Date: Sat, 9 Oct 2004 15:07:14 -0400 From: Brian Fundakowski Feldman <green@FreeBSD.org> To: Andrea Campi <andrea+freebsd_cvs@webcom.it> Cc: src-committers@FreeBSD.org Subject: Re: cvs commit: src/lib/libc/gen syslog.c Message-ID: <20041009190714.GB1093@green.homeunix.org> In-Reply-To: <20041009153916.GA2003@webcom.it> References: <200410082115.i98LFLMU034965@repoman.freebsd.org> <20041009153916.GA2003@webcom.it>
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On Sat, Oct 09, 2004 at 05:39:17PM +0200, Andrea Campi wrote:
> On Fri, Oct 08, 2004 at 09:15:21PM +0000, Gleb Smirnoff wrote:
> > glebius 2004-10-08 21:15:21 UTC
> >
> > FreeBSD src repository
> >
> > Modified files:
> > lib/libc/gen syslog.c
> > Log:
> > When send()ing to syslogd return ENOBUFS keep trying until success.
> >
> > This fixes a case, when DoSed syslogd completely loses messages.
>
> Unless I'm missing something, this would make the calling application
> loop for an unbounded time (potentially forever), thus making the DoS
> even more effective. Personally, I've never thought of syslog as a
> reliable service, and I'm quite sure I prefer to lose messages but
> keep my apps running than the opposite. If an application needs a
> failsafe logging mechanism, chances are it will use something else
> anyway.
>
> What about:
>
> retry = 1000;
> do {
> usleep(1);
> if (send(LogFile, tbuf, cnt, 0) >= 0)
> break;
> } while (errno == ENOBUFS && retry-- > 0);
I think that this is something very application-dependant, and it's probably
best to implement as a timeout that it specifies. But why would a DoSed
syslogd lose messages on its end if we're getting ENOBUFS locally? The
protocol doesn't provide a way to acknowledge reception, does it?
--
Brian Fundakowski Feldman \'[ FreeBSD ]''''''''''\
<> green@FreeBSD.org \ The Power to Serve! \
Opinions expressed are my own. \,,,,,,,,,,,,,,,,,,,,,,\
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