Date: Wed, 21 Jun 2006 17:23:49 +0100 From: Florent Thoumie <flz@FreeBSD.org> To: Yar Tikhiy <yar@comp.chem.msu.su> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/etc rc.subr src/share/man/man8 rc.subr.8 Message-ID: <1150907029.3467.49.camel@mayday.esat.net> In-Reply-To: <20060621122331.GI45947@comp.chem.msu.su> References: <200606210942.k5L9gtAi060504@repoman.freebsd.org> <1150883785.3467.4.camel@mayday.esat.net> <20060621105253.GE45947@comp.chem.msu.su> <1150887909.3467.18.camel@mayday.esat.net> <20060621113901.GG45947@comp.chem.msu.su> <1150890968.3467.39.camel@mayday.esat.net> <20060621122331.GI45947@comp.chem.msu.su>
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On Wed, 2006-06-21 at 16:23 +0400, Yar Tikhiy wrote:
> On Wed, Jun 21, 2006 at 12:56:08PM +0100, Florent Thoumie wrote:
> > On Wed, 2006-06-21 at 15:39 +0400, Yar Tikhiy wrote:
> > > On Wed, Jun 21, 2006 at 12:05:09PM +0100, Florent Thoumie wrote:
> > > > On Wed, 2006-06-21 at 14:52 +0400, Yar Tikhiy wrote:
> > > > > On Wed, Jun 21, 2006 at 10:56:25AM +0100, Florent Thoumie wrote:
> > > > > > On Wed, 2006-06-21 at 09:42 +0000, Yar Tikhiy wrote:
> > > > > > > yar 2006-06-21 09:42:55 UTC
> > > > > > >=20
> > > > > > > FreeBSD src repository
> > > > > > >=20
> > > > > > > Modified files:
> > > > > > > etc rc.subr=20
> > > > > > > share/man/man8 rc.subr.8=20
> > > > > > > Log:
> > > > > > > Quite a number of rc.d scripts try to load kernel modules. =
Many
> > > > > > > of them do that conditionally depending on kldstat. The co=
de is
> > > > > > > duplicated all over, but bugs can be uniqie.
> > > > > > > =20
> > > > > > > To make the things more consistent, introduce a new rc.subr=
function,
> > > > > > > load_kld, which takes care of loading a kernel module condi=
tionally.
> > > > > > > =20
> > > > > > > (Found this lying for a while in my p4 branch for various h=
acks.)
> > > > > >=20
> > > > > > I added such a function some weeks ago (far more simple though)=
. Talking
> > > > > > with pjd, I've backed it out to use the somewhat straight-forwa=
rd method
> > > > > > he used in rc.d/geli.
> > > > >=20
> > > > > rc.d/geli doesn't use kldload directlty, so it certainly won't
> > > > > benefit from the function I introduced.
> > > >=20
> > > > Then I'm not sure what script would benefit from this function. Can=
you
> > > > point me to an example?
> > >=20
> > > abi
> > > archdep
> > > atm1
> > > hcsecd
> > > ipfilter
> > > mdconfig
> > > mdconfig2
> > > pf
> > > pflog
> > > pfsync
> > > sdpd
> > > syscons
> > >=20
> > > They all do kldstat then kldload. Some of them do grep or egrep
> > > on kldstat output. Some of them don't forget to check status from
> > > kldload and emit a error message on failure. Besides, there are
> > > scripts that forget to do kldstat in the first place, they just do
> > > kldload. Now all this ado can become just a call to my function.
> >=20
> > Removing all scripts using 'kldstat -q -m foo', we have:
>=20
> Why should we omit them from our consideration? The scripts now
> doing 'kldstat -q -m foo' can benefit from my function, too, because
> they should do error checking and reporting, the error-handling
> code being duplicated inconsistently: some of them warn on error,
> others print a message on success and so on. The long line (or its
> multi-line equivalent):
>=20
> kldstat -q -m foo || kldload foo >/dev/null 2>&1 || echo "Damn! Failed t=
o kldload foo :-("
>=20
> becomes just:
>=20
> load_kld foo
>=20
> Note that egrep is not used to process such a request in load_kld.
>=20
> > $ grep kldstat * | grep -v -- "-q -m" | cut -d':' -f1 | sort -u
> > abi
> > archdep
> > atm1
> > ipfilter
> > syscons
> >=20
> > archdep, atm1 and ipfilter could use this 'kldstat -q -m foo' method, s=
o
> > that's only two candidates. Most scripts calling kldload without kldsta=
t
> > first could use this method as well.
> >=20
> > But ok, those are definitely scripts I do not read very often.
> >
> > > > You won't gain anything using grep instead of egrep since they're b=
oth
> > > > in /usr/bin.
> > >=20
> > > Have I ever tried to?
> >=20
> > I guessed that's what you meant saying "grep is used with -e only, one
> > can avoid using it if egrep isn't available yet." What are you planning
> > to do then?
>=20
> I meant -e to my function, not to grep. That is, if one doesn't
> specify -e to load_kld, it won't try to invoke egrep at all. (FWIW,
> grep and egrep are links to the same binary. And grep -e is not
> the same as grep -E ;-)
>=20
> Without a "-e regex" option, load_kld will just do kldstat. Therefore,
> load_kld won't break scripts that aren't broken yet by using grep
> or egrep too early in the boot sequence.
Makes sense.
> BTW, grep can be emulated with /bin/expr if needed:
>=20
> _grep()
> {
> while read _line; do
> [ `expr "$_line" : ".*$1"` !=3D 0 ] && echo "$_line"
> done
> }
>=20
> Ditto for "grep -q".
I guess we can even just use shell pattern matching with 'case'.
--=20
Florent Thoumie
flz@FreeBSD.org
FreeBSD Committer
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