Re: [PATCH v2] newlib: libc: Fix bugs in the commit 3d94e07c49b5.

[Corinna Vinschen <vinschen@redhat.com>]

On Nov 16 15:08, Corinna Vinschen wrote:
> On Nov 16 14:48, Corinna Vinschen wrote:
> > On Nov 16 14:19, Corinna Vinschen wrote:
> > > On Nov 16 21:27, Takashi Yano wrote:
> > > > 2) __swbuf_r() has ORIENT (fp, -1) call, however, result is not checked.
> > > 
> > > Good catch.  Looks like setting the orientation at this point is
> > > wrong.  __swbuf_r is called via the __sputc_r macro in stdio.h.
> > > But __sputc_r is also called from __fputwc as well as, potentially,
> > > from _fputws_r.
> > > 
> > > AFAICS, we already set the orientation from the calling functions
> > > _putc_r (covering putchar, putc, fputc) and from _puts_r as
> > > well as _fputs_r (covering puts, fputs).
> > > 
> > > On the wide-char side, we set the orientation from _fputwc_r
> > > (covering putwchar, putwc, fputwc) and from _fputws_r (covering
> > > fputws).
> > > 
> > > So I *think* we can safely remove the ORIENT call from __swbuf_r,
> > > or did I miss some other way to call __swbuf_r?
> > 
> > Yes, I did.  The _getchar_unlocked and _putchar_unlocked macros as well
> > as the __SINGLE_THREAD__ getc and putc macros(*).  I also missed the
> > putc{har}_unlocked and getc{har}_unlocked functions.
> > 
> > They all call __sgetc_r or __sputs_r, both being macros in stdio.h.
> > The underlying functions __srget_r and __swbuf_r are shared between
> > byte and wide-char orientation functions.
> > 
> > Drat.  Looks like we really have to do the ORIENT stuff inside the
> > __sgetc_r/__sputs_r macros...
> 
> That's not feasible.  The only way out as I see it is that we don't
> share the underlying functions and macros between byte and wide-char
> functions:
> 
> - _fputwc_r and _fputws_r must not call __sputc_r from stdio.h, they
>   should get their own version.
> 
> - The underlying functions __srget_r and __swbuf_r have to be split into
>   two functions each, or they have to get an additional parameter
>   deciding how to set the orientation.
> 
> - In turn, we can remove most of the ORIENT calls in the calling functions.

I applied matching patches. After checking the code for as couple of
hours I'm pretty sure __srget_r doesn't have to be split because all
wide-char oriented functions call __srefill_r directly.

I seriously hope I didn't miss anything.  Feedback appreciated.


Thanks,
Corinna