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[78.73.77.63]) by smtp.gmail.com with ESMTPSA id m2-20020a194342000000b004719502fb73sm807077lfj.73.2022.04.20.01.25.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Apr 2022 01:25:51 -0700 (PDT) From: Simon Farre To: gdb-patches@sourceware.org Subject: [PATCH v4] gdb/Python: Added ThreadExitedEvent Date: Wed, 20 Apr 2022 10:25:47 +0200 Message-Id: <20220420082547.759990-1-simon.farre.cx@gmail.com> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-12.1 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 20 Apr 2022 08:25:56 -0000 v4: Doc formatting fixed. v3: Eli: Updated docs & NEWS to reflect new changes. Added a reference from the .ptid attribute of the ThreadExitedEvent to the ptid attribute of InferiorThread. To do this, I've added an anchor to that attribute. Tom: Tom requested that I should probably just emit the thread object; I ran into two issues for this, which I could not resolve in this patch; 1 - The Thread Object (the python type) checks it's own validity by doing a comparison of it's `thread_info* thread` to nullptr. This means that any access of it's attributes may (probably, since we are in "async" land) throw Python exceptions because the thread has been removed from the thread object. Therefore I've decided in v3 of this patch to just emit most of the same fields that gdb.InferiorThread has, namely global_num, name, num and ptid (the 3-attribute tuple provided by gdb.InferiorThread.ptid). 2 - A python user can hold a global reference to an exiting thread. Thus in order to have a ThreadExit event that can provide attribute access reliably (both as a global reference, but also inside the thread exit handler, as we can never guarantee that it's executed _before_ the thread_info pointer is removed from the gdbpy thread object), the `thread_info *` thread pointer must not be null. However, this comes at the cost of gdb.InferiorThread believing it is "valid" - which means, that if a user holds takes a global reference to that exiting event thread object, they can some time later do `t.switch()` at which point GDB will 'explode' so to speak. v2: Fixed white space issues and NULL/nullptr stuff, as requested by Tom Tromey. v1: Currently no event is emitted for a thread exit. This adds this functionality by emitting a new gdb.ThreadExitedEvent. It currently provides four attributes: - global_num: The GDB assigned global thread number - num: the per-inferior thread number - name: name of the thread or none if not set - ptid: the PTID of the thread, a 3-attribute tuple, identical to InferiorThread.ptid attribute Added info to docs & the NEWS file as well. Added test to test suite. Fixed formatting. Feedback wanted and appreciated. --- gdb/NEWS | 3 ++ gdb/doc/python.texi | 22 ++++++++ gdb/python/py-all-events.def | 1 + gdb/python/py-event-types.def | 5 ++ gdb/python/py-event.h | 4 ++ gdb/python/py-inferior.c | 5 ++ gdb/python/py-threadevent.c | 35 +++++++++++++ gdb/testsuite/gdb.python/py-thread-exited.c | 37 ++++++++++++++ gdb/testsuite/gdb.python/py-thread-exited.exp | 51 +++++++++++++++++++ gdb/testsuite/gdb.python/py-thread-exited.py | 31 +++++++++++ 10 files changed, 194 insertions(+) create mode 100644 gdb/testsuite/gdb.python/py-thread-exited.c create mode 100644 gdb/testsuite/gdb.python/py-thread-exited.exp create mode 100644 gdb/testsuite/gdb.python/py-thread-exited.py diff --git a/gdb/NEWS b/gdb/NEWS index 760cb2b7abc..4231e5181fb 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -38,6 +38,9 @@ maintenance info line-table This is the same format that GDB uses when printing address, symbol, and offset information from the disassembler. + ** gdb.ThreadExitedEvent added. Emits GLOBAL NUM, NAME, PER INFERIOR NUM + and PTID of the exiting thread. + *** Changes in GDB 12 * DBX mode is deprecated, and will be removed in GDB 13 diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi index 7c414b01d70..b80904041b2 