| /* Remote notification in GDB protocol |
| |
| Copyright (C) 1988-2024 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/>. */ |
| |
| /* Remote async notification is sent from remote target over RSP. |
| Each type of notification is represented by an object of |
| 'struct notif', which has a field 'pending_reply'. It is not |
| NULL when GDB receives a notification from GDBserver, but hasn't |
| acknowledge yet. Before GDB acknowledges the notification, |
| GDBserver shouldn't send notification again (see the header comments |
| in gdbserver/notif.c). |
| |
| Notifications are processed in an almost-unified approach for both |
| all-stop mode and non-stop mode, except the timing to process them. |
| In non-stop mode, notifications are processed in |
| remote_async_get_pending_events_handler, while in all-stop mode, |
| they are processed in remote_resume. */ |
| |
| #include "remote.h" |
| #include "remote-notif.h" |
| #include "observable.h" |
| #include "gdbsupport/event-loop.h" |
| #include "target.h" |
| #include "inferior.h" |
| #include "infrun.h" |
| #include "cli/cli-cmds.h" |
| #include "async-event.h" |
| |
| bool notif_debug = false; |
| |
| /* Supported clients of notifications. */ |
| |
| static const notif_client *const notifs[] = |
| { |
| ¬if_client_stop, |
| }; |
| |
| static_assert (ARRAY_SIZE (notifs) == REMOTE_NOTIF_LAST); |
| |
| /* Parse the BUF for the expected notification NC, and send packet to |
| acknowledge. */ |
| |
| void |
| remote_notif_ack (remote_target *remote, |
| const notif_client *nc, const char *buf) |
| { |
| notif_event_up event = nc->alloc_event (); |
| |
| if (notif_debug) |
| gdb_printf (gdb_stdlog, "notif: ack '%s'\n", |
| nc->ack_command); |
| |
| nc->parse (remote, nc, buf, event.get ()); |
| nc->ack (remote, nc, buf, std::move (event)); |
| } |
| |
| /* Parse the BUF for the expected notification NC. */ |
| |
| notif_event_up |
| remote_notif_parse (remote_target *remote, |
| const notif_client *nc, const char *buf) |
| { |
| notif_event_up event = nc->alloc_event (); |
| |
| if (notif_debug) |
| gdb_printf (gdb_stdlog, "notif: parse '%s'\n", nc->name); |
| |
| nc->parse (remote, nc, buf, event.get ()); |
| |
| return event; |
| } |
| |
| /* Process notifications in STATE's notification queue one by one. |
| EXCEPT is not expected in the queue. */ |
| |
| void |
| remote_notif_process (struct remote_notif_state *state, |
| const notif_client *except) |
| { |
| while (!state->notif_queue.empty ()) |
| { |
| const notif_client *nc = state->notif_queue.front (); |
| state->notif_queue.pop_front (); |
| |
| gdb_assert (nc != except); |
| |
| if (nc->can_get_pending_events (state->remote, nc)) |
| remote_notif_get_pending_events (state->remote, nc); |
| } |
| } |
| |
| static void |
| remote_async_get_pending_events_handler (gdb_client_data data) |
| { |
| remote_notif_state *notif_state = (remote_notif_state *) data; |
| clear_async_event_handler (notif_state->get_pending_events_token); |
| gdb_assert (remote_target_is_non_stop_p (notif_state->remote)); |
| remote_notif_process (notif_state, NULL); |
| } |
| |
| /* Remote notification handler. Parse BUF, queue notification and |
| update STATE. */ |
| |
| void |
| handle_notification (struct remote_notif_state *state, const char *buf) |
| { |
| const notif_client *nc; |
| size_t i; |
| |
| for (i = 0; i < ARRAY_SIZE (notifs); i++) |
| { |
| const char *name = notifs[i]->name; |
| |
| if (startswith (buf, name) |
| && buf[strlen (name)] == ':') |
| break; |
| } |
| |
| /* We ignore notifications we don't recognize, for compatibility |
| with newer stubs. */ |
| if (i == ARRAY_SIZE (notifs)) |
