Re: [PATCH 1/1] libbpf: ensure F_DUPFD_CLOEXEC is defined

[Daniel Borkmann]

On 3/4/22 8:01 PM, Andrii Nakryiko wrote:
> On Mon, Feb 28, 2022 at 7:00 AM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:
> > On 2/27/22 3:25 PM, James Hilliard wrote:
> > > This definition seems to be missing from some older toolchains.
> > >
> > > Note that the fcntl.h in libbpf_internal.h is not a kernel header
> > > but rather a toolchain libc header.
> > >
> > > Fixes:
> > > libbpf_internal.h:521:18: error: 'F_DUPFD_CLOEXEC' undeclared (first use in this function); did you mean 'FD_CLOEXEC'?
> > >      fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
> > >                     ^~~~~~~~~~~~~~~
> > >                     FD_CLOEXEC
> > >
> > > Signed-off-by: James Hilliard <james.hilliard1@xxxxxxxxx>
> >
> > Do you have some more info on your env (e.g. libc)? Looks like F_DUPFD_CLOEXEC
> > was added back in 2.6.24 kernel. When did libc add it?
>
> It seems like it's guarded by __USE_XOPEN2K8 in glibc (from a quick
> glance at glibc code). But it's been there since 2010 or so, at the
> very least.
>
> > Should we instead just add an include for <linux/fcntl.h> to libbpf_internal.h
> > (given it defines F_DUPFD_CLOEXEC as well)?
>
> yep, this is UAPI header so we can use it easily (we'll need to sync
> it into Github repo, but that's not a problem)

Sgtm, James, could you respin with using the include?

Thanks,
Daniel