diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 10549d6f..5134ed7 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -506,17 +506,6 @@
                                             ULONG, struct _Py_stat_struct *);
 #endif
 
-#ifdef MS_WINDOWS
-static int
-win32_warn_bytes_api()
-{
-    return PyErr_WarnEx(PyExc_DeprecationWarning,
-        "The Windows bytes API has been deprecated, "
-        "use Unicode filenames instead",
-        1);
-}
-#endif
-
 
 #ifndef MS_WINDOWS
 PyObject *
@@ -3334,83 +3323,99 @@
 static PyObject *
 posix_getcwd(int use_bytes)
 {
-    char *buf, *tmpbuf;
-    char *cwd;
-    const size_t chunk = 1024;
-    size_t buflen = 0;
-    PyObject *obj;
-
 #ifdef MS_WINDOWS
-    if (!use_bytes) {
-        wchar_t wbuf[MAXPATHLEN];
-        wchar_t *wbuf2 = wbuf;
-        PyObject *resobj;
-        DWORD len;
-        Py_BEGIN_ALLOW_THREADS
-        len = GetCurrentDirectoryW(Py_ARRAY_LENGTH(wbuf), wbuf);
-        /* If the buffer is large enough, len does not include the
-           terminating \0. If the buffer is too small, len includes
-           the space needed for the terminator. */
-        if (len >= Py_ARRAY_LENGTH(wbuf)) {
+    wchar_t wbuf[MAXPATHLEN];
+    wchar_t *wbuf2 = wbuf;
+    DWORD len;
+
+    Py_BEGIN_ALLOW_THREADS
+    len = GetCurrentDirectoryW(Py_ARRAY_LENGTH(wbuf), wbuf);
+    /* If the buffer is large enough, len does not include the
+       terminating \0. If the buffer is too small, len includes
+       the space needed for the terminator. */
+    if (len >= Py_ARRAY_LENGTH(wbuf)) {
+        if (len >= PY_SSIZE_T_MAX / sizeof(wchar_t)) {
             wbuf2 = PyMem_RawMalloc(len * sizeof(wchar_t));
-            if (wbuf2)
-                len = GetCurrentDirectoryW(len, wbuf2);
         }
-        Py_END_ALLOW_THREADS
-        if (!wbuf2) {
-            PyErr_NoMemory();
-            return NULL;
+        else {
+            wbuf2 = NULL;
         }
-        if (!len) {
-            if (wbuf2 != wbuf)
-                PyMem_RawFree(wbuf2);
-            return PyErr_SetFromWindowsErr(0);
+        if (wbuf2) {
+            len = GetCurrentDirectoryW(len, wbuf2);
         }
-        resobj = PyUnicode_FromWideChar(wbuf2, len);
+    }
+    Py_END_ALLOW_THREADS
+
+    if (!wbuf2) {
+        PyErr_NoMemory();
+        return NULL;
+    }
+    if (!len) {
         if (wbuf2 != wbuf)
             PyMem_RawFree(wbuf2);
-        return resobj;
+        return PyErr_SetFromWindowsErr(0);
     }
 
-    if (win32_warn_bytes_api())
-        return NULL;
-#endif
+    PyObject *resobj = PyUnicode_FromWideChar(wbuf2, len);
+    if (wbuf2 != wbuf) {
+        PyMem_RawFree(wbuf2);
+    }
 
-    buf = cwd = NULL;
+    if (use_bytes) {
+        if (resobj == NULL) {
+            return NULL;
+        }
+        Py_SETREF(resobj, PyUnicode_EncodeFSDefault(resobj));
+    }
+
+    return resobj;
+#else
+    const size_t chunk = 1024;
+
+    char *buf = NULL;
+    char *cwd = NULL;
+    size_t buflen = 0;
+
     Py_BEGIN_ALLOW_THREADS
     do {
-        buflen += chunk;
-#ifdef MS_WINDOWS
-        if (buflen > INT_MAX) {
-            PyErr_NoMemory();
+        char *newbuf;
+        if (buflen <= PY_SSIZE_T_MAX - chunk) {
+            buflen += chunk;
+            newbuf = PyMem_RawRealloc(buf, buflen);
+        }
+        else {
+            newbuf = NULL;
+        }
+        if (newbuf == NULL) {
+            PyMem_RawFree(buf);
+            buf = NULL;
             break;
         }
-#endif
-        tmpbuf = PyMem_RawRealloc(buf, buflen);
-        if (tmpbuf == NULL)
-            break;
+        buf = newbuf;
 
-        buf = tmpbuf;
-#ifdef MS_WINDOWS
-        cwd = getcwd(buf, (int)buflen);
-#else
         cwd = getcwd(buf, buflen);
-#endif
     } while (cwd == NULL && errno == ERANGE);
     Py_END_ALLOW_THREADS
 
+    if (buf == NULL) {
+        return PyErr_NoMemory();
+    }
     if (cwd == NULL) {
         PyMem_RawFree(buf);
         return posix_error();
     }
 
-    if (use_bytes)
+    PyObject *obj;
+    if (use_bytes) {
         obj = PyBytes_FromStringAndSize(buf, strlen(buf));
-    else
+    }
+    else {
         obj = PyUnicode_DecodeFSDefault(buf);
+    }
     PyMem_RawFree(buf);
 
     return obj;
+#endif   /* !MS_WINDOWS */
 }