/*      $NetBSD: mdreloc.c,v 1.37 2025/04/18 12:56:47 riastradh Exp $   */

/*
 * Copyright 1996 John D. Polstra.
 * Copyright 1996 Matt Thomas <matt@3am-software.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by John Polstra.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * m68k ELF relocations.
 *
 * References:
 *
 *      [M68KSYSVABI] System V Application Binary Interface: Motorola
 *      68000 Processor Family Supplement, 1990, AT&T.
 *      https://people.debian.org/~glaubitz/m68k-sysv-abi.pdf
 *      https://web.archive.org/web/20250317195959/https://people.debian.org/~glaubitz/m68k-sysv-abi.pdf
 */

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: mdreloc.c,v 1.37 2025/04/18 12:56:47 riastradh Exp $");
#endif /* not lint */

#include <sys/types.h>

#include "debug.h"
#include "rtld.h"

#include <machine/lwp_private.h>

void _rtld_bind_start(void);
void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
caddr_t _rtld_bind(const Obj_Entry *, Elf_Word);
static inline int _rtld_relocate_plt_object(const Obj_Entry *,
    const Elf_Rela *, Elf_Addr *);


void
_rtld_setup_pltgot(const Obj_Entry *obj)
{
        obj->pltgot[1] = (Elf_Addr) obj;
        obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
}

void
_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
{
        const Elf_Rela *rela = 0, *relalim;
        Elf_Addr relasz = 0;
        Elf_Addr *where;

        for (; dynp->d_tag != DT_NULL; dynp++) {
                switch (dynp->d_tag) {
                case DT_RELA:
                        rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr);
                        break;
                case DT_RELASZ:
                        relasz = dynp->d_un.d_val;
                        break;
                }
        }
        relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz);
        for (; rela < relalim; rela++) {
                where = (Elf_Addr *)(relocbase + rela->r_offset);
                *where += (Elf_Addr)relocbase;
        }
}

int
_rtld_relocate_nonplt_objects(Obj_Entry *obj)
{
        const Elf_Rela *rela;
        const Elf_Sym *def = NULL;
        const Obj_Entry *defobj = NULL;
        unsigned long last_symnum = ULONG_MAX;

        for (rela = obj->rela; rela < obj->relalim; rela++) {
                Elf_Addr        *where;
                Elf_Addr         tmp;
                unsigned long    symnum;

                where = (Elf_Addr *)(obj->relocbase + rela->r_offset);

                switch (ELF_R_TYPE(rela->r_info)) {
                case R_TYPE(PC32):
                case R_TYPE(GOT32):
                case R_TYPE(32):
                case R_TYPE(GLOB_DAT):
                case R_TYPE(TLS_DTPMOD32):
                case R_TYPE(TLS_DTPREL32):
                case R_TYPE(TLS_TPREL32):
                        symnum = ELF_R_SYM(rela->r_info);
                        if (last_symnum != symnum) {
                                last_symnum = symnum;
                                def = _rtld_find_symdef(symnum, obj, &defobj,
                                    false);
                                if (def == NULL)
                                        return -1;
                        }
                        break;
                default:
                        break;
                }

                switch (ELF_R_TYPE(rela->r_info)) {
                case R_TYPE(NONE):
                        break;

#if 1 /* XXX should not occur */
                case R_TYPE(PC32):
                        tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
                            rela->r_addend) - (Elf_Addr)where;
                        if (*where != tmp)
                                *where = tmp;
                        rdbg(("PC32 %s in %s --> %p in %s",
                            obj->strtab + obj->symtab[symnum].st_name,
                            obj->path, (void *)*where, defobj->path));
                        break;

                case R_TYPE(GOT32):
#endif
                case R_TYPE(32):
                case R_TYPE(GLOB_DAT):
                        tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
                            rela->r_addend);
                        if (*where != tmp)
                                *where = tmp;
                        rdbg(("32/GLOB_DAT %s in %s --> %p in %s",
                            obj->strtab + obj->symtab[symnum].st_name,
                            obj->path, (void *)*where, defobj->path));
                        break;

                case R_TYPE(RELATIVE):
                        *where += (Elf_Addr)obj->relocbase;
                        rdbg(("RELATIVE in %s --> %p", obj->path,
                            (void *)*where));
                        break;

