gdb/doc/

2008-08-12  Sandra Loosemore  <sandra@codesourcery.com>

	* gdb.texinfo (Remote Configuration): Document set remote noack-packet.
	(Remote Protocol): Add Packet Acknowledgment to menu.
	(Overview): Mention +/- can be disabled, and point to new section
	where this is discussed in detail.
	(General Query Packets): Document QStartNoAckMode packet, and
	corresponding qSupported reply.
	(Packet Acknowledgment): New section.

gdb/
2008-08-12  Pedro Alves  <pedro@codesourcery.com>

	Add no-ack mode to the remote protocol --- optionally stop ACKing
	packets and responses when we have a reliable communication
	medium.

	Based on Apple's GDB, by Jason Molenda <jmolenda@apple.com>

	* remote.c (struct remote_state): Add noack_mode field.
	(PACKET_QStartNoAckMode): New.
	(remote_start_remote): Don't any outstanding packet here.
	(remote_open_1): Clear noack_mode.  Ack any outstanding packet
	here.  Activate noack mode if requested.
	(remote_protocol_features): Add QStartNoAckMode.
	(remote_open_1):
	(putpkt_binary): Don't send ack in noack mode.
	(read_frame): Don't recompute the checksum in noack mode.
	(getpkt_sane): Skip sending ack if in noack mode.
	(_initialize_remote): Add set/show remote noack mode.
	* NEWS:  Note the new features.

gdb/gdbserver/
2008-08-12  Pedro Alves  <pedro@codesourcery.com>

	* remote-utils.c (noack_mode, transport_is_reliable): New globals.
	(remote_open): Set or clear transport_is_reliable.
	(putpkt_binary): Don't expect acks in noack mode.
	(getpkt): Don't send ack/nac in noack mode.
	* server.c (handle_general_set): Handle QStartNoAckMode.
	(handle_query): If connected by tcp pass QStartNoAckMode+ in
	qSupported.
	(main): Reset noack_mode on every connection.
	* server.h (noack_mode): Declare.

4 files changed, 70 insertions, 9 deletions

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 8e61981..a4ea4be 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,15 @@
+2008-08-12  Pedro Alves  <pedro@codesourcery.com>
+
+	* remote-utils.c (noack_mode, transport_is_reliable): New globals.
+	(remote_open): Set or clear transport_is_reliable.
+	(putpkt_binary): Don't expect acks in noack mode.
+	(getpkt): Don't send ack/nac in noack mode.
+	* server.c (handle_general_set): Handle QStartNoAckMode.
+	(handle_query): If connected by tcp pass QStartNoAckMode+ in
+	qSupported.
+	(main): Reset noack_mode on every connection.
+	* server.h (noack_mode): Declare.
+
 2008-08-07  Ralf Wildenhues  <Ralf.Wildenhues@gmx.de>
 
 	* Makefile.in (GDBREPLAY_OBS): New variable.
diff --git a/gdb/gdbserver/remote-utils.c b/gdb/gdbserver/remote-utils.c
index e062be8..b5665f5 100644
--- a/gdb/gdbserver/remote-utils.c
+++ b/gdb/gdbserver/remote-utils.c
@@ -99,6 +99,11 @@ static int remote_desc = INVALID_DESCRIPTOR;
 extern int using_threads;
 extern int debug_threads;
 
+/* If true, then GDB has requested noack mode.  */
+int noack_mode = 0;
+/* If true, then we tell GDB to use noack mode by default.  */
+int transport_is_reliable = 0;
+
 #ifdef USE_WIN32API
 # define read(fd, buf, len) recv (fd, (char *) buf, len, 0)
 # define write(fd, buf, len) send (fd, (char *) buf, len, 0)
@@ -181,6 +186,8 @@ remote_open (char *name)
 
       fprintf (stderr, "Remote debugging using %s\n", name);
 #endif /* USE_WIN32API */
+
+      transport_is_reliable = 0;
     }
   else
     {
@@ -267,6 +274,8 @@ remote_open (char *name)
       /* Convert IP address to string.  */
       fprintf (stderr, "Remote debugging from host %s\n", 
          inet_ntoa (sockaddr.sin_addr));
+
+      transport_is_reliable = 1;
     }
 
