DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:date:from:to:subject:message-id:reply-to
	:references:mime-version:content-type:in-reply-to; q=dns; s=
	default; b=bHVUyZzPVsJ8VIi2pe6i+Qg0icqlqWQg4soXhAsFV1M3upaXDZsHV
	Lr9+HzzlvooOJF6HBlr21zwXHM5lK9ZkXsUnKYejZMd2hrCLjX0+KhVZ++zI+yLA
	wKA+Hps7BBgqpCo5w//XxwYdI+OpQ8KZVa6yUWWE/GjJ6pBGzPsimM=
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Date: Wed, 15 Jan 2014 17:50:31 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: fork() + file descriptor bug in 1.7.27(0.271/5/3) 2013-12-09 11:54
Message-ID: <20140115165031.GA30785@calimero.vinschen.de>
Reply-To: cygwin AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
References: <831845 DOT 98759 DOT bm AT smtp116 DOT sbc DOT mail DOT ne1 DOT yahoo DOT com> <52D6B9DC DOT 50903 AT coverity DOT com>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha1;	protocol="application/pgp-signature"; boundary="6c2NcOVqGQ03X4Wi"
Content-Disposition: inline
In-Reply-To: <52D6B9DC.50903@coverity.com>
User-Agent: Mutt/1.5.21 (2010-09-15)

--6c2NcOVqGQ03X4Wi
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Jan 15 11:39, Tom Honermann wrote:
> On 01/13/2014 11:06 AM, tednolan AT bellsouth DOT net wrote:
> ...
> >		switch (fork()) {
> >=09=09=09
> >			/* error */
> >			case -1:
> ...
> >			/* child */
> >			case 0:
> >				fprintf(stderr, "child\n"); fflush(stderr);
> >				exit(0);
> >				break;
>=20
> The above code is incorrect.  It is always wrong to call exit() from
> a forked process that has not yet called one of the exec() family of
> functions.  _exit() should be called instead.  Best case, calling
> exit() will result in double flushing of any stream buffers held by
> the parent at the time fork() is called (since the buffers will
> (eventually) be flushed by the parent as well as the child (unless
> at least one of the processes aborts or exits with _exit()).

Still, SUSv4 says:

  The exit() function shall then flush all open streams with unwritten
  buffered data and close all open streams. Finally, the process shall
  be terminated [...]
=20
Note that exit only flushes streams with *unwritten* data, but not
streams with *unread* data.  So this testcase is still valid and
should work.


Corinna

--=20
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

--6c2NcOVqGQ03X4Wi
Content-Type: application/pgp-signature

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1

iQIcBAEBAgAGBQJS1rxXAAoJEPU2Bp2uRE+gwdgP/1rYabBm/YAabP+DBsPHljMr
xyPUlBwmMsw2sfC04QWUHgy54/ZiMrhkICa71URANWx6G42bEBUnGghk/pwaUUbM
/YioKg/Yn9A1yUQfLw3SdBZB7DO8Gzld9C5hlcYDGHxwU88WugxhO10S4t4ZGq2X
KSRZOjLRBlHI2elVbD1U4SzH1uqnNgUQnvWbLYhry8vjidsaxcNQNnBy8LirLjYs
36GnSdfIKZqQdcZmcvIbSKYn9wcO/iwgqYDUpzcv8KA54uC1nA7GZ7qtabylStSN
7/yO83V+sy37Ck1fKkzyLOtPdJgRD/xHg3hG00VSAJ/Ao0gSCizBHfplGww8I40e
sM2NRKnjcRx6zcZpdU/y5omsmxOqDjn6gfR7auCGwLDhdQWYuk1cVBa5ZAsibGOh
3LwDTUGVveDOuNABRhrKDJX2dm3HuWTXKu9aWUiEN9dR0s16lIkuQwUvRNZlJUWX
VTfDywujeDR4frMaAP0vYY70qFghCj8bx3LFzrGWed/2mES2jgkCoFZF1I0hg2DP
c/paZQ+rknVkQr+axMhVawdz+06sWx/woTbqkvNuu0BZywebPiBsbS25Auox5Jx1
t45mU0lsGp6iFlsPsFYukUCHiymSFDjAyopaw7rxQL6csfWnSe7sJKKjtrQbQRaR
3L496GEDAzrJ/HhIgX+/
=6J3O
-----END PGP SIGNATURE-----

--6c2NcOVqGQ03X4Wi--