Re: [PATCH] Cygwin: pinfo: Additional fix for CTTY behavior.

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Jan 10 18:52, Takashi Yano wrote:
> On Mon, 9 Jan 2023 10:25:33 +0100
> Corinna Vinschen wrote:
> > On Dec 28 17:35, Takashi Yano wrote:
> > > The commit 25c4ad6ea52f did not fix the CTTY behavior enough. For
> > > example, in the following test case, TTY will be associated as
> > > a CTTY on the second open() call even though the TTY is already
> > > CTTY of another session. This patch fixes the issue.
> > 
> > The patch is ok, thanks.
> > 
> > But while looking into this patch, I realized how confusing the old code
> > is.  An unsuspecting reader will have a really hard time to figure out
> > what ctty values of -1 or -2 actually mean.  The CVS log entry from 2012
> > isn't enlightening either:
> > 
> >   On second thought, in the spirit of keeping things kludgy, set ctty to
> >   -2 here as a special flag ...
> > 
> > Would you mind to introduce speaking symbolic values for them and add
> > some comments to make them more transparent?
> 
> Ok. Do you mean, first push this CTTY patch, then,
> add comment for ctty values -1 and -2 in another patch?

Sure, that would be fine.

> 
> > Also, given this was a "kludge" from 10 years ago, is it really still
> > needed?
> > 
> > As I said, it's confusing :}
> 
> Currently, the special values mean:
> -1: CTTY is not initialized yet. Can associate with the TTY
>     which is associated with the own session.
> -2: CTTY has been released by setsid(). Can associate with
>     a new TTY as CTTY, but cannot associate with the TTYs
>     already associated with other sessions.
> 
> So, I think the two different values are necessary. 

Ok, good to know.


Thanks,
Corinna