From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55518) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fQIGn-0005zL-Da for qemu-devel@nongnu.org; Tue, 05 Jun 2018 16:09:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fQIGm-0004Zl-Gu for qemu-devel@nongnu.org; Tue, 05 Jun 2018 16:09:29 -0400 References: <20180528183058.GG2209@redhat.com> <20180528183833.GJ4580@localhost.localdomain> <20180528212054.GH2209@redhat.com> <20180528212510.GC4660@redhat.com> <20180529064415.GA4756@localhost.localdomain> <2b3eef00-f326-c1e6-0e4b-b7602646eec4@redhat.com> <20180605092159.GA2544@work-vm> <20180605190324.GA11372@localhost.localdomain> <20180605223934-mutt-send-email-mst@kernel.org> <20180605195855.GC1455@redhat.com> From: Eric Blake Message-ID: <6f6ecbb5-3175-44d0-5922-b13ac163f006@redhat.com> Date: Tue, 5 Jun 2018 15:09:17 -0500 MIME-Version: 1.0 In-Reply-To: <20180605195855.GC1455@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Qemu-block] storing machine data in qcow images? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Richard W.M. Jones" Cc: "Michael S. Tsirkin" , Eduardo Habkost , Kevin Wolf , qemu-block@nongnu.org, qemu-devel@nongnu.org, stefanha@redhat.com, Max Reitz , "Dr. David Alan Gilbert" On 06/05/2018 02:58 PM, Richard W.M. Jones wrote: >> Binary blobs can always be base64 encoded for representation within >> a valid JSON UTF-8 string (and we already have several QMP >> interfaces that utilize base64 encoding to pass through what is >> otherwise invalid UTF-8). It does inflate things slightly compared >> to a format that allows a raw length coupled with raw data, but that >> is not necessarily a problem. > > Of course how we represent them externally and/or while > using QMP / qemu-img to store and retrieve them is up for grabs. > Doesn't JSON allow binary to be encoded? (Knowing how poorly > done JSON is, I wouldn't be surprised if not) JSON itself does not have a binary primitive; to pass arbitrary data through JSON you have to first encode that data into something like base64 that can then be represented as a UTF-8 string. For reference, look at qapi/crypto.json and the definition of QCryptoSecretFormat. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org