                case R_TYPE(COPY):
                        /*
                         * These are deferred until all other relocations have
                         * been done.  All we do here is make sure that the
                         * COPY relocation is not in a shared library.  They
                         * are allowed only in executable files.
                         */
                        if (obj->isdynamic) {
                                _rtld_error(
                        "%s: Unexpected R_COPY relocation in shared library",
                                    obj->path);
                                return -1;
                        }
                        rdbg(("COPY (avoid in main)"));
                        break;

                case R_TYPE(TLS_DTPMOD32):
                        *where = (Elf_Addr)defobj->tlsindex;
                        rdbg(("DTPMOD32 %s in %s --> %p in %s",
                            obj->strtab + obj->symtab[symnum].st_name,
                            obj->path, (void *)*where, defobj->path));
                        break;

                case R_TYPE(TLS_DTPREL32):
                        *where = (Elf_Addr)(def->st_value + rela->r_addend
                            - TLS_DTV_OFFSET);
                        rdbg(("DTPREL32 %s in %s --> %p in %s",
                            obj->strtab + obj->symtab[symnum].st_name,
                            obj->path, (void *)*where, defobj->path));
                        break;

                case R_TYPE(TLS_TPREL32):
                        if (!defobj->tls_static &&
                            _rtld_tls_offset_allocate(__UNCONST(defobj)))
                                return -1;

                        *where = (Elf_Addr)(def->st_value + rela->r_addend
                            + defobj->tlsoffset - TLS_TP_OFFSET);
                        rdbg(("TPREL32 %s in %s --> %p in %s",
                            obj->strtab + obj->symtab[symnum].st_name,
                            obj->path, (void *)*where, defobj->path));
                        break;

                default:
                        rdbg(("sym = %lu, type = %lu, offset = %p, "
                            "addend = %p, contents = %p, symbol = %s",
                            (u_long)ELF_R_SYM(rela->r_info),
                            (u_long)ELF_R_TYPE(rela->r_info),
                            (void *)rela->r_offset, (void *)rela->r_addend,
                            (void *)*where,
                            obj->strtab + obj->symtab[symnum].st_name));
                        _rtld_error("%s: Unsupported relocation type %ld "
                            "in non-PLT relocations",
                            obj->path, (u_long) ELF_R_TYPE(rela->r_info));
                        return -1;
                }
        }
        return 0;
}

int
_rtld_relocate_plt_lazy(Obj_Entry *obj)
{
        const Elf_Rela *rela;

        if (!obj->relocbase)
                return 0;

        for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) {
                Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);

                assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));

                /* Just relocate the GOT slots pointing into the PLT */
                *where += (Elf_Addr)obj->relocbase;
                rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where));
        }

        return 0;
}

static inline int
_rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela,
    Elf_Addr *tp)
{
        Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
        Elf_Addr new_value;
        const Elf_Sym  *def;
        const Obj_Entry *defobj;
        unsigned long info = rela->r_info;

        assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT));

        def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL);
        if (__predict_false(def == NULL))
                return -1;
        if (__predict_false(def == &_rtld_sym_zero))
                return 0;

        assert(rela->r_addend == 0);
        if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
                if (tp == NULL)
                        return 0;
                new_value = _rtld_resolve_ifunc(defobj, def);
        } else {
                new_value = (Elf_Addr)(defobj->relocbase + def->st_value +
                    rela->r_addend);
        }
        rdbg(("bind now/fixup in %s --> old=%p new=%p",
            defobj->strtab + def->st_name, (void *)*where, (void *)new_value));
        if (*where != new_value)
                *where = new_value;

        if (tp)
                *tp = new_value - rela->r_addend;

        return 0;
}

caddr_t
_rtld_bind(const Obj_Entry *obj, Elf_Word reloff)
{
        const Elf_Rela *rela = (const Elf_Rela *)((const uint8_t *)obj->pltrela + reloff);
        Elf_Addr result;
        int err;

        result = 0;     /* XXX gcc */

        _rtld_shared_enter();
        err = _rtld_relocate_plt_object(obj, rela, &result);
        if (err)
                _rtld_die();
        _rtld_shared_exit();

        return (caddr_t)result;
}

int
_rtld_relocate_plt_objects(const Obj_Entry *obj)
{
        const Elf_Rela *rela;

        for (rela = obj->pltrela; rela < obj->pltrelalim; rela++)
                if (_rtld_relocate_plt_object(obj, rela, NULL) < 0)
                        return -1;

        return 0;
}