[PATCH] RTEMS: Synchronize <sys/time.h> with FreeBSD

Mon Sep 23 20:06:00 GMT 2019

On 2019-09-23 04:07, Sebastian Huber wrote:
> This change is based on the FreeBSD commit:
> 
> Author: asomers <asomers@FreeBSD.org>
> Date:   Mon Jul 30 15:46:40 2018 +0000
> 
>     Make timespecadd(3) and friends public
> 
>     The timespecadd(3) family of macros were imported from NetBSD back in
>     r35029. However, they were initially guarded by #ifdef _KERNEL. In the
>     meantime, we have grown at least 28 syscalls that use timespecs in some
>     way, leading many programs both inside and outside of the base system to
>     redefine those macros. It's better just to make the definitions public.
> 
>     Our kernel currently defines two-argument versions of timespecadd and
>     timespecsub.  NetBSD, OpenBSD, and FreeDesktop.org's libbsd, however, define
>     three-argument versions.  Solaris also defines a three-argument version, but
>     only in its kernel.  This revision changes our definition to match the
>     common three-argument version.
> 
>     Bump _FreeBSD_version due to the breaking KPI change.
> 
>     Discussed with: cem, jilles, ian, bde
>     Differential Revision:  https://reviews.freebsd.org/D14725
> ---
>  newlib/libc/sys/rtems/include/machine/_time.h | 42 +++++++++++++++++++++++++--
>  1 file changed, 39 insertions(+), 3 deletions(-)
> 
> diff --git a/newlib/libc/sys/rtems/include/machine/_time.h b/newlib/libc/sys/rtems/include/machine/_time.h
> index 13fa14afa..24e6c7398 100644
> --- a/newlib/libc/sys/rtems/include/machine/_time.h
> +++ b/newlib/libc/sys/rtems/include/machine/_time.h
> @@ -1,6 +1,9 @@
>  /*-
> + * SPDX-License-Identifier: BSD-3-Clause
> + *
> + * Copyright (c) 1982, 1986, 1993
> + *	The Regents of the University of California.  All rights reserved.
>   * Copyright (c) 2016 embedded brains GmbH
> - * All rights reserved.
>   *
>   * Redistribution and use in source and binary forms, with or without
>   * modification, are permitted provided that the following conditions
> @@ -10,11 +13,14 @@
>   * 2. Redistributions in binary form must reproduce the above copyright
>   *    notice, this list of conditions and the following disclaimer in the
>   *    documentation and/or other materials provided with the distribution.
> + * 3. Neither the name of the University nor the names of its contributors
> + *    may be used to endorse or promote products derived from this software
> + *    without specific prior written permission.
>   *
> - * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
> + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
>   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
>   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> - * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
> + * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
>   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
>   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
>   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> @@ -22,12 +28,42 @@
>   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
>   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
>   * SUCH DAMAGE.
> + *
> + *	@(#)time.h	8.5 (Berkeley) 5/4/95
> + * $FreeBSD: head/sys/sys/time.h 346176 2019-04-13 04:46:35Z imp $
>   */
>  
>  #ifndef _SYS_TIME_H_
>  #error "must be included via <sys/time.h>"
>  #endif /* !_SYS_TIME_H_ */
>  
> +/* Operations on timespecs */
> +#define	timespecclear(tvp)	((tvp)->tv_sec = (tvp)->tv_nsec = 0)
> +#define	timespecisset(tvp)	((tvp)->tv_sec || (tvp)->tv_nsec)
> +#define	timespeccmp(tvp, uvp, cmp)				\
> +	(((tvp)->tv_sec == (uvp)->tv_sec) ?				\
> +	    ((tvp)->tv_nsec cmp (uvp)->tv_nsec) :			\
> +	    ((tvp)->tv_sec cmp (uvp)->tv_sec))
> +
> +#define	timespecadd(tsp, usp, vsp)				\
> +	do {								\
> +		(vsp)->tv_sec = (tsp)->tv_sec + (usp)->tv_sec;		\
> +		(vsp)->tv_nsec = (tsp)->tv_nsec + (usp)->tv_nsec;	\
> +		if ((vsp)->tv_nsec >= 1000000000L) {			\
> +			(vsp)->tv_sec++;				\
> +			(vsp)->tv_nsec -= 1000000000L;			\
> +		}							\
> +	} while (0)
> +#define	timespecsub(tsp, usp, vsp)				\
> +	do {								\
> +		(vsp)->tv_sec = (tsp)->tv_sec - (usp)->tv_sec;		\
> +		(vsp)->tv_nsec = (tsp)->tv_nsec - (usp)->tv_nsec;	\
> +		if ((vsp)->tv_nsec < 0) {				\
> +			(vsp)->tv_sec--;				\
> +			(vsp)->tv_nsec += 1000000000L;			\
> +		}							\
> +	} while (0)
> +
>  #ifdef _KERNEL
>  /* Header file provided outside of Newlib */
>  #include <machine/_kernel_time.h>

It would be good to make this more generally available for Cygwin, RTEMS, and
other systems, in a similar place to timeval, in
newlib/libc/include/sys/_timespec.h.
The timeval timer... macros are already defined in
newlib/libc/include/sys/_timeval.h under the __BSD_VISIBLE feature and #if*n*def
_KERNEL, and these timespec macros are also available under most Linux distros,
standard on BSD.

The conversion macros TIMEVAL_TO_TIMESPEC and TIMESPEC_TO_TIMEVAL are already
available in newlib/libc/include/sys/timespec.h.

All the bintime... and sbintime... facilities are already available in
newlib/libc/include/sys/time.h guarded by __BSD_VISIBLE.

As the existing facilities require _BSD_SOURCE be defined to make these public,
should the new additions also be guarded, or the guards removed in all cases?

As I reinvented those wheels just last week, not knowing about these facilities,
could we please also make all the relevant BSD timeval...(3), timespec...(3),
and bintime...(9) man pages available also, perhaps under newlib/libc/time/?

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

This email may be disturbing to some readers as it contains
too much technical detail. Reader discretion is advised.