From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37D9FC433DF for ; Fri, 29 May 2020 09:08:43 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 02DB6206C3 for ; Fri, 29 May 2020 09:08:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="V94+tMYx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 02DB6206C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:51726 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jeb0M-0007RT-4z for qemu-devel@archiver.kernel.org; Fri, 29 May 2020 05:08:42 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41890) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jeazn-000718-B7 for qemu-devel@nongnu.org; Fri, 29 May 2020 05:08:07 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:26323 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jeazl-0001ew-QR for qemu-devel@nongnu.org; Fri, 29 May 2020 05:08:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590743283; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=A+siYBKkZSRvbxHKnSgaYCjqlELqxkMdGxxm63ZqxcM=; b=V94+tMYxARm7fWWZug7+ouArzI8Z5DCGxT6nXvJS6F+pzCWXor3tOiMuBkLQZ9CCcMH0Pg kZApoJYJDDzniHlpBy+hWpyr9L82LvsRpjV1N5oXSN4OMYBmRGifZ2hjRjKKlGmbX9kcGP EBcMZ6TVVlhqQFkJ8BxenJyCPafi94Y= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-425-NMP5SZajPtmnTVwP3QgxoA-1; Fri, 29 May 2020 05:07:59 -0400 X-MC-Unique: NMP5SZajPtmnTVwP3QgxoA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E6F65107ACCA; Fri, 29 May 2020 09:07:58 +0000 (UTC) Received: from work-vm (ovpn-113-111.ams2.redhat.com [10.36.113.111]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6C20560CC0; Fri, 29 May 2020 09:07:57 +0000 (UTC) Date: Fri, 29 May 2020 10:07:54 +0100 From: "Dr. David Alan Gilbert" To: Markus Armbruster Subject: Re: [PATCH 2/2] hmp: Simplify qom_set Message-ID: <20200529090754.GC2856@work-vm> References: <20200520151108.160598-1-dgilbert@redhat.com> <20200520151108.160598-3-dgilbert@redhat.com> <1f627a6b-9c5f-09b3-8f75-64e95a4f5d02@redhat.com> <20200520190344.GG2820@work-vm> <87y2pge6nv.fsf@dusky.pond.sub.org> <20200528140644.GG3069@work-vm> <871rn3p8j3.fsf@dusky.pond.sub.org> MIME-Version: 1.0 In-Reply-To: <871rn3p8j3.fsf@dusky.pond.sub.org> User-Agent: Mutt/1.13.4 (2020-02-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Disposition: inline Received-SPF: pass client-ip=207.211.31.81; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/29 01:27:49 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, T_HK_NAME_DR=0.01 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: berrange@redhat.com, qemu-devel@nongnu.org, clg@kaod.org, Paolo Bonzini , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , afaerber@suse.de Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Markus Armbruster (armbru@redhat.com) wrote: > "Dr. David Alan Gilbert" writes: > > > * Markus Armbruster (armbru@redhat.com) wrote: > >> "Dr. David Alan Gilbert" writes: > >> > >> > * Philippe Mathieu-Daudé (philmd@redhat.com) wrote: > >> >> On 5/20/20 5:11 PM, Dr. David Alan Gilbert (git) wrote: > >> >> > From: "Dr. David Alan Gilbert" > >> >> > > >> >> > Simplify qom_set by making it use qmp_qom_set and the JSON parser. > >> >> > > >> >> > Note that qom-set likes JSON strings quoted with ' not ", e.g.: > >> >> > > >> >> > (qemu) qom-get /machine smm > >> >> > "auto" > >> >> > (qemu) qom-set /machine smm 'auto' > >> >> > >> >> Will I get this output using "? > >> >> > >> >> (qemu) qom-set /machine smm "auto" > >> >> Error: Expecting a JSON value > >> > > >> > The error you get is: > >> > > >> > (qemu) qom-set /machine smm "auto" > >> > Error: JSON parse error, invalid keyword 'auto' > >> > > >> > I think, having seen alphanumerics, it's expecting a keyword; > >> > i.e. a true/false making a bool, or a null. > >> > >> The command parses its argument as JSON. > >> > >> Before we get there, the HMP core extracts the argument from the line of > >> input. The extraction is guided by the command's .args_type, in this > >> case the 's' in "value:s" in > >> > >> { > >> .name = "qom-set", > >> .args_type = "path:s,property:s,value:s", > >> [...] > >> }, > >> > >> monitor/monitor-internal.h documents type code 's' as > >> > >> * 's' string (accept optional quote) > >> > >> The implementation boils down to: > >> > >> 1. Skip whitespace. > >> > >> 2. If looking at '"', get the string enclosed in '"', with C-like escape > >> sequences \n, \r, \\, \', \". > >> > >> 3. Else, get the string up to the next whitespace. > >> > >> See get_str(). > >> > >> Therefore, argument "auto" is the same as auto. Parsing auto as JSON > >> duly fails. > >> > >> Argument 'auto' works, but only because qobject_from_json() recognizes > >> single-quoted strings. This is as extension over RFC 8259. > >> > >> Using single quotes falls apart when you want to pass something > >> containing whitespace. Then you'd have to use > >> > >> "\"ugly and unintuitive\"" > >> > >> or, again relying on the extension > >> > >> "'ugly and unintuitive'" > >> > >> There's a better way, and Paolo pointed it out in > >> > >> Subject: Re: [RFC PATCH] qom: Implement qom-get HMP command > >> Date: Thu, 21 May 2020 16:24:12 +0200 > >> Message-ID: <2c148331-78ae-31f7-8702-d65c37a090b0@redhat.com> > >> > >> Use argument type 'S'. Documented as > >> > >> * 'S' it just appends the rest of the string (accept optional quote) > >> > >> but the parenthesis is confusing. It really just skips whitespace, then > >> extracts the remainder of the line. Can't do string with leading > >> whitespace, but that's just fine for us. > > > > Yep, thanks - I spotted Paolo's response but thanks for the deeper > > explanation. > > With that would you give me a Review-by? > > Also fix the typo in the title "hmp: Simplify qom_set": it's qom-set. Done. > Reviewed-by: Markus Armbruster Thanks. -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK