/*
 * 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   */

/*
 * readdir_r -- C library extension routine
 */

#include        <sys/feature_tests.h>

#if !defined(_LP64)
#pragma weak _readdir64_r = readdir64_r
#endif

#include "lint.h"
#include "libc.h"
#include <mtlib.h>
#include <unistd.h>
#include <dirent.h>
#include <string.h>
#include <limits.h>
#include <errno.h>

#ifdef _LP64

/*
 * POSIX.1c standard version of the thread function readdir_r.
 */

int
readdir_r(DIR *dirp, dirent_t *entry, dirent_t **result)
{
        private_DIR *pdirp = (private_DIR *)dirp;
        dirent_t *dp;           /* -> directory data */
        int saveloc = 0;

        lmutex_lock(&pdirp->dd_lock);
        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 */
                        lmutex_unlock(&pdirp->dd_lock);
                        *result = NULL;
                        return (0);
                }
                lmutex_unlock(&pdirp->dd_lock);
                *result = NULL;
                return (errno);         /* error */
        }

        dp = (dirent_t *)(uintptr_t)&dirp->dd_buf[dirp->dd_loc];
        (void) memcpy(entry, dp, (size_t)dp->d_reclen);
        lmutex_unlock(&pdirp->dd_lock);
        *result = entry;
        return (0);
}

#else   /* _LP64 */

/*
 * POSIX.1c standard version of the thr function readdir_r.
 * Large file version.
 */

int
readdir64_r(DIR *dirp, dirent64_t *entry, dirent64_t **result)
{
        private_DIR *pdirp = (private_DIR *)(uintptr_t)dirp;
        dirent64_t *dp64;       /* -> directory data */
        int saveloc = 0;

        lmutex_lock(&pdirp->dd_lock);
        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; /* -> 32 bit directory data */

                        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 */
                        lmutex_unlock(&pdirp->dd_lock);
                        *result = NULL;
                        return (0);
                }
                lmutex_unlock(&pdirp->dd_lock);
                *result = NULL;
                return (errno);         /* error */
        }

        dp64 = (dirent64_t *)(uintptr_t)&dirp->dd_buf[dirp->dd_loc];
        (void) memcpy(entry, dp64, (size_t)dp64->d_reclen);
        *result = entry;
        lmutex_unlock(&pdirp->dd_lock);
        return (0);
}

/*
 * POSIX.1c standard version of the function readdir_r.
 * User gets it via static readdir_r from header file.
 */

int
__posix_readdir_r(DIR *dirp, dirent_t *entry, dirent_t **result)
{
        int error;
        dirent64_t *dp64;
        struct {
                dirent64_t dirent64;
                char chars[MAXNAMLEN];
        } buf;

        error = readdir64_r(dirp, (dirent64_t *)&buf, &dp64);
        if (error != 0 || dp64 == NULL) {
                *result = NULL;
                return (error);
        }

        if (dp64->d_ino > SIZE_MAX ||
            (uint64_t)dp64->d_off > (uint64_t)UINT32_MAX) {
                *result = NULL;
                return (EOVERFLOW);
        }

        entry->d_ino = (ino_t)dp64->d_ino;
        entry->d_off = (off_t)dp64->d_off;
        entry->d_reclen = (unsigned short)((((char *)entry->d_name -
            (char *)entry) + strlen(dp64->d_name) + 1 + 3) & ~3);
        (void) strcpy(entry->d_name, dp64->d_name);
        *result = entry;
        return (0);
}

/*
 * POSIX.1c Draft-6 version of the function readdir_r.
 * It was implemented by Solaris 2.3.
 */

dirent_t *
readdir_r(DIR *dirp, dirent_t *entry)
{
        int error;
        dirent_t *result;

        if ((error = __posix_readdir_r(dirp, entry, &result)) != 0)
                errno = error;
        return (result);
}

#endif  /* _LP64 */