From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1DYlCK-0005HW-C4 for user-mode-linux-devel@lists.sourceforge.net; Thu, 19 May 2005 06:36:24 -0700 Received: from smtp004.mail.ukl.yahoo.com ([217.12.11.35]) by sc8-sf-mx1.sourceforge.net with smtp (Exim 4.41) id 1DYlCH-0000H8-J1 for user-mode-linux-devel@lists.sourceforge.net; Thu, 19 May 2005 06:36:24 -0700 From: Blaisorblade Subject: Re: [uml-devel] [patch 1/1] uml: replace pause with sigsuspend References: <20050516180143.95BDB1993E0@zion.home.lan> <200505181718.18455.blaisorblade@yahoo.it> <428B9544.60902@fujitsu-siemens.com> In-Reply-To: <428B9544.60902@fujitsu-siemens.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200505191535.51279.blaisorblade@yahoo.it> Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Thu, 19 May 2005 15:35:50 +0200 To: user-mode-linux-devel@lists.sourceforge.net Cc: Bodo Stroesser , jdike@addtoit.com On Wednesday 18 May 2005 21:19, Bodo Stroesser wrote: > Blaisorblade wrote: > > On Tuesday 17 May 2005 12:14, Bodo Stroesser wrote: > >>I didn't have the time to test the patch, but I guess, it won't work. > >> > >>Maybe, the man pages for sigsuspend are somewhat missleading, saying: > >> > >> The sigsuspend call temporarily replaces the signal mask for > >> the process with that given by mask and then suspends the > >> process until a signal is received. > > > > In fact, I assumed that was correct... > > > >>Reading the code of sys_sigsuspend() in arch/i386/kernel/signal.c, > >>you'll find that it will return to user only, if do_signal() returns 1. > >>This will happen, if there was a signal to deliver. Ignored signals > >>will not be delivered, so sys_sigsupend will not return on SIGWINCH, > >>if SIGWINCH handler is set to SIG_IGN. > > > > Doh! You're right, actually. > > > >>So, for UML's winch_handler, there is no difference between pause() > >>and sigsuspend(), because sigsuspend's feature of accepting a sigmask > >>for use while waiting, in fact isn't needed here as the same mask is > >>set already before with sigprocmask(). > > > > Ok, seems like I'll drop this patch. Thanks for the review. > Maybe, we really should use sigsuspend() instead of pause(), but the > reason for this isn't to remove the winch_handler. > The current loop in winch_thread() might miss a SIGWINCH, if a SIGWINCH > comes in while winch_thread() isn't waiting in wait(). wait()? You mean the pause()/sigsuspend() call, right? Then I probably agree. > So I think, winch_thread() should block all signals including SIGWINCH. > In its loop it should call sigsuspend() with a mask as argument, that > unblocks SIGWINCH while sigsuspend() waits. > > I've attached a patch (tested a bit only). > > Bodo -- Paolo Giarrusso, aka Blaisorblade Skype user "PaoloGiarrusso" Linux registered user n. 292729 http://www.user-mode-linux.org/~blaisorblade ------------------------------------------------------- This SF.Net email is sponsored by Oracle Space Sweepstakes Want to be the first software developer in space? Enter now for the Oracle Space Sweepstakes! http://ads.osdn.com/?ad_id=7412&alloc_id=16344&op=click _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel