gdb/gdbserver/

2012-12-15  Yao Qi  <yao@codesourcery.com>

	* Makefile.in (OBS): Add notif.o.
	* notif.c, notif.h: New.
	* server.c: Include "notif.h".
	(struct vstop_notif) <next>: Remove.
	<base>: New field.
	(queue_stop_reply): Update.
	(push_event, send_next_stop_reply): Remove.
	(discard_queued_stop_replies): Update.
	(notif_stop): New variable.
	(handle_v_stopped): Remove.
	(handle_v_requests): Don't call handle_v_stopped.  Call
	handle_ack_notif instead.
	(queue_stop_reply_callback): Call notif_event_enque instead
	of queue_stop_reply.
	(handle_status): Don't call send_next_stop_reply, call
	notif_write_event instead.
	(kill_inferior_callback): Likewise.
	(detach_or_kill_inferior_callback): Likewise.
	(main): Call initialize_notif.
	(process_serial_event): Call QUEUE_is_empty.
	(handle_target_event): Call notif_push instead of push event.
	* server.h (push_event): Remove declaration.

6 files changed, 313 insertions, 113 deletions

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 75bb70b..35b2c76 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,28 @@
+2012-12-15  Yao Qi  <yao@codesourcery.com>
+
+	* Makefile.in (OBS): Add notif.o.
+	* notif.c, notif.h: New.
+	* server.c: Include "notif.h".
+	(struct vstop_notif) <next>: Remove.
+	<base>: New field.
+	(queue_stop_reply): Update.
+	(push_event, send_next_stop_reply): Remove.
+	(discard_queued_stop_replies): Update.
+	(notif_stop): New variable.
+	(handle_v_stopped): Remove.
+	(handle_v_requests): Don't call handle_v_stopped.  Call
+	handle_ack_notif instead.
+	(queue_stop_reply_callback): Call notif_event_enque instead
+	of queue_stop_reply.
+	(handle_status): Don't call send_next_stop_reply, call
+	notif_write_event instead.
+	(kill_inferior_callback): Likewise.
+	(detach_or_kill_inferior_callback): Likewise.
+	(main): Call initialize_notif.
+	(process_serial_event): Call QUEUE_is_empty.
+	(handle_target_event): Call notif_push instead of push event.
+	* server.h (push_event): Remove declaration.
+
 2012-12-10  Tom Tromey  <tromey@redhat.com>
 
