From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44148) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bwTjy-00007u-Ms for qemu-devel@nongnu.org; Tue, 18 Oct 2016 08:43:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bwTjv-0001LH-Jb for qemu-devel@nongnu.org; Tue, 18 Oct 2016 08:43:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55704) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1bwTjv-0001KR-EA for qemu-devel@nongnu.org; Tue, 18 Oct 2016 08:43:31 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9B95EC04B311 for ; Tue, 18 Oct 2016 12:43:30 +0000 (UTC) Date: Tue, 18 Oct 2016 13:43:27 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20161018124326.GF2190@work-vm> References: <20161012191502.GC16187@work-vm> <20161018100409.GH4349@redhat.com> <87d1ixlv0x.fsf@dusky.pond.sub.org> <20161018121355.GP4349@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161018121355.GP4349@redhat.com> Subject: Re: [Qemu-devel] chardev's and fd's in monitors List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: Markus Armbruster , qemu-devel@nongnu.org * Daniel P. Berrange (berrange@redhat.com) wrote: > On Tue, Oct 18, 2016 at 02:08:14PM +0200, Markus Armbruster wrote: > > "Daniel P. Berrange" writes: > > > > > On Wed, Oct 12, 2016 at 08:15:02PM +0100, Dr. David Alan Gilbert wrote: > > >> Hi, > > >> I had a look at a couple of readline like libraries; > > >> editline and linenoise. A difficulty with using them is that > > >> they both want fd's or FILE*'s; editline takes either but > > >> from a brief look I think it's expecting to extract the fd. > > >> That makes them tricky to integrate into qemu, where > > >> the chardev's hide a whole bunch of non-fd things; in particular > > >> tls, mux, ringbuffers etc. > > >> > > >> If we could get away with just a FILE* then we could use fopencookie, > > >> but that's GNU only. > > >> > > >> Is there any sane way of shepherding all chardev's into having an > > >> fd? > > > > > > The entire chardev abstraction model exists precisely because we cannot > > > make all chardevs look like a single fd. Even those which are fd based > > > may have separate FDs for input and output. > > > > > > IMHO the only viable approach would be to enhance linenoise/editline to > > > not assume use of fd* or FILE * abstractions. > > > > The real thing (GNU readline) has hooks rl_getc_function, > > rl_input_available_hook, rl_redisplay_function and so forth, which might > > do the trick. Unfortunately, we're stuck with cheap copies due to our > > foolish acceptance of GPLv2-only contributions. > > I'm wondering if improving read line facilities in HMP is really important > enough for us to bother dealing with the problems, as opposed to just > staying with our current impl ? It's worth us understanding it, but not worth us putting infrastructure in for. If we can find a way to do it sanely on top of what we've got I think it's worth it. Dave > Regards, > Daniel > -- > |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| > |: http://libvirt.org -o- http://virt-manager.org :| > |: http://entangle-photo.org -o- http://search.cpan.org/~danberr/ :| -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK