Date: Tue, 17 Dec 2013 08:42:06 -0700 From: Warner Losh <imp@bsdimp.com> To: Adrian Chadd <adrian@freebsd.org> Cc: Bruce Evans <bde@freebsd.org>, "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org> Subject: Re: Using sys/types.h types in sys/socket.h Message-ID: <9C1291B5-215B-440E-B8B0-6308840F755C@bsdimp.com> In-Reply-To: <CAJ-Vmo=MWPQWfP9duWPPwaKee5Zp9Gemj3GKqE8=bxkjn_1YYA@mail.gmail.com> References: <CAJ-Vmo=MWPQWfP9duWPPwaKee5Zp9Gemj3GKqE8=bxkjn_1YYA@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
The tl;dr version: use sys/_types.h and use the usual conventions to =
avoid namespace pollution. I read Bruce's reply, and I think I'm saying =
the same things he is...
Warner
On Dec 17, 2013, at 1:23 AM, Adrian Chadd wrote:
> Hi,
>=20
> I have a patch to implement some new sendfile functionality, but this
> involves adding stuff to sys/socket.h:
>=20
> Index: sys/sys/socket.h
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> --- sys/sys/socket.h (revision 258883)
> +++ sys/sys/socket.h (working copy)
> @@ -577,11 +577,27 @@
> };
>=20
> /*
> + * sendfile(2) kqueue information
> + */
> +struct sf_hdtr_kq {
> + int kq_fd; /* kq fd to post completion events on */
> + uint32_t kq_flags; /* extra flags to pass in */
> + void *kq_udata; /* user data pointer */
> + uintptr_t kq_ident; /* ident (from userland?) */
> +};
This is a terrible interface. Or I'd say that the ordering of the =
elements in this structure is suboptimal. Having the uint32_t in the =
middle like that causes badness. Guess not much can be done about that =
given that fd must be an int, eh?
To avoid namespace pollution, you'll need to include sys/_types.h use =
__uint32_t and __uintptr_t respectively. You'd also need
#if __BSD_VISIBLE
#ifndef _UINT32_T_DECLARED
typedef __uint32_t uint32_t;
#define _UINT32_T_DECLARED
#endif
and similar for __uintptr_t. thankfully, sys/_stdint.h already does this =
dance to avoid namespace pollution, so you just need a few lines at the =
top of socket.h to do this righ.
> +struct sf_hdtr_all {
> + struct sf_hdtr hdtr;
> + struct sf_hdtr_kq kq;
> +};
> +
> +/*
> * Sendfile-specific flag(s)
> */
> #define SF_NODISKIO 0x00000001
> #define SF_MNOWAIT 0x00000002
> #define SF_SYNC 0x00000004
> +#define SF_KQUEUE 0x00000008
>=20
> #ifdef _KERNEL
> #define SFK_COMPAT 0x00000001
>=20
>=20
> ... now, uintptr_t upsets things, because we don't include sys/types.h
> before sys/socket.h.
>=20
> The POSIX spec for sys/socket.h doesn't mention a dependency on
> sys/types.h and in fact says it should define a couple of types
> itself.
>=20
> =
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_socket.h.html=
>=20
> .. so, what suggestions do people have? I'd like to do this right and
> not cause header pollution.
>=20
> Thanks!
>=20
>=20
> -a
> _______________________________________________
> freebsd-arch@freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-arch
> To unsubscribe, send any mail to =
"freebsd-arch-unsubscribe@freebsd.org"
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?9C1291B5-215B-440E-B8B0-6308840F755C>