| return; |
| |
| nc = notifs[i]; |
| |
| if (state->pending_event[nc->id] != NULL) |
| { |
| /* We've already parsed the in-flight reply, but the stub for some |
| reason thought we didn't, possibly due to timeout on its side. |
| Just ignore it. */ |
| if (notif_debug) |
| gdb_printf (gdb_stdlog, |
| "notif: ignoring resent notification\n"); |
| } |
| else |
| { |
| notif_event_up event |
| = remote_notif_parse (state->remote, nc, buf + strlen (nc->name) + 1); |
| |
| /* Be careful to only set it after parsing, since an error |
| may be thrown then. */ |
| state->pending_event[nc->id] = std::move (event); |
| |
| /* Notify the event loop there's a stop reply to acknowledge |
| and that there may be more events to fetch. */ |
| state->notif_queue.push_back (nc); |
| if (target_is_non_stop_p ()) |
| { |
| /* In non-stop, We mark REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN |
| in order to go on what we were doing and postpone |
| querying notification events to some point safe to do so. |
| See details in the function comment of |
| remote.c:remote_notif_get_pending_events. |
| |
| In all-stop, GDB may be blocked to wait for the reply, we |
| shouldn't return to event loop until the expected reply |
| arrives. For example: |
| |
| 1.1) --> vCont;c |
| GDB expects getting stop reply 'T05 thread:2'. |
| 1.2) <-- %Notif |
| <GDB marks the REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN> |
| |
| After step #1.2, we return to the event loop, which |
| notices there is a new event on the |
| REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN and calls the |
| handler, which will send 'vNotif' packet. |
| 1.3) --> vNotif |
| It is not safe to start a new sequence, because target |
| is still running and GDB is expecting the stop reply |
| from stub. |
| |
| To solve this, whenever we parse a notification |
| successfully, we don't mark the |
| REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN and let GDB blocked |
| there as before to get the sequence done. |
| |
| 2.1) --> vCont;c |
| GDB expects getting stop reply 'T05 thread:2' |
| 2.2) <-- %Notif |
| <Don't mark the REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN> |
| 2.3) <-- T05 thread:2 |
| |
| These pending notifications can be processed later. */ |
| mark_async_event_handler (state->get_pending_events_token); |
| } |
| |
| if (notif_debug) |
| gdb_printf (gdb_stdlog, |
| "notif: Notification '%s' captured\n", |
| nc->name); |
| } |
| } |
| |
| /* Return an allocated remote_notif_state. */ |
| |
| struct remote_notif_state * |
| remote_notif_state_allocate (remote_target *remote) |
| { |
| struct remote_notif_state *notif_state = new struct remote_notif_state; |
| |
| notif_state->remote = remote; |
| |
| /* Register async_event_handler for notification. */ |
| |
| notif_state->get_pending_events_token |
| = create_async_event_handler (remote_async_get_pending_events_handler, |
| notif_state, "remote-notif"); |
| |
| return notif_state; |
| } |
| |
| /* Free STATE and its fields. */ |
| |
| remote_notif_state::~remote_notif_state () |
| { |
| /* Unregister async_event_handler for notification. */ |
| if (get_pending_events_token != NULL) |
| delete_async_event_handler (&get_pending_events_token); |
| } |
| |
| void _initialize_notif (); |
| void |
| _initialize_notif () |
| { |
| add_setshow_boolean_cmd ("notification", no_class, ¬if_debug, |
| _("\ |
| Set debugging of async remote notification."), _("\ |
| Show debugging of async remote notification."), _("\ |
| When non-zero, debugging output about async remote notifications" |
| " is enabled."), |
| NULL, |
| NULL, |
| &setdebuglist, &showdebuglist); |
| } |