Date: 07 Aug 1998 21:32:31 +0200 From: dag-erli@ifi.uio.no (Dag-Erling Coidan =?iso-8859-1?Q?Sm=F8rgrav?= ) To: Archie Cobbs <archie@whistle.com> Cc: wollman@khavrinen.lcs.mit.edu (Garrett Wollman), freebsd-current@FreeBSD.ORG, bde@zeta.org.au, dg@root.com Subject: Re: memory leaks in libc Message-ID: <xzpogtw37w0.fsf@hrotti.ifi.uio.no> In-Reply-To: Archie Cobbs's message of "Fri, 7 Aug 1998 10:37:26 -0700 (PDT)" References: <199808071737.KAA29957@bubba.whistle.com>
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Archie Cobbs <archie@whistle.com> writes:
> Garrett Wollman writes:
> > No, you've missed the point entirely. *Any program which does enough
> > playing around with the environment to be harmed by this memory leak
> > is using a totally inappropriate interface.*
> I disagree with that statement! And I base my disagreement not on
> conjecture but on experience.
There is only one situation in which you need to change the
environment: fork-and-exec, in which case it is trivial to construct a
fresh environment for your child process in a safe manner. If you're
not fork-and-execing, use program variables instead (which you
initialize with getenv()). If you're writing a shell and need to keep
track of lots of environment variables and pass them to your children,
you're in both situations at once; use a hash table for quick lookup
(you'll need it for variable substitution in command lines) and pass
execve() a list of pointers to the contents of your hash table.
> How can it possibly do this? The only way to get strftime() to
> acknowledge a change in timezone is to do something like this:
>
> unsetenv("TZ");
> tzset();
> setenv("TZ", "/etc/localtime", 1);
> tzset();
Then strftime() should be taken out and shot.
Arguably, so should setenv(), but fixing setenv() will only hide the
symptoms of bad programming practice.
That said, I don't really see any reason *not* to commit your setenv()
replacement, if it works properly. It's just that there aren't really
any arguments *for* the commit, either.
DES
--
Dag-Erling Smørgrav - dag-erli@ifi.uio.no
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