Date: Mon, 12 Jun 2017 13:47:05 -0700 From: Mark Johnston <markj@FreeBSD.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r319868 - in head/sys: kern sys Message-ID: <20170612204704.GA73695@wkstn-mjohnston.west.isilon.com> In-Reply-To: <20170612202952.GU2088@kib.kiev.ua> References: <201706122014.v5CKEitK071089@repo.freebsd.org> <20170612202952.GU2088@kib.kiev.ua>
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On Mon, Jun 12, 2017 at 11:29:52PM +0300, Konstantin Belousov wrote:
> On Mon, Jun 12, 2017 at 08:14:44PM +0000, Mark Johnston wrote:
> > +int
> > +uuidcmp(const struct uuid *uuid1, const struct uuid *uuid2)
> > +{
> > +
> > + return (memcmp(uuid1, uuid2, sizeof(struct uuid)));
> > +}
>
> This is unsafe. The function operation depends on the ABI properties
> that there is no padding either between members, or at the end of
> the structure. Why not use by-member comparision ?
I interpreted the CTASSERT at the beginning of kern_uuid.c as a
guarantee that no such padding will be present. kern_uuid.c also defines
an alternate representation, struct uuid_private, and casts between the
two.
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