[v2] fileops: Don't process , ccs= as individual mode flags (BZ#18906)

In processing the first 7 individual characters of the mode for fopen
if ,ccs= is used those characters will be processed as well.  Stop
processing individual mode flags once a comma is encountered.  This has
the effect of requiring ,ccs= to be the last mode flag in the mode
string.  Add a testcase to check that the ,ccs= mode flag is not
processed as individual mode flags.
---
Changes to v1:
 * fclose fp when fopen succeeds.  Fixes memory leak found by try-bot

 libio/fileops.c      |  1 +
 libio/tst-fopenloc.c | 34 +++++++++++++++++++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

On Thu, Jun 15, 2023 at 01:12:43PM -0400, Joe Simmons-Talbott wrote:
> In processing the first 7 individual characters of the mode for fopen
> if ,ccs= is used those characters will be processed as well.  Stop
> processing individual mode flags once a comma is encountered.  This has
> the effect of requiring ,ccs= to be the last mode flag in the mode
> string.  Add a testcase to check that the ,ccs= mode flag is not
> processed as individual mode flags.
> ---
> Changes to v1:
>  * fclose fp when fopen succeeds.  Fixes memory leak found by try-bot

Ping.

Thanks,
Joe
> 
>  libio/fileops.c      |  1 +
>  libio/tst-fopenloc.c | 34 +++++++++++++++++++++++++++++++++-
>  2 files changed, 34 insertions(+), 1 deletion(-)
> 
> diff --git a/libio/fileops.c b/libio/fileops.c
> index 58c9e985e4..1c1113e339 100644
> --- a/libio/fileops.c
> +++ b/libio/fileops.c
> @@ -247,6 +247,7 @@ _IO_new_file_fopen (FILE *fp, const char *filename, const char *mode,
>        switch (*++mode)
>  	{
>  	case '\0':
> +	case ',':
>  	  break;
>  	case '+':
>  	  omode = O_RDWR;
> diff --git a/libio/tst-fopenloc.c b/libio/tst-fopenloc.c
> index 089c61bf41..8cd35f01f2 100644
> --- a/libio/tst-fopenloc.c
> +++ b/libio/tst-fopenloc.c
> @@ -17,6 +17,7 @@
>     <https://www.gnu.org/licenses/>.  */
>  
>  #include <errno.h>
> +#include <fcntl.h>
>  #include <locale.h>
>  #include <mcheck.h>
>  #include <stdio.h>
> @@ -24,6 +25,7 @@
>  #include <string.h>
>  #include <wchar.h>
>  #include <sys/resource.h>
> +#include <support/check.h>
>  #include <support/support.h>
>  #include <support/xstdio.h>
>  
> @@ -48,13 +50,40 @@ do_bz17916 (void)
>    if (fp != NULL)
>      {
>        printf ("unexpected success\n");
> +      free (ccs);
> +      fclose (fp);
>        return 1;
>      }
> +
>    free (ccs);
>  
>    return 0;
>  }
>  
> +static int
> +do_bz18906 (void)
> +{
> +  /* BZ #18906 -- check processing of ,ccs= as flags case.  */
> +
> +  const char *ccs = "r,ccs=+ISO-8859-1";
> +  size_t retval;
> +
> +  FILE *fp = fopen (inputfile, ccs);
> +  int flags;
> +
> +  TEST_VERIFY(fp != NULL);
> +
> +  if (fp != NULL)
> +    {
> +      flags = fcntl(fileno(fp), F_GETFL);
> +      retval = (flags & O_RDWR) | (flags & O_WRONLY);
> +      TEST_COMPARE(retval, false);
> +      fclose (fp);
> +    }
> +
> +  return EXIT_SUCCESS;
> +}
> +
>  static int
>  do_test (void)
>  {
> @@ -78,7 +107,10 @@ do_test (void)
>  
>    xfclose (fp);
>  
> -  return do_bz17916 ();
> +  TEST_COMPARE(do_bz17916 (), 0);
> +  TEST_COMPARE(do_bz18906 (), 0);
> +
> +  return EXIT_SUCCESS;
>  }
>  
>  #include <support/test-driver.c>
> -- 
> 2.39.2
>

On Wed, Jul 05, 2023 at 03:45:03PM -0400, DJ Delorie wrote:
> 
> This patch looks semantically correct to me, but needs a few syntactical
> changes to meet our coding style.  Please post a v3 and I'll prioritize
> re-reviewing it.  Thanks!

