/*
 * 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   */

#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <libelf.h>
#include "decl.h"
#include "msg.h"


/*
 * Convert data from file format to memory format.
 */


static const size_t     align32[ELF_T_NUM] =
{
        1,                      /* ELF_T_BYTE */
        sizeof (Elf32),         /* ELF_T_ADDR */
        sizeof (Elf32),         /* ELF_T_DYN */
        sizeof (Elf32),         /* ELF_T_EHDR */
        sizeof (Elf32_Half),    /* ELF_T_HALF */
        sizeof (Elf32),         /* ELF_T_OFF */
        sizeof (Elf32),         /* ELF_T_PHDR */
        sizeof (Elf32),         /* ELF_T_RELA */
        sizeof (Elf32),         /* ELF_T_REL */
        sizeof (Elf32),         /* ELF_T_SHDR */
        sizeof (Elf32),         /* ELF_T_SWORD */
        sizeof (Elf32),         /* ELF_T_SYM */
        sizeof (Elf32),         /* ELF_T_WORD */
        sizeof (Elf32),         /* ELF_T_VERDEF */
        sizeof (Elf32),         /* ELF_T_VERNEED */
        sizeof (Elf64_Sxword),  /* ELF_T_SXWORD */
        sizeof (Elf64),         /* ELF_T_XWORD */
        sizeof (Elf32_Half),    /* ELF_T_SYMINFO */
        sizeof (Elf32),         /* ELF_T_NOTE */
        sizeof (Elf32_Lword),   /* ELF_T_MOVE */
        sizeof (Elf32_Lword),   /* ELF_T_MOVEP */
        sizeof (Elf32_Word)     /* ELF_T_CAP */

};

#define Nalign32        (sizeof (align32)/sizeof (align32[0]))

static const size_t     align64[ELF_T_NUM] =
{
        1,                      /* ELF_T_BYTE */
        sizeof (Elf64),         /* ELF_T_ADDR */
        sizeof (Elf64),         /* ELF_T_DYN */
        sizeof (Elf64),         /* ELF_T_EHDR */
        sizeof (Elf64_Half),    /* ELF_T_HALF */
        sizeof (Elf64),         /* ELF_T_OFF */
        sizeof (Elf64),         /* ELF_T_PHDR */
        sizeof (Elf64),         /* ELF_T_RELA */
        sizeof (Elf64),         /* ELF_T_REL */
        sizeof (Elf64),         /* ELF_T_SHDR */
        sizeof (Elf64_Word),    /* ELF_T_SWORD */
        sizeof (Elf64),         /* ELF_T_SYM */
        sizeof (Elf64_Word),    /* ELF_T_WORD */
        sizeof (Elf64),         /* ELF_T_VDEF */
        sizeof (Elf64),         /* ELF_T_VNEED */
        sizeof (Elf64),         /* ELF_T_SXWORD */
        sizeof (Elf64),         /* ELF_T_XWORD */
        sizeof (Elf32_Half),    /* ELF_T_SYMINFO */
        sizeof (Elf32),         /* ELF_T_NOTE */
        sizeof (Elf64),         /* ELF_T_MOVE */
        sizeof (Elf64),         /* ELF_T_MOVEP */
        sizeof (Elf64_Word)     /* ELF_T_CAP */
};

#define Nalign64        (sizeof (align64)/sizeof (align64[0]))


/*
 * Could use an array indexed by ELFCLASS*, but I'd rather
 * avoid .data over something this infrequently used.  The
 * next choice would be to add extra conditionals.
 */
#define NALIGN(elf)     ((elf->ed_class == ELFCLASS32) ? Nalign32 : Nalign64)
#define ALIGN(elf)      ((elf->ed_class == ELFCLASS32) ? align32 : align64)


Elf_Data *
_elf_locked_getdata(Elf_Scn * scn, Elf_Data * data)
{
        Dnode *         d = (Dnode *)data;
        Elf *           elf;
        Elf_Data        src;
        unsigned        work;

        assert(!elf_threaded || RW_LOCK_HELD(&(scn->s_elf->ed_rwlock)));
        assert(!elf_threaded || MUTEX_HELD(&(scn->s_mutex)));
        elf = scn->s_elf;

        if ((scn->s_myflags & SF_READY) == 0) {
                UPGRADELOCKS(elf, scn)
                /*
                 * make sure someone else didn't come along and cook
                 * this stuff.
                 */
                if ((scn->s_myflags & SF_READY) == 0)
                        (void) _elf_cookscn(scn);
                DOWNGRADELOCKS(elf, scn)
        }

        if (d == 0)
                d = scn->s_hdnode;
        else
                d = d->db_next;

        if (scn->s_err != 0) {
                /*LINTED*/
                _elf_seterr((Msg)scn->s_err, 0);
                return (0);
        }

        if (d == 0) {
                return (0);
        }

        if (d->db_scn != scn) {
                _elf_seterr(EREQ_DATA, 0);
                return (0);
        }

        if (d->db_myflags & DBF_READY) {
                return (&d->db_data);
        }
        elf = scn->s_elf;

