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From: Anthony PERARD <anthony.perard@citrix.com>
To: Ian Jackson <ian.jackson@citrix.com>
Cc: xen-devel@lists.xenproject.org, Wei Liu <wei.liu2@citrix.com>
Subject: Re: [PATCH v5 15/15] libxl: Re-implement domain_suspend_device_model using libxl__ev_qmp
Date: Fri, 9 Nov 2018 16:59:18 +0000	[thread overview]
Message-ID: <20181109165918.GD1302@perard.uk.xensource.com> (raw)
In-Reply-To: <23494.951.777903.157046@mariner.uk.xensource.com>

On Tue, Oct 16, 2018 at 04:28:55PM +0100, Ian Jackson wrote:
> Anthony PERARD writes ("[PATCH v5 15/15] libxl: Re-implement domain_suspend_device_model using libxl__ev_qmp"):
> > +    if (rc)
> > +        goto error;
> > +
> > +    libxl__carefd_begin();
> > +    ev->cfd = libxl__carefd_opened(CTX,
> > +                                 open(filename, O_WRONLY | O_CREAT, 0600));
> 
> Does this statefile fd really need to be a carefd ?  Is it a pipe or a
> file ?  If it is a file, is it of nontrivial size ?

Yes, it needs to be caredfd, because that's what the libxl__ev_qmp API
wants. I don't know yet if it is a good idee to have the _ev_qmp API
only takes fd. Do you think it's fine to have libxl__ev_qmp API takes a
simple fd and let callers handle the fd the way they want?

(In previous version of the patch series, libxl__ev_qmp used to close
the carefd. That's not the case anymore, and that carefd is only read,
so I don't think it matter anymore which kind it is between int and
carefd.)

> If it's a file of a few kb, which I think is the case, then the worst
> result of (with very low probability) leaking this fd into another
> process is simply that the file might be kept alive for a while after
> it was deleted.


-- 
Anthony PERARD

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  reply	other threads:[~2018-11-09 16:59 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20181015151630.3887-1-ian.jackson@eu.citrix.com>
2018-09-07 15:10 ` [PATCH v5 00/15] libxl: Enable save/restore/migration of a restricted QEMU + libxl__ev_qmp_* Anthony PERARD
2018-09-07 15:10   ` [PATCH v5 01/15] libxl: Design of an async API to issue QMP commands to QEMU Anthony PERARD
2018-10-10 15:18     ` Ian Jackson
2018-10-11 11:17       ` Anthony PERARD
2018-10-11 11:21         ` Ian Jackson
2018-10-10 23:49     ` Marek Marczykowski-Górecki
2018-10-11 14:29       ` Anthony PERARD
2018-09-07 15:10   ` [PATCH v5 02/15] libxl_qmp: Connect to QMP socket Anthony PERARD
2018-10-10 15:29     ` Ian Jackson
2018-10-11 11:27       ` Anthony PERARD
2018-09-07 15:10   ` [PATCH v5 03/15] libxl_qmp: Implement fd callback and read data Anthony PERARD
2018-10-10 15:47     ` Ian Jackson
2018-10-11 14:06       ` Anthony PERARD
2018-10-15 14:04         ` Ian Jackson
2018-10-15 16:35         ` [PATCH v5 03/15] libxl_qmp: Implement fd callback and read data [and 1 more messages] Ian Jackson
2018-10-29 15:52           ` Anthony PERARD
2018-10-29 17:31             ` Ian Jackson
2018-10-30 18:03               ` Anthony PERARD
2018-10-30 18:25                 ` Ian Jackson
2018-09-07 15:10   ` [PATCH v5 04/15] libxl_qmp: Parse JSON input from QMP Anthony PERARD
2018-09-07 15:10   ` [PATCH v5 05/15] libxl_qmp: Separate QMP message generation from qmp_send_prepare Anthony PERARD
2018-09-07 15:10   ` [PATCH v5 06/15] libxl_qmp: Prepare the command to be sent Anthony PERARD
2018-09-07 15:10   ` [PATCH v5 07/15] libxl_qmp: Handle write to QMP socket Anthony PERARD
2018-09-07 15:10   ` [PATCH v5 08/15] libxl_qmp: Handle messages from QEMU Anthony PERARD
2018-09-07 15:10   ` [PATCH v5 09/15] libxl_qmp: Respond to QMP greeting Anthony PERARD
2018-09-07 15:10   ` [PATCH v5 10/15] libxl_exec: Add libxl__spawn_initiate_failure Anthony PERARD
2018-10-16 14:02     ` Ian Jackson
2018-11-09 12:26       ` Anthony PERARD
2018-09-07 15:11   ` [PATCH v5 11/15] libxl_dm: Pre-open QMP socket for QEMU Anthony PERARD
2018-10-16 14:11     ` Ian Jackson
2018-11-12 14:52       ` Anthony PERARD
2018-11-12 15:14         ` Ian Jackson
2018-11-12 15:22           ` Anthony PERARD
2018-11-12 15:54             ` Ian Jackson
2018-09-07 15:11   ` [PATCH v5 12/15] libxl: QEMU startup sync based on QMP Anthony PERARD
2018-10-16 14:23     ` Ian Jackson
2018-11-12 15:00       ` Anthony PERARD
2018-11-12 15:17         ` Ian Jackson
2018-09-07 15:11   ` [PATCH v5 13/15] libxl_qmp: Store advertised QEMU version in libxl__ev_qmp Anthony PERARD
2018-10-16 14:25     ` Ian Jackson
2018-09-07 15:11   ` [PATCH v5 14/15] libxl: Change libxl__domain_suspend_device_model() to be async Anthony PERARD
2018-10-16 15:14     ` Ian Jackson
2018-09-07 15:11   ` [PATCH v5 15/15] libxl: Re-implement domain_suspend_device_model using libxl__ev_qmp Anthony PERARD
2018-10-16 15:28     ` Ian Jackson
2018-11-09 16:59       ` Anthony PERARD [this message]
2018-11-09 17:11         ` Ian Jackson
2018-11-09 17:30           ` Anthony PERARD

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