X-Recipient: archive-cygwin@delorie.com X-Spam-Check-By: sourceware.org Date: Wed, 19 Nov 2008 15:02:50 +0100 From: Corinna Vinschen To: cygwin@cygwin.com Subject: Re: rsync 3.0.4 over ssh hanging on cygwin 1.7 Message-ID: <20081119140250.GF9927@calimero.vinschen.de> Reply-To: cygwin@cygwin.com Mail-Followup-To: cygwin@cygwin.com References: <1227077428.12724.ezmlm@cygwin.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.16 (2007-06-09) Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com On Nov 19 07:24, Brett Serkez wrote: > On Wed, Nov 19, 2008 at 6:54 AM, Fred Kemp wrote: > > In the meantime, if anyone has any ideas as to where the problem lies, I > > would be willing to spend some time investigating it further. It does seem > > to be a longstanding issue, with posts as far back as 2002 and as recent as > > last month on the subject. > > I spent considerable time on this and reported were the problem is > occurring to no avail, don't waste your time. In a nutshell the issue > is with Cygwin's bi-directional pipe emulation, this is a fundamental Pipes are uni-directional. > feature of all UNIXies. Secure Shell "forks and execs" rsync, > connecting standard out and in so that data flows over the internet > to/from SSH and then locally to/from rsync. The problem is that > eventually a "signal" is missed and SSH and rsync deadlock, the local > pipe emulation is imperfect, and the rsync protocol has no provision > to recover from this dead lock. > > A fix would require a change to this fundamental feature of Cygwin, it > is not clear to me that Windows has the necessary functionality to > properly implement, such a fix would require extensive retesting. Efforts have been made to rectify this problem (most notably by Bob Byrnes and cgf) but the right fix/hack/workaround hasn't been found yet. There's always a border situation in which the the NT kernel seems to refuse to give the required information back to the application. Patches are *extremly* thoughtfully considered in this case... Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/