Re: tty initialization failure under cygwin 1.7.2?

[Shaddy Baddah <helium at shaddybaddah dot name>]

Hi,

On 2/04/2010 11:36 AM, Corinna Vinschen wrote:
> On Apr  1 14:31, Eric Berge wrote:
>    
> > I recently updated to 1.7.2 from 1.7.1 with the March 15 development
> > patch and noticed I was getting some process failures.  In particular
> > I was running the Coverity static analysis tool, and was getting an
> > error about not being able to "initialize fd 0 for /dev/tty0".
> >
> > This problem does not appear to occur with remote desktop, just with
> > ssh.
> >
> > I've been searching around for a simpler version of the problem
> > and this is what I found:
> >
> > The test scenario is to do the following:
> >
> > 1. ssh into an cygwin sshd server with an explicit password
> > 2. Run "cmd"
> > 3. From "cmd" run "ls"
> >
> > I unfortunately no longer have the 1.7.1 + Mar15 patch running but
> > with cygwin 1.5 and running "ls" lists the entries of the directory
> > as expected.  However, running on 1.7.2 has the following output:
> >
> > C:\cygwin\home\eberge>ls
> > ls
> >       12 [main] ls 3984 C:\cygwin\bin\ls.exe: *** fatal error - couldn't initialize fd 0 for /dev/tty0
> >
> > C:\cygwin\home\eberge>
> >
> > I hope this is reflective of the problem I had with Coverity.  It is
> > the same error message at least.  Is this indicative of an underlying
> > problem in 1.7.2 or is this related to any sort of reconfiguration I
> > need to do on my box after updating to 1.7.2?
> >      
> I'm wondering if that's a side effect with some other software.  I can
> not reproduce your problem.  I tried your test scenario and it works for
> me.  I don't get any weird error from ls.
>    

I suspect this is related to the same issue, related to user
privilege, that I described in
http://cygwin.com/ml/cygwin-developers/2010-02/msg00005.html. As I
understood it from that bit of debug (which I have not returned to
btw), it boils down to an OS limitation preventing Cygwin from
emulating the correct permissions of a tty device. ie. the tty device
appears to be owned by the user, but the tty master is in fact
owned/permed as the SYSTEM(like) user of the sshd session
process. Only Administrators can get at it (with the underlying
OpenProcess() call).

I would have expected this to occur with 1.7.1 as well though.

Is that accurate?

Regards,
Shaddy


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