Commit Graph

1517 Commits

Author SHA1 Message Date
Tom Tromey
b0e7d28eae Remove 'if' from GDB_PY_HANDLE_EXCEPTION
This removes the embedded 'if' from GDB_PY_HANDLE_EXCEPTION and
GDB_PY_SET_HANDLE_EXCEPTION.  I believe this 'if' was necessary with
the old gdb try/catch macros, but it no longer is: these should only
ever be called from a 'catch' block, where it's already known that an
exception was thrown.

Simon pointed out, though, that in a few spots, these were in facts
called outside of 'catch' blocks.  This patch cleans up these spots.
I also found one spot where a redundant 'return nullptr' could be
removed.
2024-03-14 08:57:00 -06:00
Tom de Vries
2cf3c79c80 [gdb/python] Handle deprecation of PyErr_{Fetch,Restore} in 3.12
Starting python version 3.12, PyErr_Fetch and PyErr_Restore are deprecated.

Use PyErr_GetRaisedException and PyErr_SetRaisedException instead, for
python >= 3.12.

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>
2024-03-09 16:13:10 +01:00
Tom de Vries
50ede76876 [gdb/python] Normalize exceptions in gdbpy_err_fetch
With python 3.12, I run into:
...
(gdb) PASS: gdb.python/py-block.exp: check variable access
python print (block['nonexistent'])^M
Python Exception <class 'KeyError'>: 'nonexistent'^M
Error occurred in Python: 'nonexistent'^M
(gdb) FAIL: gdb.python/py-block.exp: check nonexistent variable
...

The problem is that that PyErr_Fetch returns a normalized exception, while the
test-case matches the output for an unnormalized exception.

With python 3.6, PyErr_Fetch returns an unnormalized exception, and the
test passes.

Fix this by:
- updating the test-case to match the output for a normalized exception, and
- lazily forcing normalized exceptions using PyErr_NormalizeException.

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>
2024-03-09 16:13:10 +01:00
Tom de Vries
b1abf8b1b9 [gdb/python] Use gdbpy_err_fetch::{type,value} as getters
Similar to gdbpy_err_fetch::value, add a getter gdbpy_err_fetch::type, and use
both consistently to get gdbpy_err_fetch members m_error_value and
m_error_type.

Tested on aarch64-linux.
2024-03-09 16:13:10 +01:00
Tom Tromey
2755241d02 Add return value to DAP scope
A bug report in the DAP specification repository pointed out that it
is typical for DAP implementations to put a function's return value
into the outermost scope.

This patch changes gdb to follow this convention.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31341
Reviewed-By: Kévin Le Gouguec <legouguec@adacore.com>
2024-03-08 10:50:13 -07:00
Tom Tromey
99761c5ab5 Export "finish" return value to Python
This patch changes the Python "stop" event emission code to also add
the function return value, if it is known.  This happens when the stop
comes from a "finish" command and when the value can be fetched.

The test is in the next patch.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
2024-03-08 10:50:12 -07:00
Tom de Vries
032d23a6db [gdb/dap] Fix stray KeyboardInterrupt after cancel
When running test-case gdb.dap/pause.exp 100 times in a loop, it passes
100/100.

But if we remove the two "sleep 0.2" from the test-case, we run into
(copied from dap.log and edited for readability):
...
Traceback (most recent call last):
  File "startup.py", line 251, in message
    def message():

KeyboardInterrupt
Quit
...

This happens as follows.

CancellationHandler.cancel calls gdb.interrupt to cancel a request in flight.

The idea is that this interrupt triggers while in fn here in message (a nested
function of send_gdb_with_response):
...
    def message():
        try:
            val = fn()
            result_q.put(val)
        except (Exception, KeyboardInterrupt) as e:
            result_q.put(e)
...
but instead it triggers outside the try/except.

Fix this by:
- in CancellationHandler, renaming variable in_flight to in_flight_dap_thread,
  and adding a variable in_flight_gdb_thread to be able to distinguish when
  a request is in flight in the dap thread or the gdb thread.
- adding a wrapper Cancellable to to deal with cancelling the wrapped
  event
- using Cancellable in send_gdb and send_gdb_with_response to wrap the posted
  event
- in CancellationHandler.cancel, only call gdb.interrupt if
  req == self.in_flight_gdb_thread.

This makes the test-case pass 100/100, also when adding the extra stressor of
"taskset -c 0", which makes the fail more likely without the patch.

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>

PR dap/31275
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31275
2024-02-29 21:29:34 +01:00
Tom de Vries
fd09caf44f [gdb/dap] Move send_gdb and send_gdb_with_response to server module
Move functions send_gdb and send_gdb_with_response, as well as class Invoker
to server module.

Separated out to make the following patch easier to read.

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>
2024-02-29 21:29:34 +01:00
Tom Tromey
8bb8f83467 Fix gdb.interrupt race
gdb.interrupt was introduced to implement DAP request cancellation.
However, because it can be run from another thread, and because I
didn't look deeply enough at the implementation, it turns out to be
racy.

The fix here is to lock accesses to certain globals in extension.c.

Note that this won't work in the case where configure detects that the
C++ compiler doesn't provide thread support.  This version of the
patch disables DAP entirely in this situation.

Regression tested on x86-64 Fedora 38.  I also ran gdb.dap/pause.exp
in a thread-sanitizer build tree to make sure the reported race is
gone.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31263
2024-02-28 09:08:16 -07:00
Tom Tromey
b452b96c1e Explicitly quit gdb from DAP server thread
This changes the DAP code to explicitly request that gdb exit.
Previously this could cause crashes, but with the previous cleanups,
this should no longer happen.

This also adds a tests that ensures that gdb exits with status 0.
2024-02-27 10:30:30 -07:00
Tom Tromey
beadf91284 Add extension_language_ops::shutdown
Right now, Python is shut down via a final cleanup.  However, it seems
to me that it is better for extension languages to be shut down
explicitly, after all the ordinary final cleanups are run.  The main
reason for this is that a subsequent patch adds another case like
finalize_values; and rather than add a series of workarounds for
Python shutdown, it seemed better to let these be done via final
cleanups, and then have Python shutdown itself be the special case.
2024-02-27 10:30:29 -07:00
Tom Tromey
1eae7be116 Rewrite final cleanups
This patch rewrites final cleanups to use std::function and otherwise
be more C++-ish.
2024-02-27 10:30:29 -07:00
Tom Tromey
a207f6b3a3 Rewrite "python" command exception handling
The "python" command (and the Python implementation of the gdb
"source" command) does not handle Python exceptions in the same way as
other gdb-facing Python code.  In particular, exceptions are turned
into a generic error rather than being routed through
gdbpy_handle_exception, which takes care of converting to 'quit' as
appropriate.

I think this was done this way because PyRun_SimpleFile and friends do
not propagate the Python exception -- they simply indicate that one
occurred.

This patch reimplements these functions to respect the general gdb
convention here.  As a bonus, some Windows-specific code can be
removed, as can the _execute_file function.

The bulk of this change is tweaking the test suite to match the new
way that exceptions are displayed.  These changes are largely
uninteresting.  However, it's worth pointing out the py-error.exp
change.  Here, the failure changes because the test changes the host
charset to something that isn't supported by Python.  This then
results in a weird error in the new setup.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31354
Acked-By: Tom de Vries <tdevries@suse.de>
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
2024-02-27 09:46:31 -07:00
Tom Tromey
8ee6f71b1a Fix formatting buglet in python.c
python.c has a split string that is missing a space.  There's also a
stray backslash in this code.

Reviewed-By: Tom de Vries <tdevries@suse.de>
2024-02-27 09:46:31 -07:00
Tom Tromey
bf8ab2ae8d Remove unused import
flake8 points out that dap/io.py does not use send_gdb.  This patch
removes the unused import.
2024-02-23 11:43:58 -07:00
Tom de Vries
706c6624c2 [gdb/dap] Fix race between dap exit and gdb exit
When DAP shuts down due to an EOF event, there's a race between:
- gdb's main thread handling a SIGHUP, and
- the DAP main thread exiting.

Fix this by waiting for DAP's main thread exit during the gdb_exiting event.

