Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm 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 Date: Tue, 11 Jan 2005 13:20:15 +0100 From: Corinna Vinschen To: cygwin@cygwin.com Subject: Re: execv and then socket: "operation not permitted" Message-ID: <20050111122015.GP23702@cygbert.vinschen.de> Reply-To: cygwin@cygwin.com Mail-Followup-To: cygwin@cygwin.com References: <20050109121953.GA5017@cygbert.vinschen.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2i On Jan 10 22:54, Eric Hoffman wrote: > On Sun, 9 Jan 2005 13:19:53 +0100, Corinna Vinschen wrote: > > Could you please prepare a short testcase, only containing the > > necessary lines to reproduce the problem? > > I have attached 2 files to reproduce the problem. It is linked to the > putenv() call and the env variable then being reset. Thanks for the testcase. > strcpy(fooflags,"fooflags=1"); > putenv(fooflags); > *fooflags = '\0'; /* remove from environment after all */ Oh well. What happens is that your empty string results in a fatal change in the Win32 environment propagated to the child application. A Win32 environment consists of a long string of \0-terminated strings. The end of the environment is indicated by a second \0, like this: "a=b\0c=d\0e=f\0\0" By setting one of the strings to \0 as you do, the propagated environment contains an early \0: "\0\0c=d\0e=f\0\0" The result is that the propagated Win32 environment is actually empty. Missing $PATH and $SYSTEMROOT are fatal and explain the socket problem you encountered. This is a bug in Cygwin insofar as Cygwin should not allow to propagate empty strings to the child application. I'm preparing a patch right now. In the meantime, don't do that. Replace *fooflags = '\0'; by unsetenv ("fooflags"); NB: The use of setenv/unsetenv is preferrable over using putenv anyway. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader mailto:cygwin@cygwin.com Red Hat, Inc. -- 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/