 	* Makefile.in (DEPMODE, DEPDIR, depcomp, COMPILE.pre)
diff --git a/gdb/gdbserver/Makefile.in b/gdb/gdbserver/Makefile.in
index d7dad29..c4f1a2d 100644
--- a/gdb/gdbserver/Makefile.in
+++ b/gdb/gdbserver/Makefile.in
@@ -168,7 +168,7 @@ OBS = agent.o ax.o inferiors.o regcache.o remote-utils.o server.o signals.o targ
 	utils.o version.o vec.o gdb_vecs.o \
 	mem-break.o hostio.o event-loop.o tracepoint.o \
 	xml-utils.o common-utils.o ptid.o buffer.o format.o \
-	dll.o \
+	dll.o notif.o \
 	$(XML_BUILTIN) \
 	$(DEPFILES) $(LIBOBJS)
 GDBREPLAY_OBS = gdbreplay.o version.o
diff --git a/gdb/gdbserver/notif.c b/gdb/gdbserver/notif.c
new file mode 100644
index 0000000..0713b36
--- /dev/null
+++ b/gdb/gdbserver/notif.c
@@ -0,0 +1,168 @@
+/* Notification to GDB.
+   Copyright (C) 1989, 1993-1995, 1997-2000, 2002-2012 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/>.  */
+
+/* Async notifications to GDB.  When the state of remote target is
+   changed or something interesting to GDB happened, async
+   notifications are used to tell GDB.
+
+   Each type of notification is represented by an object
+   'struct notif_server', in which there is a queue for events to GDB
+   represented by 'struct notif_event'.  GDBserver writes (by means of
+   'write' field) each event in the queue into the buffer and send the
+   contents in buffer to GDB.  The contents in buffer is specified in
+   RSP.  See more in the comments to field 'queue' of
+   'struct notif_server'.
+
+   Here is the workflow of sending events and managing queue:
+   1.  At any time, when something interesting FOO happens, a object
+   of 'struct notif_event' or its sub-class EVENT is created for FOO.
+
+   2.  Enque EVENT to the 'queue' field of 'struct notif_server' for
+   FOO and send corresponding notification packet to GDB if EVENT is
+   the first one.
+   #1 and #2 are done by function 'notif_push'.
+
+   3.  EVENT is not deque'ed until the ack of FOO from GDB arrives.
+   Before ack of FOO arrives, FOO happens again, a new object of
+   EVENT is created and enque EVENT silently.
+   Once GDB has a chance to ack to FOO, it sends an ack to GDBserver,
+   and GDBserver repeatedly sends events to GDB and gets ack of FOO,
+   until queue is empty.  Then, GDBserver sends 'OK' to GDB that all
+   queued notification events are done.
+
+   # 3 is done by function 'handle_notif_ack'.  */
+
+#include "notif.h"
+
+static struct notif_server *notifs[] =
+{
+  &notif_stop,
+};
+
+/* Write another event or an OK, if there are no more left, to
+   OWN_BUF.  */
+
+void
+notif_write_event (struct notif_server *notif, char *own_buf)
+{
+  if (!QUEUE_is_empty (notif_event_p, notif->queue))
+    {
+      struct notif_event *event
+	= QUEUE_peek (notif_event_p, notif->queue);
+
+      notif->write (event, own_buf);
+    }
+  else
+    write_ok (own_buf);
+}
+
+/* Handle the ack in buffer OWN_BUF,and packet length is PACKET_LEN.
+   Return 1 if the ack is handled, and return 0 if the contents
+   in OWN_BUF is not a ack.  */
+
+int
+handle_notif_ack (char *own_buf, int packet_len)
+{
+  int i = 0;
+  struct notif_server *np = NULL;
+
+  for (i = 0; i < ARRAY_SIZE (notifs); i++)
+    {
+      np = notifs[i];
+      if (strncmp (own_buf, np->ack_name, strlen (np->ack_name)) == 0
+	  && packet_len == strlen (np->ack_name))
+	break;
+    }
+
+  if (np == NULL)
+    return 0;
+
+  /* If we're waiting for GDB to acknowledge a pending event,
+     consider that done.  */
+  if (!QUEUE_is_empty (notif_event_p, np->queue))
+    {
+      struct notif_event *head
+	= QUEUE_deque (notif_event_p, np->queue);
+
+      if (remote_debug)
+	fprintf (stderr, "%s: acking %d\n", np->ack_name,
+		 QUEUE_length (notif_event_p, np->queue));
+
+      xfree (head);
+    }
+
+  notif_write_event (np, own_buf);
+
+  return 1;
+}
+
+/* Put EVENT to the queue of NOTIF.  */
+
+void
+notif_event_enque (struct notif_server *notif,
+		   struct notif_event *event)
+{
+  QUEUE_enque (notif_event_p, notif->queue, event);
+
+  if (remote_debug)
+    fprintf (stderr, "pending events: %s %d\n", notif->notif_name,
+	     QUEUE_length (notif_event_p, notif->queue));
+
+}
+
+/* Push one event NEW_EVENT of notification NP into NP->queue.  */
+
+void
+notif_push (struct notif_server *np, struct notif_event *new_event)
+{
+  int is_first_event = QUEUE_is_empty (notif_event_p, np->queue);
+
+  /* Something interesting.  Tell GDB about it.  */
+  notif_event_enque (np, new_event);
+
+  /* If this is the first stop reply in the queue, then inform GDB
+     about it, by sending a corresponding notification.  */
+  if (is_first_event)
+    {
+      char buf[PBUFSIZ];
+      char *p = buf;
+
+      xsnprintf (p, PBUFSIZ, "%s:", np->notif_name);
+      p += strlen (p);
+
+      np->write (new_event, p);
+      putpkt_notif (buf);
+    }
+}
+
+static void
+notif_event_xfree (struct notif_event *event)
+{
+  xfree (event);
+}
+
+void
+initialize_notif (void)
+{
+  int i = 0;
+
+  for (i = 0; i < ARRAY_SIZE (notifs); i++)
+    notifs[i]->queue
+      = QUEUE_alloc (notif_event_p, notif_event_xfree);
+}
diff --git a/gdb/gdbserver/notif.h b/gdb/gdbserver/notif.h
new file mode 100644
index 0000000..b76ecfa
--- /dev/null
+++ b/gdb/gdbserver/notif.h
@@ -0,0 +1,65 @@
+/* Notification to GDB.
+   Copyright (C) 1989, 1993-1995, 1997-2000, 2002-2012 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/>.  */
+
+#include "ptid.h"
+#include "server.h"
+#include "target.h"
+#include "queue.h"
+
+/* Structure holding information related to a single event.  We
+   keep a queue of these to push to GDB.  It can be extended if
+   the event of given notification contains more information.  */
+
+typedef struct notif_event
+{
+} *notif_event_p;
+
+DECLARE_QUEUE_P (notif_event_p);
+
+/* A type notification to GDB.  An object of 'struct notif_server'
+   represents a type of notification.  */
+
+typedef struct notif_server
+{
+  /* The name of ack packet, for example, 'vStopped'.  */
+  const char *ack_name;
+
+  /* The notification packet, for example, '%Stop'.  Note that '%' is
+     not in 'notif_name'.  */
+  const char *notif_name;
+
+  /* A queue of events to GDB.  A new notif_event can be enque'ed
+     into QUEUE at any appropriate time, and the notif_reply is
+     deque'ed only when the ack from GDB arrives.  */
+  QUEUE (notif_event_p) *queue;
+
+  /* Write event EVENT to OWN_BUF.  */
+  void (*write) (struct notif_event *event, char *own_buf);
+} *notif_server_p;
+
+extern struct notif_server notif_stop;
+
+int handle_notif_ack (char *own_buf, int packet_len);
+void notif_write_event (struct notif_server *notif, char *own_buf);
+
+void notif_push (struct notif_server *np, struct notif_event *event);
+void notif_event_enque (struct notif_server *notif,
+			struct notif_event *event);
+
+void initialize_notif (void);
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index fae9199..fb7322c 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -20,6 +20,7 @@
 #include "server.h"
 #include "gdbthread.h"
 #include "agent.h"
+#include "notif.h"
 
