/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (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

 */

/*

 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include "lint.h"

#include <libc.h>

#include <fcntl.h>

#include <stdlib.h>

#include <unistd.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <sys/auxv.h>

#include <mtlib.h>

#include <thread.h>

#include <synch.h>

#include <atomic.h>

static mutex_t auxlock = DEFAULTMUTEX;

/*

 * Get auxiliary entry.

 * Returns pointer to entry, or 0 if entry does not exist.

 */

static auxv_t *

_getaux(int type)

{

	static auxv_t *auxb = NULL;

	static size_t nauxv = 0;

	ssize_t i;

	/*

	 * The first time through, read the initial aux vector that was

	 * passed to the process at exec(2).  Only do this once.

	 */

	if (auxb == NULL) {

		lmutex_lock(&auxlock);

		if (auxb == NULL) {

			struct stat statb;

			auxv_t *buf = NULL;

			int fd;

			if ((fd = open("/proc/self/auxv", O_RDONLY)) != -1 &&

			    fstat(fd, &statb) != -1)

				buf = libc_malloc(

				    statb.st_size + sizeof (auxv_t));

			if (buf != NULL) {

				i = read(fd, buf, statb.st_size);

				if (i != -1) {

					nauxv = i / sizeof (auxv_t);

					buf[nauxv].a_type = AT_NULL;

				} else {

					libc_free(buf);

					buf = NULL;

				}

			}

			if (fd != -1)

				(void) close(fd);

			membar_producer();

			auxb = buf;

		}

		lmutex_unlock(&auxlock);

	}

	membar_consumer();

	/*

	 * Scan the auxiliary entries looking for the required type.

	 */

	for (i = 0; i < nauxv; i++)

		if (auxb[i].a_type == type)

			return (&auxb[i]);

	/*

	 * No auxiliary array (static executable) or entry not found.

	 */

	return ((auxv_t *)0);

}

/*

 * These two routines are utilities exported to the rest of libc.

 */

long

___getauxval(int type)

{

	auxv_t *auxp;

	if ((auxp = _getaux(type)) != (auxv_t *)0)

		return (auxp->a_un.a_val);

	return (0);

}

void *

___getauxptr(int type)

{

	auxv_t *auxp;

	if ((auxp = _getaux(type)) != (auxv_t *)0)

		return (auxp->a_un.a_ptr);

	return (0);

}