From owner-freebsd-hackers@FreeBSD.ORG Thu Oct 8 10:02:13 2009 Return-Path: Delivered-To: hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id F0790106568B; Thu, 8 Oct 2009 10:02:13 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (skuns.zoral.com.ua [91.193.166.194]) by mx1.freebsd.org (Postfix) with ESMTP id 46D858FC1A; Thu, 8 Oct 2009 10:02:13 +0000 (UTC) Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id n98A295h042067 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 8 Oct 2009 13:02:09 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.3/8.14.3) with ESMTP id n98A29rT032312; Thu, 8 Oct 2009 13:02:09 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.3/8.14.3/Submit) id n98A29iC032311; Thu, 8 Oct 2009 13:02:09 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Thu, 8 Oct 2009 13:02:09 +0300 From: Kostik Belousov To: Stephen Hocking Message-ID: <20091008100209.GG2259@deviant.kiev.zoral.com.ua> References: <6300771b0910071753s6580c099i8c348824a6fe1a72@mail.gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="2e7L0d/MUbHEOUYO" Content-Disposition: inline In-Reply-To: <6300771b0910071753s6580c099i8c348824a6fe1a72@mail.gmail.com> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-4.4 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: ports@freebsd.org, hackers@freebsd.org Subject: Re: sigwait - differences between Linux & FreeBSD X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 08 Oct 2009 10:02:14 -0000 --2e7L0d/MUbHEOUYO Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Oct 08, 2009 at 11:53:21AM +1100, Stephen Hocking wrote: > Hi all, >=20 > In my efforts to make the xrdp port more robust under FreeBSD, I have > discovered that sigwait (kind of an analogue to select(2), but for > signals rather than I/O) re-enables ignored signals in its list under > Linux, but not FreeBSD. The sesman daemon uses SIGCHLD to clean up > after a session has exited. Under Linux this works OK, under FreeSBD > it doesn't. I have worked around it in a very hackish manner (define a > dummy signal handler and enable it using signal, which means that the > sigwait call can then be unblocked by it), but am wondering if anyone > else has run across the same problem, and if so, if they fixed it in > an elegant manner. Also, does anyone know the correct semantics of > sigwait under this situation? ports@ is the wrong list to discuss the issue in the base system. Solaris 10 sigwait(2) manpage says the following: If sigwait() is called on an ignored signal, then the occurrence of the signal will be ignored, unless sigaction() changes the disposition. We have the same behaviour as Solaris, ingored signals are not queued or recorded regardeless of the presence of sigwaiting thread. --2e7L0d/MUbHEOUYO Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkrNuKEACgkQC3+MBN1Mb4gQJwCgvgLOveItqyok4c9LdZ3RRpfB s0QAoNSiwghMw1i+hPC671bwMtptj0K0 =j41b -----END PGP SIGNATURE----- --2e7L0d/MUbHEOUYO--