talloc: add pytalloc_get_name() helper

In several places we go

   talloc_get_name(pytalloc_get_ptr(py_obj))

which is a certain NULL derefernce if py_obj is not a talloc object.

This is a helper function that chooses to say "non-talloc object"
rather than crash.

Signed-off-by: Douglas Bagnall <[email protected]>
Reviewed-by: Gary Lockyer <[email protected]>
Reviewed-by: Andrew Bartlett <[email protected]>

lib/talloc/pytalloc.h

@@ -54,6 +54,10 @@ void *_pytalloc_get_ptr(PyObject *py_obj);
 TALLOC_CTX *_pytalloc_get_mem_ctx(PyObject *py_obj);
 #define pytalloc_get_mem_ctx(py_obj) _pytalloc_get_mem_ctx((PyObject *)(py_obj))
 
+const char *_pytalloc_get_name(PyObject *py_obj);
+#define pytalloc_get_name(py_obj) _pytalloc_get_name((PyObject *)(py_obj))
+
+
 PyObject *pytalloc_steal_ex(PyTypeObject *py_type, TALLOC_CTX *mem_ctx, void *ptr);
 PyObject *pytalloc_steal(PyTypeObject *py_type, void *ptr);
 PyObject *pytalloc_reference_ex(PyTypeObject *py_type, TALLOC_CTX *mem_ctx, void *ptr);

lib/talloc/pytalloc_util.c

@@ -331,3 +331,12 @@ _PUBLIC_ int pytalloc_BaseObject_PyType_Ready(PyTypeObject *type)
 
 	return PyType_Ready(type);
 }
+
+_PUBLIC_ const char *_pytalloc_get_name(PyObject *obj)
+{
+	void *ptr = pytalloc_get_ptr(obj);
+	if (ptr == NULL) {
+		return "non-talloc object";
+	}
+	return talloc_get_name(ptr);
+}