Re: [1/1] Use pid in inotify events.

Hi Evgeniy,

On Mon, Nov 10, 2008 at 10:20 AM, Evgeniy Polyakov [off-list ref] wrote:

Hi Michael.

On Sat, Nov 08, 2008 at 11:58:30AM -0500, Michael Kerrisk (mtk.manpages-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org) wrote:

quoted

It's perhaps unfortunate that the structure wasn't padded out with a
few additional fields "for future use".  But -- maybe it is not really
true that we can't change things.  Two things to consider:

a) We now (since 2.6.27) have an inotify_init1() which has a flags argument.
b) There are spare bits in the mask argument of inotify_add_watch()

We could use a flag in either of these to say that we want a different
structure returned on read() from the inotify descriptor.  In the
first case, this would be a global setting for all inotify events on
that descriptor.  In the second, we could do it on a per-watch basis
(I'm not so sure that that is a nice idea).  Since we are in any case
extending the ABI, and new applications would need to be taught about
the extension, it seems we could consider either of the alternative
extensions I mentioned, which woul also allow the PID to be obtained
for rename() events.  What do you think?

This may be a good idea for some serious ABI change. I think we could
extend it even more to include IO offset/size into events and attribute
changes.

Are you going to revise your patch to use this idea?

Cheers,

Michael

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Michael Kerrisk
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