python: a patch for getting target thread id from a thread object

python: a patch for getting target thread id from a thread object

[Noam Yorav-Raphael]

Hello,

Here's a simple patch which adds a method for getting the target
thread id of a Thread object.

My use case is this: I'm writing a gdb script in python which allows
you to attach to running Python processes with a Python debugger
(winpdb).
This is done by switching to the thread which has the Python GIL and
running there some Python commands which start the winpdb debugging
server.
The ID of the thread which has the GIL is available in a global
(_PyThreadState_Current->thread_id). However, currently there's no way
for the python script to know to which thread it should switch, since
it only has access to the internal GDB thread number. The patch fixes
it.

Thanks,
Noam


diff --git a/gdb/python/python-infthread.c b/gdb/python/python-infthread.c
index 21e4eab..7e97f8c 100644
--- a/gdb/python/python-infthread.c
+++ b/gdb/python/python-infthread.c
@@ -73,7 +73,19 @@ thpy_get_num (PyObject *self, void *closure)
   return PyLong_FromLong (thread_obj->thread->num);
 }

+/* Implementation of Thread.get_target_id () -> str.
+   Returns the target ID.  */
+PyObject *
+thpy_get_target_id (PyObject *self, PyObject *args)
+{
+  thread_object *thread_obj = (thread_object *) self;
+
+  THPY_REQUIRE_VALID (thread_obj);
+
+  return PyString_FromString (target_pid_to_str (thread_obj->thread->ptid));
+}
+
+

 /* Implementation of Inferior.frames () -> (gdb.Frame, ...).
    Returns a tuple of all frame objects.  */
@@ -238,6 +251,9 @@ Return the newest frame in the thread." },
   { "switch", thpy_switch, METH_NOARGS,
     "switch ()\n\
 Makes this the GDB selected thread." },
+  { "get_target_id", thpy_get_target_id, METH_NOARGS,
+    "get_target_id () -> str\n\
+Return the target ID of the thread." },

   { NULL }
 };

Re: python: a patch for getting target thread id from a thread object

[Tom Tromey]

>>>>> "Noam" == Noam Yorav-Raphael <noamraph@gmail.com> writes:

Noam> Here's a simple patch which adds a method for getting the target
Noam> thread id of a Thread object.

I think the idea is fine.

BTW do you have copyright papers on file?  I don't remember, and I can't
easily look... if not we have to do that before we can accept
non-trivial patches.

Noam> +  { "get_target_id", thpy_get_target_id, METH_NOARGS,
Noam> +    "get_target_id () -> str\n\
Noam> +Return the target ID of the thread." },

We went through and remove the "get_" prefixes everywhere a while back.
Also, I think this should be an attribute (see thread_object_getset), as
that is more consistent with our current API decisions.

Finally, this patch needs an update to doc/gdb.texinfo.

thanks,
Tom