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>

PR dap/31380
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31380
2024-02-22 11:35:26 +01:00
Tom de Vries
05bf17f03b [gdb/dap] Fix race between dap startup and dap log file
In dap_gdb_start we do:
...
        append GDBFLAGS " -iex \"set debug dap-log-file $logfile\" -q -i=dap"
...

While the dap log file setting comes before the dap interpreter setting,
the order is the other way around:
- first, the dap interpreter is started
- second, the -iex commands are executed and the log file is initialized.

Consequently, there's a race between dap interpreter startup and dap log file
initialization.

This cannot be fixed by using -eiex instead.  Before the interpreter is
started, the "set debug dap-log-file" command is not yet registered.

Fix this by postponing the start of the DAP server until GDB has processed all
command files.

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>

PR dap/31386
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31386
2024-02-22 11:35:26 +01:00
Tom de Vries
67cf0bd885 [gdb/dap] Factor out thread_log
In thread_wrapper I used a style where a message is prefixed with the thread
name.

Factor this out into a new function thread_log.

Also treat the GDB main thread special, because it's usual name is MainThread:
...
MainThread: <msg>
...
which is the default name assigned by python, so instead use the more
explicit:
...
GDB main: <msg>
...

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>
2024-02-22 11:35:26 +01:00
Tom Tromey
a4af05ca66 Don't allow multiple request registrations in DAP
This changes the DAP code to check that a given request or capability
is only registered a single time.  This is just a precaution against
accidentally introducing a second definition of a request somewhere.
2024-02-21 14:55:22 -07:00
Tom de Vries
7c34de9efd [gdb/dap] Join JSON writer thread with DAP thread
The DAP interpreter runs in its own thread, and starts a few threads:
- the JSON reader thread,
- the JSON writer thread, and
- the inferior output reader thread.

As part of the DAP shutdown, both the JSON reader thread and the JSON writer
thread, as well as the DAP main thread run to exit, but these exits are not
ordered in any way.

Wait in the main DAP thread for the exit of the JSON writer thread.

This makes sure that the responses are flushed to the DAP client before DAP
shutdown.

An earlier version of this patch used Queue.task_done() to accomplish the
same, but that didn't guarantee writing the "<thread name>: terminating"
log entry from thread_wrapper before DAP shutdown.

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>

PR dap/31380
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31380
2024-02-21 10:46:08 +01:00
Tom de Vries
d619334108 [gdb/dap] Make dap log printing thread-safe
I read that printing from different python threads is thread-unsafe, and I
noticed that the dap log printing is used from different threads, but doesn't
take care to make the printing thread-safe.

Fix this by using a lock to access LoggingParam.log_file.

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>
2024-02-21 10:46:08 +01:00
Tom de Vries
84a227694d [gdb/dap] Flush after printing in log_stack
I noticed that function log flushes the dap log file after printing, but
that function log_stack doesn't.

Fix this by also flushing the dap log file in log_stack.

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>
2024-02-21 10:46:08 +01:00
Simon Marchi
8480a37e14 gdb: pass frames as const frame_info_ptr &
We currently pass frames to function by value, as `frame_info_ptr`.
This is somewhat expensive:

 - the size of `frame_info_ptr` is 64 bytes, which is a bit big to pass
   by value
 - the constructors and destructor link/unlink the object in the global
   `frame_info_ptr::frame_list` list.  This is an `intrusive_list`, so
   it's not so bad: it's just assigning a few points, there's no memory
   allocation as if it was `std::list`, but still it's useless to do
   that over and over.

As suggested by Tom Tromey, change many function signatures to accept
`const frame_info_ptr &` instead of `frame_info_ptr`.

Some functions reassign their `frame_info_ptr` parameter, like:

  void
  the_func (frame_info_ptr frame)
  {
    for (; frame != nullptr; frame = get_prev_frame (frame))
      {
        ...
      }
  }

I wondered what to do about them, do I leave them as-is or change them
(and need to introduce a separate local variable that can be
re-assigned).  I opted for the later for consistency.  It might not be
clear why some functions take `const frame_info_ptr &` while others take
`frame_info_ptr`.  Also, if a function took a `frame_info_ptr` because
it did re-assign its parameter, I doubt that we would think to change it
to `const frame_info_ptr &` should the implementation change such that
it doesn't need to take `frame_info_ptr` anymore.  It seems better to
have a simple rule and apply it everywhere.

Change-Id: I59d10addef687d157f82ccf4d54f5dde9a963fd0
Approved-By: Andrew Burgess <aburgess@redhat.com>
2024-02-20 10:42:25 -05:00
Tankut Baris Aktemur
046a94c18c gdb, python: selectively omit enabling stdin in gdb.execute
From the Python API, we can execute GDB commands via gdb.execute.  If
the command gives an exception, however, we need to recover the GDB
prompt and enable stdin, because the exception does not reach
top-level GDB or normal_stop.  This was done in commit

  commit 1ba1ac8801
  Author: Andrew Burgess <andrew.burgess@embecosm.com>
  Date:   Tue Nov 19 11:17:20 2019 +0000

    gdb: Enable stdin on exception in execute_gdb_command

with the following code:

  catch (const gdb_exception &except)
    {
      /* If an exception occurred then we won't hit normal_stop (), or have
         an exception reach the top level of the event loop, which are the
         two usual places in which stdin would be re-enabled. So, before we
         convert the exception and continue back in Python, we should
         re-enable stdin here.  */
      async_enable_stdin ();
      GDB_PY_HANDLE_EXCEPTION (except);
    }

In this patch, we explain what happens when we run a GDB command in
the context of a synchronous command, e.g.  via Python observer
notifications.

As an example, suppose we have the following objfile event listener,
specified in a file named file.py:

~~~
import gdb

class MyListener:
    def __init__(self):
        gdb.events.new_objfile.connect(self.handle_new_objfile_event)
        self.processed_objfile = False

    def handle_new_objfile_event(self, event):
        if self.processed_objfile:
            return

        print("loading " + event.new_objfile.filename)
        self.processed_objfile = True
        gdb.execute('add-inferior -no-connection')
        gdb.execute('inferior 2')
        gdb.execute('target remote | gdbserver - /tmp/a.out')
        gdb.execute('inferior 1')

the_listener = MyListener()
~~~

Using this Python file, we see the behavior below:

  $ gdb -q -ex "source file.py" -ex "run" --args a.out
  Reading symbols from a.out...
  Starting program: /tmp/a.out
  loading /lib64/ld-linux-x86-64.so.2
  [New inferior 2]
  Added inferior 2
  [Switching to inferior 2 [<null>] (<noexec>)]
  stdin/stdout redirected
  Process /tmp/a.out created; pid = 3075406
  Remote debugging using stdio
  Reading /tmp/a.out from remote target...
  ...
  [Switching to inferior 1 [process 3075400] (/tmp/a.out)]
  [Switching to thread 1.1 (process 3075400)]
  #0  0x00007ffff7fe3290 in ?? () from /lib64/ld-linux-x86-64.so.2
  (gdb) [Thread debugging using libthread_db enabled]
  Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
  [Inferior 1 (process 3075400) exited normally]

Note how the GDB prompt comes in-between the debugger output.  We have this
obscure behavior, because the executed command, "target remote", triggers
an invocation of `normal_stop` that enables stdin.  After that, however,
the Python notification context completes and GDB continues with its normal
flow of executing the 'run' command.  This can be seen in the call stack
below:

