1.7.5: Occasional failure of CreatePipe or signal handing due to thread-unsafe code in cwdstuff::set
Sat Sep 4 09:26:00 GMT 2010
On Sep 3 16:18, John Carey wrote:
> On Sep 03 12:37 Corinna Vinschen wrote:
> > On Sep 2 23:32, John Carey wrote:
> > > In Aug 17 10:15, Corinna Vinschen wrote:
> > > > I just released 1.7.6-1.
> > > ...
> > > > What changed since Cygwin 1.7.5:
> > > > ================================
> > > >
> > > > - Cygwin handles the current working directory entirely on its own. The
> > > > Win32 current working directory is set to an invalid path to be out of
> > > > the way. This affects calls to the Win32 file API (CreateFile, etc.).
> > > > See http://cygwin.com/htdocs/cygwin-ug-net/using.html#pathnames-win32-api
> > >
> > > Thank you very much for the fix!
> > >
> > > I've been running tests against Cygwin 1.7.6, and then 1.7.7,
> > > and those sporadic, non-deterministic failures in CreatePipe
> > > did stop after the 1.7.6 upgrade, and are still gone in 1.7.7.
> > > I think it's been long enough to conclude that it is not just
> > > the non-determinism--it really is fixed, as expected.
> > >
> > > I understand that this issue opened a can of worms;
> > > thanks again for your efforts to overcome those difficulties.
> > I still don't like the final workaround, which is, to set the Win32 CWD
> > to the Cygwin CWD. It would be nice if we could revert that change to
> > the pre-1.7.6 behaviour in a Vista-friendly way. If you ever find out
> > how to make sure that the new handle in the PEB's user parameter block
> > is used even on Vista and later, pray tell me.
> Thus far the only ideas I have come up with are somewhat
> shaky and go well beyond the documented Win32 API.
> (If only there was the equivalent of dup2(), but for Win32
> Just how much undocumented behavior is
> tolerable, do you think?
Up to XP/2K3, we can simply set the handle in the user parameter block
and be done with it, just as in 1.7.5, but without the Vista workaround.
The problem only starts with Vista. I have no objections to use
undocumented features, if they work. If there's any way to replace the
cwd handle with our own *and* keep the Win32 API happy, I'll take it.
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Project Co-Leader cygwin AT cygwin DOT com
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