* [PATCH 0/4] Python safety initial work
@ 2026-05-15 18:23 Tom Tromey
2026-05-15 18:23 ` [PATCH 1/4] Add gdbpy_borrowed_ref Tom Tromey
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: Tom Tromey @ 2026-05-15 18:23 UTC (permalink / raw)
To: gdb-patches; +Cc: Tom Tromey
I rewrote my earlier Python safety series to use methods a while back.
And while I like the result, I got bogged down converting things, so I
thought I'd send some initial work, with the idea that if this looks
good, other code can be transformed in pieces.
Since this is extracted from a larger series, there is some code in
here that isn't currently used in-tree. This is mainly true for the
gdb functions that wrap Python APIs, see patch 2.
Patch 4 shows what the end effect is, but the patch is somewhat hard
to read IMO. So for instance now the 'title' getter for a TUI window
is just an ordinary method:
const std::string &
gdbpy_tui_window::title ()
{
require_valid ();
return window->title ();
}
Since it wants to only operate on a valid window, require_valid will
throw if that isn't the case.
Note there's no explicit error checking, no casts, no messing with
reference counts, and the return type is just a string. All these
boilerplate details are handled by a template wrapper function.
Signed-off-by: Tom Tromey <tom@tromey.com>
---
Tom Tromey (4):
Add gdbpy_borrowed_ref
Add wrappers for some Python APIs
Add wrappers for Python implementation functions and methods
Convert py-tui.c to the "python safety" approach
gdb/python/py-ref.h | 80 +++++++++++
gdb/python/py-safety.h | 321 +++++++++++++++++++++++++++++++++++++++++
gdb/python/py-tui.c | 208 +++++++++++----------------
gdb/python/py-wrappers.h | 334 +++++++++++++++++++++++++++++++++++++++++++
gdb/python/python-internal.h | 8 +-
gdb/python/python.c | 5 +-
6 files changed, 830 insertions(+), 126 deletions(-)
---
base-commit: 776715ea683b93c0415fc4eb31b4fcec5f2153fc
change-id: 20260515-python-safety-initial-422bf34a8ce3
Best regards,
--
Tom Tromey <tom@tromey.com>
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 1/4] Add gdbpy_borrowed_ref
2026-05-15 18:23 [PATCH 0/4] Python safety initial work Tom Tromey
@ 2026-05-15 18:23 ` Tom Tromey
2026-05-15 18:23 ` [PATCH 2/4] Add wrappers for some Python APIs Tom Tromey
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Tom Tromey @ 2026-05-15 18:23 UTC (permalink / raw)
To: gdb-patches; +Cc: Tom Tromey
This adds new gdbpy_opt_borrowed_ref and gdbpy_borrowed_ref classes.
These class is primarily for code "documentation" purposes -- it makes
it clear to the reader that a given reference is borrowed. However,
they also add a tiny bit of safety, in that conversion to gdbpy_ref<>
will either be rejected (by the "opt" class) or acquire a new
reference.
---
gdb/python/py-ref.h | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 80 insertions(+)
diff --git a/gdb/python/py-ref.h b/gdb/python/py-ref.h
index dc0b14814af..ef6b9fb427c 100644
--- a/gdb/python/py-ref.h
+++ b/gdb/python/py-ref.h
@@ -41,6 +41,86 @@ struct gdbpy_ref_policy
template<typename T = PyObject> using gdbpy_ref
= gdb::ref_ptr<T, gdbpy_ref_policy>;
+/* A class representing an optional borrowed reference. It is
+ "optional" because NULL is a valid value.
+
+ This is a simple wrapper for a PyObject*. Aside from documenting
+ what the code does, the main advantage of using this is that
+ conversion to a gdbpy_ref<> is prevented.
+
+ An optional borrowed reference is only used in situations where
+ Python says NULL is valid. For example, it is used as the type of
+ the "keywords" argument to a varargs method. Most code should
+ prefer an ordinary gdbpy_borrowed_ref, see below. */
+class gdbpy_opt_borrowed_ref
+{
+public:
+
+ gdbpy_opt_borrowed_ref (PyObject *obj)
+ : m_obj (obj)
+ {
+ }
+
+ template<typename T>
+ gdbpy_opt_borrowed_ref (const gdbpy_ref<T> &ref)
+ : m_obj (ref.get ())
+ {
+ }
+
+ operator PyObject * ()
+ {
+ return m_obj;
+ }
+
+ operator gdbpy_ref<> () = delete;
+
+protected:
+ PyObject *m_obj;
+};
+
+/* A borrowed reference that is guaranteed not to be NULL.
