Re: [take 3] Use pid in inotify events.

Michael Kerrisk
2008-11-19T14:44:05Z

[RESENT, because LKML bounced some HTML that accidentally got put in the mail.]
[CC+=John McCutchan, this time with hopefully a live email address;
John, some context here: http://marc.info/?t=122633022400003&r=1&w=2 ]

Evgeniy,

On Wed, Nov 19, 2008 at 9:05 AM, Evgeniy Polyakov <zbr@ioremap.net> wrote:
>
> Hi Christoph.
>
> On Tue, Nov 18, 2008 at 02:19:37PM +0100, Christoph Hellwig (hch@lst.de) wrote:
> > Yes, this kind of thing should be enable using an flag to inotify1, and
> > be consistant even for rename. Doing it as a flag to inotify1 also has
> > the advantage to be able to return an -EPERM when the feature is
> > requested but not allowed instead of letting applications that assume it
> > silently fail.
>
> So effectively you propose to have second generation of the inotify
> which will have additional pid field, which will be unused by all but
> the same uid events?

I suspect that Christoph wants the same thing as I do: some thinking
towards a future-proof design, rather than a quick hack to address the
needs of a single application.

> If you want to return -EPERM, than it will be _always_ returned for non
> sysadmin capable user, which effectively makes it unusable.

Again, appropriate flags in inotify_init1() could fix this -- e.g.,
only fill the field (and give an error if no perms) if a flag is set.

I think what is really needed at this point is some consideration of
what other extensions (if any) might be desired for inotify, and how
we might be best create a design that suits those and future needs.

Cheers,

Michael

--
Michael Kerrisk
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