Thanks for reviewing it.  I've posted a v3 with the changes you've
suggested.

Thanks,
Joe
> 
> Joe Simmons-Talbott via Libc-alpha <libc-alpha@sourceware.org> writes:
> > diff --git a/libio/fileops.c b/libio/fileops.c
> > index 58c9e985e4..1c1113e339 100644
> > --- a/libio/fileops.c
> > +++ b/libio/fileops.c
> > @@ -247,6 +247,7 @@ _IO_new_file_fopen (FILE *fp, const char *filename, const char *mode,
> >        switch (*++mode)
> >  	{
> >  	case '\0':
> > +	case ',':
> >  	  break;
> >  	case '+':
> >  	  omode = O_RDWR;
> 
> While this does force the ,ccs= to be after any other flags, effectively
> this was true before as the characters in "ccs" and/or the conversion
> name would conflict anyway.  Ok.
> 
> > diff --git a/libio/tst-fopenloc.c b/libio/tst-fopenloc.c
> > index 089c61bf41..8cd35f01f2 100644
> > --- a/libio/tst-fopenloc.c
> > +++ b/libio/tst-fopenloc.c
> > @@ -17,6 +17,7 @@
> >     <https://www.gnu.org/licenses/>.  */
> >  
> >  #include <errno.h>
> > +#include <fcntl.h>
> >  #include <locale.h>
> >  #include <mcheck.h>
> >  #include <stdio.h>
> > @@ -24,6 +25,7 @@
> >  #include <string.h>
> >  #include <wchar.h>
> >  #include <sys/resource.h>
> > +#include <support/check.h>
> >  #include <support/support.h>
> >  #include <support/xstdio.h>
> >  
> > @@ -48,13 +50,40 @@ do_bz17916 (void)
> >    if (fp != NULL)
> >      {
> >        printf ("unexpected success\n");
> > +      free (ccs);
> > +      fclose (fp);
> >        return 1;
> >      }
> > +
> >    free (ccs);
> >  
> >    return 0;
> >  }
> 
> Ok.
> 
> > +static int
> > +do_bz18906 (void)
> > +{
> > +  /* BZ #18906 -- check processing of ,ccs= as flags case.  */
> > +
> > +  const char *ccs = "r,ccs=+ISO-8859-1";
> > +  size_t retval;
> > +
> > +  FILE *fp = fopen (inputfile, ccs);
> > +  int flags;
> > +
> > +  TEST_VERIFY(fp != NULL);
> > +
> > +  if (fp != NULL)
> > +    {
> > +      flags = fcntl(fileno(fp), F_GETFL);
> > +      retval = (flags & O_RDWR) | (flags & O_WRONLY);
> > +      TEST_COMPARE(retval, false);
> > +      fclose (fp);
> > +    }
> > +
> > +  return EXIT_SUCCESS;
> > +}
> 
> Ok.  Needs space between "TEST_VERIFY" and "(" though, and
> "TEST_COMPARE" and "("
> 
> Needs spaces in fcntl( and fileno(
> 
> > @@ -78,7 +107,10 @@ do_test (void)
> >  
> >    xfclose (fp);
> >  
> > -  return do_bz17916 ();
> > +  TEST_COMPARE(do_bz17916 (), 0);
> > +  TEST_COMPARE(do_bz18906 (), 0);
> > +
> > +  return EXIT_SUCCESS;
> >  }
> 
> Ok, but same here - needs spaces before parens.
>