+
+ Like gdbpy_opt_borrowed_ref, this mostly serves a documentary
+ purpose. However, it also allows a checked cast to any subclass of
+ PyObject, and conversion to a gdbpy_ref<> will automatically
+ acquire a new reference -- a safety improvement over plain
+ PyObject*. */
+class gdbpy_borrowed_ref : public gdbpy_opt_borrowed_ref
+{
+public:
+
+ gdbpy_borrowed_ref (PyObject *obj)
+ : gdbpy_opt_borrowed_ref (obj)
+ {
+ gdb_assert (m_obj != nullptr);
+ }
+
+ template<typename T>
+ gdbpy_borrowed_ref (const gdbpy_ref<T> &ref)
+ : gdbpy_opt_borrowed_ref (ref)
+ {
+ gdb_assert (m_obj != nullptr);
+ }
+
+ gdbpy_borrowed_ref (std::nullptr_t) = delete;
+
+ /* Allow a (checked) conversion to any subclass of PyObject. */
+ template<typename T,
+ typename = std::is_convertible<T *, PyObject *>>
+ operator T * ()
+ {
+ gdb_assert (PyObject_TypeCheck (m_obj, T::corresponding_object_type));
+ return static_cast<T *> (m_obj);
+ }
+
+ /* When converting a borrowed reference to a gdbpy_ref<>, a new
+ reference is acquired. */
+ operator gdbpy_ref<> ()
+ {
+ return gdbpy_ref<>::new_reference (m_obj);
+ }
+};
+
/* A wrapper class for Python extension objects that have a __dict__ attribute.
Any Python C object extension needing __dict__ should inherit from this
--
2.49.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 2/4] Add wrappers for some Python APIs
2026-05-15 18:23 [PATCH 0/4] Python safety initial work Tom Tromey
2026-05-15 18:23 ` [PATCH 1/4] Add gdbpy_borrowed_ref Tom Tromey
@ 2026-05-15 18:23 ` Tom Tromey
2026-05-15 18:23 ` [PATCH 3/4] Add wrappers for Python implementation functions and methods Tom Tromey
2026-05-15 18:23 ` [PATCH 4/4] Convert py-tui.c to the "python safety" approach Tom Tromey
3 siblings, 0 replies; 5+ messages in thread
From: Tom Tromey @ 2026-05-15 18:23 UTC (permalink / raw)
To: gdb-patches; +Cc: Tom Tromey
This adds some new functions that wrap Python APIs. The wrapping
follows some proposed rules for Python safety in gdb:
* Functions returning a new reference return gdbpy_ref<>
* Errors are reported via exceptions, not special values
* Functions accepting a stolen reference take a gdbpy_ref<>&&
---
gdb/python/py-wrappers.h | 334 +++++++++++++++++++++++++++++++++++++++++++
gdb/python/python-internal.h | 2 +
2 files changed, 336 insertions(+)
diff --git a/gdb/python/py-wrappers.h b/gdb/python/py-wrappers.h
new file mode 100644
index 00000000000..78c1f8070cf
--- /dev/null
+++ b/gdb/python/py-wrappers.h
@@ -0,0 +1,334 @@
+/* Wrappers for some Python safety.
+
+ Copyright (C) 2026 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#ifndef GDB_PYTHON_PY_WRAPPERS_H
+#define GDB_PYTHON_PY_WRAPPERS_H
+
+#include "py-ref.h"
+
+/* Gdb implements its own wrappers for many Python APIs. This is done
+ in an attempt to be more safe.
+
+ In particular, in gdb:
+
+ - APIs returning a new reference will return gdbpy_ref<>. This
+ makes reference counting errors less likely.
+
+ - APIs will throw an exception rather than return a special value
+ (NULL or -1). This makes error checking simpler.
+
+ - APIs requiring a stolen reference take a gdbpy_ref<>&&, to make
+ reference counting errors less likely.
+
+ This file holds the currently-defined wrappers. If new APIs are
+ needed, the normal approach is to add a wrapper here.
+
+ APIs here are named after the underlying Python function, but using
+ lower case and an "_" at each word break. */
+
+/* The type of exception thrown when the Python exception has been
+ set. */
+struct gdb_python_exception
+{
+ gdb_python_exception ()
+ {
+ gdb_assert (PyErr_Occurred ());
+ }
+};
+
+template<typename T>
+gdbpy_ref<T>
+gdbpy_new ()
+{
+ gdbpy_ref<T> result (PyObject_New (T, T::corresponding_object_type));
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline gdbpy_ref<>
+gdbpy_bool_from_long (long value)
+{
+ /* This cannot fail. */
+ return gdbpy_ref<> (PyBool_FromLong (value));
+}
+
+static inline char *
+gdbpy_bytes_as_string (gdbpy_borrowed_ref ref)
+{
+ char *result = PyBytes_AsString (ref);
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline void
+gdbpy_bytes_as_string_and_size (gdbpy_borrowed_ref ref,
+ char **buffer,
+ Py_ssize_t *length)
+{
+ if (PyBytes_AsStringAndSize (ref, buffer, length) == -1)
+ throw gdb_python_exception ();
+}
+
+static inline gdbpy_ref<>
+gdbpy_bytes_from_string (const char *str)
+{
+ gdb_assert (str != nullptr);
+ gdbpy_ref<> result (PyBytes_FromString (str));
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline gdbpy_ref<>
+gdbpy_bytes_from_string_and_size (const char *str, Py_ssize_t len)
+{
+ /* Python allows STR==nullptr but it leaves the object
