Function sysctl_handle_opaque

freebsd/kern/kern_sysctl.c:1813–1843

 */

int
sysctl_handle_opaque(SYSCTL_HANDLER_ARGS)
{
	int error, tries;
	u_int generation;
	struct sysctl_req req2;

	/*
	 * Attempt to get a coherent snapshot, by using the thread
	 * pre-emption counter updated from within mi_switch() to
	 * determine if we were pre-empted during a bcopy() or
	 * copyout(). Make 3 attempts at doing this before giving up.
	 * If we encounter an error, stop immediately.
	 */
	tries = 0;
	req2 = *req;
retry:
	generation = curthread->td_generation;
	error = SYSCTL_OUT(req, arg1, arg2);
	if (error)
		return (error);
	tries++;
	if (generation != curthread->td_generation && tries < 3) {
		*req = req2;
		goto retry;
	}

	error = SYSCTL_IN(req, arg1, arg2);

	return (error);
}

/*
 * Based on on sysctl_handle_int() convert microseconds to a sbintime.