Re: RFA: remote.c : allow long monitor cmds + allow user to C-c

[Philippe Waroquiers <philippe.waroquiers@skynet.be>]

On Mon, 2012-01-23 at 12:31 +0000, Pedro Alves wrote:
> Please use "cvs diff -up", or put "diff -up" in your ~/.cvsrc file.
Oops, 2nd trial.

The remote stub can implement monitor commands which are not
known by gdb. Such monitor commands can take a long time
to execute. An example of this is the "leak_search" monitor
command implemented in the Valgrind gdbserver.

Currently, gdb will timeout on such a long monitor command.
The remote stub however will continue to execute the
command and send the output later. Gdb and the remote
stub can then be desynchronised : gdb sends a packet,
and the reply read from the stub is the one of a previous packet.

The change below uses getpkt_sane to detect a timeout.
In this case, it continues the loop.
A QUIT; is inserted in the loop to allow the user
to stop handling the current command. possibly
still creating a desynchronisation between gdb and the stub
but that will be upon user request.

Regression tested on linux x86, with and without gdbserver.

Ok to apply ?

Philippe

Index: gdb/ChangeLog
===================================================================
RCS file: /cvs/src/src/gdb/ChangeLog,v
retrieving revision 1.13761
diff -u -p -r1.13761 ChangeLog
--- gdb/ChangeLog	20 Jan 2012 10:31:25 -0000	1.13761
+++ gdb/ChangeLog	23 Jan 2012 20:22:22 -0000
@@ -1,3 +1,8 @@
+2012-01-22  Philippe Waroquiers  <philippe.waroquiers@skynet.be>
+
+	* remote.c (remote_rcmd): use getpkt_sane to detect timeout
+	and continue the loop. Add QUIT statement.
+
 2012-01-20  Ulrich Weigand  <ulrich.weigand@linaro.org>
 
 	* NEWS: Document remote "info proc" and "generate-core-file".
Index: gdb/remote.c
===================================================================
RCS file: /cvs/src/src/gdb/remote.c,v
retrieving revision 1.478
diff -u -p -r1.478 remote.c
--- gdb/remote.c	20 Jan 2012 09:47:32 -0000	1.478
+++ gdb/remote.c	23 Jan 2012 20:22:24 -0000
@@ -8583,8 +8583,17 @@ remote_rcmd (char *command,
       char *buf;
 
       /* XXX - see also remote_get_noisy_reply().  */
+      QUIT;			/* Allow user to bail out with ^C.  */
       rs->buf[0] = '\0';
-      getpkt (&rs->buf, &rs->buf_size, 0);
+      if (getpkt_sane (&rs->buf, &rs->buf_size, 0) == -1)
+        { 
+          /* Timeout. Continue to (try to) read responses.
+             This is better than stopping with an error, assuming the stub
+             is still executing the (long) monitor command.
+             If needed, the user can interrupt gdb using C-c, obtaining
+             an effect similar to stop on timeout.  */
+          continue;
+        }
       buf = rs->buf;
       if (buf[0] == '\0')
 	error (_("Target does not support this command."));