Re: How to identify specific wait-state for a "DE" process?

[Paul Goyette <paul%whooppee.com@localhost>]

On Sat, 9 Jan 2016, Rhialto wrote:

> On Wed 06 Jan 2016 at 17:44:45 +0000, Taylor R Campbell wrote:
> > This only fixes the problem for certain orderings of file descriptors.
>
> I was thinking of a different hack.
>
> Given tha filemon now knows there are issues if it has to use a fd lower
> than its own fd, it can avoid the situation.
>
> If it happens, it might dup2() the output fd so that it gets one that is
> high enough, to use instead. That ought to work, since as I understand
> the issue is references to the file descriptor, not references to the
> file structure.
>
> Of course I can immediately see some disadvantages to this apprroach:
>
> - this will use an extra fd and that is observable by the process
> - and the process might even close that fd if it is doing some blanket
>  close-all-fds action.
>
> Maybe these potential issues can be avoided somehow?

Yes, we avoid all these issues by taking the reference on the file 
itself, rather than on the descriptor.


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