From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35824) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bwTBv-0004te-7M for qemu-devel@nongnu.org; Tue, 18 Oct 2016 08:08:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bwTBp-0003fs-K8 for qemu-devel@nongnu.org; Tue, 18 Oct 2016 08:08:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38826) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1bwTBp-0003fj-Ei for qemu-devel@nongnu.org; Tue, 18 Oct 2016 08:08:17 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (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 ADB3880087 for ; Tue, 18 Oct 2016 12:08:16 +0000 (UTC) From: Markus Armbruster References: <20161012191502.GC16187@work-vm> <20161018100409.GH4349@redhat.com> Date: Tue, 18 Oct 2016 14:08:14 +0200 In-Reply-To: <20161018100409.GH4349@redhat.com> (Daniel P. Berrange's message of "Tue, 18 Oct 2016 11:04:10 +0100") Message-ID: <87d1ixlv0x.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain 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: "Dr. David Alan Gilbert" , qemu-devel@nongnu.org "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.