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/* vi: set sw=4 ts=4: */

/* i386 ELF shared library loader suppport

 *

 * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,

 *                              David Engel, Hongjiu Lu and Mitch D'Souza

 * Copyright (C) 2001-2002, Erik Andersen

 *

 * 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. The name of the above contributors may not be

 *    used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``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 CONTRIBUTORS 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.

 */

#if defined (__SUPPORT_LD_DEBUG__)

static const char *_dl_reltypes_tab[] =

{

  [0]    "R_386_NONE",       "R_386_32",     "R_386_PC32",       "R_386_GOT32",

  [4]   "R_386_PLT32",      "R_386_COPY",   "R_386_GLOB_DAT",   "R_386_JMP_SLOT",

  [8]   "R_386_RELATIVE",   "R_386_GOTOFF", "R_386_GOTPC",

};

static const char *

_dl_reltypes(int type)

{

  static char buf[22];

  const char *str;

  if (type >= (int)(sizeof (_dl_reltypes_tab)/sizeof(_dl_reltypes_tab[0])) ||

      NULL == (str = _dl_reltypes_tab[type]))

  {

    str =_dl_simple_ltoa( buf, (unsigned long)(type));

  }

  return str;

}

static

void debug_sym(Elf32_Sym *symtab,char *strtab,int symtab_index)

{

  if(_dl_debug_symbols)

  {

    if(symtab_index){

      _dl_dprintf(_dl_debug_file, "\n%s\n\tvalue=%x\tsize=%x\tinfo=%x\tother=%x\tshndx=%x",

                  strtab + symtab[symtab_index].st_name,

                  symtab[symtab_index].st_value,

                  symtab[symtab_index].st_size,

                  symtab[symtab_index].st_info,

                  symtab[symtab_index].st_other,

                  symtab[symtab_index].st_shndx);

    }

  }

}

static void debug_reloc(Elf32_Sym *symtab,char *strtab, ELF_RELOC *rpnt)

{

  if(_dl_debug_reloc)

  {

    int symtab_index;

    const char *sym;

    symtab_index = ELF32_R_SYM(rpnt->r_info);

    sym = symtab_index ? strtab + symtab[symtab_index].st_name : "sym=0x0";

  if(_dl_debug_symbols)

          _dl_dprintf(_dl_debug_file, "\n\t");

  else

          _dl_dprintf(_dl_debug_file, "\n%s\n\t", sym);

#ifdef ELF_USES_RELOCA

    _dl_dprintf(_dl_debug_file, "%s\toffset=%x\taddend=%x",

                _dl_reltypes(ELF32_R_TYPE(rpnt->r_info)),

                rpnt->r_offset,

                rpnt->r_addend);

#else

    _dl_dprintf(_dl_debug_file, "%s\toffset=%x\n",

                _dl_reltypes(ELF32_R_TYPE(rpnt->r_info)),

                rpnt->r_offset);

#endif

  }

}

#endif

/* Program to load an ELF binary on a linux system, and run it.

   References to symbols in sharable libraries can be resolved by either

   an ELF sharable library or a linux style of shared library. */

/* Disclaimer:  I have never seen any AT&T source code for SVr4, nor have

   I ever taken any courses on internals.  This program was developed using

   information available through the book "UNIX SYSTEM V RELEASE 4,

   Programmers guide: Ansi C and Programming Support Tools", which did

   a more than adequate job of explaining everything required to get this

   working. */

extern int _dl_linux_resolve(void);

unsigned long _dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry)

{

        int reloc_type;

        ELF_RELOC *this_reloc;

        char *strtab;

        Elf32_Sym *symtab;

        int symtab_index;

        char *rel_addr;

        char *new_addr;

        char **got_addr;

        unsigned long instr_addr;

        char *symname;

        rel_addr = (char *) (tpnt->dynamic_info[DT_JMPREL] + tpnt->loadaddr);

        this_reloc = (ELF_RELOC *)(intptr_t)(rel_addr + reloc_entry);

        reloc_type = ELF32_R_TYPE(this_reloc->r_info);

        symtab_index = ELF32_R_SYM(this_reloc->r_info);

        symtab = (Elf32_Sym *)(intptr_t) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr);

        strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr);

        symname= strtab + symtab[symtab_index].st_name;

        if (reloc_type != R_386_JMP_SLOT) {

                _dl_dprintf(2, "%s: Incorrect relocation type in jump relocations\n",

                                _dl_progname);

                _dl_exit(1);

        }

        /* Address of jump instruction to fix up */

        instr_addr = ((unsigned long) this_reloc->r_offset +

                        (unsigned long) tpnt->loadaddr);

        got_addr = (char **) instr_addr;

        /* Get the address of the GOT entry */

        new_addr = _dl_find_hash(symname, tpnt->symbol_scope, tpnt, resolver);

        if (!new_addr) {

                new_addr = _dl_find_hash(symname, NULL, NULL, resolver);

                if (new_addr) {

                        return (unsigned long) new_addr;