  (top-gdb) bt
  #0  async_enable_stdin () at src/gdb/event-top.c:523
  #1  0x00005555561c3acd in normal_stop () at src/gdb/infrun.c:9432
  #2  0x00005555561b328e in start_remote (from_tty=0) at src/gdb/infrun.c:3801
  #3  0x0000555556441224 in remote_target::start_remote_1 (this=0x5555587882e0, from_tty=0, extended_p=0) at src/gdb/remote.c:5225
  #4  0x000055555644166c in remote_target::start_remote (this=0x5555587882e0, from_tty=0, extended_p=0) at src/gdb/remote.c:5316
  #5  0x00005555564430cf in remote_target::open_1 (name=0x55555878525e "| gdbserver - /tmp/a.out", from_tty=0, extended_p=0) at src/gdb/remote.c:6175
  #6  0x0000555556441707 in remote_target::open (name=0x55555878525e "| gdbserver - /tmp/a.out", from_tty=0) at src/gdb/remote.c:5338
  #7  0x00005555565ea63f in open_target (args=0x55555878525e "| gdbserver - /tmp/a.out", from_tty=0, command=0x555558589280)  at src/gdb/target.c:824
  #8  0x0000555555f0d89a in cmd_func (cmd=0x555558589280, args=0x55555878525e "| gdbserver - /tmp/a.out", from_tty=0) at src/gdb/cli/cli-decode.c:2735
  #9  0x000055555661fb42 in execute_command (p=0x55555878529e "t", from_tty=0) at src/gdb/top.c:575
  #10 0x0000555555f1a506 in execute_control_command_1 (cmd=0x555558756f00, from_tty=0) at src/gdb/cli/cli-script.c:529
  #11 0x0000555555f1abea in execute_control_command (cmd=0x555558756f00, from_tty=0) at src/gdb/cli/cli-script.c:701
  #12 0x0000555555f19fc7 in execute_control_commands (cmdlines=0x555558756f00, from_tty=0) at src/gdb/cli/cli-script.c:411
  #13 0x0000555556400d91 in execute_gdb_command (self=0x7ffff43b5d00, args=0x7ffff440ab60, kw=0x0) at src/gdb/python/python.c:700
  #14 0x00007ffff7a96023 in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #15 0x00007ffff7a4dadc in _PyObject_MakeTpCall () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #16 0x00007ffff79e9a1c in _PyEval_EvalFrameDefault () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #17 0x00007ffff7b303af in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #18 0x00007ffff7a50358 in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #19 0x00007ffff7a4f3f4 in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #20 0x00007ffff7a4f883 in PyObject_CallFunctionObjArgs () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #21 0x00005555563a9758 in evpy_emit_event (event=0x7ffff42b5430, registry=0x7ffff42b4690) at src/gdb/python/py-event.c:104
  #22 0x00005555563cb874 in emit_new_objfile_event (objfile=0x555558761700) at src/gdb/python/py-newobjfileevent.c:52
  #23 0x00005555563b53bc in python_new_objfile (objfile=0x555558761700) at src/gdb/python/py-inferior.c:195
  #24 0x0000555555d6dff0 in std::__invoke_impl<void, void (*&)(objfile*), objfile*> (__f=@0x5555585b5860: 0x5555563b5360 <python_new_objfile(objfile*)>) at /usr/include/c++/11/bits/invoke.h:61
  #25 0x0000555555d6be18 in std::__invoke_r<void, void (*&)(objfile*), objfile*> (__fn=@0x5555585b5860: 0x5555563b5360 <python_new_objfile(objfile*)>) at /usr/include/c++/11/bits/invoke.h:111
  #26 0x0000555555d69661 in std::_Function_handler<void (objfile*), void (*)(objfile*)>::_M_invoke(std::_Any_data const&, objfile*&&) (__functor=..., __args#0=@0x7fffffffd080: 0x555558761700) at /usr/include/c++/11/bits/std_function.h:290
  #27 0x0000555556314caf in std::function<void (objfile*)>::operator()(objfile*) const (this=0x5555585b5860, __args#0=0x555558761700) at /usr/include/c++/11/bits/std_function.h:590
  #28 0x000055555631444e in gdb::observers::observable<objfile*>::notify (this=0x55555836eea0 <gdb::observers::new_objfile>, args#0=0x555558761700) at src/gdb/../gdbsupport/observable.h:166
  #29 0x0000555556599b3f in symbol_file_add_with_addrs (abfd=..., name=0x55555875d310 "/lib64/ld-linux-x86-64.so.2", add_flags=..., addrs=0x7fffffffd2f0, flags=..., parent=0x0) at src/gdb/symfile.c:1125
  #30 0x0000555556599ca4 in symbol_file_add_from_bfd (abfd=..., name=0x55555875d310 "/lib64/ld-linux-x86-64.so.2", add_flags=..., addrs=0x7fffffffd2f0, flags=..., parent=0x0) at src/gdb/symfile.c:1160
  #31 0x0000555556546371 in solib_read_symbols (so=..., flags=...) at src/gdb/solib.c:692
  #32 0x0000555556546f0f in solib_add (pattern=0x0, from_tty=0, readsyms=1) at src/gdb/solib.c:1015
  #33 0x0000555556539891 in enable_break (info=0x55555874e180, from_tty=0) at src/gdb/solib-svr4.c:2416
  #34 0x000055555653b305 in svr4_solib_create_inferior_hook (from_tty=0) at src/gdb/solib-svr4.c:3058
  #35 0x0000555556547cee in solib_create_inferior_hook (from_tty=0) at src/gdb/solib.c:1217
  #36 0x0000555556196f6a in post_create_inferior (from_tty=0) at src/gdb/infcmd.c:275
  #37 0x0000555556197670 in run_command_1 (args=0x0, from_tty=1, run_how=RUN_NORMAL) at src/gdb/infcmd.c:486
  #38 0x000055555619783f in run_command (args=0x0, from_tty=1) at src/gdb/infcmd.c:512
  #39 0x0000555555f0798d in do_simple_func (args=0x0, from_tty=1, c=0x555558567510) at src/gdb/cli/cli-decode.c:95
  #40 0x0000555555f0d89a in cmd_func (cmd=0x555558567510, args=0x0, from_tty=1) at src/gdb/cli/cli-decode.c:2735
  #41 0x000055555661fb42 in execute_command (p=0x7fffffffe2c4 "", from_tty=1) at src/gdb/top.c:575
  #42 0x000055555626303b in catch_command_errors (command=0x55555661f4ab <execute_command(char const*, int)>, arg=0x7fffffffe2c1 "run", from_tty=1, do_bp_actions=true) at src/gdb/main.c:513
  #43 0x000055555626328a in execute_cmdargs (cmdarg_vec=0x7fffffffdaf0, file_type=CMDARG_FILE, cmd_type=CMDARG_COMMAND, ret=0x7fffffffda3c) at src/gdb/main.c:612
  #44 0x0000555556264849 in captured_main_1 (context=0x7fffffffdd40) at src/gdb/main.c:1293
  #45 0x0000555556264a7f in captured_main (data=0x7fffffffdd40) at src/gdb/main.c:1314
  #46 0x0000555556264b2e in gdb_main (args=0x7fffffffdd40) at src/gdb/main.c:1343
  #47 0x0000555555ceccab in main (argc=9, argv=0x7fffffffde78) at src/gdb/gdb.c:39
  (top-gdb)

The use of the "target remote" command here is just an example.  In
principle, we would reproduce the problem with any command that
triggers an invocation of `normal_stop`.

To omit enabling the stdin in `normal_stop`, we would have to check the
context we are in.  Since we cannot do that, we add a new field to
`struct ui` to track whether the prompt was already blocked, and set
the tracker flag in the Python context before executing a GDB command.

After applying this patch, the output becomes

  ...
  Reading symbols from a.out...
  Starting program: /tmp/a.out
  loading /lib64/ld-linux-x86-64.so.2
  [New inferior 2]
  Added inferior 2
  [Switching to inferior 2 [<null>] (<noexec>)]
  stdin/stdout redirected
  Process /tmp/a.out created; pid = 3032261
  Remote debugging using stdio
  Reading /tmp/a.out from remote target...
  ...
  [Switching to inferior 1 [process 3032255] (/tmp/a.out)]
  [Switching to thread 1.1 (process 3032255)]
  #0  0x00007ffff7fe3290 in ?? () from /lib64/ld-linux-x86-64.so.2
  [Thread debugging using libthread_db enabled]
  Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
  [Inferior 1 (process 3032255) exited normally]
  (gdb)

Let's now consider a secondary scenario, where the command executed from
the Python raises an error.  As an example, suppose we have the Python
file below:

    def handle_new_objfile_event(self, event):
        ...
        print("loading " + event.new_objfile.filename)
        self.processed_objfile = True
        gdb.execute('print a')

The executed command, "print a", gives an error because "a" is not
defined.  Without this patch, we see the behavior below, where the
prompt is again placed incorrectly:

  ...
  Reading symbols from /tmp/a.out...
  Starting program: /tmp/a.out
  loading /lib64/ld-linux-x86-64.so.2
  Python Exception <class 'gdb.error'>: No symbol "a" in current context.
  (gdb) [Inferior 1 (process 3980401) exited normally]

This time, `async_enable_stdin` is called from the 'catch' block in
`execute_gdb_command`:

  (top-gdb) bt
  #0  async_enable_stdin () at src/gdb/event-top.c:523
  #1  0x0000555556400f0a in execute_gdb_command (self=0x7ffff43b5d00, args=0x7ffff440ab60, kw=0x0) at src/gdb/python/python.c:713
  #2  0x00007ffff7a96023 in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #3  0x00007ffff7a4dadc in _PyObject_MakeTpCall () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #4  0x00007ffff79e9a1c in _PyEval_EvalFrameDefault () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #5  0x00007ffff7b303af in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #6  0x00007ffff7a50358 in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #7  0x00007ffff7a4f3f4 in ?? () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #8  0x00007ffff7a4f883 in PyObject_CallFunctionObjArgs () from /lib/x86_64-linux-gnu/libpython3.10.so.1.0
  #9  0x00005555563a9758 in evpy_emit_event (event=0x7ffff42b5430, registry=0x7ffff42b4690) at src/gdb/python/py-event.c:104
  #10 0x00005555563cb874 in emit_new_objfile_event (objfile=0x555558761410) at src/gdb/python/py-newobjfileevent.c:52
  #11 0x00005555563b53bc in python_new_objfile (objfile=0x555558761410) at src/gdb/python/py-inferior.c:195
  #12 0x0000555555d6dff0 in std::__invoke_impl<void, void (*&)(objfile*), objfile*> (__f=@0x5555585b5860: 0x5555563b5360 <python_new_objfile(objfile*)>) at /usr/include/c++/11/bits/invoke.h:61
  #13 0x0000555555d6be18 in std::__invoke_r<void, void (*&)(objfile*), objfile*> (__fn=@0x5555585b5860: 0x5555563b5360 <python_new_objfile(objfile*)>) at /usr/include/c++/11/bits/invoke.h:111
  #14 0x0000555555d69661 in std::_Function_handler<void (objfile*), void (*)(objfile*)>::_M_invoke(std::_Any_data const&, objfile*&&) (__functor=..., __args#0=@0x7fffffffd080: 0x555558761410) at /usr/include/c++/11/bits/std_function.h:290
  #15 0x0000555556314caf in std::function<void (objfile*)>::operator()(objfile*) const (this=0x5555585b5860, __args#0=0x555558761410) at /usr/include/c++/11/bits/std_function.h:590
  #16 0x000055555631444e in gdb::observers::observable<objfile*>::notify (this=0x55555836eea0 <gdb::observers::new_objfile>, args#0=0x555558761410) at src/gdb/../gdbsupport/observable.h:166
  #17 0x0000555556599b3f in symbol_file_add_with_addrs (abfd=..., name=0x55555875d020 "/lib64/ld-linux-x86-64.so.2", add_flags=..., addrs=0x7fffffffd2f0, flags=..., parent=0x0) at src/gdb/symfile.c:1125
  #18 0x0000555556599ca4 in symbol_file_add_from_bfd (abfd=..., name=0x55555875d020 "/lib64/ld-linux-x86-64.so.2", add_flags=..., addrs=0x7fffffffd2f0, flags=..., parent=0x0) at src/gdb/symfile.c:1160
  #19 0x0000555556546371 in solib_read_symbols (so=..., flags=...) at src/gdb/solib.c:692
  #20 0x0000555556546f0f in solib_add (pattern=0x0, from_tty=0, readsyms=1) at src/gdb/solib.c:1015
  #21 0x0000555556539891 in enable_break (info=0x55555874a670, from_tty=0) at src/gdb/solib-svr4.c:2416
  #22 0x000055555653b305 in svr4_solib_create_inferior_hook (from_tty=0) at src/gdb/solib-svr4.c:3058
  #23 0x0000555556547cee in solib_create_inferior_hook (from_tty=0) at src/gdb/solib.c:1217
  #24 0x0000555556196f6a in post_create_inferior (from_tty=0) at src/gdb/infcmd.c:275
  #25 0x0000555556197670 in run_command_1 (args=0x0, from_tty=1, run_how=RUN_NORMAL) at src/gdb/infcmd.c:486
  #26 0x000055555619783f in run_command (args=0x0, from_tty=1) at src/gdb/infcmd.c:512
  #27 0x0000555555f0798d in do_simple_func (args=0x0, from_tty=1, c=0x555558567510) at src/gdb/cli/cli-decode.c:95
  #28 0x0000555555f0d89a in cmd_func (cmd=0x555558567510, args=0x0, from_tty=1) at src/gdb/cli/cli-decode.c:2735
  #29 0x000055555661fb42 in execute_command (p=0x7fffffffe2c4 "", from_tty=1) at src/gdb/top.c:575
  #30 0x000055555626303b in catch_command_errors (command=0x55555661f4ab <execute_command(char const*, int)>, arg=0x7fffffffe2c1 "run", from_tty=1, do_bp_actions=true) at src/gdb/main.c:513
  #31 0x000055555626328a in execute_cmdargs (cmdarg_vec=0x7fffffffdaf0, file_type=CMDARG_FILE, cmd_type=CMDARG_COMMAND, ret=0x7fffffffda3c) at src/gdb/main.c:612
  #32 0x0000555556264849 in captured_main_1 (context=0x7fffffffdd40) at src/gdb/main.c:1293
  #33 0x0000555556264a7f in captured_main (data=0x7fffffffdd40) at src/gdb/main.c:1314
  #34 0x0000555556264b2e in gdb_main (args=0x7fffffffdd40) at src/gdb/main.c:1343
  #35 0x0000555555ceccab in main (argc=9, argv=0x7fffffffde78) at src/gdb/gdb.c:39
  (top-gdb)

Again, after we enable stdin, GDB continues with its normal flow
of the 'run' command and receives the inferior's exit event, where
it would have enabled stdin, if we had not done it prematurely.

  (top-gdb) bt
  #0  async_enable_stdin () at src/gdb/event-top.c:523
  #1  0x00005555561c3acd in normal_stop () at src/gdb/infrun.c:9432
  #2  0x00005555561b5bf1 in fetch_inferior_event () at src/gdb/infrun.c:4700
  #3  0x000055555618d6a7 in inferior_event_handler (event_type=INF_REG_EVENT) at src/gdb/inf-loop.c:42
  #4  0x000055555620ecdb in handle_target_event (error=0, client_data=0x0) at src/gdb/linux-nat.c:4316
  #5  0x0000555556f33035 in handle_file_event (file_ptr=0x5555587024e0, ready_mask=1) at src/gdbsupport/event-loop.cc:573
  #6  0x0000555556f3362f in gdb_wait_for_event (block=0) at src/gdbsupport/event-loop.cc:694
  #7  0x0000555556f322cd in gdb_do_one_event (mstimeout=-1) at src/gdbsupport/event-loop.cc:217
  #8  0x0000555556262df8 in start_event_loop () at src/gdb/main.c:407
  #9  0x0000555556262f85 in captured_command_loop () at src/gdb/main.c:471
  #10 0x0000555556264a84 in captured_main (data=0x7fffffffdd40) at src/gdb/main.c:1324
  #11 0x0000555556264b2e in gdb_main (args=0x7fffffffdd40) at src/gdb/main.c:1343
  #12 0x0000555555ceccab in main (argc=9, argv=0x7fffffffde78) at src/gdb/gdb.c:39
  (top-gdb)

The solution implemented by this patch addresses the problem.  After
applying the patch, the output becomes

  $ gdb -q -ex "source file.py" -ex "run" --args a.out
  Reading symbols from /tmp/a.out...
  Starting program: /tmp/a.out
  loading /lib64/ld-linux-x86-64.so.2
  Python Exception <class 'gdb.error'>: No symbol "a" in current context.
  [Inferior 1 (process 3984511) exited normally]
  (gdb)

Regression-tested on X86_64 Linux using the default board file (i.e.  unix).

Co-Authored-By: Oguzhan Karakaya <oguzhan.karakaya@intel.com>
Reviewed-By: Guinevere Larsen <blarsen@redhat.com>
Approved-By: Tom Tromey <tom@tromey.com>
2024-02-19 10:55:32 +01:00
Tom de Vries
98e1896364 [gdb/dap] Fix exit race
When running test-case gdb.dap/eof.exp, we're likely to get a coredump due to
a segfault in new_threadstate.

