linux-kernel - Why does timerfd() only support CLOCK_REALTIME and CLOCK

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 9 Feb 2009 07:25:50 +1300
From:	Michael Kerrisk <mtk.manpages@...glemail.com>
To:	Davide Libenzi <davidel@...ilserver.org>
Cc:	"linux-man@...r.kernel.org" <linux-man@...r.kernel.org>,
	lkml <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Why does timerfd() only support CLOCK_REALTIME and CLOCK_MONOTONIC?

Hi Davide,

At the moment I'm looking into writing man pages for timer_create(2)
and friends.  (Somewhat bizarrely, these pages do not yet exist.)  As
I looked into the source code of timer_create(), etc., and did some
tests, I saw that timer_create() supports the following clocks:

TIMER_REALTIME
TIMER_MONOTONIC
TIMER_PROCESS_CPUTIME_ID
TIMER_THREAD_CPUTIME_ID
clockid obtained from clock_getcpuclockid(3)
clockid obtained from pthread_getcpuclockid(3)

On the other hand, timerfd() only permits the first two of these.
What's the reason for that limitation of timerfd()?  (It may be worth
adding something to the man page on this point.)

Cheers,

Michael
-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
git://git.kernel.org/pub/scm/docs/man-pages/man-pages.git
man-pages online: http://www.kernel.org/doc/man-pages/online_pages.html
Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/