", unipath);