        /*
         * Prepare return buffer.  The data comes from the memory
         * image of the file.  "Empty" regions get an empty buffer.
         *
         * Only sections of an ELF_C_READ file can be not READY here.
         * Furthermore, the input file must have been cooked or
         * frozen by now.  Translate cooked files in place if possible.
         */

        ELFACCESSDATA(work, _elf_work)
        d->db_data.d_version = work;
        if ((d->db_off == 0) || (d->db_fsz == 0)) {
                d->db_myflags |= DBF_READY;
                return (&d->db_data);
        }

        if (elf->ed_class == ELFCLASS32) {
                Elf32_Shdr      *sh = scn->s_shdr;
                size_t          sz = sh->sh_entsize;
                Elf_Type        t = d->db_data.d_type;

                if ((t != ELF_T_BYTE) &&
                    (sz > 1) && (sz != elf32_fsize(t, 1, elf->ed_version))) {
                        _elf_seterr(EFMT_ENTSZ, 0);
                        return (0);
                }
        } else if (elf->ed_class == ELFCLASS64) {
                Elf64_Shdr      *sh = scn->s_shdr;
                Elf64_Xword     sz = sh->sh_entsize;
                Elf_Type        t = d->db_data.d_type;

                if (t != ELF_T_BYTE && sz > 1 &&
                    sz != elf64_fsize(t, 1, elf->ed_version)) {
                        _elf_seterr(EFMT_ENTSZ, 0);
                        return (0);
                }
        } else {
                _elf_seterr(EREQ_CLASS, 0);
                return (0);
        }


        /*
         * validate the region
         */

        if ((d->db_off < 0) || (d->db_off >= elf->ed_fsz) ||
            (elf->ed_fsz - d->db_off < d->db_fsz)) {
                _elf_seterr(EFMT_DATA, 0);
                return (0);
        }

        /*
         * set up translation buffers and validate
         */

        src.d_buf = (Elf_Void *)(elf->ed_ident + d->db_off);
        src.d_size = d->db_fsz;
        src.d_type = d->db_data.d_type;
        src.d_version = elf->ed_version;
        if (elf->ed_vm) {
                UPGRADELOCKS(elf, scn)
                if (_elf_vm(elf, (size_t)d->db_off, d->db_fsz) != OK_YES) {
                        DOWNGRADELOCKS(elf, scn)
                        return (0);
                }
                DOWNGRADELOCKS(elf, scn)
        }

        /*
         * decide where to put destination
         */

        switch (elf->ed_status) {
        case ES_COOKED:
                if ((size_t)d->db_data.d_type >= NALIGN(elf)) {
                        _elf_seterr(EBUG_COOKTYPE, 0);
                        return (0);
                }

                /*
                 * If the destination size (memory) is at least as
                 * big as the source size (file), and has the necessary
                 * alignment, reuse the space.
                 *
                 * Note that it is not sufficient to check the alignment
                 * of the offset within the object. Rather, we must check
                 * the alignment of the actual data buffer. The offset is
                 * sufficient if the file is a plain object file, which
                 * will always be mapped on a page boundary. In an archive
                 * however, the only guarantee is that the object will start
                 * on an even boundary within the archive file. The
                 * Solaris ar(1) adds padding in most (but not all cases)
                 * which minimizes this issue, but it is still important
                 * for the remaining cases that do not get padded. It also
                 * matters with archives produced by other versions of
                 * ar(1), such as the GNU version, or one from another
                 * ELF based operating system.
                 */

                if (d->db_data.d_size <= src.d_size) {
                        d->db_data.d_buf = (Elf_Void *)(elf->ed_ident +
                            d->db_off);
                        if (((uintptr_t)d->db_data.d_buf
                            % ALIGN(elf)[d->db_data.d_type]) == 0) {
                                break;
                        } else {   /* Failure: Restore NULL buffer pointer */
                                d->db_data.d_buf = 0;
                        }
                }

                /*FALLTHRU*/
        case ES_FROZEN:
                if ((d->db_buf = malloc(d->db_data.d_size)) == 0) {
                        _elf_seterr(EMEM_DATA, errno);
                        return (0);
                }
                d->db_data.d_buf = d->db_buf;
                break;

        default:
                _elf_seterr(EBUG_COOKSTAT, 0);
                return (0);
        }

        if (elf->ed_class == ELFCLASS32) {
                if (elf32_xlatetom(&d->db_data, &src, elf->ed_encode) == 0)
                        return (0);
        } else {        /* ELFCLASS64 */
                if (elf64_xlatetom(&d->db_data, &src, elf->ed_encode) == 0)
                        return (0);
        }
        d->db_myflags |= DBF_READY;

        return (&d->db_data);
}

Elf_Data *
elf_getdata(Elf_Scn * scn, Elf_Data * data)
{
        Elf_Data *      rc;
        Elf *   elf;

        /*
         * trap null args, end of list, previous buffer.
         * SHT_NULL sections have no buffer list, so they
         * fall out here too.
         */
        if (scn == 0)
                return (0);

        elf = scn->s_elf;
        READLOCKS(elf, scn);
        rc = _elf_locked_getdata(scn, data);
        READUNLOCKS(elf, scn);
        return (rc);
}