[Python-checkins] r51215 - python/trunk/Modules/_ctypes/callbacks.c
thomas.heller
python-checkins at python.org
Fri Aug 11 21:55:35 CEST 2006
Author: thomas.heller
Date: Fri Aug 11 21:55:35 2006
New Revision: 51215
Modified:
python/trunk/Modules/_ctypes/callbacks.c
Log:
When a ctypes C callback function is called, zero out the result
storage before converting the result to C data. See the comment in
the code for details.
Provide a better context for errors when the conversion of a callback
function's result cannot be converted.
Modified: python/trunk/Modules/_ctypes/callbacks.c
==============================================================================
--- python/trunk/Modules/_ctypes/callbacks.c (original)
+++ python/trunk/Modules/_ctypes/callbacks.c Fri Aug 11 21:55:35 2006
@@ -205,14 +205,24 @@
result = PyObject_CallObject(callable, arglist);
CHECK("'calling callback function'", result);
+#ifdef WORDS_BIGENDIAN
+ /* See the corresponding code in callproc.c, around line 961 */
+ if (restype->type != FFI_TYPE_FLOAT && restype->size < sizeof(ffi_arg))
+ mem = (char *)mem + sizeof(ffi_arg) - restype->size;
+#endif
+ /* The code that converts 'result' into C data is not executed when
+ 'callable' returns Py_None, so we zero out the memory that will
+ receive the C return data to not return random data.
+
+ Cleaner would be to call 'setfunc' anyway and complain with
+ PyErr_WriteUnraisable(), but ctypes has always accepted a Py_None
+ return value for *any* 'restype' and it would probably break too
+ much code if this is changed now.
+ */
+ memset(mem, 0, restype->size);
if ((restype != &ffi_type_void) && result && result != Py_None) {
PyObject *keep;
assert(setfunc);
-#ifdef WORDS_BIGENDIAN
- /* See the corresponding code in callproc.c, around line 961 */
- if (restype->type != FFI_TYPE_FLOAT && restype->size < sizeof(ffi_arg))
- mem = (char *)mem + sizeof(ffi_arg) - restype->size;
-#endif
keep = setfunc(mem, result, 0);
CHECK("'converting callback result'", keep);
/* keep is an object we have to keep alive so that the result
@@ -225,13 +235,13 @@
itself knows how to manage the refcount of these objects.
*/
if (keep == NULL) /* Could not convert callback result. */
- PyErr_WriteUnraisable(Py_None);
+ PyErr_WriteUnraisable(callable);
else if (keep == Py_None) /* Nothing to keep */
Py_DECREF(keep);
else if (setfunc != getentry("O")->setfunc) {
if (-1 == PyErr_Warn(PyExc_RuntimeWarning,
"memory leak in callback function."))
- PyErr_WriteUnraisable(Py_None);
+ PyErr_WriteUnraisable(callable);
}
}
Py_XDECREF(result);
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