/*

 * 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.

 */

/*	Copyright (c) 1988 AT&T	*/

/*	  All Rights Reserved  	*/

/*

 * University Copyright- Copyright (c) 1982, 1986, 1988

 * The Regents of the University of California

 * All Rights Reserved

 *

 * University Acknowledgment- Portions of this document are derived from

 * software developed by the University of California, Berkeley, and its

 * contributors.

 */

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

/*

 * readdir -- C library extension routine

 */

#include	<sys/feature_tests.h>

#if !defined(_LP64)

#pragma weak _readdir64 = readdir64

#endif

#pragma weak _readdir = readdir

#include "lint.h"

#include <dirent.h>

#include <limits.h>

#include <errno.h>

#include "libc.h"

#ifdef _LP64

dirent_t *

readdir(DIR *dirp)

{

	dirent_t *dp;	/* -> directory data */

	int saveloc = 0;

	if (dirp->dd_size != 0) {

		dp = (dirent_t *)(uintptr_t)&dirp->dd_buf[dirp->dd_loc];

		saveloc = dirp->dd_loc;		/* save for possible EOF */

		dirp->dd_loc += (int)dp->d_reclen;

	}

	if (dirp->dd_loc >= dirp->dd_size)

		dirp->dd_loc = dirp->dd_size = 0;

	if (dirp->dd_size == 0 && 	/* refill buffer */

	    (dirp->dd_size = getdents(dirp->dd_fd,

	    (dirent_t *)(uintptr_t)dirp->dd_buf, DIRBUF)) <= 0) {

		if (dirp->dd_size == 0)		/* This means EOF */

			dirp->dd_loc = saveloc;	/* so save for telldir */

		return (NULL);		/* error or EOF */

	}

	return ((dirent_t *)(uintptr_t)&dirp->dd_buf[dirp->dd_loc]);

}

#else	/* _LP64 */

/*

 * Welcome to the complicated world of large files on a small system.

 */

dirent64_t *

readdir64(DIR *dirp)

{

	dirent64_t *dp64;	/* -> directory data */

	int saveloc = 0;

	if (dirp->dd_size != 0) {

		dp64 = (dirent64_t *)(uintptr_t)&dirp->dd_buf[dirp->dd_loc];

		/* was converted by readdir and needs to be reversed */

		if (dp64->d_ino == (ino64_t)-1) {

			dirent_t *dp32;

			dp32 = (dirent_t *)(&dp64->d_off);

			dp64->d_ino = (ino64_t)dp32->d_ino;

			dp64->d_off = (off64_t)dp32->d_off;

			dp64->d_reclen = (unsigned short)(dp32->d_reclen +

			    ((char *)&dp64->d_off - (char *)dp64));

		}

		saveloc = dirp->dd_loc;		/* save for possible EOF */

		dirp->dd_loc += (int)dp64->d_reclen;

	}

	if (dirp->dd_loc >= dirp->dd_size)

		dirp->dd_loc = dirp->dd_size = 0;

	if (dirp->dd_size == 0 && 	/* refill buffer */

	    (dirp->dd_size = getdents64(dirp->dd_fd,

	    (dirent64_t *)(uintptr_t)dirp->dd_buf, DIRBUF)) <= 0) {

		if (dirp->dd_size == 0)		/* This means EOF */

			dirp->dd_loc = saveloc;	/* so save for telldir */

		return (NULL);		/* error or EOF */

	}

	dp64 = (dirent64_t *)(uintptr_t)&dirp->dd_buf[dirp->dd_loc];

	return (dp64);

}

/*

 * readdir now does translation of dirent64 entries into dirent entries.

 * We rely on the fact that dirents are smaller than dirent64s and we

 * reuse the space accordingly.

 */

dirent_t *

readdir(DIR *dirp)

{

	dirent64_t *dp64;	/* -> directory data */

	dirent_t *dp32;		/* -> directory data */

	if ((dp64 = readdir64(dirp)) == NULL)

		return (NULL);

	/*

	 * Make sure that the offset fits in 32 bits.

	 */

	if (((off_t)dp64->d_off != dp64->d_off &&

	    (uint64_t)dp64->d_off > (uint64_t)UINT32_MAX) ||

	    dp64->d_ino > SIZE_MAX) {

		errno = EOVERFLOW;

		return (NULL);

	}

	dp32 = (dirent_t *)(&dp64->d_off);

	dp32->d_off = (off_t)dp64->d_off;

	dp32->d_ino = (ino_t)dp64->d_ino;

	dp32->d_reclen = (unsigned short)(dp64->d_reclen -

	    ((char *)&dp64->d_off - (char *)dp64));

	dp64->d_ino = (ino64_t)-1;	/* flag as converted for readdir64 */

	/* d_name d_reclen should not move */

	return (dp32);

}

#endif	/* _LP64 */