At the point of the core dump, the gdb main thread looks like:
...
 (gdb) bt
 #0  0x0000fffee30d2280 in __pthread_kill_implementation () from /lib64/libc.so.6
 #1  0x0000fffee3085800 [PAC] in raise () from /lib64/libc.so.6
 #2  0x00000000007b03e8 [PAC] in handle_fatal_signal (sig=11)
     at gdb/event-top.c:926
 #3  0x00000000007b0470 in handle_sigsegv (sig=11)
     at gdb/event-top.c:976
 #4  <signal handler called>
 #5  0x0000fffee3a4db14 in new_threadstate () from /lib64/libpython3.12.so.1.0
 #6  0x0000fffee3ab0548 [PAC] in PyGILState_Ensure () from /lib64/libpython3.12.so.1.0
 #7  0x0000000000a6d034 [PAC] in gdbpy_gil::gdbpy_gil (this=0xffffcb279738)
     at gdb/python/python-internal.h:787
 #8  0x0000000000ab87ac in gdbpy_event::~gdbpy_event (this=0xfffea8001ee0,
     __in_chrg=<optimized out>) at gdb/python/python.c:1051
 #9  0x0000000000ab9460 in std::_Function_base::_Base_manager<...>::_M_destroy
     (__victim=...) at /usr/include/c++/13/bits/std_function.h:175
 #10 0x0000000000ab92dc in std::_Function_base::_Base_manager<...>::_M_manager
     (__dest=..., __source=..., __op=std::__destroy_functor)
     at /usr/include/c++/13/bits/std_function.h:203
 #11 0x0000000000ab8f14 in std::_Function_handler<...>::_M_manager(...) (...)
     at /usr/include/c++/13/bits/std_function.h:282
 #12 0x000000000042dd9c in std::_Function_base::~_Function_base (this=0xfffea8001c10,
     __in_chrg=<optimized out>) at /usr/include/c++/13/bits/std_function.h:244
 #13 0x000000000042e654 in std::function<void ()>::~function() (this=0xfffea8001c10,
     __in_chrg=<optimized out>) at /usr/include/c++/13/bits/std_function.h:334
 #14 0x0000000000b68e60 in std::_Destroy<std::function<void ()> >(...) (...)
     at /usr/include/c++/13/bits/stl_construct.h:151
 #15 0x0000000000b68cd0 in std::_Destroy_aux<false>::__destroy<...>(...) (...)
     at /usr/include/c++/13/bits/stl_construct.h:163
 #16 0x0000000000b689d8 in std::_Destroy<...>(...) (...)
     at /usr/include/c++/13/bits/stl_construct.h:196
 #17 0x0000000000b68414 in std::_Destroy<...>(...) (...)
     at /usr/include/c++/13/bits/alloc_traits.h:948
 #18 std::vector<...>::~vector() (this=0x2a183c8 <runnables>)
     at /usr/include/c++/13/bits/stl_vector.h:732
 #19 0x0000fffee3088370 in __run_exit_handlers () from /lib64/libc.so.6
 #20 0x0000fffee3088450 [PAC] in exit () from /lib64/libc.so.6
 #21 0x0000000000c95600 [PAC] in quit_force (exit_arg=0x0, from_tty=0)
     at gdb/top.c:1822
 #22 0x0000000000609140 in quit_command (args=0x0, from_tty=0)
     at gdb/cli/cli-cmds.c:508
 #23 0x0000000000c926a4 in quit_cover () at gdb/top.c:300
 #24 0x00000000007b09d4 in async_disconnect (arg=0x0)
     at gdb/event-top.c:1230
 #25 0x0000000000548acc in invoke_async_signal_handlers ()
     at gdb/async-event.c:234
 #26 0x000000000157d2d4 in gdb_do_one_event (mstimeout=-1)
     at gdbsupport/event-loop.cc:199
 #27 0x0000000000943a84 in start_event_loop () at gdb/main.c:401
 #28 0x0000000000943bfc in captured_command_loop () at gdb/main.c:465
 #29 0x000000000094567c in captured_main (data=0xffffcb279d08)
     at gdb/main.c:1335
 #30 0x0000000000945700 in gdb_main (args=0xffffcb279d08)
     at gdb/main.c:1354
 #31 0x0000000000423ab4 in main (argc=14, argv=0xffffcb279e98)
     at gdb/gdb.c:39
...

The direct cause of the segfault is calling PyGILState_Ensure after
calling Py_Finalize.

AFAICT the problem is a race between the gdb main thread and DAP's JSON writer
thread.

On one side, we have the following events:
- DAP's JSON reader thread reads an EOF, and lets DAP's main thread known
  by writing None into read_queue
- DAP's main thread lets DAP's JSON writer thread known by writing None into
  write_queue
- DAP's JSON writer thread sees the None in its queue, and calls
  send_gdb("quit")
- a corresponding gdbpy_event is deposited in the runnables vector, to be
  run by the gdb main thread

On the other side, we have the following events:
- the gdb main thread receives a SIGHUP
- the corresponding handler calls quit_force, which calls do_final_cleanups
- one of the final cleanups is finalize_python, which calls Py_Finalize
- quit_force calls exit, which triggers the exit handlers
- one of the exit handlers is the destructor of the runnables vector
- destruction of the vector triggers destruction of the remaining element
- the remaining element is a gdbpy_event, and the destructor (indirectly)
  calls PyGILState_Ensure

It's good to note that both events (EOF and SIGHUP) are caused by this line in
the test-case:
...
catch "close -i $gdb_spawn_id"
...
where "expect close" closes the stdin and stdout file descriptors, which
causes the SIGHUP to be send.

So, for the system I'm running this on, the send_gdb("quit") is actually not
needed.

I'm not sure if we support any systems where it's actually needed.

Fix this by removing the send_gdb("quit").

Tested on aarch64-linux.

PR dap/31306
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31306
2024-02-14 18:24:39 +01:00
Tom de Vries
e25a613437 [gdb] Re-format dap/startup.py with black
Commit 433ae2c245 ("[gdb/dap] Catch and log exceptions in dap threads") made
some changes to gdb/python/lib/gdb/dap/startup.py.

Re-format it with black.
2024-02-12 21:45:25 +01:00
Tom de Vries
433ae2c245 [gdb/dap] Catch and log exceptions in dap threads
When running test-case gdb.dap/eof.exp, it occasionally coredumps.

The thread triggering the coredump is:
...
 #0  0x0000ffff42bb2280 in __pthread_kill_implementation () from /lib64/libc.so.6
 #1  0x0000ffff42b65800 [PAC] in raise () from /lib64/libc.so.6
 #2  0x00000000007b03e8 [PAC] in handle_fatal_signal (sig=11)
     at gdb/event-top.c:926
 #3  0x00000000007b0470 in handle_sigsegv (sig=11)
     at gdb/event-top.c:976
 #4  <signal handler called>
 #5  0x0000000000606080 in cli_ui_out::do_message (this=0xffff2f7ed728, style=...,
     format=0xffff0c002af1 "%s", args=...) at gdb/cli-out.c:232
 #6  0x0000000000ce6358 in ui_out::call_do_message (this=0xffff2f7ed728, style=...,
     format=0xffff0c002af1 "%s") at gdb/ui-out.c:584
 #7  0x0000000000ce6610 in ui_out::vmessage (this=0xffff2f7ed728, in_style=...,
     format=0x16f93ea "", args=...) at gdb/ui-out.c:621
 #8  0x0000000000ce3a9c in ui_file::vprintf (this=0xfffffbea1b18, ...)
     at gdb/ui-file.c:74
 #9  0x0000000000d2b148 in gdb_vprintf (stream=0xfffffbea1b18, format=0x16f93e8 "%s",
     args=...) at gdb/utils.c:1898
 #10 0x0000000000d2b23c in gdb_printf (stream=0xfffffbea1b18, format=0x16f93e8 "%s")
     at gdb/utils.c:1913
 #11 0x0000000000ab5208 in gdbpy_write (self=0x33fe35d0, args=0x342ec280, kw=0x345c08b0)
     at gdb/python/python.c:1464
 #12 0x0000ffff434acedc in cfunction_call () from /lib64/libpython3.12.so.1.0
 #13 0x0000ffff4347c500 [PAC] in _PyObject_MakeTpCall ()
     from /lib64/libpython3.12.so.1.0
 #14 0x0000ffff43488b64 [PAC] in _PyEval_EvalFrameDefault ()
    from /lib64/libpython3.12.so.1.0
 #15 0x0000ffff434d8cd0 [PAC] in method_vectorcall () from /lib64/libpython3.12.so.1.0
 #16 0x0000ffff434b9824 [PAC] in PyObject_CallOneArg () from /lib64/libpython3.12.so.1.0
 #17 0x0000ffff43557674 [PAC] in PyFile_WriteObject () from /lib64/libpython3.12.so.1.0
 #18 0x0000ffff435577a0 [PAC] in PyFile_WriteString () from /lib64/libpython3.12.so.1.0
 #19 0x0000ffff43465354 [PAC] in thread_excepthook () from /lib64/libpython3.12.so.1.0
 #20 0x0000ffff434ac6e0 [PAC] in cfunction_vectorcall_O ()
    from /lib64/libpython3.12.so.1.0
 #21 0x0000ffff434a32d8 [PAC] in PyObject_Vectorcall () from /lib64/libpython3.12.so.1.0
 #22 0x0000ffff43488b64 [PAC] in _PyEval_EvalFrameDefault ()
    from /lib64/libpython3.12.so.1.0
 #23 0x0000ffff434d8d88 [PAC] in method_vectorcall () from /lib64/libpython3.12.so.1.0
 #24 0x0000ffff435e0ef4 [PAC] in thread_run () from /lib64/libpython3.12.so.1.0
 #25 0x0000ffff43591ec0 [PAC] in pythread_wrapper () from /lib64/libpython3.12.so.1.0
 #26 0x0000ffff42bb0584 [PAC] in start_thread () from /lib64/libc.so.6
 #27 0x0000ffff42c1fd4c [PAC] in thread_start () from /lib64/libc.so.6
...

