Subject: Re: [PATCH] be paranoid about closed stdin/stdout/stderr

From: "Stephen R. van den Berg" <[email-masked]>
Date: Thu, 28 Aug 2008 14:52:58 +0200

Nick Andrew wrote:
>On Wed, Aug 27, 2008 at 02:22:39PM -0400, Avery Pennarun wrote:
>> I'm just feeling protective of the future sanity of other developers
>> here, hoping they don't have to go through what I did on a multi-week

>You're not alone. I've been having trouble with a combination of
>fetchmail, procmail and ssmtp, in which situation the ssmtp program
>_somehow_ sometimes opens /dev/urandom as file descriptor 0 (while

>in controlled circumstances. It's possible that fetchmail or procmail
>is doing something stupid - but a little more defensive programming
>in ssmtp could avoid the total disaster area of sending an endless
>binary stream to an SMTP server.

Procmail I can vouch for, it basically assumes your OS is broken and
fights it's way back to sanity (it can be setuid root, so it has to
be rather careful).
Nonetheless, I still maintain that hiding problems doesn't help, it
only makes the bugs even rarer and more difficult to find.

The filedescriptor problem is a programmer-error, not a user-error,
which is why not hiding it should be preferred.  If it were a
user-error, thing would be different, assisting the user is a Good
Thing.
-- 
Sincerely,
           Stephen R. van den Berg.

"Listen carefully, I shall say this only wence."