Re: [Qemu-devel] [PATCH v2] qemu-io: fix EOF Ctrl-D handling in qemu-io readline code

["Daniel P. Berrange" <berrange@redhat.com>]

On Fri, Dec 08, 2017 at 10:21:35AM -0600, Eric Blake wrote:
> On 12/08/2017 07:34 AM, Daniel P. Berrange wrote:
> > qemu-io puts the TTY into non-canonical mode, which means no EOF processing is
> > done and thus getchar() will never return the EOF constant. Instead we have to
> > query the TTY attributes to determine the configured EOF character (usually
> > Ctrl-D / 0x4), and then explicitly check for that value. This fixes the
> > regression that prevented Ctrl-D from triggering an exit of qemu-io that has
> > existed since readline was first added in
> > 
> >   commit 0cf17e181798063c3824c8200ba46f25f54faa1a
> >   Author: Stefan Hajnoczi <stefanha@redhat.com>
> >   Date:   Thu Nov 14 11:54:17 2013 +0100
> > 
> >     qemu-io: use readline.c
> > 
> > Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> > ---
> > Changed in v2:
> 
> > +++ b/qemu-io.c
> > @@ -10,6 +10,9 @@
> >  #include "qemu/osdep.h"
> >  #include <getopt.h>
> >  #include <libgen.h>
> > +#ifndef _WIN32
> > +#include <termios.h>
> > +#endif
> 
> Wouldn't a configure probe for the existence of <termios.h> be more
> reliable than just hard-coding the list of platforms where it is
> currently not found?
> 
> >  
> >  #include "qapi/error.h"
> >  #include "qemu-io.h"
> > @@ -41,6 +44,26 @@ static bool imageOpts;
> >  
> >  static ReadLineState *readline_state;
> >  
> > +static int ttyEOF;
> > +
> > +static int get_eof_char(void)
> > +{
> > +#ifdef _WIN32
> 
> in which case this also should be #if HAVE_TERMIOS_H
> 
> But I guess unless someone complains, all other platforms that we care
> about have termios.h, so a weak:

FYI, vl.c already includes termios.h, with merely  #ifndef _WIN32
protection, so that shows this is sufficient for our immediate
needs.

> Reviewed-by: Eric Blake <eblake@redhat.com>


Regards,
Daniel
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