libelf/common/newdata.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"

#include "libelf.h"
#include "decl.h"
#include "msg.h"


Elf_Data *
elf_newdata(Elf_Scn * s)
{
    Dnode *     d;
    Elf_Data *  rc;
    Elf *       elf;
    unsigned    work;

    if (s == 0)
        return (0);
    elf = s->s_elf;
    READLOCKS(elf, s)
    if (s->s_index == SHN_UNDEF) {
        _elf_seterr(EREQ_SCNNULL, 0);
        READUNLOCKS(elf, s)
        return (0);
    }

    if ((s->s_myflags & SF_READY) == 0) {
        UPGRADELOCKS(elf, s)
        /*
         * re-confirm that another 'thread' hasn't come along
         * and cooked this section while the locks were
         * obtained.
         */
        if ((s->s_myflags & SF_READY) == 0)
            (void) _elf_cookscn(s);
        DOWNGRADELOCKS(elf, s)
    }

    /*
     * If this is the first new node, use the one allocated
     * in the scn itself.  Update data buffer in both cases.
     */
    ELFACCESSDATA(work, _elf_work)
    if (s->s_hdnode == 0) {
        s->s_dnode.db_uflags |= ELF_F_DIRTY;
        s->s_dnode.db_myflags |= DBF_READY;
        s->s_hdnode = &s->s_dnode;
        s->s_tlnode = &s->s_dnode;
        s->s_dnode.db_scn = s;
        s->s_dnode.db_data.d_version = work;
        rc = &s->s_dnode.db_data;
        READUNLOCKS(elf, s)
        return (rc);
    }
    if ((d = _elf_dnode()) == 0) {
        READUNLOCKS(elf, s)
        return (0);
    }
    NOTE(NOW_INVISIBLE_TO_OTHER_THREADS(*d))
    d->db_data.d_version = work;
    d->db_scn = s;
    d->db_uflags |= ELF_F_DIRTY;
    d->db_myflags |= DBF_READY;
    s->s_tlnode->db_next = d;
    s->s_tlnode = d;
    rc = &d->db_data;
    NOTE(NOW_VISIBLE_TO_OTHER_THREADS(*d))
    READUNLOCKS(elf, s)
    return (rc);
}