+ uninitialized, and I think we should avoid this in gdb. */
+ gdb_assert (str != nullptr);
+ gdbpy_ref<> result (PyBytes_FromStringAndSize (str, len));
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline Py_ssize_t
+gdbpy_bytes_size (gdbpy_borrowed_ref ref)
+{
+ Py_ssize_t result = PyBytes_Size (ref);
+ if (result == -1)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline gdbpy_ref<>
+gdbpy_new_list (Py_ssize_t len)
+{
+ gdbpy_ref<> result (PyList_New (len));
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline void
+gdbpy_list_append (gdbpy_borrowed_ref list, gdbpy_borrowed_ref val)
+{
+ if (PyList_Append (list, val) < 0)
+ throw gdb_python_exception ();
+}
+
+static inline gdbpy_ref<>
+gdbpy_new_dict ()
+{
+ gdbpy_ref<> result (PyDict_New ());
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline void
+gdbpy_dict_set_item_string (gdbpy_borrowed_ref dict,
+ const char *key,
+ gdbpy_borrowed_ref value)
+{
+ if (PyDict_SetItemString (dict, key, value) != 0)
+ throw gdb_python_exception ();
+}
+
+static inline void
+gdbpy_dict_del_item_string (gdbpy_borrowed_ref dict,
+ const char *key)
+{
+ if (PyDict_DelItemString (dict, key) == -1)
+ throw gdb_python_exception ();
+}
+
+static inline gdbpy_borrowed_ref
+gdbpy_dict_get_item_with_error (gdbpy_borrowed_ref dict,
+ gdbpy_borrowed_ref key)
+{
+ PyObject *result = PyDict_GetItemWithError (dict, key);
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline gdbpy_ref<>
+gdbpy_dict_keys (gdbpy_borrowed_ref dict)
+{
+ gdbpy_ref<> result (PyDict_Keys (dict));
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline gdbpy_ref<>
+gdbpy_unicode_from_string (std::string_view str)
+{
+ gdbpy_ref<> result (PyUnicode_FromStringAndSize (str.data (), str.size ()));
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline gdbpy_ref<>
+gdbpy_unicode_from_format (const char *fmt, ...)
+{
+ va_list args;
+ va_start (args, fmt);
+ gdbpy_ref<> result (PyUnicode_FromFormatV (fmt, args));
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ va_end (args);
+ return result;
+}
+
+[[noreturn]] static inline void
+gdbpy_err_set_string (gdbpy_borrowed_ref type, const char *str)
+{
+ PyErr_SetString (type, str);
+ throw gdb_python_exception ();
+}
+
+/* This is a template because PyErr_FormatV was only added in Python
+ 3.5. */
+template<typename... Arg>
+[[noreturn]] void
+gdbpy_err_format (gdbpy_borrowed_ref type, const char *fmt, Arg... args)
+{
+ PyErr_Format (type, fmt, std::forward<Arg> (args)...);
+ throw gdb_python_exception ();
+}
+
+template<typename... Arg>
+void
+gdbpy_arg_parse_tuple_and_keywords (gdbpy_borrowed_ref args,
+ gdbpy_opt_borrowed_ref kw,
+ const char *fmt,
+ const char **keywords,
+ Arg... outputs)
+{
+ /* It would be cool if callers could use references to the
+ out-parameters and also if gdbpy_borrowed_ref could be used for
+ those. That requires some hairy template metaprogramming
+ though. */
+ if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, fmt, keywords,
+ std::forward<Arg> (outputs)...))
+ throw gdb_python_exception ();
+}
+
+static inline void
+gdbpy_arg_parse_tuple (gdbpy_borrowed_ref param, const char *format, ...)
+{
+ va_list args;
+ va_start (args, format);
+ if (!PyArg_VaParse (param, format, args))
+ throw gdb_python_exception ();
+ va_end (args);
+}
+
+static inline long
+gdbpy_long_as_long (gdbpy_borrowed_ref arg)
+{
+ long result = PyLong_AsLong (arg);
+ if (result == -1 && PyErr_Occurred ())
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline gdbpy_ref<>
+gdbpy_tuple_new (Py_ssize_t len)
+{
+ gdbpy_ref<> result (PyTuple_New (len));
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline gdbpy_borrowed_ref
+gdbpy_tuple_get_item (gdbpy_borrowed_ref tuple, Py_ssize_t pos)
+{
+ PyObject *result = PyTuple_GetItem (tuple, pos);
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline void
+gdbpy_tuple_set_item (gdbpy_borrowed_ref tuple, Py_ssize_t pos,
+ gdbpy_ref<> &&item)
+{
+ if (PyTuple_SetItem (tuple, pos, item.release ()) == -1)
+ throw gdb_python_exception ();
+}
+
+static inline Py_ssize_t
+gdbpy_tuple_size (gdbpy_borrowed_ref tuple)
+{
+ Py_ssize_t result = PyTuple_Size (tuple);
+ if (result == -1)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline Py_ssize_t
+gdbpy_sequence_size (gdbpy_borrowed_ref seq)
+{
+ Py_ssize_t result = PySequence_Size (seq);
+ if (result == -1)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline gdbpy_ref<>
+gdbpy_sequence_get_item (gdbpy_borrowed_ref seq, Py_ssize_t i)
+{
+ gdbpy_ref<> result (PySequence_GetItem (seq, i));
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline void
+gdbpy_sequence_del_item (gdbpy_borrowed_ref seq, Py_ssize_t i)