                }

                _dl_dprintf(2, "%s: can't resolve symbol '%s'\n", _dl_progname, symname);

                _dl_exit(1);

        }

#if defined (__SUPPORT_LD_DEBUG__)

        if ((unsigned long) got_addr < 0x40000000)

        {

                if (_dl_debug_bindings)

                {

                        _dl_dprintf(_dl_debug_file, "\nresolve function: %s", symname);

                        if(_dl_debug_detail) _dl_dprintf(_dl_debug_file,

                                        "\n\tpatched %x ==> %x @ %x\n", *got_addr, new_addr, got_addr);

                }

        }

        if (!_dl_debug_nofixups) {

                *got_addr = new_addr;

        }

#else

        *got_addr = new_addr;

#endif

        return (unsigned long) new_addr;

}

static int

_dl_parse(struct elf_resolve *tpnt, struct dyn_elf *scope,

          unsigned long rel_addr, unsigned long rel_size,

          int (*reloc_fnc) (struct elf_resolve *tpnt, struct dyn_elf *scope,

                            ELF_RELOC *rpnt, Elf32_Sym *symtab, char *strtab))

{

        unsigned int i;

        char *strtab;

        Elf32_Sym *symtab;

        ELF_RELOC *rpnt;

        int symtab_index;

        /* Now parse the relocation information */

        rpnt = (ELF_RELOC *)(intptr_t) (rel_addr + tpnt->loadaddr);

        rel_size = rel_size / sizeof(ELF_RELOC);

        symtab = (Elf32_Sym *)(intptr_t) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr);

        strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr);

          for (i = 0; i < rel_size; i++, rpnt++) {

                int res;

                symtab_index = ELF32_R_SYM(rpnt->r_info);

                /* When the dynamic linker bootstrapped itself, it resolved some symbols.

                   Make sure we do not do them again */

                if (!symtab_index && tpnt->libtype == program_interpreter)

                        continue;

                if (symtab_index && tpnt->libtype == program_interpreter &&

                    _dl_symbol(strtab + symtab[symtab_index].st_name))

                        continue;

#if defined (__SUPPORT_LD_DEBUG__)

                debug_sym(symtab,strtab,symtab_index);

                debug_reloc(symtab,strtab,rpnt);

#endif

                res = reloc_fnc (tpnt, scope, rpnt, symtab, strtab);

                if (res==0) continue;

                _dl_dprintf(2, "\n%s: ",_dl_progname);

                if (symtab_index)

                  _dl_dprintf(2, "symbol '%s': ", strtab + symtab[symtab_index].st_name);

                if (res <0)

                {

                        int reloc_type = ELF32_R_TYPE(rpnt->r_info);

#if defined (__SUPPORT_LD_DEBUG__)

                        _dl_dprintf(2, "can't handle reloc type %s\n ", _dl_reltypes(reloc_type));

#else

                        _dl_dprintf(2, "can't handle reloc type %x\n", reloc_type);

#endif                  

                        _dl_exit(-res);

                }

                else if (res >0)

                {

                        _dl_dprintf(2, "can't resolve symbol\n");

                        return res;

                }

          }

          return 0;

}

static int

_dl_do_reloc (struct elf_resolve *tpnt,struct dyn_elf *scope,

              ELF_RELOC *rpnt, Elf32_Sym *symtab, char *strtab)

{

        int reloc_type;

        int symtab_index;

        char *symname;

        unsigned long *reloc_addr;

        unsigned long symbol_addr;

#if defined (__SUPPORT_LD_DEBUG__)

        unsigned long old_val;

#endif

        reloc_addr   = (unsigned long *)(intptr_t) (tpnt->loadaddr + (unsigned long) rpnt->r_offset);

        reloc_type   = ELF32_R_TYPE(rpnt->r_info);

        symtab_index = ELF32_R_SYM(rpnt->r_info);

        symbol_addr  = 0;

        symname      = strtab + symtab[symtab_index].st_name;

        if (symtab_index) {

                symbol_addr = (unsigned long) _dl_find_hash(symname, scope,

                                (reloc_type == R_386_JMP_SLOT ? tpnt : NULL), symbolrel);

                /*

                 * We want to allow undefined references to weak symbols - this might

                 * have been intentional.  We should not be linking local symbols

                 * here, so all bases should be covered.

