/*
 * wrap.c: a way to wrap another NSAPI program with a log
 *
 *
 * Rob Crittenden
 *
 * How to install this program:
 *
 *    Add the following lines to your obj.conf:
 *
 *    Init fn=load-modules shlib=<path to wrap.so> funcs=wrap_init
 *    Init fn=wrap_init function=<name of function to wrap>
 *
 */

#include "nsapi.h"

static CRITICAL wrap_lock;
static FuncPtr wrap_function;

int wentin, cameout;
char *function2wrap;

/* Forward declarations */
static int wrap(pblock *pb, Session *sn, Request *rq);

NSAPI_PUBLIC void clean_up(void *parameter);
/*
 * wrap_init()
 * 
 * Initialization function. *
 *
 */
NSAPI_PUBLIC int wrap_init(pblock *pb, Session *sn, Request *rq)
{
    function2wrap = pblock_findval("function", pb);

    wrap_lock = crit_init();
    daemon_atrestart(clean_up, NULL);

    wentin = 0;
    cameout = 0;

    ereport(LOG_INFORM, " replacing %s", function2wrap);

    wrap_function = func_replace(function2wrap, wrap);

    if (!wrap_function) {
        ereport(LOG_FAILURE, "wrap: failed to replace %s function", function2wrap);
        return REQ_ABORTED;
    }
    
    return REQ_PROCEED;
}


/* 
 * wrap()
 *
 * Print messages around the actual call, and return the value from the call
 *
 */
static int wrap(pblock *pb, Session *sn, Request *rq)
{
    int value;
    char *request;

    /* increment the counter within a thread-safe lock */
    crit_enter(wrap_lock);
    wentin++;
    crit_exit(wrap_lock);

    request = pblock_findval("clf-request", rq->reqpb);

    log_error(LOG_INFORM, "wrap", sn, rq, " %s entered %s", function2wrap, request);
    
    /* call the wrapped function */
    value = wrap_function(pb,sn,rq);

    /* increment the counter within a thread-safe lock */
    crit_enter(wrap_lock);
    cameout++;
    crit_exit(wrap_lock);

    log_error(LOG_INFORM, "wrap", sn, rq, "%s returned from %s, Entered %d times, Exited %d times", function2wrap, request, wentin, cameout);

    FREE(request);

    return(value);
}

/*
 * clean_up()
 *
 * this is run when the server is stopped
 *
 */
NSAPI_PUBLIC void clean_up(void* parameter)
{
    ereport(LOG_INFORM, "Process ending with %s entered %d times and exited %d times", function2wrap, wentin, cameout);

    FREE(function2wrap);
    FREE(wrap_lock);
}