The direct cause for the coredump seems to be that cli_ui_out::do_message
is trying to write to a stream variable which does not look sound:
...
(gdb) p *stream
$8 = {_vptr.ui_file = 0x0, m_applied_style = {m_foreground = {m_simple = true, {
        m_value = 0, {m_red = 0 '\000', m_green = 0 '\000', m_blue = 0 '\000'}}},
    m_background = {m_simple = 32, {m_value = 65535, {m_red = 255 '\377',
          m_green = 255 '\377', m_blue = 0 '\000'}}},
    m_intensity = (unknown: 0x438fe710), m_reverse = 255}}
...

The string that is being printed is:
...
(gdb) p str
$9 = "Exception in thread "
...
so AFAICT this is a DAP thread running into an exception and trying to print
it.

If we look at the state of gdb's main thread, we have:
...
 #0  0x0000ffff42bac914 in __futex_abstimed_wait_cancelable64 () from /lib64/libc.so.6
 #1  0x0000ffff42bafb44 [PAC] in pthread_cond_timedwait@@GLIBC_2.17 ()
    from /lib64/libc.so.6
 #2  0x0000ffff43466e9c [PAC] in take_gil () from /lib64/libpython3.12.so.1.0
 #3  0x0000ffff43484fe0 [PAC] in PyEval_RestoreThread ()
     from /lib64/libpython3.12.so.1.0
 #4  0x0000000000ab8698 [PAC] in gdbpy_allow_threads::~gdbpy_allow_threads (
     this=0xfffffbea1cf8, __in_chrg=<optimized out>)
     at gdb/python/python-internal.h:769
 #5  0x0000000000ab2fec in execute_gdb_command (self=0x33fe35d0, args=0x34297b60,
     kw=0x34553d20) at gdb/python/python.c:681
 #6  0x0000ffff434acedc in cfunction_call () from /lib64/libpython3.12.so.1.0
 #7  0x0000ffff4347c500 [PAC] in _PyObject_MakeTpCall ()
     from /lib64/libpython3.12.so.1.0
 #8  0x0000ffff43488b64 [PAC] in _PyEval_EvalFrameDefault ()
    from /lib64/libpython3.12.so.1.0
 #9  0x0000ffff4353bce8 [PAC] in _PyObject_VectorcallTstate.lto_priv.3 ()
    from /lib64/libpython3.12.so.1.0
 #10 0x0000000000ab87fc [PAC] in gdbpy_event::operator() (this=0xffff14005900)
     at gdb/python/python.c:1061
 #11 0x0000000000ab93e8 in std::__invoke_impl<void, gdbpy_event&> (__f=...)
     at /usr/include/c++/13/bits/invoke.h:61
 #12 0x0000000000ab9204 in std::__invoke_r<void, gdbpy_event&> (__fn=...)
     at /usr/include/c++/13/bits/invoke.h:111
 #13 0x0000000000ab8e90 in std::_Function_handler<..>::_M_invoke(...) (...)
     at /usr/include/c++/13/bits/std_function.h:290
 #14 0x000000000062e0d0 in std::function<void ()>::operator()() const (
     this=0xffff14005830) at /usr/include/c++/13/bits/std_function.h:591
 #15 0x0000000000b67f14 in run_events (error=0, client_data=0x0)
     at gdb/run-on-main-thread.c:76
 #16 0x000000000157e290 in handle_file_event (file_ptr=0x33dae3a0, ready_mask=1)
     at gdbsupport/event-loop.cc:573
 #17 0x000000000157e760 in gdb_wait_for_event (block=1)
     at gdbsupport/event-loop.cc:694
 #18 0x000000000157d464 in gdb_do_one_event (mstimeout=-1)
     at gdbsupport/event-loop.cc:264
 #19 0x0000000000943a84 in start_event_loop () at gdb/main.c:401
 #20 0x0000000000943bfc in captured_command_loop () at gdb/main.c:465
 #21 0x000000000094567c in captured_main (data=0xfffffbea23e8)
     at gdb/main.c:1335
 #22 0x0000000000945700 in gdb_main (args=0xfffffbea23e8)
     at gdb/main.c:1354
 #23 0x0000000000423ab4 in main (argc=14, argv=0xfffffbea2578)
     at gdb/gdb.c:39
...

AFAIU, there's a race between the two threads on gdb_stderr:
- the DAP thread samples the gdb_stderr value, and uses it a bit later to
  print to
- the gdb main thread changes the gdb_stderr value forth and back,
  using a temporary value for string capture purposes

The non-sound stream value is caused by gdb_stderr being sampled while
pointing to a str_file object, and used once the str_file object is already
destroyed.

The error here is that the DAP thread attempts to print to gdb_stderr.

Fix this by adding a thread_wrapper that:
- catches all exceptions and logs them to dap.log, and
- while we're at it, logs when exiting
and using the thread_wrapper for each DAP thread.

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>
2024-02-12 20:07:46 +01:00
Tom Tromey
25558d2fc0 Fix DAP launch and configurationDone requests
Co-workers at AdaCore pointed out that gdb incorrectly implements the
DAP launch and configurationDone requests.  It's somewhat strange to
me, but the spec does in fact say that configuration requests should
occur before the executable is known to gdb.  This was clarified in
this bug report against the spec:

    https://github.com/microsoft/debug-adapter-protocol/issues/452

Fixing 'launch' to start the inferior was straightforward, but this
then required some changes to how breakpoints are handled.  In
particular, now gdb will emit the "pending" reason on a breakpoint,
and will suppress breakpoint events during breakpoint setting.
2024-02-12 10:43:17 -07:00
Tom Tromey
95fc420a40 Clean up suppress_new_breakpoint_event
Kévin pointed out that suppress_new_breakpoint_event would do the
wrong thing if it happened to be used reentrantly.  While I don't
think this can happen, it's also easy and clearly better to make it
robust.
2024-02-12 10:42:21 -07:00
Simon Marchi
b9885796f8 gdb: re-format Python files with black 24.1.1
New year, new black version.

