[PATCH v11] posix: Deprecate group_member for Linux
Joe Simmons-Talbott
josimmon@redhat.com
Thu Mar 28 15:11:18 GMT 2024
On Wed, Mar 27, 2024 at 4:57 PM Paul Eggert <eggert@cs.ucla.edu> wrote:
>
> On 3/27/24 12:43, Joe Simmons-Talbott wrote:
> > + int granted;
> > +
> > + if (uid == stats.st_uid)
> > + granted = (unsigned int) (stats.st_mode & (mode << 6)) >> 6;
> > + else
> > + {
> > + if (((flag & AT_EACCESS) && stats.st_gid == __getegid()) ||
> > + (!(flag & AT_EACCESS) && stats.st_gid == __getgid()))
> > + granted = (unsigned int) (stats.st_mode & (mode << 3)) >> 3;
> > + else
> > + {
> > + int gm = __group_member2 (stats.st_gid);
> > + if (gm == -1)
> > + return -1;
> > + else if (gm)
> > + granted = (unsigned int) (stats.st_mode & (mode << 3)) >> 3;
> > + else
> > + granted = (stats.st_mode & mode);
> > + }
> > + }
> >
> > if (granted == mode)
> > return 0;
>
> This is still too complicated, with repetitions of AT_EACCESS that were
> not in the original. Come to think of it, it has unnecessary casts and
> repetitive shifting and masking, and that indentation of || is not GNU
> style. How about something like the following untested code instead?
>
> int shift;
>
> if (uid == stats.st_uid)
> shift = 6;
> else
> {
> int gm = (stats.st_gid
> == (flag & AT_EACCESS ? __getegid () : __getgid ()));
> if (!gm)
> {
> gm = __group_member2 (stats.st_gid);
> if (gm < 0)
> return gm;
> }
> shift = gm ? 3 : 0;
> }
>
> if ((stats.st_mode >> shift & mode) == mode)
> return 0;
>
I like that much better. I've posted a v12[1] with your suggestion
that was tested via 'make check'.
Thanks,
Joe
[1] https://sourceware.org/pipermail/libc-alpha/2024-March/155666.html
--
Joe Simmons-Talbott
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