From: Eric Wong <normalperson@...>
Date: 2013-10-23T20:06:22+00:00
Subject: [ruby-core:58003] Re: [ruby-trunk - Bug #9040] Readline duplicate file descriptors but doesn't close them

"akr (Akira Tanaka)" <akr@fsij.org> wrote:
> Issue #9040 has been updated by akr (Akira Tanaka).
> 
> File readline-release-gvl-5.patch added
> 
> normalperson (Eric Wong) wrote:
> >  
> >  Btw, on a separate note, it would be a good idea to check the return
> >  value of fileno() in case another extension accidentally fclose()
> 
> I think avoiding accidental fclose() is not the responsibility of readline_getc().
> It is because readline_getc() cannot determine the FILE structure is closed or not.
> So the only appropriate action for the situation is rb_bug()
> because fileno() for a closed stream is undefined behavior
> (possibly SEGV if memory for FILE structure is returned to OS).

Agreed, thanks.

On a related note: should rb_fd_set/rb_fd_resize call rb_bug on
negative FD?  Otherwise it could OOM/SEGV, I think