libelf/common/strptr.c

	strptr.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"


char *
elf_strptr(Elf * elf, size_t ndx, size_t off)
{
    Elf_Scn     *s;
    Elf_Data    *d;
    char        *rc;

    if (elf == 0)
        return (0);
    if ((s = elf_getscn(elf, ndx)) == 0) {
        _elf_seterr(EREQ_STRSCN, 0);
        return (0);
    }
    READLOCKS(elf, s)
    if (elf->ed_class == ELFCLASS32) {
        Elf32_Shdr* sh = (Elf32_Shdr*)s->s_shdr;

        if ((sh == 0) || (sh->sh_type != SHT_STRTAB)) {
            _elf_seterr(EREQ_STRSCN, 0);
            READUNLOCKS(elf, s)
            return (0);
        }
    } else if (elf->ed_class == ELFCLASS64) {
        Elf64_Shdr* sh = (Elf64_Shdr*)s->s_shdr;

        if ((sh == 0) || (sh->sh_type != SHT_STRTAB)) {
            _elf_seterr(EREQ_STRSCN, 0);
            READUNLOCKS(elf, s)
            return (0);
        }
    } else {
        _elf_seterr(EREQ_STRSCN, 0);
        READUNLOCKS(elf, s)
        return (0);
    }


    /*
     * If the layout bit is set, use the offsets and
     * sizes in the data buffers.  Otherwise, take
     * data buffers in order.
     */

    d = 0;
    if (elf->ed_uflags & ELF_F_LAYOUT) {
        while ((d = _elf_locked_getdata(s, d)) != 0) {
            if (d->d_buf == 0)
                continue;
            if ((off >= d->d_off) &&
                (off < d->d_off + d->d_size)) {
                rc = (char *)d->d_buf + off - d->d_off;
                READUNLOCKS(elf, s)
                return (rc);
            }
        }
    } else {
        size_t  sz = 0, j;
        while ((d = _elf_locked_getdata(s, d)) != 0) {
            if (((j = d->d_align) > 1) && (sz % j != 0)) {
                j -= sz % j;
                sz += j;
                if (off < j)
                    break;
                off -= j;
            }
            if (d->d_buf != 0) {
                if (off < d->d_size) {
                    rc = (char *)d->d_buf + off;
                    READUNLOCKS(elf, s)
                    return (rc);
                }
            }
            sz += d->d_size;
            if (off < d->d_size)
                break;
            off -= d->d_size;
        }
    }
    _elf_seterr(EREQ_STROFF, 0);
    READUNLOCKS(elf, s)
    return (0);
}