 #if defined(F_SETFL) && defined (FASYNC)
@@ -551,6 +560,17 @@ putpkt_binary (char *buf, int cnt)
 	  return -1;
 	}
 
+      if (noack_mode)
+	{
+	  /* Don't expect an ack then.  */
+	  if (remote_debug)
+	    {
+	      fprintf (stderr, "putpkt (\"%s\"); [noack mode]\n", buf2);
+	      fflush (stderr);
+	    }
+	  break;
+	}
+
       if (remote_debug)
 	{
 	  fprintf (stderr, "putpkt (\"%s\"); [looking for ack]\n", buf2);
@@ -774,23 +794,34 @@ getpkt (char *buf)
       if (csum == (c1 << 4) + c2)
 	break;
 
+      if (noack_mode)
+	{
+	  fprintf (stderr, "Bad checksum, sentsum=0x%x, csum=0x%x, buf=%s [no-ack-mode, Bad medium?]\n",
+		   (c1 << 4) + c2, csum, buf);
+	  /* Not much we can do, GDB wasn't expecting an ack/nac.  */
+	  break;
+	}
+
       fprintf (stderr, "Bad checksum, sentsum=0x%x, csum=0x%x, buf=%s\n",
 	       (c1 << 4) + c2, csum, buf);
       write (remote_desc, "-", 1);
     }
 
-  if (remote_debug)
+  if (!noack_mode)
     {
-      fprintf (stderr, "getpkt (\"%s\");  [sending ack] \n", buf);
-      fflush (stderr);
-    }
+      if (remote_debug)
+	{
+	  fprintf (stderr, "getpkt (\"%s\");  [sending ack] \n", buf);
+	  fflush (stderr);
+	}
 
-  write (remote_desc, "+", 1);
+      write (remote_desc, "+", 1);
 
-  if (remote_debug)
-    {
-      fprintf (stderr, "[sent ack]\n");
-      fflush (stderr);
+      if (remote_debug)
+	{
+	  fprintf (stderr, "[sent ack]\n");
+	  fflush (stderr);
+	}
     }
 
   return bp - buf;
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 1fa1694..60df3d8 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -270,6 +270,19 @@ handle_general_set (char *own_buf)
       return;
     }
 
+  if (strcmp (own_buf, "QStartNoAckMode") == 0)
+    {
+      if (remote_debug)
+	{
+	  fprintf (stderr, "[noack mode enabled]\n");
+	  fflush (stderr);
+	}
+
+      noack_mode = 1;
+      write_ok (own_buf);
+      return;
+    }
+
   /* Otherwise we didn't know what packet it was.  Say we didn't
      understand it.  */
   own_buf[0] = 0;
@@ -777,6 +790,8 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
 	 qXfer:feature:read at all, we will never be re-queried.  */
       strcat (own_buf, ";qXfer:features:read+");
 
+      if (transport_is_reliable)
+	strcat (own_buf, ";QStartNoAckMode+");
       return;
     }
 
@@ -1447,6 +1462,7 @@ main (int argc, char *argv[])
 
   while (1)
     {
+      noack_mode = 0;
       remote_open (port);
 
     restart:
diff --git a/gdb/gdbserver/server.h b/gdb/gdbserver/server.h
index b519696..817b5c4 100644
--- a/gdb/gdbserver/server.h
+++ b/gdb/gdbserver/server.h
@@ -175,6 +175,8 @@ extern void hostio_last_error_from_errno (char *own_buf);
 
 extern int remote_debug;
 extern int all_symbols_looked_up;
+extern int noack_mode;
+extern int transport_is_reliable;
 
 int putpkt (char *buf);
 int putpkt_binary (char *buf, int len);