 #if HAVE_UNISTD_H
 #include <unistd.h>
@@ -115,13 +116,13 @@ static ptid_t last_ptid;
 static char *own_buf;
 static unsigned char *mem_buf;
 
-/* Structure holding information relative to a single stop reply.  We
-   keep a queue of these (really a singly-linked list) to push to GDB
-   in non-stop mode.  */
+/* A sub-class of 'struct notif_event' for stop, holding information
+   relative to a single stop reply.  We keep a queue of these to
+   push to GDB in non-stop mode.  */
+
 struct vstop_notif
 {
-  /* Pointer to next in list.  */
-  struct vstop_notif *next;
+  struct notif_event base;
 
   /* Thread or process that got the event.  */
   ptid_t ptid;
@@ -130,66 +131,39 @@ struct vstop_notif
   struct target_waitstatus status;
 };
 
-/* The pending stop replies list head.  */
-static struct vstop_notif *notif_queue = NULL;
+DEFINE_QUEUE_P (notif_event_p);
 
 /* Put a stop reply to the stop reply queue.  */
 
 static void
 queue_stop_reply (ptid_t ptid, struct target_waitstatus *status)
 {
-  struct vstop_notif *new_notif;
+  struct vstop_notif *new_notif = xmalloc (sizeof (*new_notif));
 