Change-Id: I664601e6dd255358063e15f6d73bc5f02c8f2b9d
2024-02-12 12:10:34 -05:00
Andrew Burgess
4eba08320b gdb/python: fix 'set python ignore-environment' white space
I noticed that the help text for set/show python ignore-environment
was messed up, some lines had unwanted leading white space, like this:

  (gdb) help set python ignore-environment
  Set whether the Python interpreter should ignore environment variables.
   When enabled GDB's Python interpreter will ignore any Python related
          flags in the environment.  This is equivalent to passing `-E' to a
          python executable.
  (gdb)

This has been present since the ignore-environment setting was added
in commit:

  commit edeaceda7b
  Date:   Thu Aug 27 16:53:13 2020 +0100

      gdb: startup commands to control Python extension language

Fixed in this commit.
2024-02-10 17:54:10 +00:00
Hannes Domani
2e08907d06 Allow calling of C++ methods from python
Currently it's not possible to call C++ methods from python.
Using this example:
```
class B
{
  static int static_func ();
  int arg0_func ();
  int arg1_func (int arg1);
  int arg2_func (int arg1, int arg2);
};

B *b_obj = new B;
```

Trying to call B::static_func gives this error:
```
(gdb) py b_obj = gdb.parse_and_eval('b_obj')
(gdb) py print(b_obj['static_func']())
Traceback (most recent call last):
  File "<string>", line 1, in <module>
RuntimeError: Value is not callable (not TYPE_CODE_FUNC).
Error while executing Python code.
```

TYPE_CODE_METHOD was simply missing as a possible type in
valpy_call, now the same is possible:
```
(gdb) py b_obj = gdb.parse_and_eval('b_obj')
(gdb) py print(b_obj['static_func']())
1111
```

Note that it's necessary to explicitely add the this pointer
as the first argument in a call of non-static methods:
```
(gdb) py print(b_obj['arg0_func']())
Traceback (most recent call last):
  File "<string>", line 1, in <module>
gdb.error: Too few arguments in function call.
Error while executing Python code.
(gdb) py print(b_obj['arg0_func'](b_obj))
198
```

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=13326
Approved-By: Tom Tromey <tom@tromey.com>
2024-02-08 20:09:56 +01:00
Hannes Domani
276d9db22d Raise exception if ambiguous name is used in gdb.parameter
Currently gdb.parameter doesn't raise an exception if an
ambiguous name is used, it instead returns the value of the
last partly matching parameter:
```
(gdb) show print sym
Ambiguous show print command "sym": symbol, symbol-filename, symbol-loading.
(gdb) show print symbol-loading
Printing of symbol loading messages is "full".
(gdb) py print(gdb.parameter("print sym"))
full
```

It's because lookup_cmd_composition_1 tries to detect
ambigous names by checking the return value of find_cmd
for CMD_LIST_AMBIGUOUS, which never happens, since only
lookup_cmd_1 returns CMD_LIST_AMBIGUOUS.
Instead the nfound argument contains the number of found
matches.

By using it instead, and by setting *CMD to the special value
CMD_LIST_AMBIGUOUS in this case, gdbpy_parameter can now show
the appropriate error message:
```
(gdb) py print(gdb.parameter("print sym"))
Traceback (most recent call last):
  File "<string>", line 1, in <module>
RuntimeError: Parameter `print sym' is ambiguous.
Error while executing Python code.
(gdb) py print(gdb.parameter("print symbol"))
True
(gdb) py print(gdb.parameter("print symbol-"))
Traceback (most recent call last):
  File "<string>", line 1, in <module>
RuntimeError: Parameter `print symbol-' is ambiguous.
Error while executing Python code.
(gdb) py print(gdb.parameter("print symbol-load"))
full
```

Since the document command also uses lookup_cmd_composition, it needed
to check for CMD_LIST_AMBIGUOUS as well, so it now also shows an
"Ambiguous command" error message in this case.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=14639
Approved-By: Tom Tromey <tom@tromey.com>
2024-02-07 19:59:32 +01:00
Hannes Domani
ad7b7cb1f4 Fix raw-frame-arguments in combination with frame-filters
Currently, if frame-filters are active, raw-values is used instead of
raw-frame-arguments to decide if a pretty-printer should be invoked for
frame arguments in a backtrace.

In this example, "super struct" is the output of the pretty-printer:

    (gdb) disable frame-filter global BasicFrameFilter
    (gdb) bt
    #0  foo (x=42, ss=super struct = {...}) at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:47
    #1  0x004016aa in main () at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:57

If no frame-filter is active, then the raw-values print option does not
affect the backtrace output:

    (gdb) set print raw-values on
    (gdb) bt
    #0  foo (x=42, ss=super struct = {...}) at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:47
    #1  0x004016aa in main () at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:57
    (gdb) set print raw-values off

Instead, the raw-frame-arguments option disables the pretty-printer in the
backtrace:

    (gdb) bt -raw-frame-arguments on
    #0  foo (x=42, ss=...) at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:47
    #1  0x004016aa in main () at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:57

But if a frame-filter is active, the same rules don't apply.
The option raw-frame-arguments is ignored, but raw-values decides if the
pretty-printer is used:

    (gdb) enable frame-filter global BasicFrameFilter
    (gdb) bt
    #0  foo (x=42, ss=super struct = {...}) at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:47
    #1  0x004016aa in main () at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:57
    (gdb) set print raw-values on
    (gdb) bt
    #0  foo (x=42, ss=...) at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:47
    #1  0x004016aa in main () at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:57
    (gdb) set print raw-values off
    (gdb) bt -raw-frame-arguments on
    #0  foo (x=42, ss=super struct = {...}) at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:47
    #1  0x004016aa in main () at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:57

So this adds the PRINT_RAW_FRAME_ARGUMENTS flag to frame_filter_flag, which
is then used in the frame-filter to override the raw flag in enumerate_args.

Then the output is the same if a frame-filter is active, the pretty-printer
for backtraces is only disabled with the raw-frame-arguments option:

    (gdb) enable frame-filter global BasicFrameFilter
    (gdb) bt
    #0  foo (x=42, ss=super struct = {...}) at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:47
    #1  0x004016aa in main () at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:57
    (gdb) set print raw-values on
    (gdb) bt
    #0  foo (x=42, ss=super struct = {...}) at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:47
    #1  0x004016aa in main () at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:57
    (gdb) set print raw-values off
    (gdb) bt -raw-frame-arguments on
    #0  foo (x=42, ss=...) at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:47
    #1  0x004016aa in main () at C:/src/repos/gdb-testsuite/gdb/testsuite/gdb.python/py-frame-args.c:57

Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
Approved-By: Tom Tromey <tom@tromey.com>
2024-02-07 19:52:06 +01:00
Tom Tromey
f214edceb8 Rename SEARCH_ALL
The constant SEARCH_ALL conflicts with a define in a Windows header.
This patch renames the constant to SEARCH_ALL_DOMAINS to avoid the
conflict.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31307
2024-02-01 07:10:57 -07:00
Lancelot SIX
878e894801 gdb: Use SYM_DOMAIN instead of DOMAIN when calling sym-domains.def
Since commit 6771fc6f1d "Use a .def file for domain_enum", the
sym-domains.def file has been introduced, and requires the user to
define the DOMAIN(x) macro.

On older systems (centos-7 with glibc-2.17 for example), this DOMAIN
macro conflicts with another macro defined in /usr/include/math.h.

Fix this conflict by changing sym-domains.def to use a macro named
SYM_DOMAIN instead of DOMAIN.

Change-Id: I679df30e2bd2f4333343f16bbd2a3511a37550a3
Approved-By: Tom Tromey <tom@tromey.com>
2024-01-29 20:20:30 +00:00
Tom Tromey
880e58fbc2 Remove some obsolete Python constants
The Python code has exported some constants, but they are no longer
documented, and were never useful.  This patch removes them.
2024-01-28 10:58:16 -07:00
Tom Tromey
ccf41c2487 Use domain_search_flags in lookup_symbol et al
This changes lookup_symbol and associated APIs to accept
domain_search_flags rather than a domain_enum.

Note that this introduces some new constants to Python and Guile.  I
chose to break out the documentation patch for this, because the
internals here do not change until a later patch, and it seemed
simpler to patch the docs just once, rather than twice.
2024-01-28 10:58:16 -07:00
Tom Tromey
c92d4de16a Replace search_domain with domain_search_flags
This patch changes gdb to replace search_domain with
domain_search_flags everywhere.  search_domain is removed.
2024-01-28 10:58:16 -07:00
Tom Tromey
6771fc6f1d Use a .def file for domain_enum
Future patches will change and reuse the names from domain_enum.  This
patch makes this less error-prone by having a single point to define
these names, using the typical gdb ".def" file.
2024-01-28 10:58:16 -07:00
Tom Tromey
0c566ea7f1 Emit stopped event for DAP attach request
In an earlier patch, I wrote:

    ...  It also adds some machinery so that attach stops can be
    suppressed, which I think is the right thing to do.