+{
+ if (PySequence_DelItem (seq, i) == -1)
+ throw gdb_python_exception ();
+}
+
+static inline gdbpy_ref<>
+gdbpy_sequence_list (gdbpy_borrowed_ref seq)
+{
+ gdbpy_ref<> result (PySequence_List (seq));
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+static inline gdbpy_ref<>
+gdbpy_sequence_concat (gdbpy_borrowed_ref first, gdbpy_borrowed_ref second)
+{
+ gdbpy_ref<> result (PySequence_Concat (first, second));
+ if (result == nullptr)
+ throw gdb_python_exception ();
+ return result;
+}
+
+#endif /* GDB_PYTHON_PY_WRAPPERS_H */
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index 3147156d5be..8921854a120 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -1343,4 +1343,6 @@ class gdbpy_memoizing_registry_storage
extern int eval_python_command (const char *command, int start_symbol,
const char *filename = nullptr);
+#include "py-wrappers.h"
+
#endif /* GDB_PYTHON_PYTHON_INTERNAL_H */
--
2.49.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 3/4] Add wrappers for Python implementation functions and methods
2026-05-15 18:23 [PATCH 0/4] Python safety initial work Tom Tromey
2026-05-15 18:23 ` [PATCH 1/4] Add gdbpy_borrowed_ref Tom Tromey
2026-05-15 18:23 ` [PATCH 2/4] Add wrappers for some Python APIs Tom Tromey
@ 2026-05-15 18:23 ` Tom Tromey
2026-05-15 18:23 ` [PATCH 4/4] Convert py-tui.c to the "python safety" approach Tom Tromey
3 siblings, 0 replies; 5+ messages in thread
From: Tom Tromey @ 2026-05-15 18:23 UTC (permalink / raw)
To: gdb-patches; +Cc: Tom Tromey
This adds some wrappers for Python implementation functions and
methods, and a couple of new constexpr functions to create PyMethodDef
entries. This provides a few safety benefits:
* The new-style API approach (see previous patch) is implemented by
the wrapper. That is, exceptions are caught here and transformed.
* The implementation functions can now return any reasonable type,
with automatic conversion by the wrapper.
* The function API and the appropriate METH_* flags are handled
together, avoiding any possible discrepancy.
This approach also means that we can modify the old rule that gdb
calls must be wrapped in a try/catch -- the try/catch is now provided
by the wrapper function, so the implementation can be written in a
more natural way.
Note this patch is not 100% complete. There should be one more
wrapper for case where a method takes a single argument (though we
probably cannot use METH_O unfortunately). There may be some other
holes as well.
---
gdb/python/py-safety.h | 321 +++++++++++++++++++++++++++++++++++++++++++
gdb/python/python-internal.h | 1 +
2 files changed, 322 insertions(+)
diff --git a/gdb/python/py-safety.h b/gdb/python/py-safety.h
new file mode 100644
index 00000000000..d84358b72b4
--- /dev/null
+++ b/gdb/python/py-safety.h
@@ -0,0 +1,321 @@
+/* Wrappers for some Python safety.
+
+ Copyright (C) 2026 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#ifndef GDB_PYTHON_PY_SAFETY_H
+#define GDB_PYTHON_PY_SAFETY_H
+
+#include "gdbsupport/traits.h"
+#include "py-ref.h"
+#include "py-wrappers.h"
+#include "charset.h"
+
+/* This file holds wrapper templates for the various ways that gdb
+ code might be exposed to Python. These wrappers are part of gdb's
+ "Python safety" approach -- utilities designed to try to prevent
+ refcount problems, missing error checks, and that also remove the
+ need to wrap calls into gdb in an explicit try/catch.
+
+ See py-wrappers.h for some more discussion of this.
+
+ Implementation functions and methods -- the stuff you write to
+ expose some part of gdb to Python -- are written in a certain
+ style.
+
+ An implementation function is a module-level function. For example
+ something like 'gdb.register_window_type' is implemented as a
+ function. An implementation method is a method of the gdb class
+ implementing a certain Python type; for example
+ 'gdb.TuiWindow.width' is implemented via a method of
+ gdbpy_tui_window.
+
+ Each of these will accept gdbpy_borrowed_ref arguments (or in some
+ more limited situations, a gdbpy_opt_borrowed_ref) and return any
+ relevant type, which will be automatically converted (see the
+ 'to_python' overloads below) to the correct Python type. Note that
+ if the 'to_python' functions aren't appropriate in your case, you
+ can always use the escape hatch of returning a gdbpy_ref<> and
+ handling type conversion manually.
+
+ There are some constexpr functions below that wrap the
+ implementation methods, and create PyMethodDef objects and the
+ like.
+
+ Implementation methods are expected to use the wrappers in
+ py-wrappers.h and not generally call into Python directly.
