set_open_status

Corinna Vinschen corinna-cygwin@cygwin.com
Thu Feb 18 13:07:48 GMT 2021


On Feb 18 10:07, Corinna Vinschen via Cygwin-developers wrote:
> On Feb 17 16:35, Ken Brown via Cygwin-developers wrote:
> > Most fhandlers call set_open_status in their 'open' method before a
> > successful return.  I just noticed that fhandler_fifo::open doesn't do this.
> > I thought at first that it was an oversight on my part from when I
> > overhauled the FIFO implementation, but I just checked fhandler_fifo.cc as
> > of cygwin 2.9.0, and I don't see it there either.
> > 
> > Is there some reason this would be wrong for FIFOs?
> 
> I guess this was just an oversight.  It's certainly not fatal, given how
> open_status is used exclusively by fhandler_base::reset_to_open_binmode()
> in turn *only* called from setmode(fd, 0).  This is quite a bordercase.
> Combined with FIFOs supporting only O_BINARY mode anyway...
> 
> It won't hurt to add the set_open_mode call to FIFOs but it won't change
> anything, except avoiding to report O_TEXT mode after a call to
> setmode(fd, 0).
> 
> Maybe it would be better to change fhandler_base::reset_to_open_binmode
> instead.  Right now, if open_status hasn't been initialized, it prefers
> O_TEXT over O_BINARY.  That's unfortunate, because it forces us to call
> set_open_mode everywhere to make sure the mode is stored correctly for
> this single, and seldom, invocation of setmode(fd, 0).  It would be nice
> if set_open_mode would only be necessary on fhandlers supporting O_TEXT
> at all.

On second thought, this should do the trick:

diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h
index e457e2785e9b..ac9ee7c9e787 100644
--- a/winsup/cygwin/fhandler.h
+++ b/winsup/cygwin/fhandler.h
@@ -274,7 +274,8 @@ class fhandler_base
   void reset_to_open_binmode ()
   {
     set_flags ((get_flags () & ~(O_TEXT | O_BINARY))
-	       | ((open_status.wbinary || open_status.rbinary)
+	       | (((open_status.wbinset ? open_status.wbinary : 1)
+		   || (open_status.rbinset ? open_status.rbinary : 1))
 		   ? O_BINARY : O_TEXT));
   }
 

Corinna


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