X-Recipient: archive-cygwin@delorie.com X-Spam-Check-By: sourceware.org Date: Sat, 22 Mar 2008 22:08:59 -0400 From: Christopher Faylor To: cygwin@cygwin.com Subject: Re: Usage of LD_PRELOAD Message-ID: <20080323020858.GA31503@ednor.casa.cgf.cx> Reply-To: cygwin@cygwin.com Mail-Followup-To: cygwin@cygwin.com References: 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 Wed, Mar 05, 2008 at 08:47:13AM +0000, Matthieu CASTET wrote: >Hi, > >I am trying to use LD_PRELOAD on cygwin, but I don't manage to make work. >I suppose I do something wrong when creating my library. > >What I do is : > >$ cat << EOF > /tmp/toto1.c >#include >int chmod(const char *path, mode_t mode) >{ > printf("123\n"); > return -1; >} >EOF > >$ module=toto1 gcc -shared -o /tmp/cyg${module}.dll >-Wl,--out-implib=lib${module}.dll.a -Wl,--export-all-symbols >-Wl,--enable-auto-import -Wl,--whole-archive /tmp/toto1.c -Wl,--no-whole-archive > >$ export LD_PRELOAD=/tmp/cygtoto1.dll > >$ chmod a+w /tmp/toto1.c <-- chmod isn't redirected here (but the >library is loaded). > > >Any idea why it doesn't work ? Sorry for the delay. I had to research this to refresh my memory. Cygwin requires that you hook the symbol using something like the following: cygwin_internal (CW_HOOK, symname, sym); Where "symname" is the name of the symbol and sym is the address of the hook function. cgf -- 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/