rtld/common/move.c

	move.c revision f441771b0ce9f9d6122d318ff8290cb1a2848f9d
/*
 * 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 (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * 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    "_inline_gen.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;

/*
 * Warning message for bad move target.
 */
void
elf_move_bad(Lm_list *lml, Rt_map *lmp, Sym *sym, ulong_t num, Addr addr)
{
    const char  *name;
    int     trace;

    trace = (lml->lm_flags & LML_FLG_TRC_ENABLE) &&
        (((rtld_flags & RT_FL_SILENCERR) == 0) ||
        (lml->lm_flags & (LML_FLG_TRC_VERBOSE | LML_FLG_TRC_WARN)));

    if ((trace == 0) && (DBG_ENABLED == 0))
        return;

    if (ELF_ST_BIND(sym->st_info) != STB_LOCAL)
        name = (const char *)(STRTAB(lmp) + sym->st_name);
    else
        name = MSG_INTL(MSG_STR_UNKNOWN);

    if (trace)
        (void) printf(MSG_INTL(MSG_LDD_MOVE_ERR), EC_XWORD(num), name,
            EC_ADDR(addr));
    else
        DBG_CALL(Dbg_move_bad(lml, num, name, addr));
}

/*
 * Move data.  Apply sparse initialization to data in zeroed bss.
 */
int
move_data(Rt_map *lmp, APlist **textrel)
{
    Lm_list     *lml = LIST(lmp);
    Move        *mv = MOVETAB(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) && ((FLAGS1(lmp) & FL1_RT_DTFLAGS) == 0);

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

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

        stride = mv->m_stride + 1;
        addr = sym->st_value;

        /*
         * Determine the move data target, and verify the address is
         * writable.
         */
        if ((FLAGS(lmp) & FLG_RT_FIXED) == 0)
            addr += ADDR(lmp);
        taddr = addr + mv->m_poffset;

        if ((mpp = find_segment((caddr_t)taddr, lmp)) == NULL) {
            elf_move_bad(lml, lmp, sym, num, taddr);
            continue;
        }
        if (((mpp->mr_prot & PROT_WRITE) == 0) &&
            ((set_prot(lmp, mpp, 1) == 0) ||
            (aplist_append(textrel, mpp, AL_CNT_TEXTREL) == NULL)))
            return (0);

        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) == NULL))
            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);
}