Re: Apache calls initialize module twice

[Bill Stoddard]

Nasko wrote:

   

Hello guys.
 
    I'm running Apache2 on WindowsXP as a service (path to executable = 
"c:\apache2\Apache.exe" -k runservice in my service configuration ) .
 
    I have also 
ap_hook_post_config  (initialize_module,  NULL,NULL,APR_HOOK_MIDDLE ) in 
my source code...
 
    The problem I have is that when run as a service initalize_module() 
is called twice.
    However when I debug in Visual C++ and call Apache2 with  -X , 
initalize_module() is called only once !!!!

    Any ideas how to avoid the second call to initalize_module when I 
run as a service ?
 
Thanks in advance,
Nasko
   
You can't avoid the second call but there are ways to gracefully handle 
it. Here is a snip of code from a module I developed a while back:

    /* Run post_config only on the second config pass */
    void *data;
    apr_pool_userdata_get(&data, userdata_key, s->process->pool);
    if (!data) {
        apr_pool_userdata_set((const void *)1, userdata_key,
                              apr_pool_cleanup_null, s->process->pool);
        return OK;
    }
#ifdef WIN32
    /* Do not run post_config in the Windows parent process
     * The envar AP_PARENT_PID is set in the env list (by mpm_winnt)
     * for the child process.
     * **WARNING**:
     * This check is not as robust as I would like because the name of 
this
     * envar is subject to change from release to release.
     */
    if (!getenv("AP_PARENT_PID")) {
        return OK;
    }
#endif

This code actually does two things:
1. only allows post_config to run on the -second- pass (you can easily 
tweak the code to make your hook run only on the first pass), and
2. only run post_config in the child process on Windows.

The second check is useful if your hook needs to allocate a lot of 
resources; any resources you allocate in the Windows parent process are 
probably not used or needed.

Bill