Re: MC no longer working with cygwin 3.1.x

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Dec 18 23:09, Ken Brown wrote:
> On 12/18/2019 5:55 PM, Thomas Wolff wrote:
> > Am 18.12.2019 um 22:14 schrieb Ken Brown:
> >> On 12/18/2019 2:32 PM, Corinna Vinschen wrote:
> >>> On Dec 18 17:23, Marco Atzeri wrote:
> >>>> Am 18.12.2019 um 15:42 schrieb Laurent R:
> >>>>> Dear all,
> >>>>>
> >>>>> After the update to cygwin-3.1.1, mc (aka Midnight Commander) no longer 
> >>>>> starts. It goes into an infinite loop, if I go back to cygwin-3.0.7, mc 
> >>>>> works perfectly.
> >>>>>
> >>>>> I tested with cygwin-3.1.0, same problem.
> >>>>>
> >>>>> The MC version is 4.8.23 and the operating system is Windows 10 Pro x64 1903.
> >>>> confirmed
> >>>>
> >>>> there must be a race somewhere as running /usr/bin/mc.exe from strace
> >>>> works fine.
> >>> But that's not the only problem running mc AFAICS.  I'm seeing an
> >>> error message in the background:
> >>>
> >>> Cannot open named pipe /tmp/mc-corinna/mc.pipe.384
> >>>     
> >>> /cygdrive/d/cyg_pub/devel/mc/mc-4.8.23-1.x86_64/src/mc-4.8.23/src/subshell/common.c: 
> >>> open: Permission denied
> >>> [...]
> >> I've just looked at the mc source code, and it seems that (under tcsh only), mc
> >> creates a fifo and tries to open it twice as O_RDWR.  This is not supported on
> >> Cygwin, so the second attempt fails.
> >>
> >> Here's the relevant code from src/subshell/common.c:
> >> [...]
> >> Under bash, zsh, and some other shells, mc uses ordinary pipes rather than
> >> FIFOs.  I have no idea why tcsh is treated differently.
> >>
> >> Until someone[*] gets around to making it possible to open a FIFO twice for
> >> reading, I don't think there's anything we can do about it.  I also don't know
> >> how important this is for mc.  I don't use tcsh or mc, so I can't judge.

Not using mc either here.  I see the STATUS_ACCESS_DENIED in the strace
output when calling NtCreateNamedPipeFile, but I wonder why that is.

Ken, btw., we should add a PIPE_REJECT_REMOTE_CLIENTS flag, just for
paranoia.

> > I've reproduced mc to fail, from bash, in cygwin 3.1.0 and 3.1.1, Windows 1809 
> > and 1903.
> 
> That's not related to what I've been talking about, which is the error
> message "Cannot open named pipe /tmp/mc-corinna/mc.pipe.384" that
> Corinna reported.  The failure you're talking about occurs in all
> shells and has already been fixed by Takashi.  I imagine Corinna will
> release 3.1.2 with the fix very soon.

Yes, today or tomorrow.  Maybe some other low-hanging fruit roles past...


Corinna

-- 
Corinna Vinschen
Cygwin Maintainer

Attachment: signature.asc
Description: PGP signature