+
+ Implementation details of the method-wrapping safety code are put
+ into this namespace, just to emphasize that these shouldn't be used
+ elsewhere. Skip past the namespace to find the public APIs. */
+namespace safety_details
+{
+/* Overloads of "to_python" are used by the safety wrappers to convert
+ a function's real return value to a Python object. A new reference
+ will always be returned. For the time being these are kept as a
+ detail of the method-wrapping code. However we may want to
+ consider exposing these more generally. */
+
+static inline PyObject *
+to_python (bool value)
+{
+ if (value)
+ Py_RETURN_TRUE;
+ Py_RETURN_FALSE;
+}
+
+template<typename T, typename = std::is_integral<T>>
+static inline PyObject *
+to_python (T value)
+{
+ if constexpr (std::is_signed<T>::value)
+ return gdb_py_object_from_longest (value).release ();
+ else
+ return gdb_py_object_from_ulongest (value).release ();
+}
+
+static inline PyObject *
+to_python (const char *value)
+{
+ if (value == nullptr)
+ Py_RETURN_NONE;
+ return PyUnicode_Decode (value, strlen (value), host_charset (), nullptr);
+}
+
+static inline PyObject *
+to_python (std::string &&value)
+{
+ return PyUnicode_Decode (value.c_str (), value.size (),
+ host_charset (), nullptr);
+}
+
+static inline PyObject *
+to_python (const std::string &value)
+{
+ return PyUnicode_Decode (value.c_str (), value.size (),
+ host_charset (), nullptr);
+}
+
+static inline PyObject *
+to_python (gdb::unique_xmalloc_ptr<char> &&value)
+{
+ if (value == nullptr)
+ Py_RETURN_NONE;
+ return PyUnicode_Decode (value.get (), strlen (value.get ()),
+ host_charset (), nullptr);
+}
+
+static inline PyObject *
+to_python (gdbpy_ref<> &&value)
+{
+ return value.release ();
+}
+
+/* An instantiation of this function is used when calling a gdb method
+ from Python. It accepts some number of arguments (normally
+ gdbpy_borrowed_ref or gdbpy_opt_borrowed_ref), and then then calls
+ the underlying function F. Any exceptions are caught and
+ converted, and the return value of F is converted to a Python
+ object as appropriate. */
+template<auto F, typename... Args>
+PyObject *
+wrapped_function (Args... args)
+{
+ try
+ {
+ using result_type = typename std::invoke_result_t<decltype (F), Args...>;
+
+ if constexpr (std::is_void_v<result_type>)
+ {
+ F (args...);
+ Py_RETURN_NONE;
+ }
+ else
+ return to_python (F (args...));
+ }
+ catch (const gdb_python_exception &pye)
+ {
+ gdb_assert (PyErr_Occurred () != nullptr);
+ return nullptr;
+ }
+ catch (const gdb_exception &exc)
+ {
+ return gdbpy_handle_gdb_exception (nullptr, exc);
+ }
+}
+
+/* An instantiation of this function is used when calling a gdb method
+ from Python. It accepts some number of arguments (normally
+ gdbpy_borrowed_ref or gdbpy_opt_borrowed_ref), and then then calls
+ the underlying function F. Any exceptions are caught and
+ converted, and the return value of F is converted to a Python
+ object as appropriate. */
+template<typename Class, typename Ret, typename... Args>
+PyObject *
+wrapped_method (Ret (Class::*meth) (Args...), Class *self, Args... args)
+{
+ try
+ {
+ if constexpr (std::is_void_v<Ret>)
+ {
+ (self->*meth) (args...);
+ Py_RETURN_NONE;
+ }
+ else
+ return to_python ((self->*meth) (args...));
+ }
+ catch (const gdb_python_exception &pye)
+ {
+ gdb_assert (PyErr_Occurred () != nullptr);
+ return nullptr;
+ }
+ catch (const gdb_exception &exc)
+ {
+ return gdbpy_handle_gdb_exception (nullptr, exc);
+ }
+}
+
+template<auto F>
+PyObject *
+fn_wrapper (PyObject *self, PyObject *args, PyObject *kw)
+{
+ return wrapped_function<F> (gdbpy_borrowed_ref (args),
+ gdbpy_opt_borrowed_ref (kw));
+}
+
+template<typename C, auto M>
+PyObject *
+varargs_wrapper (PyObject *self, PyObject *args, PyObject *kw)
+{
+ return wrapped_method (M, static_cast<C *> (self),
+ gdbpy_borrowed_ref (args),
+ gdbpy_opt_borrowed_ref (kw));
+}
+
+} /* namespace safety_details */
+
+/* Create a PyMethodDef for a no-argument method. It takes the
+ underlying class C and a pointer-to-method M as template
+ parameters, and the name and documentation as arguments. The
+ method M is wrapped to call to_python and to catch exceptions per
+ the safety protocol. */
+template<typename C, auto M>
+constexpr PyMethodDef
+noargs_method (std::string_view name, std::string_view doc)
+{
+ using namespace safety_details;
+ return {
+ name.data (),
+ [] (PyObject *self, PyObject *args) -> PyObject *
+ {
+ return wrapped_method (M, static_cast<C *> (self));
+ },
+ METH_NOARGS,
+ doc.data (),
+ };
+}
+
+/* This is used to create the PyMethodDef for a varargs function. It
+ takes the underlying implementation function as a template
+ argument, and also arguments for the method name and documentation
+ string.
+
+ The underlying function should accept a gdbpy_borrowed_ref argument
+ (the arguments to the Python function), and then a
+ gdbpy_opt_borrowed_ref for the keywords. The function can return
+ any type (see the to_python overloads); and should throw an
+ exception on error. If gdb_python_exception is thrown, the Python
+ exception must already have been set.
