rtld/sparc/common_sparc.c

/*
 * 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.
 */

#include    <stdio.h>
#include    <strings.h>
#include    <sys/elf.h>
#include    <sys/elf_SPARC.h>
#include    <alloca.h>
#include    "_rtld.h"
#include    "_elf.h"
#include    "msg.h"
#include    "conv.h"

/*
 *
 *  Matrix of legal combinations of usage of a given register:
 *
 *  Obj1\Obj2       Scratch Named
 *  Scratch          OK      NO
 *  Named            NO      *
 *
 *  * OK if the symbols are identical, NO if they are not.  Two symbols
 *  are identical if and only if one of the following is true:
 *        A. They are both global and have the same name.
 *        B. They are both local, have the same name, and are defined in
 *        the same object.  (Note that a local symbol in one object is
 *        never identical to a local symbol in another object, even if the
 *        name is the same.)
 *
 *  Matrix of legal combinations of st_shndx for the same register symbol:
 *
 *  Obj1\Obj2       UNDEF   ABS
 *  UNDEF            OK      OK
 *  ABS              OK      NO
 */

/*
 * Test the compatiblity of two register symbols, 0 pass, >0 fail
 */
static uintptr_t
check_regsyms(Sym *sym1, const char *name1, Sym *sym2, const char *name2)
{
    if ((sym1->st_name == 0) && (sym2->st_name == 0))
        return (0); /* scratches are always compatible */

    if ((ELF_ST_BIND(sym1->st_info) == STB_LOCAL) ||
        (ELF_ST_BIND(sym2->st_info) == STB_LOCAL)) {
        if (sym1->st_value == sym2->st_value)
            return (1); /* local symbol incompat */
        return (0);     /* no other prob from locals */
    }

    if (sym1->st_value == sym2->st_value) {
        /* NOTE this just avoids strcmp */
        if ((sym1->st_name == 0) || (sym2->st_name == 0))
            return (2); /* can't match scratch to named */

        if (strcmp(name1, name2) != 0)
            return (4); /* diff name, same register value */

        if ((sym1->st_shndx == SHN_ABS) && (sym2->st_shndx == SHN_ABS))
            return (3); /* multiply defined */
    } else if (strcmp(name1, name2) == 0)
        return (5); /* same name, diff register value */

    return (0);
}

int
elf_regsyms(Rt_map *lmp)
{
    Dyn *dyn;
    Dyninfo *dip;
    Sym *symdef;
    ulong_t rsymndx;

    /*
     * Scan through the .dynamic section of this object looking for all
     * DT_REGISTER entries.  For each DT_REGISTER entry found identify the
     * register symbol it identifies and confirm that it doesn't conflict
     * with any other register symbols.
     */
    for (dyn = DYN(lmp), dip = DYNINFO(lmp);
        !(dip->di_flags & FLG_DI_IGNORE); dyn++, dip++) {
        Reglist *rp;

        if ((dip->di_flags & FLG_DI_REGISTER) == 0)
            continue;

        /*
         * Get the local symbol table entry.
         */
        rsymndx = dyn->d_un.d_val;
        symdef = (Sym *)((unsigned long)SYMTAB(lmp) +
            (rsymndx * SYMENT(lmp)));

        for (rp = reglist; rp; rp = rp->rl_next) {
            Conv_inv_buf_t  inv_buf;
            const char  *str, *sym1, *sym2;

            if (rp->rl_sym == symdef) {
                /*
                 * Same symbol definition - everything is a-ok.
                 */
                return (1);
            }

            sym1 = (STRTAB(rp->rl_lmp) + rp->rl_sym->st_name);
            sym2 = (STRTAB(lmp) + symdef->st_name);

            if (check_regsyms(rp->rl_sym, sym1, symdef, sym2) == 0)
                continue;

            if ((str = demangle(sym1)) != sym1) {
                char    *_str = alloca(strlen(str) + 1);
                (void) strcpy(_str, str);
                sym1 = (const char *)_str;
            }
            sym2 = demangle(sym2);

            if (LIST(lmp)->lm_flags & LML_FLG_TRC_WARN) {
                (void) printf(MSG_INTL(MSG_LDD_REG_SYMCONF),
                    conv_sym_SPARC_value(symdef->st_value,
                    0, &inv_buf), NAME(rp->rl_lmp),
                    sym1, NAME(lmp), sym2);
            } else {
                eprintf(LIST(lmp), ERR_FATAL,
                    MSG_INTL(MSG_REG_SYMCONF),
                    conv_sym_SPARC_value(symdef->st_value,
                    0, &inv_buf), NAME(rp->rl_lmp),
                    sym1, NAME(lmp), sym2);
                return (0);
            }
        }
        if ((rp = calloc(sizeof (Reglist), 1)) == NULL)
            return (0);
        rp->rl_lmp = lmp;
        rp->rl_sym = symdef;
        rp->rl_next = reglist;
        reglist = rp;
    }
    return (1);
}