/*
 * 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);
}