1 /* Remote notification in GDB protocol
3 Copyright (C) 1988-2013 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20 /* Remote async notification is sent from remote target over RSP.
21 Each type of notification is represented by an object of
22 'struct notif', which has a field 'pending_reply'. It is not
23 NULL when GDB receives a notification from GDBserver, but hasn't
24 acknowledge yet. Before GDB acknowledges the notification,
25 GDBserver shouldn't send notification again (see the header comments
26 in gdbserver/notif.c).
28 Notifications are processed in an almost-unified approach for both
29 all-stop mode and non-stop mode, except the timing to process them.
30 In non-stop mode, notifications are processed in
31 remote_async_get_pending_events_handler, while in all-stop mode,
32 they are processed in remote_resume. */
36 #include "remote-notif.h"
38 #include "event-loop.h"
47 /* Supported clients of notifications. */
49 static struct notif_client *notifs[] =
54 static void do_notif_event_xfree (void *arg);
56 /* Parse the BUF for the expected notification NC, and send packet to
60 remote_notif_ack (struct notif_client *nc, char *buf)
62 struct notif_event *event = nc->alloc_event ();
63 struct cleanup *old_chain
64 = make_cleanup (do_notif_event_xfree, event);
67 fprintf_unfiltered (gdb_stdlog, "notif: ack '%s'\n",
70 nc->parse (nc, buf, event);
71 nc->ack (nc, buf, event);
73 discard_cleanups (old_chain);
76 /* Parse the BUF for the expected notification NC. */
79 remote_notif_parse (struct notif_client *nc, char *buf)
81 struct notif_event *event = nc->alloc_event ();
82 struct cleanup *old_chain
83 = make_cleanup (do_notif_event_xfree, event);
86 fprintf_unfiltered (gdb_stdlog, "notif: parse '%s'\n", nc->name);
88 nc->parse (nc, buf, event);
90 discard_cleanups (old_chain);
94 DEFINE_QUEUE_P (notif_client_p);
96 /* Process notifications in STATE's notification queue one by one.
97 EXCEPT is not expected in the queue. */
100 remote_notif_process (struct remote_notif_state *state,
101 struct notif_client *except)
103 while (!QUEUE_is_empty (notif_client_p, state->notif_queue))
105 struct notif_client *nc = QUEUE_deque (notif_client_p,
108 gdb_assert (nc != except);
110 if (nc->can_get_pending_events (nc))
111 remote_notif_get_pending_events (nc);
116 remote_async_get_pending_events_handler (gdb_client_data data)
118 gdb_assert (non_stop);
119 remote_notif_process (data, NULL);
122 /* Remote notification handler. Parse BUF, queue notification and
126 handle_notification (struct remote_notif_state *state, char *buf)
128 struct notif_client *nc = NULL;
131 for (i = 0; i < ARRAY_SIZE (notifs); i++)
134 if (strncmp (buf, nc->name, strlen (nc->name)) == 0
135 && buf[strlen (nc->name)] == ':')
139 /* We ignore notifications we don't recognize, for compatibility
144 if (nc->pending_event)
146 /* We've already parsed the in-flight reply, but the stub for some
147 reason thought we didn't, possibly due to timeout on its side.
150 fprintf_unfiltered (gdb_stdlog,
151 "notif: ignoring resent notification\n");
155 struct notif_event *event
156 = remote_notif_parse (nc, buf + strlen (nc->name) + 1);
158 /* Be careful to only set it after parsing, since an error
159 may be thrown then. */
160 nc->pending_event = event;
162 /* Notify the event loop there's a stop reply to acknowledge
163 and that there may be more events to fetch. */
164 QUEUE_enque (notif_client_p, state->notif_queue, nc);
167 /* In non-stop, We mark REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN
168 in order to go on what we were doing and postpone
169 querying notification events to some point safe to do so.
170 See details in the function comment of
171 remote.c:remote_notif_get_pending_events.
173 In all-stop, GDB may be blocked to wait for the reply, we
174 shouldn't return to event loop until the expected reply
175 arrives. For example:
178 GDB expects getting stop reply 'T05 thread:2'.
180 <GDB marks the REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN>
182 After step #1.2, we return to the event loop, which
183 notices there is a new event on the
184 REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN and calls the
185 handler, which will send 'vNotif' packet.
187 It is not safe to start a new sequence, because target
188 is still running and GDB is expecting the stop reply
191 To solve this, whenever we parse a notification
192 successfully, we don't mark the
193 REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN and let GDB blocked
194 there as before to get the sequence done.
197 GDB expects getting stop reply 'T05 thread:2'
199 <Don't mark the REMOTE_ASYNC_GET_PENDING_EVENTS_TOKEN>
200 2.3) <-- T05 thread:2
202 These pending notifications can be processed later. */
203 mark_async_event_handler (state->get_pending_events_token);
207 fprintf_unfiltered (gdb_stdlog,
208 "notif: Notification '%s' captured\n",
213 /* Cleanup wrapper. */
216 do_notif_event_xfree (void *arg)
218 struct notif_event *event = arg;
220 if (event && event->dtr)
226 /* Return an allocated remote_notif_state. */
228 struct remote_notif_state *
229 remote_notif_state_allocate (void)
231 struct remote_notif_state *notif_state = xzalloc (sizeof (*notif_state));
233 notif_state->notif_queue = QUEUE_alloc (notif_client_p, NULL);
235 /* Register async_event_handler for notification. */
237 notif_state->get_pending_events_token
238 = create_async_event_handler (remote_async_get_pending_events_handler,
244 /* Free STATE and its fields. */
247 remote_notif_state_xfree (struct remote_notif_state *state)
249 QUEUE_free (notif_client_p, state->notif_queue);
251 /* Unregister async_event_handler for notification. */
252 if (state->get_pending_events_token != NULL)
253 delete_async_event_handler (&state->get_pending_events_token);
258 /* -Wmissing-prototypes */
259 extern initialize_file_ftype _initialize_notif;
262 _initialize_notif (void)
264 add_setshow_boolean_cmd ("notification", no_class, ¬if_debug,
266 Set debugging of async remote notification."), _("\
267 Show debugging of async remote notification."), _("\
268 When non-zero, debugging output about async remote notifications"
272 &setdebuglist, &showdebuglist);