+
+ The gdb policy is that varargs methods must also accept keywords,
+ and this is enforced here. */
+template<auto F>
+constexpr PyMethodDef
+varargs_function (std::string_view name, std::string_view doc)
+{
+ using namespace safety_details;
+ return {
+ name.data (),
+ (PyCFunction) fn_wrapper<F>,
+ /* gdb's rule is that varargs should also use keywords. */
+ METH_VARARGS | METH_KEYWORDS,
+ doc.data (),
+ };
+}
+
+/* Like a varargs function, but this implements a method on some
+ Python type that gdb provides. The implementation class and a
+ pointer-to-method must be specified. */
+template<typename C, auto M>
+constexpr PyMethodDef
+varargs_method (std::string_view name, std::string_view doc)
+{
+ using namespace safety_details;
+ return {
+ name.data (),
+ (PyCFunction) varargs_wrapper<C, M>,
+ /* gdb's rule is that varargs should also use keywords. */
+ METH_VARARGS | METH_KEYWORDS,
+ doc.data (),
+ };
+}
+
+/* A function that wraps a "repr" or "str" method. */
+template<typename C, auto M>
+PyObject *
+wrap_repr (PyObject *arg)
+{
+ using namespace safety_details;
+ return wrapped_method (M, static_cast<C *> (arg));
+}
+
+/* A function that wraps a "get" method. */
+template<typename C, auto M>
+PyObject *
+wrap_getter (PyObject *arg, void *closure)
+{
+ using namespace safety_details;
+ /* In gdb the closure argument is never used. */
+ return wrapped_method (M, static_cast<C *> (arg));
+}
+
+/* A function that wraps a "set" method. */
+template<typename C, void (C::*M) (gdbpy_opt_borrowed_ref)>
+int
+wrap_setter (PyObject *arg, PyObject *value, void *closure)
+{
+ using namespace safety_details;
+ try
+ {
+ C *self = static_cast<C *> (arg);
+ /* In gdb the closure argument is never used. */
+ (self->*M) (gdbpy_opt_borrowed_ref (value));
+ }
+ catch (const gdb_python_exception &pye)
+ {
+ gdb_assert (PyErr_Occurred () != nullptr);
+ return -1;
+ }
+ catch (const gdb_exception &exc)
+ {
+ return gdbpy_handle_gdb_exception (-1, exc);
+ }
+
+ return 0;
+}
+
+#endif /* GDB_PYTHON_PY_SAFETY_H */
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index 8921854a120..ca667681cb7 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -1344,5 +1344,6 @@ extern int eval_python_command (const char *command, int start_symbol,
const char *filename = nullptr);
#include "py-wrappers.h"
+#include "py-safety.h"
#endif /* GDB_PYTHON_PYTHON_INTERNAL_H */
--
2.49.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 4/4] Convert py-tui.c to the "python safety" approach
2026-05-15 18:23 [PATCH 0/4] Python safety initial work Tom Tromey
` (2 preceding siblings ...)
2026-05-15 18:23 ` [PATCH 3/4] Add wrappers for Python implementation functions and methods Tom Tromey
@ 2026-05-15 18:23 ` Tom Tromey
3 siblings, 0 replies; 5+ messages in thread
From: Tom Tromey @ 2026-05-15 18:23 UTC (permalink / raw)
To: gdb-patches; +Cc: Tom Tromey
This patch mostly converts py-tui.c to use the new Python safety code.
In particular:
* All methods of gdb.TuiWindow are now implemented as straightforward
methods of gdbpy_tui_window.
* gdb.register_tui_window is converted and simply returns 'void'.
I converted this particular file because it was relatively
straightforward, while also demonstrating most of the features of the
new approach. For example, explicit result checks aren't needed,
try/catch can be removed, and the methods are now written in a natural
style.
Note that more conversion remains to be done here:
* gdbpy_tui_enabled hasn't been converted and still does explicit
checks.
* There's one explicit check in gdbpy_tui_window::set_title. Fully
implementing the safety approach means that some low-level things
should eventually be converted to throw; but some work has to be
deferred until a lot of the work is complete.
