port/gen/readdir_r.c

/*
 * 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   */

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

/*
 * 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 */