GDB 7.6.50

gdb/remote-notif.c

Index: gdb/remote-notif.c
diff --git a/gdb/remote-notif.c b/gdb/remote-notif.c
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+++ b/gdb/remote-notif.c
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+/* Remote notification in GDB protocol
+
+   Copyright (C) 1988-2013 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 "defs.h"
+#include "remote.h"
+#include "remote-notif.h"
+#include "observer.h"
+#include "event-loop.h"
+#include "target.h"
+#include "inferior.h"
+#include "gdbcmd.h"
+
+#include <string.h>
+
+int notif_debug = 0;
+
+/* Supported clients of notifications.  */
+
+static struct notif_client *notifs[] =
+{
+  &notif_client_stop,
+};
+
+gdb_static_assert (ARRAY_SIZE (notifs) == REMOTE_NOTIF_LAST);
+
+static void do_notif_event_xfree (void *arg);
+
+/* Parse the BUF for the expected notification NC, and send packet to
+   acknowledge.  */
+
+void
+remote_notif_ack (struct notif_client *nc, char *buf)
+{
+  struct notif_event *event = nc->alloc_event ();
+  struct cleanup *old_chain
+    = make_cleanup (do_notif_event_xfree, event);
+
+  if (notif_debug)
+    fprintf_unfiltered (gdb_stdlog, "notif: ack '%s'\n",
+			nc->ack_command);
+
+  nc->parse (nc, buf, event);
+  nc->ack (nc, buf, event);
+
+  discard_cleanups (old_chain);
+}
+
+/* Parse the BUF for the expected notification NC.  */
+
+struct notif_event *
+remote_notif_parse (struct notif_client *nc, char *buf)
+{
+  struct notif_event *event = nc->alloc_event ();
+  struct cleanup *old_chain
+    = make_cleanup (do_notif_event_xfree, event);
+
+  if (notif_debug)
+    fprintf_unfiltered (gdb_stdlog, "notif: parse '%s'\n", nc->name);
+
+  nc->parse (nc, buf, event);
+
+  discard_cleanups (old_chain);
+  return event;
+}
+
+DEFINE_QUEUE_P (notif_client_p);
+
+/* 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,
+		      struct notif_client *except)
+{
+  while (!QUEUE_is_empty (notif_client_p, state->notif_queue))
+    {
+      struct notif_client *nc = QUEUE_deque (notif_client_p,
+					     state->notif_queue);
+
+      gdb_assert (nc != except);
+
+      if (nc->can_get_pending_events (nc))
+	remote_notif_get_pending_events (nc);
+    }
+}
+
+static void
+remote_async_get_pending_events_handler (gdb_client_data data)
+{
+  gdb_assert (non_stop);
+  remote_notif_process (data, NULL);
+}
+
+/* Remote notification handler.  Parse BUF, queue notification and
+   update STATE.  */
+
+void
+handle_notification (struct remote_notif_state *state, char *buf)
+{
+  struct notif_client *nc;
+  size_t i;
+
+  for (i = 0; i < ARRAY_SIZE (notifs); i++)
+    {
+      const char *name = notifs[i]->name;
+
+      if (strncmp (buf, name, strlen (name)) == 0
+	  && 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)
+	fprintf_unfiltered (gdb_stdlog,
+			    "notif: ignoring resent notification\n");
+    }
+  else
+    {
+      struct notif_event *event
+	= remote_notif_parse (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] = event;
+
+      /* Notify the event loop there's a stop reply to acknowledge
+	 and that there may be more events to fetch.  */
+      QUEUE_enque (notif_client_p, state->notif_queue, nc);
+      if (non_stop)
+	{
+	  /* 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)
+	fprintf_unfiltered (gdb_stdlog,
+			    "notif: Notification '%s' captured\n",
+			    nc->name);
+    }
+}
+
+/* Invoke destructor of EVENT and xfree it.  */
+
+void
+notif_event_xfree (struct notif_event *event)
+{
+  if (event != NULL && event->dtr != NULL)
+    event->dtr (event);
+
+  xfree (event);
+}
+
+/* Cleanup wrapper.  */
+
+static void
+do_notif_event_xfree (void *arg)
+{
+  notif_event_xfree (arg);
+}
+
+/* Return an allocated remote_notif_state.  */
+
+struct remote_notif_state *
+remote_notif_state_allocate (void)
+{
+  struct remote_notif_state *notif_state = xzalloc (sizeof (*notif_state));
+
+  notif_state->notif_queue = QUEUE_alloc (notif_client_p, NULL);
+
+  /* Register async_event_handler for notification.  */
+
+  notif_state->get_pending_events_token
+    = create_async_event_handler (remote_async_get_pending_events_handler,
+				  notif_state);
+
+  return notif_state;
+}
+
+/* Free STATE and its fields.  */
+
+void
+remote_notif_state_xfree (struct remote_notif_state *state)
+{
+  int i;
+
+  QUEUE_free (notif_client_p, state->notif_queue);
+
+  /* Unregister async_event_handler for notification.  */
+  if (state->get_pending_events_token != NULL)
+    delete_async_event_handler (&state->get_pending_events_token);
+
+  for (i = 0; i < REMOTE_NOTIF_LAST; i++)
+    notif_event_xfree (state->pending_event[i]);
+
+  xfree (state);
+}
+
+/* -Wmissing-prototypes */
+extern initialize_file_ftype _initialize_notif;
+
+void
+_initialize_notif (void)
+{
+  add_setshow_boolean_cmd ("notification", no_class, &notif_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);
+}