---
gdb/python/py-tui.c | 208 ++++++++++++++++++-------------------------
gdb/python/python-internal.h | 5 +-
gdb/python/python.c | 5 +-
3 files changed, 92 insertions(+), 126 deletions(-)
diff --git a/gdb/python/py-tui.c b/gdb/python/py-tui.c
index be19193770f..0755d7b92e3 100644
--- a/gdb/python/py-tui.c
+++ b/gdb/python/py-tui.c
@@ -50,7 +50,34 @@ struct gdbpy_tui_window: public PyObject
tui_py_window *window;
/* Return true if this object is valid. */
- bool is_valid () const;
+ bool is_valid ();
+
+ /* Require that this object be valid. Throws exception if not. */
+ void require_valid ()
+ {
+ if (!is_valid ())
+ gdbpy_err_format (PyExc_RuntimeError, _("TUI window is invalid."));
+ }
+
+ /* Erase the TUI window. */
+ void erase ();
+
+ /* Python function that writes some text to a TUI window. */
+ void write (gdbpy_borrowed_ref args, gdbpy_opt_borrowed_ref kw);
+
+ /* Return the width of the TUI window. */
+ int width ();
+
+ /* Return the height of the TUI window. */
+ int height ();
+
+ /* Return the title of the TUI window. */
+ const std::string &title ();
+
+ /* Set the title of the TUI window. */
+ void set_title (gdbpy_opt_borrowed_ref new_title);
+
+ static PyTypeObject *corresponding_object_type;
};
extern PyTypeObject gdbpy_tui_window_object_type;
@@ -150,7 +177,7 @@ class tui_py_window : public tui_win_info
/* See gdbpy_tui_window declaration above. */
bool
-gdbpy_tui_window::is_valid () const
+gdbpy_tui_window::is_valid ()
{
return window != nullptr && tui_active;
}
@@ -406,173 +433,109 @@ gdbpy_tui_window_maker::operator() (const char *win_name)
/* Implement "gdb.register_window_type". */
-PyObject *
-gdbpy_register_tui_window (PyObject *self, PyObject *args, PyObject *kw)
+void
+gdbpy_register_tui_window (gdbpy_borrowed_ref args,
+ gdbpy_opt_borrowed_ref kw)
{
static const char *keywords[] = { "name", "constructor", nullptr };
-
const char *name;
PyObject *cons_obj;
+ gdbpy_arg_parse_tuple_and_keywords (args, kw, "sO", keywords,
+ &name, &cons_obj);
- if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "sO", keywords,
- &name, &cons_obj))
- return nullptr;
-
- try
- {
- gdbpy_tui_window_maker constr (gdbpy_ref<>::new_reference (cons_obj));
- tui_register_window (name, constr);
- }
- catch (const gdb_exception &except)
- {
- return gdbpy_handle_gdb_exception (nullptr, except);
- }
-
- Py_RETURN_NONE;
+ gdbpy_tui_window_maker constr (gdbpy_ref<>::new_reference (cons_obj));
+ tui_register_window (name, constr);
}
\f
-/* Require that "Window" be a valid window. */
-
-#define REQUIRE_WINDOW(Window) \
- do { \
- if (!(Window)->is_valid ()) \
- return PyErr_Format (PyExc_RuntimeError, \
- _("TUI window is invalid.")); \
- } while (0)
-
-/* Require that "Window" be a valid window. */
-
-#define REQUIRE_WINDOW_FOR_SETTER(Window) \
- do { \
- if (!(Window)->is_valid ()) \
- { \
- PyErr_Format (PyExc_RuntimeError, \
- _("TUI window is invalid.")); \
- return -1; \
- } \
- } while (0)
-
-/* Python function which checks the validity of a TUI window
- object. */
-static PyObject *
-gdbpy_tui_is_valid (PyObject *self, PyObject *args)
-{
- gdbpy_tui_window *win = (gdbpy_tui_window *) self;
-
- if (win->is_valid ())
- Py_RETURN_TRUE;
- Py_RETURN_FALSE;
-}
-
/* Python function that erases the TUI window. */
-static PyObject *
-gdbpy_tui_erase (PyObject *self, PyObject *args)
+void
+gdbpy_tui_window::erase ()
{
- gdbpy_tui_window *win = (gdbpy_tui_window *) self;
-
- REQUIRE_WINDOW (win);
-
- win->window->erase ();
-
- Py_RETURN_NONE;
+ require_valid ();
+ window->erase ();
}
/* Python function that writes some text to a TUI window. */
-static PyObject *
-gdbpy_tui_write (PyObject *self, PyObject *args, PyObject *kw)
+void
+gdbpy_tui_window::write (gdbpy_borrowed_ref args, gdbpy_opt_borrowed_ref kw)
{
+ require_valid ();
+
static const char *keywords[] = { "string", "full_window", nullptr };
- gdbpy_tui_window *win = (gdbpy_tui_window *) self;
const char *text;
int full_window = 0;
- if (!gdb_PyArg_ParseTupleAndKeywords (args, kw, "s|i", keywords,
- &text, &full_window))
- return nullptr;
-
- REQUIRE_WINDOW (win);
+ gdbpy_arg_parse_tuple_and_keywords (args, kw, "s|i", keywords,
+ &text, &full_window);
- win->window->output (text, full_window);
-
- Py_RETURN_NONE;
+ window->output (text, full_window);
}
-/* Return the width of the TUI window. */
-static PyObject *
-gdbpy_tui_width (PyObject *self, void *closure)
+int
+gdbpy_tui_window::width ()
{
- gdbpy_tui_window *win = (gdbpy_tui_window *) self;
- REQUIRE_WINDOW (win);
- gdbpy_ref<> result
- = gdb_py_object_from_longest (win->window->viewport_width ());
- return result.release ();
+ require_valid ();
+ return window->viewport_width ();
}
-/* Return the height of the TUI window. */
-static PyObject *
-gdbpy_tui_height (PyObject *self, void *closure)
+int
+gdbpy_tui_window::height ()
{
- gdbpy_tui_window *win = (gdbpy_tui_window *) self;
- REQUIRE_WINDOW (win);
- gdbpy_ref<> result
- = gdb_py_object_from_longest (win->window->viewport_height ());
