Re: [PATCH] libio: Add __nonnull for FILE * arguments of fclose and freopen

[Xi Ruoyao <xry111@xry111.site>]

On Fri, 2023-04-21 at 10:00 -0300, Adhemerval Zanella Netto wrote:
> 
> 
> On 21/04/23 03:21, Xi Ruoyao wrote:
> > Calling fclose or freopen with a null FILE * is undefined behavior,
> > and
> > doing so in practice will cause a SIGSEGV.  So it seems suitable for
> > __nonnull.
> > 
> > This will help the compiler to warn for some buggy code, like
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109570.
> 
> LGTM, thanks.

Thanks, please commit it if there is no objections.  Or may I get a
write after approve access for glibc.git?

> 
> Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
> 
> > ---
> >  libio/stdio.h | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/libio/stdio.h b/libio/stdio.h
> > index 45ddafdf20..bfb8415d3b 100644
> > --- a/libio/stdio.h
> > +++ b/libio/stdio.h
> > @@ -180,7 +180,7 @@ extern int renameat2 (int __oldfd, const char
> > *__old, int __newfd,
> >  
> >     This function is a possible cancellation point and therefore not
> >     marked with __THROW.  */
> > -extern int fclose (FILE *__stream);
> > +extern int fclose (FILE *__stream) __nonnull ((1));
> >  
> >  #undef __attr_dealloc_fclose
> >  #define __attr_dealloc_fclose __attr_dealloc (fclose, 1)
> > @@ -269,7 +269,7 @@ extern FILE *fopen (const char *__restrict
> > __filename,
> >     marked with __THROW.  */
> >  extern FILE *freopen (const char *__restrict __filename,
> >                       const char *__restrict __modes,
> > -                     FILE *__restrict __stream) __wur;
> > +                     FILE *__restrict __stream) __wur __nonnull
> > ((3));
> >  #else
> >  # ifdef __REDIRECT
> >  extern FILE *__REDIRECT (fopen, (const char *__restrict __filename,
> > @@ -290,7 +290,7 @@ extern FILE *fopen64 (const char *__restrict
> > __filename,
> >    __attribute_malloc__ __attr_dealloc_fclose __wur;
> >  extern FILE *freopen64 (const char *__restrict __filename,
> >                         const char *__restrict __modes,
> > -                       FILE *__restrict __stream) __wur;
> > +                       FILE *__restrict __stream) __wur __nonnull
> > ((3));
> >  #endif
> >  
> >  #ifdef __USE_POSIX

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University