-  new_notif = xmalloc (sizeof (*new_notif));
-  new_notif->next = NULL;
   new_notif->ptid = ptid;
   new_notif->status = *status;
 
-  if (notif_queue)
-    {
-      struct vstop_notif *tail;
-      for (tail = notif_queue;
-	   tail && tail->next;
-	   tail = tail->next)
-	;
-      tail->next = new_notif;
-    }
-  else
-    notif_queue = new_notif;
-
-  if (remote_debug)
-    {
-      int i = 0;
-      struct vstop_notif *n;
-
-      for (n = notif_queue; n; n = n->next)
-	i++;
-
-      fprintf (stderr, "pending stop replies: %d\n", i);
-    }
+  notif_event_enque (&notif_stop, (struct notif_event *) new_notif);
 }
 
-/* Place an event in the stop reply queue, and push a notification if
-   we aren't sending one yet.  */
-
-void
-push_event (ptid_t ptid, struct target_waitstatus *status)
+static int
+remove_all_on_match_pid (QUEUE (notif_event_p) *q,
+			    QUEUE_ITER (notif_event_p) *iter,
+			    struct notif_event *event,
+			    void *data)
 {
-  gdb_assert (status->kind != TARGET_WAITKIND_IGNORE);
+  int *pid = data;
 
-  queue_stop_reply (ptid, status);
-
-  /* If this is the first stop reply in the queue, then inform GDB
-     about it, by sending a Stop notification.  */
-  if (notif_queue->next == NULL)
+  if (*pid == -1
+      || ptid_get_pid (((struct vstop_notif *) event)->ptid) == *pid)
     {
-      char *p = own_buf;
-      strcpy (p, "Stop:");
-      p += strlen (p);
-      prepare_resume_reply (p,
-			    notif_queue->ptid, &notif_queue->status);
-      putpkt_notif (own_buf);
+      if (q->free_func != NULL)
+	q->free_func (event);
+
+      QUEUE_remove_elem (notif_event_p, q, iter);
     }
+
+  return 1;
 }
 
 /* Get rid of the currently pending stop replies for PID.  If PID is
@@ -198,40 +172,23 @@ push_event (ptid_t ptid, struct target_waitstatus *status)
 static void
 discard_queued_stop_replies (int pid)
 {
-  struct vstop_notif *prev = NULL, *reply, *next;
-
-  for (reply = notif_queue; reply; reply = next)
-    {
-      next = reply->next;
-
-      if (pid == -1
-	  || ptid_get_pid (reply->ptid) == pid)
-	{
-	  if (reply == notif_queue)
-	    notif_queue = next;
-	  else
-	    prev->next = reply->next;
-
-	  free (reply);
-	}
-      else
-	prev = reply;
-    }
+  QUEUE_iterate (notif_event_p, notif_stop.queue,
+		 remove_all_on_match_pid, &pid);
 }
 
-/* If there are more stop replies to push, push one now.  */
-
 static void
-send_next_stop_reply (char *own_buf)
+vstop_notif_reply (struct notif_event *event, char *own_buf)
 {
-  if (notif_queue)
-    prepare_resume_reply (own_buf,
-			  notif_queue->ptid,
-			  &notif_queue->status);
-  else
-    write_ok (own_buf);
+  struct vstop_notif *vstop = (struct vstop_notif *) event;
+
+  prepare_resume_reply (own_buf, vstop->ptid, &vstop->status);
 }
 
+struct notif_server notif_stop =
+{
+  "vStopped", "Stop", NULL, vstop_notif_reply,
+};
+
 static int
 target_running (void)
 {
@@ -2169,29 +2126,6 @@ handle_v_kill (char *own_buf)
     }
 }
 
