[PATCH] Fix misreported errno on preadv2/pwritev2 (BZ#23579)

[Adhemerval Zanella]

On 28/09/2018 11:10, Florian Weimer wrote:
> * Adhemerval Zanella:
> 
>> 	[BZ #23579]
>> 	* misc/tst-preadvwritev2-common.c (do_test_with_invalid_fd): New
>> 	test.
>> 	* misc/tst-preadvwritev2.c, misc/tst-preadvwritev64v2.c (do_test):
>> 	Call do_test_with_invalid_fd.
>> 	* sysdeps/unix/sysv/linux/preadv2.c (preadv2): Use fallback code iff
>> 	errno is ENOSYS.
>> 	* sysdeps/unix/sysv/linux/preadv64v2.c (preadv64v2): Likewise.
>> 	* sysdeps/unix/sysv/linux/pwritev2.c (pwritev2): Likewise.
>> 	* sysdeps/unix/sysv/linux/pwritev64v2.c (pwritev64v2): Likewise.
> 
> Looks okay to me.
> 
> I see that we return ENOTSUP for invalid flags, but the kernel returns
> EINVAL.  But this is a preexisting problem, unrelated to this patch.

Yeah, I described this discrepancy in commit message and I can't really see
how to easy emulate it.