ioctl: FIONREAD and ENOTTY

Corinna Vinschen corinna-cygwin@cygwin.com
Wed Jul 20 15:47:00 GMT 2011


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;


Corinna

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

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