However, after some discussions here at AdaCore, I now believe this to
be incorrect -- while DAP says that expected "continue" events should
be suppressed, there is no corresponding language for expected "stop"
events, and indeed "stop" events explicitly mention cases like "step".

This patch arranges for the stop event to be emitted again.
2024-01-24 08:50:01 -07:00
Tom Tromey
46bdb64164 Handle EOF more gracefully in DAP
A user pointed out that gdb will print a Python exception when it gets
an EOF in DAP mode.  And, it turns out that an EOF like this also
causes gdb not to exit.  This is due to the refactoring that moved the
JSON reader to its own thread -- previously this caused an exception
to propagate and cause an exit, but now it just leaves the reader
hung.

This patch fixes these problems by arranging to handle EOF more
gracefully.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31217
2024-01-22 08:54:27 -07:00
Aaron Merey
519d634396 gdb: Buffer output streams during events that might download debuginfo
Introduce new ui_file buffering_file to temporarily collect output
written to gdb_std* output streams during print_thread, print_frame_info
and print_stop_event.

This ensures that output during these functions is not interrupted
by debuginfod progress messages.

With the addition of deferred debuginfo downloading it is possible
for download progress messages to print during these events.
Without any intervention we can end up with poorly formatted output:

    (gdb) backtrace
    [...]
    #8  0x00007fbe8af7d7cf in pygi_invoke_c_callable (Downloading separate debug info for /lib64/libpython3.11.so.1.0
    function_cache=0x561221b224d0, state=<optimized out>...

To fix this we buffer writes to gdb_std* output streams while allowing
debuginfod progress messages to skip the buffers and print to the
underlying output streams immediately.  Buffered output is then written
to the output streams.  This ensures that progress messages print first,
followed by uninterrupted frame/thread/stop info:

    (gdb) backtrace
    [...]
    Downloading separate debug info for /lib64/libpython3.11.so.1.0
    #8  0x00007fbe8af7d7cf in pygi_invoke_c_callable (function_cache=0x561221b224d0, state=<optimized out>...

Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
Approved-By: Andrew Burgess <aburgess@redhat.com>
2024-01-19 00:18:00 -05:00
Andrew Burgess
1d506c26d9 Update copyright year range in header of all files managed by GDB
This commit is the result of the following actions:

  - Running gdb/copyright.py to update all of the copyright headers to
    include 2024,

  - Manually updating a few files the copyright.py script told me to
    update, these files had copyright headers embedded within the
    file,

  - Regenerating gdbsupport/Makefile.in to refresh it's copyright
    date,

  - Using grep to find other files that still mentioned 2023.  If
    these files were updated last year from 2022 to 2023 then I've
    updated them this year to 2024.

I'm sure I've probably missed some dates.  Feel free to fix them up as
you spot them.
2024-01-12 15:49:57 +00:00
Andrew Burgess
1d586eda5c gdb/python: Add gdb.InferiorThread.__dict__ attribute
The gdb.Objfile, gdb.Progspace, gdb.Type, and gdb.Inferior Python
types already have a __dict__ attribute, which allows users to create
user defined attributes within the objects.  This is useful if the
user wants to cache information within an object.

This commit adds the same functionality to the gdb.InferiorThread
type.

After this commit there is a new gdb.InferiorThread.__dict__
attribute, which is a dictionary.  A user can, for example, do this:

  (gdb) pi
  >>> t = gdb.selected_thread()
  >>> t._user_attribute = 123
  >>> t._user_attribute
  123
  >>>

There's a new test included.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>
2024-01-12 11:21:31 +00:00
Andrew Burgess
13cd9bceea gdb/python: Add gdb.Inferior.__dict__ attribute
The gdb.Objfile, gdb.Progspace, and gdb.Type Python types already have
a __dict__ attribute, which allows users to create user defined
attributes within the objects.  This is useful if the user wants to
cache information within an object.

This commit adds the same functionality to the gdb.Inferior type.

After this commit there is a new gdb.Inferior.__dict__ attribute,
which is a dictionary.  A user can, for example, do this:

  (gdb) pi
  >>> i = gdb.selected_inferior()
  >>> i._user_attribute = 123
  >>> i._user_attribute
  123
  >>>

There's a new test included.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>
2024-01-12 11:21:30 +00:00
Andrew Burgess
2f47f48fe5 gdb/python: remove users ability to create gdb.Progspace objects
I noticed that it is possible for the user to create a new
gdb.Progspace object, like this:

  (gdb) pi
  >>> p = gdb.Progspace()
  >>> p
  <gdb.Progspace object at 0x7ffad4219c10>
  >>> p.is_valid()
  False

As the new gdb.Progspace object is not associated with an actual C++
program_space object within GDB core, then the new gdb.Progspace is
created invalid, and there is no way in which the new object can ever
become valid.

Nor do I believe there's anywhere in the Python API where it makes
sense to consume an invalid gdb.Progspace created in this way, for
example, the gdb.Progspace could be passed as the locus to
register_type_printer, but all that would happen is that the
registered printer would never be used.

In this commit I propose to remove the ability to create new
gdb.Progspace objects.  Attempting to do so now gives an error, like
this:

  (gdb) pi
  >>> gdb.Progspace()
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
  TypeError: cannot create 'gdb.Progspace' instances

Of course, there is a small risk here that some existing user code
might break ... but if that happens I don't believe the user code can
have been doing anything useful, so I see this as a small risk.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>
2024-01-12 11:21:28 +00:00
Andrew Burgess
d6defe8761 gdb/python: add gdb.Frame.__repr__() method
Add a gdb.Frame.__repr__() method.  Before this patch we would see
output like this:

  (gdb) pi
  >>> gdb.selected_frame()
  <gdb.Frame object at 0x7fa8cc2df270>

After this patch, we now see:

  (gdb) pi
  >>> gdb.selected_frame()
  <gdb.Frame level=0 frame-id={stack=0x7ffff7da0ed0,code=0x000000000040115d,!special}>

More verbose, but, I hope, more useful.

If the gdb.Frame becomes invalid, then we will see:

  (gdb) pi
  >>> invalid_frame_variable
  <gdb.Frame (invalid)>

which is inline with how other invalid objects are displayed.

Approved-By: Tom Tromey <tom@tromey.com>
2024-01-12 11:21:27 +00:00
Andrew Burgess
1925bba80e gdb/python: add gdb.InferiorThread.__repr__() method
Add a gdb.InferiorThread.__repr__() method.  Before this patch we
would see output like this:

  (gdb) pi
  >>> gdb.selected_thread()
  <gdb.InferiorThread object at 0x7f4dcc49b970>

After this patch, we now see:

  (gdb) pi
  >>> gdb.selected_thread()
  <gdb.InferiorThread id=1.2 target-id="Thread 0x7ffff7da1700 (LWP 458134)">

More verbose, but, I hope, more useful.

If the gdb.InferiorThread becomes invalid, then we will see:

  (gdb) pi
  >>> invalid_thread_variable
  <gdb.InferiorThread (invalid)>

Which is inline with how other invalid objects are displayed.

Approved-By: Tom Tromey <tom@tromey.com>
2024-01-12 11:21:26 +00:00
Andrew Burgess
aef117b737 gdb/python: hoist common invalid object repr code into py-utils.c
Many object types now have a __repr__() function implementation.  A
common pattern is that, if an object is invalid, we print its
representation as: <TYPENAME (invalid)>.

I thought it might be a good idea to move the formatting of this
specific representation into a utility function, and then update all
of our existing code to call the new function.

The only place where I haven't made use of the new function is in
unwind_infopy_repr, where we currently return a different string.
This case is a little different as the UnwindInfo is invalid because
it references a frame, and it is the frame itself which is invalid.
That said, I think it would be fine to switch to using the standard
format; if the UnwindInfo references an invalid frame, then the
UnwindInfo is itself invalid.  But changing this would be an actual
change in behaviour, while all the other changes in this commit are
just refactoring.

Approved-By: Tom Tromey <tom@tromey.com>
2024-01-12 11:21:25 +00:00