- return result.release ();
+ require_valid ();
+ return window->viewport_height ();
}
-/* Return the title of the TUI window. */
-static PyObject *
-gdbpy_tui_title (PyObject *self, void *closure)
+const std::string &
+gdbpy_tui_window::title ()
{
- gdbpy_tui_window *win = (gdbpy_tui_window *) self;
- REQUIRE_WINDOW (win);
- return host_string_to_python_string (win->window->title ().c_str ()).release ();
+ require_valid ();
+ return window->title ();
}
/* Set the title of the TUI window. */
-static int
-gdbpy_tui_set_title (PyObject *self, PyObject *newvalue, void *closure)
+void
+gdbpy_tui_window::set_title (gdbpy_opt_borrowed_ref new_title)
{
- gdbpy_tui_window *win = (gdbpy_tui_window *) self;
+ require_valid ();
- REQUIRE_WINDOW_FOR_SETTER (win);
-
- if (newvalue == nullptr)
- {
- PyErr_Format (PyExc_TypeError, _("Cannot delete \"title\" attribute."));
- return -1;
- }
+ if (new_title == nullptr)
+ gdbpy_err_format (PyExc_TypeError,
+ _("Cannot delete \"title\" attribute."));
+ /* FIXME: safety */
gdb::unique_xmalloc_ptr<char> value
- = python_string_to_host_string (newvalue);
+ = python_string_to_host_string (new_title);
if (value == nullptr)
- return -1;
+ throw gdb_python_exception ();
- win->window->set_title (value.get ());
- return 0;
+ window->set_title (value.get ());
}
static gdb_PyGetSetDef tui_object_getset[] =
{
- { "width", gdbpy_tui_width, NULL, "Width of the window.", NULL },
- { "height", gdbpy_tui_height, NULL, "Height of the window.", NULL },
- { "title", gdbpy_tui_title, gdbpy_tui_set_title, "Title of the window.",
- NULL },
- { NULL } /* Sentinel */
+ { "width", wrap_getter<gdbpy_tui_window, &gdbpy_tui_window::width>, nullptr,
+ "Width of the window.", nullptr },
+ { "height", wrap_getter<gdbpy_tui_window, &gdbpy_tui_window::height>, nullptr,
+ "Height of the window.", nullptr },
+ { "title", wrap_getter<gdbpy_tui_window, &gdbpy_tui_window::title>,
+ wrap_setter<gdbpy_tui_window, &gdbpy_tui_window::set_title>,
+ "Title of the window.", nullptr },
+ { nullptr } /* Sentinel */
};
static PyMethodDef tui_object_methods[] =
{
- { "is_valid", gdbpy_tui_is_valid, METH_NOARGS,
+ noargs_method<gdbpy_tui_window, &gdbpy_tui_window::is_valid> ("is_valid",
"is_valid () -> Boolean\n\
-Return true if this TUI window is valid, false if not." },
- { "erase", gdbpy_tui_erase, METH_NOARGS,
- "Erase the TUI window." },
- { "write", (PyCFunction) gdbpy_tui_write, METH_VARARGS | METH_KEYWORDS,
- "Append a string to the TUI window." },
- { NULL } /* Sentinel. */
+Return true if this TUI window is valid, false if not."),
+ noargs_method<gdbpy_tui_window, &gdbpy_tui_window::erase>
+ ("erase", "Erase the TUI window."),
+ varargs_method<gdbpy_tui_window, &gdbpy_tui_window::write> ("write",
+ "Append a string to the TUI window."),
+ { nullptr } /* Sentinel. */
};
PyTypeObject gdbpy_tui_window_object_type =
@@ -616,6 +579,9 @@ PyTypeObject gdbpy_tui_window_object_type =
0, /* tp_alloc */
};
+PyTypeObject *gdbpy_tui_window::corresponding_object_type
+ = &gdbpy_tui_window_object_type;
+
/* Called when TUI is enabled or disabled. */
static void
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index ca667681cb7..e656ca73617 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -496,8 +496,9 @@ gdb::unique_xmalloc_ptr<char> gdbpy_parse_command_name
(const char *name, struct cmd_list_element ***base_list,
struct cmd_list_element **start_list,
struct cmd_list_element **prefix_cmd = nullptr);
-PyObject *gdbpy_register_tui_window (PyObject *self, PyObject *args,
- PyObject *kw);
+
+void gdbpy_register_tui_window (gdbpy_borrowed_ref args,
+ gdbpy_opt_borrowed_ref kw);
gdbpy_ref<> symtab_and_line_to_sal_object (struct symtab_and_line sal);
gdbpy_ref<> symtab_to_symtab_object (struct symtab *symtab);
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 045626b70fd..689d121ce2d 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -3274,10 +3274,9 @@ or None if not set." },
Set the value of the convenience variable $NAME." },
#ifdef TUI
- { "register_window_type", (PyCFunction) gdbpy_register_tui_window,
- METH_VARARGS | METH_KEYWORDS,
+ varargs_function<gdbpy_register_tui_window> ("register_window_type",
"register_window_type (NAME, CONSTRUCTOR) -> None\n\
-Register a TUI window constructor." },
+Register a TUI window constructor."),
#endif /* TUI */
{ "architecture_names", gdbpy_all_architecture_names, METH_NOARGS,
--
2.49.0
^ permalink raw reply [flat|nested] 5+ messages in thread
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2026-05-15 18:23 [PATCH 0/4] Python safety initial work Tom Tromey
2026-05-15 18:23 ` [PATCH 1/4] Add gdbpy_borrowed_ref Tom Tromey
2026-05-15 18:23 ` [PATCH 2/4] Add wrappers for some Python APIs Tom Tromey
2026-05-15 18:23 ` [PATCH 3/4] Add wrappers for Python implementation functions and methods Tom Tromey
2026-05-15 18:23 ` [PATCH 4/4] Convert py-tui.c to the "python safety" approach Tom Tromey
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