Date: Sun, 18 May 1997 15:07:12 +0400 (MSD) From: =?KOI8-R?B?4c7E0sXKIP7F0s7P1w==?= <ache@nagual.pp.ru> To: Peter Wemm <peter@spinner.dialix.com> Cc: Bruce Evans <bde@zeta.org.au>, peter@FreeBSD.ORG, cvs-all@FreeBSD.ORG, cvs-committers@FreeBSD.ORG, cvs-lib@FreeBSD.ORG Subject: Re: cvs commit: src/lib/libc/gen sleep.c Message-ID: <Pine.BSF.3.96.970518150412.1533B-100000@nagual.pp.ru> In-Reply-To: <199705180940.RAA06430@spinner.DIALix.COM>
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On Sun, 18 May 1997, Peter Wemm wrote:
> (void) sigvec(SIGALRM, &vec, &ovec);
> if (setjmp(&jmpbuf) == 0) {
> .. unmask SIGALRM ..
I think here is a race place -->
> nanosleep(&time_to_sleep, &time_remaining);
> (void) sigvec(SIGALRM, &ovec, (struct sigvec *)0);
> ... but this has several problems..
> 1: it's starting to get messy with lots of syscalls.
> 2: it doesn't deal with an aborted nanosleep() due to SIGALRM. It'd have
> to calculate the elapsed time itself by calling gettimeofday or
> clock_gettime() before and after. It'd also suffer from time adjustments
> and contribute to the mess.
Yes.
> On the other hand, perhaps we could change the nanosleep syscall so that
> it takes a mask argument and handle the differences in the libc wrapper
> and have sleep(3) do this:
>
>
> sigprocmask(SIG_BLOCK, ..SIGALRM.., &oset);
> ...
> setsignal(SIGALRM, sleephandler);
> ...
> nanosleep_mask(&time, &remaining, &oset);
> ...
>
> and have nanosleep(ts1, ts2) be implemented as nanosleep_mask(ts1, ts2,
> NULL);
The second variant looks much better.
--
Andrey A. Chernov
<ache@null.net>
http://www.nagual.pp.ru/~ache/
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