rtld/common/move.c

	move.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.
 */

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

/*
 * Object file dependent support for ELF objects.
 */

#include    <stdio.h>
#include    <sys/procfs.h>
#include    <sys/mman.h>
#include    <dlfcn.h>
#include    <debug.h>
#include    <conv.h>
#include    "_rtld.h"
#include    "_audit.h"
#include    "_elf.h"
#include    "msg.h"

/*
 * For backward compatibility copy relocation processing, it can be necessary to
 * determine if a copy destination is also the recipient of a move record.  For
 * these instances, the move record addresses are retained for is_move_data().
 */
static  APlist  *alp = NULL;

/*
 * Move data
 */
int
move_data(Rt_map *lmp)
{
    Lm_list *lml = LIST(lmp);
    Move    *mv = MOVETAB(lmp);
    Phdr    *pptr = SUNWBSS(lmp);
    ulong_t num, mvnum = MOVESZ(lmp) / MOVEENT(lmp);
    int moves;

    /*
     * If these records are against the executable, and the executable was
     * built prior to Solaris 8, keep track of the move record symbol.  See
     * comment in analyze.c:lookup_sym_interpose() in regards Solaris 8
     * objects and DT_FLAGS.
     */
    moves = (lmp == lml->lm_head) && ((FLAGS2(lmp) & FL2_RT_DTFLAGS) == 0);

    DBG_CALL(Dbg_move_data(lmp));
    for (num = 0; num < mvnum; num++, mv++) {
        Addr    addr, taddr;
        Half    rep, repno, stride;
        Sym *sym;

        /*
         * If the target address needs to be mapped in,
         * map it first.
         *  (You have to protect the code, thread safe)
         */
        if (FLAGS(lmp) & FLG_RT_SUNWBSS) {
            long    zlen;
            Off foff;
            caddr_t zaddr, eaddr;

            foff = (Off) (pptr->p_vaddr + ADDR(lmp));
            zaddr = (caddr_t)M_PROUND(foff);
            eaddr = pptr->p_vaddr + ADDR(lmp) +
                (caddr_t)pptr->p_memsz;
            zero((caddr_t)foff, (long)(zaddr - foff));
            zlen = eaddr - zaddr;
            if (zlen > 0) {
                if (dz_map(lml, zaddr, zlen,
                    (PROT_READ | PROT_WRITE),
                    (MAP_FIXED | MAP_PRIVATE)) == MAP_FAILED)
                    return (0);
            }

            FLAGS(lmp) &= ~FLG_RT_SUNWBSS;
        }

        if ((sym = (Sym *)SYMTAB(lmp) + ELF_M_SYM(mv->m_info)) == 0)
            continue;

        stride = mv->m_stride + 1;
        addr = sym->st_value;
        if ((FLAGS(lmp) & FLG_RT_FIXED) == 0)
            addr += ADDR(lmp);
        taddr = addr + mv->m_poffset;

        DBG_CALL(Dbg_move_entry2(lml, mv, sym->st_name,
            (const char *)(sym->st_name + STRTAB(lmp))));

        for (rep = 0, repno = 0; rep < mv->m_repeat; rep++) {
            DBG_CALL(Dbg_move_expand(lml, mv, taddr));

            switch (ELF_M_SIZE(mv->m_info)) {
            case 1:
                *((char *)taddr) = (char)mv->m_value;
                taddr += stride;
                repno++;
                break;
            case 2:
                /* LINTED */
                *((Half *)taddr) = (Half)mv->m_value;
                taddr += 2 * stride;
                repno++;
                break;
            case 4:
                /* LINTED */
                *((Word *)taddr) = (Word)mv->m_value;
                taddr += 4 * stride;
                repno++;
                break;
            case 8:
                /* LINTED */
                *((unsigned long long *)taddr) = mv->m_value;
                taddr += 8 * stride;
                repno++;
                break;
            default:
                eprintf(lml, ERR_NONE, MSG_INTL(MSG_MOVE_ERR1));
                break;
            }
        }

        /*
         * If any move records have been applied to this symbol, retain
         * the symbol address if required for backward compatibility
         * copy relocation processing.
         */
        if (moves && repno &&
            (aplist_append(&alp, (void *)addr, AL_CNT_MOVES) == 0))
            return (0);
    }

    /*
     * Binaries built in the early 1990's prior to Solaris 8, using the ild
     * incremental linker are known to have zero filled move sections
     * (presumably place holders for new, incoming move sections).  If no
     * move records have been processed, remove the move identifier to
     * optimize the amount of backward compatibility copy relocation
     * processing that is needed.
     */
    if (moves && (alp == NULL))
        FLAGS(lmp) &= ~FLG_RT_MOVE;

    return (1);
}

/*
 * Determine whether an address is the recipient of a move record.
 * Returns 1 if the address matches a move symbol, 0 otherwise.
 */
int
is_move_data(caddr_t addr)
{
    caddr_t maddr;
    Aliste  idx;

    for (APLIST_TRAVERSE(alp, idx, maddr)) {
        if (addr == maddr)
            return (1);
    }
    return (0);
}