How to programmatically obtain the apache2.conf file directory or path inside a module?

I have a module that is hooking ap_hook_child_init. From that callback I would like to obtain the directory where the main apache2.conf file lives (or the full path to that file, I'll parse out the directory).

That callback takes a server_rec struct and a apr_poot_t struct. server_rec has a path member, but it is null.

You can't find this directly, and of course "apache2.conf" may not exist at all. This file is a debian-ism.

However, one option you have is to:

• Find a directive commonly present in this config file or whatever substitutes you'd like treat the same
• Add the directive to your module with the same definition as the core module
• When you get control in the callback for handling the directive, look at cmd->directive->fname and save the path away in a global variable.

Multiple modules can share the same directive name and they all get called to process it.