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Date: Thu, 21 Jul 2011 16:39:31 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: ioctl: FIONREAD and ENOTTY
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On Jul 20 17:37, Yaakov (Cygwin/X) wrote:
> On Wed, 2011-07-20 at 17:46 +0200, Corinna Vinschen wrote:
> > On Jul 20 03:11, Yaakov (Cygwin/X) wrote:
> > > On Linux, ioctl(2) returns several different errors[1]:
> > > 
> > > EBADF  d is not a valid descriptor.
> > > EFAULT argp references an inaccessible memory area.
> > > EINVAL Request or argp is not valid.
> > > ENOTTY d is not associated with a character special device.
> > > ENOTTY The specified request does not apply to the kind of object that
> > >        the descriptor d references.
> > > 
> > > In the case of FIONREAD, Cygwin doesn't seem to distinguish between
> > > EINVAL and ENOTTY, and this causes at least one major bug:
> > > 
> > > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35536
> > > 
> > > I have patched GCJ and GNU classpath to work around it, but this really
> > > needs to be fixed in Cygwin itself.
> > 
> > Would this patch be sufficient?
> > 
> > Index: fhandler.cc
> > ===================================================================
> > RCS file: /cvs/src/src/winsup/cygwin/fhandler.cc,v
> > retrieving revision 1.397
> > diff -u -p -r1.397 fhandler.cc
> > --- fhandler.cc	5 Jul 2011 12:02:10 -0000	1.397
> > +++ fhandler.cc	20 Jul 2011 15:46:40 -0000
> > @@ -1151,6 +1151,10 @@ fhandler_base::ioctl (unsigned int cmd, 
> >        set_nonblocking (*(int *) buf);
> >        res = 0;
> >        break;
> > +    case FIONREAD:
> > +      set_errno (ENOTTY);
> > +      res = -1;
> > +      break;
> >      default:
> >        set_errno (EINVAL);
> >        res = -1;
> 
> Given my testcases, give me a few days to check this out.

Ok, but the patch doesn't build as is.  You have to add

  #include <asm/socket.h>

to get the FIONREAD definition.  Sorry about that.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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