From owner-freebsd-audit  Wed Jun  5  1:36:47 2002
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Date: Wed, 5 Jun 2002 10:38:00 +0200 (CEST)
From: Alexander Leidinger <Alexander@Leidinger.net>
Subject: Re: [PATCH] making dump EINTR resistant
To: bde@zeta.org.au
Cc: Todd.Miller@courtesan.com, drosih@rpi.edu, audit@FreeBSD.ORG
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On  5 Jun, Bruce Evans wrote:

>> It would probably be better to just make the code in question to
>> just use sigaction() if you are concerned about portability.  That
>> way you get consistent handling of syscall restarts.
> 
> I agree, but not that SA_RESTART wasn't portable until tomorrow (sic),
> since it is in POSIX.1-2001 but not in older POSIXes (.1-1996 at least).

Stevens uses this as a portable example for a signal() with restartable
syscalls:

---snip---
#include <signal.h>

typedef void Sigfunc(int);

Sigfunc *
signal(int signo, Sigfunc *func)
{
	struct sigaction	act, oact;

	act.sa_handler = func;
	sigemptyset(&act.sa_mask);
	act.sa_flags = 0;
	if (signo == SIGALRM) {
#ifdef	SA_INTERRUPT
		act.sa_flags |= SA_INTERRUPT;	/* SunOS */
#endif
	} else {
#ifdef	SA_RESTART
		act.sa_flags |= SA_RESTART;	/* SVR4, 4.3+BSD */
#endif
	}
	if (sigaction(signo, &act, &oact) < 0)
		return(SIG_ERR);
	return (oact.sa_handler);
}
---snip---

He doesn't want restartable syscalls for SIGALRM to allow to set a time
out for I/O operations.

Bye,
Alexander.

-- 
            Give a man a fish and you feed him for a day;
     teach him to use the Net and he won't bother you for weeks.

http://www.Leidinger.net                       Alexander @ Leidinger.net
  GPG fingerprint = C518 BC70 E67F 143F BE91  3365 79E2 9C60 B006 3FE7


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