From mboxrd@z Thu Jan  1 00:00:00 1970
From: Scott James Remnant <scott@canonical.com>
Date: Wed, 22 Oct 2008 16:22:30 +0000
Subject: Re: Report: Threaded udevd
Message-Id: <1224692550.7588.11.camel@quest>
MIME-Version: 1
Content-Type: multipart/mixed; boundary="=-oJEOUIPsa50iLU+aVYjz"
List-Id: <linux-hotplug.vger.kernel.org>
References: <48FF3458.6030909@tuffmail.co.uk>
In-Reply-To: <48FF3458.6030909@tuffmail.co.uk>
To: linux-hotplug@vger.kernel.org


--=-oJEOUIPsa50iLU+aVYjz
Content-Type: text/plain
Content-Transfer-Encoding: quoted-printable

On Wed, 2008-10-22 at 17:12 +0100, Alan Jenkins wrote:

> > The pipe2() syscall allows you to specify flags for the returned file
> > descriptors:
> >
> > 	pipe2 (&fds, O_CLOEXEC)
> >  =20
>=20
> Ah!  I see how it's supposed to be used now.
>=20
> pipe2 (&fds, O_CLOEXEC)
> if (fork() =3D=3D 0) {
>    dup2(&fds[WRITE_END], STDOUT_FILENO);
>    /* insert call to fcntl to remove O_CLOEXEC */
>    exec(program_name);
>=20
You don't need the call to fcntl.  From the dup2(2) manpage:

       The two descriptors do not share file descriptor flags  (the  close-=
on-
       exec  flag).  The close-on-exec flag (FD_CLOEXEC; see fcntl(2)) for =
the
       duplicate descriptor is off.

So after you dup2() the writing end to standard output, standard output
will not be closed on exec.

Scott
--=20
Scott James Remnant
scott@canonical.com

--=-oJEOUIPsa50iLU+aVYjz
Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: This is a digitally signed message part

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)

iEYEABECAAYFAkj/U0YACgkQSnQiFMl4yK7rbwCgmcXYrgk1jp6jkqL0sHpw5yZQ
bKkAnif9rp/c/rpL63+V6nOs7oTWEAu9
=8sWe
-----END PGP SIGNATURE-----

--=-oJEOUIPsa50iLU+aVYjz--