Date: Mon, 23 Apr 2001 23:02:05 +0100 From: Brian Somers <brian@Awfulhak.org> To: freebsd-current@FreeBSD.ORG Cc: brian@Awfulhak.org Subject: Re: cp -d dir patch for review (or 'xargs'?) Message-ID: <200104232202.f3NM25607648@hak.lan.Awfulhak.org> In-Reply-To: Message from Oliver Fromme <olli@secnetix.de> of "Mon, 23 Apr 2001 15:08:27 %2B0200." <200104231308.PAA18220@lurza.secnetix.de>
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> Rodney W. Grimes <freebsd@gndrsh.dnsmgr.net> wrote:
> > > Before anyone starts writing scripts, consider that {} will be =
> > > replaced by xargs with (roughly) ARG_MAX - 10 characters worth of =
the =
> > > stuff coming off the pipe. If your combined arguments plus =
> > > environment exceeds ARG_MAX execve(2) will give you E2BIG.
> > =
> > No rain here, it is ARG_MAX - 2048:
> > -s size
> > Set the maximum number of bytes for the command line le=
ngth pro-
> > vided to utility. The sum of the length of the utility =
name and
> > the arguments passed to utility (including NULL termina=
tors) will
> > be less than or equal to this number. The current defa=
ult value
> > for size is ARG_MAX - 2048.
> > =
> > 2K would be a pretty big env, root default std is about 367 bytes.
> > =
> > Yes, that is probably not a portable assumption to make, but it is
> > far better than using non-standard options to xargs.
> =
> If I'm not mistaken, the size of the environment is already
> taken into account by the xargs utility (subtracted from
> ARG_MAX). So this isn't an issue at all.
Unless xargs runs a command with lots of arguments and that command =
increases the environment size then tries to run another command with =
the same arguments - bang (E2BIG).
> Regards
> Oliver
> =
> -- =
> Oliver Fromme, secnetix GmbH & Co KG, Oettingenstr. 2, 80538 M=FCnchen
> Any opinions expressed in this message may be personal to the author
> and may not necessarily reflect the opinions of secnetix in any way.
> =
> "All that we see or seem is just a dream within a dream" (E. A. Poe)
-- =
Brian <brian@Awfulhak.org> <brian@[uk.]FreeBSD.org=
>
<http://www.Awfulhak.org>; <brian@[uk.]OpenBSD.org=
>
Don't _EVER_ lose your sense of humour !
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