Mailing-List: contact modules-dev-help@httpd.apache.org; run by ezmlm
Precedence: bulk
Reply-To: modules-dev@httpd.apache.org
Message-ID: <1452147362.3892.41.camel@mimir.webthing.com>
Subject: Re: dlopen a .so from a module
From: Nick Kew <niq@apache.org>
To: modules-dev@httpd.apache.org
Date: Thu, 07 Jan 2016 06:16:02 +0000
In-Reply-To: 
 <CAK_-e8sovT03CWajuvyFbcb-V=NeiNrYhbP-QjBvRe+KJhk1Gw@mail.gmail.com>
References: 
	<CAK_-e8sovT03CWajuvyFbcb-V=NeiNrYhbP-QjBvRe+KJhk1Gw@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit

On Wed, 2016-01-06 at 21:30 -0600, Mark Taylor wrote:
> Hi all,
> 
> I have a module that dlopens a .so, gets a handle to a function in the so
> and calls it. The function in the so calls ap_rputs.  dlopen returns the
> error 'undefined symbol ap_rputs'.

Looks like you're falling victim to
http://svn.apache.org/viewvc?view=revision&revision=1131465
which also points to ap_rwrite as an obvious workaround.
That would've caught me out, too!

> nm tells me ap_rputs is defined in httpd, and via some dark magic, httpd
> symbols are available to modules compiles the apxs -c.  But when I compile
> my .so to be loaded into my module, the symbols from httpd aren't
> available. My hypothesis, now disproven, was that symbols available to my
> module would be visible to my .so.

Does your module use dlopen or apr_dso_load/family?

Is your module loading/unloading anything per-request or
per-connection?  If not, why not use LoadFile in httpd.conf
to load the .so?

-- 
Nick Kew