dtrace_anon.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * DTrace Anonymous Enabling Functions
 */
static void
dtrace_anon_init(void *dummy)
{
	dtrace_state_t *state = NULL;
	dtrace_enabling_t *enab;

	mutex_enter(&cpu_lock);
	mutex_enter(&dtrace_provider_lock);
	mutex_enter(&dtrace_lock);

	dtrace_anon_property();

	mutex_exit(&cpu_lock);

	/*
	 * If there are already providers, we must ask them to provide their
	 * probes, and then match any anonymous enabling against them.  Note
	 * that there should be no other retained enablings at this time:
	 * the only retained enablings at this time should be the anonymous
	 * enabling.
	 */
	if (dtrace_anon.dta_enabling != NULL) {
		ASSERT(dtrace_retained == dtrace_anon.dta_enabling);

		dtrace_enabling_provide(NULL);
		state = dtrace_anon.dta_state;

		/*
		 * We couldn't hold cpu_lock across the above call to
		 * dtrace_enabling_provide(), but we must hold it to actually
		 * enable the probes.  We have to drop all of our locks, pick
		 * up cpu_lock, and regain our locks before matching the
		 * retained anonymous enabling.
		 */
		mutex_exit(&dtrace_lock);
		mutex_exit(&dtrace_provider_lock);

		mutex_enter(&cpu_lock);
		mutex_enter(&dtrace_provider_lock);
		mutex_enter(&dtrace_lock);

		if ((enab = dtrace_anon.dta_enabling) != NULL)
			(void) dtrace_enabling_match(enab, NULL);

		mutex_exit(&cpu_lock);
	}

	mutex_exit(&dtrace_provider_lock);
	mutex_exit(&dtrace_lock);

	if (state != NULL) {
		/*
		 * If we created any anonymous state, set it going now.
		 */
		(void) dtrace_state_go(state, &dtrace_anon.dta_beganon);
	}
}