-/* Handle a 'vStopped' packet.  */
-static void
-handle_v_stopped (char *own_buf)
-{
-  /* If we're waiting for GDB to acknowledge a pending stop reply,
-     consider that done.  */
-  if (notif_queue)
-    {
-      struct vstop_notif *head;
-
-      if (remote_debug)
-	fprintf (stderr, "vStopped: acking %s\n",
-		 target_pid_to_str (notif_queue->ptid));
-
-      head = notif_queue;
-      notif_queue = notif_queue->next;
-      free (head);
-    }
-
-  /* Push another stop reply, or if there are no more left, an OK.  */
-  send_next_stop_reply (own_buf);
-}
-
 /* Handle all of the extended 'v' packets.  */
 void
 handle_v_requests (char *own_buf, int packet_len, int *new_packet_len)
@@ -2252,11 +2186,8 @@ handle_v_requests (char *own_buf, int packet_len, int *new_packet_len)
       return;
     }
 
-  if (strncmp (own_buf, "vStopped", 8) == 0)
-    {
-      handle_v_stopped (own_buf);
-      return;
-    }
+  if (handle_notif_ack (own_buf, packet_len))
+    return;
 
   /* Otherwise we didn't know what packet it was.  Say we didn't
      understand it.  */
@@ -2337,9 +2268,14 @@ queue_stop_reply_callback (struct inferior_list_entry *entry, void *arg)
      manage the thread's last_status field.  */
   if (the_target->thread_stopped == NULL)
     {
+      struct vstop_notif *new_notif = xmalloc (sizeof (*new_notif));
+
+      new_notif->ptid = entry->id;
+      new_notif->status = thread->last_status;
       /* Pass the last stop reply back to GDB, but don't notify
 	 yet.  */
-      queue_stop_reply (entry->id, &thread->last_status);
+      notif_event_enque (&notif_stop,
+			 (struct notif_event *) new_notif);
     }
   else
     {
@@ -2420,7 +2356,7 @@ handle_status (char *own_buf)
       /* The first is sent immediatly.  OK is sent if there is no
 	 stopped thread, which is the same handling of the vStopped
 	 packet (by design).  */
-      send_next_stop_reply (own_buf);
+      notif_write_event (&notif_stop, own_buf);
     }
   else
     {
@@ -2789,6 +2725,8 @@ main (int argc, char *argv[])
       last_ptid = minus_one_ptid;
     }
 
+  initialize_notif ();
+
   /* Don't report shared library events on the initial connection,
      even if some libraries are preloaded.  Avoids the "stopped by
      shared library event" notice on gdb side.  */
@@ -3400,7 +3338,7 @@ process_serial_event (void)
     {
       /* In non-stop, defer exiting until GDB had a chance to query
 	 the whole vStopped list (until it gets an OK).  */
-      if (!notif_queue)
+      if (QUEUE_is_empty (notif_event_p, notif_stop.queue))
 	{
 	  fprintf (stderr, "GDBserver exiting\n");
 	  remote_close ();
@@ -3498,8 +3436,14 @@ handle_target_event (int err, gdb_client_data client_data)
 	}
       else
 	{
-	  /* Something interesting.  Tell GDB about it.  */
-	  push_event (last_ptid, &last_status);
+	  struct vstop_notif *vstop_notif
+	    = xmalloc (sizeof (struct vstop_notif));
+
+	  vstop_notif->status = last_status;
+	  vstop_notif->ptid = last_ptid;
+	  /* Push Stop notification.  */
+	  notif_push (&notif_stop,
+		      (struct notif_event *) vstop_notif);
 	}
     }
 
diff --git a/gdb/gdbserver/server.h b/gdb/gdbserver/server.h
index 929819e..7104ef7 100644
--- a/gdb/gdbserver/server.h
+++ b/gdb/gdbserver/server.h
@@ -265,8 +265,6 @@ extern void start_event_loop (void);
 extern int handle_serial_event (int err, gdb_client_data client_data);
 extern int handle_target_event (int err, gdb_client_data client_data);
 
-extern void push_event (ptid_t ptid, struct target_waitstatus *status);
-
 /* Functions from hostio.c.  */
 extern int handle_vFile (char *, int, int *);