                 */

                if (!symbol_addr && ELF32_ST_BIND(symtab[symtab_index].st_info) == STB_GLOBAL) {

#if defined (__SUPPORT_LD_DEBUG__)

                        _dl_dprintf(2, "\tglobal symbol '%s' already defined in '%s'\n",

                                        symname, tpnt->libname);

#endif

                        return 0;

                }

        }

#if defined (__SUPPORT_LD_DEBUG__)

        old_val = *reloc_addr;

#endif

                switch (reloc_type) {

                        case R_386_NONE:

                                break;

                        case R_386_32:

                                *reloc_addr += symbol_addr;

                                break;

                        case R_386_PC32:

                                *reloc_addr += symbol_addr - (unsigned long) reloc_addr;

                                break;

                        case R_386_GLOB_DAT:

                        case R_386_JMP_SLOT:

                                *reloc_addr = symbol_addr;

                                break;

                        case R_386_RELATIVE:

                                *reloc_addr += (unsigned long) tpnt->loadaddr;

                                break;

                        case R_386_COPY:

                                /* handled later on */

                                break;

                        default:

                                return -1; /*call _dl_exit(1) */

                }

#if defined (__SUPPORT_LD_DEBUG__)

        if(_dl_debug_reloc && _dl_debug_detail)

                _dl_dprintf(_dl_debug_file, "\tpatched: %x ==> %x @ %x", old_val, *reloc_addr, reloc_addr);

#endif

        return 0;

}

static int

_dl_do_lazy_reloc (struct elf_resolve *tpnt, struct dyn_elf *scope,

                   ELF_RELOC *rpnt, Elf32_Sym *symtab, char *strtab)

{

        int reloc_type;

        unsigned long *reloc_addr;

#if defined (__SUPPORT_LD_DEBUG__)

        unsigned long old_val;

#endif

        (void)scope;

        (void)symtab;

        (void)strtab;

        reloc_addr = (unsigned long *)(intptr_t) (tpnt->loadaddr + (unsigned long) rpnt->r_offset);

        reloc_type = ELF32_R_TYPE(rpnt->r_info);

#if defined (__SUPPORT_LD_DEBUG__)

        old_val = *reloc_addr;

#endif

                switch (reloc_type) {

                        case R_386_NONE:

                                break;

                        case R_386_JMP_SLOT:

                                *reloc_addr += (unsigned long) tpnt->loadaddr;

                                break;

                        default:

                                return -1; /*call _dl_exit(1) */

                }

#if defined (__SUPPORT_LD_DEBUG__)

        if(_dl_debug_reloc && _dl_debug_detail)

                _dl_dprintf(_dl_debug_file, "\tpatched: %x ==> %x @ %x", old_val, *reloc_addr, reloc_addr);

#endif

        return 0;

}

/* This is done as a separate step, because there are cases where

   information is first copied and later initialized.  This results in

   the wrong information being copied.  Someone at Sun was complaining about

   a bug in the handling of _COPY by SVr4, and this may in fact be what he

   was talking about.  Sigh. */

/* No, there are cases where the SVr4 linker fails to emit COPY relocs

   at all */

static int

_dl_do_copy (struct elf_resolve *tpnt, struct dyn_elf *scope,

             ELF_RELOC *rpnt, Elf32_Sym *symtab, char *strtab)

{

        int reloc_type;

        int symtab_index;

        unsigned long *reloc_addr;

        unsigned long symbol_addr;

        int goof = 0;

        char *symname;

        reloc_addr = (unsigned long *)(intptr_t) (tpnt->loadaddr + (unsigned long) rpnt->r_offset);

        reloc_type = ELF32_R_TYPE(rpnt->r_info);

        if (reloc_type != R_386_COPY)

                return 0;

        symtab_index = ELF32_R_SYM(rpnt->r_info);

        symbol_addr = 0;

        symname      = strtab + symtab[symtab_index].st_name;

        if (symtab_index) {

                symbol_addr = (unsigned long) _dl_find_hash(symname, scope, NULL, copyrel);

                if (!symbol_addr) goof++;

        }

        if (!goof) {

#if defined (__SUPPORT_LD_DEBUG__)

                if(_dl_debug_move)

                  _dl_dprintf(_dl_debug_file,"\n%s move %x bytes from %x to %x",

                             symname, symtab[symtab_index].st_size,

                             symbol_addr, symtab[symtab_index].st_value);

#endif

                _dl_memcpy((char *) symtab[symtab_index].st_value,

                        (char *) symbol_addr, symtab[symtab_index].st_size);

        }

        return goof;

}

void _dl_parse_lazy_relocation_information(struct elf_resolve *tpnt,

        unsigned long rel_addr, unsigned long rel_size, int type)

{

        (void) type;

        (void)_dl_parse(tpnt, NULL, rel_addr, rel_size, _dl_do_lazy_reloc);

}

int _dl_parse_relocation_information(struct elf_resolve *tpnt,

        unsigned long rel_addr, unsigned long rel_size, int type)

{

        (void) type;

        return _dl_parse(tpnt, tpnt->symbol_scope, rel_addr, rel_size, _dl_do_reloc);

}

int _dl_parse_copy_information(struct dyn_elf *xpnt, unsigned long rel_addr,

        unsigned long rel_size, int type)

{

        (void) type;

        return _dl_parse(xpnt->dyn, xpnt->next, rel_addr, rel_size, _dl_do_copy);

}