100644 --- a/gdb/doc/python.texi +++ b/gdb/doc/python.texi @@ -3568,6 +3568,27 @@ This has a single attribute: The new thread. @end defvar +@item events.thread_exited +This is emitted when @value{GDBN} notices a thread has exited. The event +is of type @code{gdb.ThreadExitedEvent}. This has four attributes: + +@defvar ThreadExitedEvent.global_num +Global thread number. +@end defvar + +@defvar ThreadExitedEvent.name +The thread's name. Returns @code{None} if it has none or can't be resolved. +@end defvar + +@defvar ThreadExitedEvent.num +The thread's per-inferior number. +@end defvar + +@defvar ThreadExitedEvent.ptid +The thread's ptid +(@pxref{inferior_thread_ptid,,The InferiorThread.ptid attribute}). +@end defvar + @item events.gdb_exiting This is emitted when @value{GDBN} exits. This event is not emitted if @value{GDBN} exits as a result of an internal error, or after an @@ -3632,6 +3653,7 @@ make Python breakpoints thread-specific, for example (@pxref{python_breakpoint_thread,,The Breakpoint.thread attribute}). @end defvar +@anchor{inferior_thread_ptid} @defvar InferiorThread.ptid ID of the thread, as assigned by the operating system. This attribute is a tuple containing three integers. The first is the Process ID (PID); the second diff --git a/gdb/python/py-all-events.def b/gdb/python/py-all-events.def index 7db8efa1390..0dd1a295135 100644 --- a/gdb/python/py-all-events.def +++ b/gdb/python/py-all-events.def @@ -31,6 +31,7 @@ GDB_PY_DEFINE_EVENT(clear_objfiles) GDB_PY_DEFINE_EVENT(new_inferior) GDB_PY_DEFINE_EVENT(inferior_deleted) GDB_PY_DEFINE_EVENT(new_thread) +GDB_PY_DEFINE_EVENT(thread_exited) GDB_PY_DEFINE_EVENT(inferior_call) GDB_PY_DEFINE_EVENT(memory_changed) GDB_PY_DEFINE_EVENT(register_changed) diff --git a/gdb/python/py-event-types.def b/gdb/python/py-event-types.def index 596e68a852a..4529ddc7caa 100644 --- a/gdb/python/py-event-types.def +++ b/gdb/python/py-event-types.def @@ -51,6 +51,11 @@ GDB_PY_DEFINE_EVENT_TYPE (new_thread, "GDB new thread event object", thread_event_object_type); +GDB_PY_DEFINE_EVENT_TYPE (thread_exited, + "ThreadExitedEvent", + "GDB thread exited event object", + event_object_type); + GDB_PY_DEFINE_EVENT_TYPE (new_inferior, "NewInferiorEvent", "GDB new inferior event object", diff --git a/gdb/python/py-event.h b/gdb/python/py-event.h index 56e53b7a1e7..3619e12df10 100644 --- a/gdb/python/py-event.h +++ b/gdb/python/py-event.h @@ -61,6 +61,10 @@ extern int emit_memory_changed_event (CORE_ADDR addr, ssize_t len); extern int evpy_emit_event (PyObject *event, eventregistry_object *registry); +/* Emits a thread exit event for THREAD containing the attributes + global_num, name, num and ptid */ +extern int emit_thread_exit_event (thread_info * thread); + extern gdbpy_ref<> create_event_object (PyTypeObject *py_type); /* thread events can either be thread specific or process wide. If gdb is diff --git a/gdb/python/py-inferior.c b/gdb/python/py-inferior.c index ebcd5b0a70f..5f0cd67970e 100644 --- a/gdb/python/py-inferior.c +++ b/gdb/python/py-inferior.c @@ -363,6 +363,11 @@ delete_thread_object (struct thread_info *tp, int ignore) return; tmp = *entry; + if (!evregpy_no_listeners_p (gdb_py_events.thread_exited)) + { + if (emit_thread_exit_event (tmp->thread_obj->thread) < 0) + gdbpy_print_stack (); + } tmp->thread_obj->thread = NULL; *entry = (*entry)->next; diff --git a/gdb/python/py-threadevent.c b/gdb/python/py-threadevent.c index 0a5d30087fb..305941306af 100644 --- a/gdb/python/py-threadevent.c +++ b/gdb/python/py-threadevent.c @@ -54,3 +54,38 @@ create_thread_event_object (PyTypeObject *py_type, PyObject *thread) return thread_event_obj; } + +/* Emits a thread exit event for THREAD containing the attributes + global_num, name, num and ptid */ + +int +emit_thread_exit_event (thread_info * thread) +{ + gdbpy_ref<> thread_event_obj + = create_event_object (&thread_exited_event_object_type); + ptid_t ptid = thread->ptid; + int global_num = thread->global_num; + const char* name = thread_name (thread); + int num = thread->per_inf_num; + + if (thread_event_obj == nullptr) + return -1; + + if (evpy_add_attribute (thread_event_obj.get (), "global_num", + PyLong_FromLong (global_num)) < 0) + return -1; + PyObject * t_name = name == nullptr ? Py_None : PyUnicode_FromString (name); + + if (evpy_add_attribute (thread_event_obj.get (), "name", t_name) < 0) + return -1; + + if (evpy_add_attribute (thread_event_obj.get (), "num", + PyLong_FromLong (num)) < 0) + return -1; + + if (evpy_add_attribute (thread_event_obj.get (), "ptid", + gdbpy_create_ptid_object (ptid)) < 0) + return -1; + + return evpy_emit_event (thread_event_obj.get (), gdb_py_events.thread_exited); +} diff --git a/gdb/testsuite/gdb.python/py-thread-exited.c b/gdb/testsuite/gdb.python/py-thread-exited.c new file mode 100644 index 00000000000..d4ff55b1b44 --- /dev/null +++ b/gdb/testsuite/gdb.python/py-thread-exited.c @@ -0,0 +1,37 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2010-2022 Free Software Foundation, Inc. + + 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 . */ + +#include +#include +#include +#include +pthread_t thread2_id; +pthread_t thread3_id; + +void* do_thread (void* d) +{ + return NULL; +} + +int main (void) +{ + pthread_create (&thread2_id, NULL, do_thread, NULL); + pthread_join (thread2_id, NULL); + pthread_create (&thread3_id, NULL, do_thread, NULL); + pthread_join (thread3_id, NULL); + return 12; +} diff --git a/gdb/testsuite/gdb.python/py-thread-exited.exp b/gdb/testsuite/gdb.python/py-thread-exited.exp new file mode 100644 index 00000000000..3c66cc5e08d --- /dev/null +++ b/gdb/testsuite/gdb.python/py-thread-exited.exp @@ -0,0 +1,51 @@ +# Copyright (C) 2022-2022 Free Software Foundation, Inc. + +# 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 . + +if { ![support_displaced_stepping] } { + unsupported "displaced stepping" + return -1 +} + +load_lib gdb-python.exp + +standard_testfile + +if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } { + return -1 +} + +save_vars { GDBFLAGS } { + clean_restart $testfile +} + +if { [skip_python_tests] } { continue } + +set pyfile [gdb_remote_download host ${srcdir}/${subdir}/py-thread-exited.py] +gdb_test_no_output "source ${pyfile}" "load python file" + +gdb_test "test-events" "Event testers registered." + +if ![runto_main] { + return -1 +} + +gdb_breakpoint 37 "last of main" + +gdb_continue_to_breakpoint "continue to breakpoint" + +gdb_test "python print(threadOneExit)" \ + ".*event type: thread-exited. global num: 2.*" +gdb_test "python print(threadTwoExit)" \ + ".*event type: thread-exited. global num: 3.*" diff --git a/gdb/testsuite/gdb.python/py-thread-exited.py b/gdb/testsuite/gdb.python/py-thread-exited.py new file mode 100644 index 00000000000..217fcd0ff6b --- /dev/null +++ b/gdb/testsuite/gdb.python/py-thread-exited.py @@ -0,0 +1,31 @@ +import gdb + +threadOneExit = "" +threadTwoExit = "" +# we don't want to overwrite the 2nd thread's exit event, thus +# store it here. we don't care about it though. +mainThreadExit = "" + +def thread_exited_handler(event): + global threadOneExit, threadTwoExit, mainThreadExit + print("{}".format(event)) + assert isinstance(event, gdb.ThreadExitedEvent) + if threadOneExit == "": + threadOneExit = "event type: thread-exited. global num: {}".format(event.global_num) + else: + if threadTwoExit == "": + threadTwoExit = "event type: thread-exited. global num: {}".format(event.global_num) + else: + mainThreadExit = "event type: thread-exited. global num: {}".format(event.global_num) + +class test_events(gdb.Command): + """Test events.""" + + def __init__(self): + gdb.Command.__init__(self, "test-events", gdb.COMMAND_STACK) + + def invoke(self, arg, from_tty): + gdb.events.thread_exited.connect(thread_exited_handler) + print("Event testers registered.") + +test_events() base-commit: bd1c798f0aef38493c5292917e47f76e1205f4e3 -- 2.32.0