libelf/common/getscn.c

	getscn.c revision 7257d1b4d25bfac0c802847390e98a464fd787ac
/*
 * 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_Scn *
elf_getscn(Elf * elf, size_t index)
{
    Elf_Scn *   s;
    Elf_Scn *   prev_s;
    size_t      j = index;
    size_t      tabsz;

    if (elf == 0)
        return (0);

    ELFRLOCK(elf)
    tabsz = elf->ed_scntabsz;
    if (elf->ed_hdscn == 0) {
        ELFUNLOCK(elf)
        ELFWLOCK(elf)
        if ((elf->ed_hdscn == 0) && (_elf_cook(elf) != OK_YES)) {
            ELFUNLOCK(elf);
            return (0);
        }
        ELFUNLOCK(elf);
        ELFRLOCK(elf)
    }
    /*
     * If the section in question is part of a table allocated
     * from within _elf_prescn() then we can index straight
     * to it.
     */
    if (index < tabsz) {
        s = &elf->ed_hdscn[index];
        ELFUNLOCK(elf);
        return (s);
    }

#ifndef __lock_lint
    if (tabsz)
        s = &elf->ed_hdscn[tabsz - 1];
    else
        s = elf->ed_hdscn;

    for (prev_s = 0; s != 0; prev_s = s, s = s->s_next) {
        if (prev_s) {
            SCNUNLOCK(prev_s)
        }
        SCNLOCK(s)
        if (j == 0) {
            if (s->s_index == index) {
                SCNUNLOCK(s)
                ELFUNLOCK(elf);
                return (s);
            }
            _elf_seterr(EBUG_SCNLIST, 0);
            SCNUNLOCK(s)
            ELFUNLOCK(elf)
            return (0);
        }
        --j;
    }
    if (prev_s) {
        SCNUNLOCK(prev_s)
    }
#endif
    _elf_seterr(EREQ_NDX, 0);
    ELFUNLOCK(elf);
    return (0);
}