Date: Tue, 10 Mar 2009 13:17:12 +0200 From: Kostik Belousov <kostikbel@gmail.com> To: Robert Watson <rwatson@freebsd.org> Cc: Timothy Redaelli <timothy@redaelli.eu>, freebsd-hackers@freebsd.org Subject: Re: lockf: Invalid argument on pipe Message-ID: <20090310111712.GA41617@deviant.kiev.zoral.com.ua> In-Reply-To: <alpine.BSF.2.00.0903092335060.92752@fledge.watson.org> References: <ac9bf7980903091448w1c3b8405la2a0084e5a947a05@mail.gmail.com> <alpine.BSF.2.00.0903092335060.92752@fledge.watson.org>
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On Mon, Mar 09, 2009 at 11:35:58PM +0000, Robert Watson wrote:
>=20
> On Mon, 9 Mar 2009, Timothy Redaelli wrote:
>=20
> >Why can't I do a lockf on a file descriptor that does not point a real=
=20
> >file (such as stderr, stdout, or a character device)?
> >
> >Since it works under NetBSD, Linux, Solaris. For portability between=20
> >systems I hope I can do it under FreeBSD.
> >
> >The following code is simple, but It reproduce the problem. Under=20
> >non-FreeBSD systems, It will block before the puts. Instead under FreeBS=
D=20
> >the lockf calls return error and, so, the lock does not works.
>=20
> Could you file a PR for this, with pretty much this e-mail and sample cod=
e=20
> included? There's no real reason not for it to work other than that it i=
s=20
> likely not implemented for devfs; that should be easy to fix it but openi=
ng=20
> a PR will help us keep track of the fact that it wants to be fixed.
>=20
> thanks,
>=20
> Robert N M Watson
> Computer Laboratory
> University of Cambridge
>=20
> >
> >Any suggest?
> >
> ><snip>
> >#include <stdio.h>
> >#include <unistd.h>
> >#include <stdlib.h>
> >#include <string.h>
> >
> >int main(int argc, char *argv[]) {
> > char tmp[256];
> >
> > if (lockf(2, F_LOCK, 0) =3D=3D -1)
> > perror("lock");
> > snprintf (tmp, 256, "%s XXX", argv[0]);
> > if (!argv[1] || strcmp(argv[1], "XXX"))
> > system(tmp);
> > puts("You should see it only after ctrl+c");
> > return EXIT_SUCCESS;
> >}
> ><end snip>
It is explicitely disabled in devfs code. The following patch works
for me.
diff --git a/sys/fs/devfs/devfs_vnops.c b/sys/fs/devfs/devfs_vnops.c
index 1087452..b890da7 100644
--- a/sys/fs/devfs/devfs_vnops.c
+++ b/sys/fs/devfs/devfs_vnops.c
@@ -452,14 +452,6 @@ devfs_access(struct vop_access_args *ap)
=20
/* ARGSUSED */
static int
-devfs_advlock(struct vop_advlock_args *ap)
-{
-
- return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL);
-}
-
-/* ARGSUSED */
-static int
devfs_close(struct vop_close_args *ap)
{
struct vnode *vp =3D ap->a_vp, *oldvp;
@@ -1552,7 +1544,6 @@ static struct vop_vector devfs_specops =3D {
.vop_default =3D &default_vnodeops,
=20
.vop_access =3D devfs_access,
- .vop_advlock =3D devfs_advlock,
.vop_bmap =3D VOP_PANIC,
.vop_close =3D devfs_close,
.vop_create =3D VOP_PANIC,
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