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

/* ARM ELF shared library loader suppport

 *

 * 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_ARM_NONE",       "R_ARM_PC24",       "R_ARM_ABS32",          "R_ARM_REL32",

  [4]   "R_ARM_PC13",       "R_ARM_ABS16",      "R_ARM_ABS12",          "R_ARM_THM_ABS5",

  [8]   "R_ARM_ABS8",           "R_ARM_SBREL32","R_ARM_THM_PC22",       "R_ARM_THM_PC8",

  [12]  "R_ARM_AMP_VCALL9",     "R_ARM_SWI24",  "R_ARM_THM_SWI8",       "R_ARM_XPC25",

  [16]  "R_ARM_THM_XPC22",

  [20]  "R_ARM_COPY",           "R_ARM_GLOB_DAT","R_ARM_JUMP_SLOT",     "R_ARM_RELATIVE",

  [24]  "R_ARM_GOTOFF",         "R_ARM_GOTPC",   "R_ARM_GOT32",         "R_ARM_PLT32",

  [32]  "R_ARM_ALU_PCREL_7_0","R_ARM_ALU_PCREL_15_8","R_ARM_ALU_PCREL_23_15","R_ARM_LDR_SBREL_11_0",

  [36]  "R_ARM_ALU_SBREL_19_12","R_ARM_ALU_SBREL_27_20",

  [100] "R_ARM_GNU_VTENTRY","R_ARM_GNU_VTINHERIT","R_ARM_THM_PC11","R_ARM_THM_PC9",

  [249] "R_ARM_RXPC25", "R_ARM_RSBREL32", "R_ARM_THM_RPC22", "R_ARM_RREL32",

  [253] "R_ARM_RABS22", "R_ARM_RPC24", "R_ARM_RBASE",

};

static const char *

_dl_reltypes(int type)

{

  static char buf[22];

  const char *str;

  if (type >= (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\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";

#ifdef ELF_USES_RELOCA

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

                _dl_reltypes(ELF32_R_TYPE(rpnt->r_info)),

                rpnt->r_offset,

                rpnt->r_addend,

                sym);

#else

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

                _dl_reltypes(ELF32_R_TYPE(rpnt->r_info)),

                rpnt->r_offset,

                sym);

#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;

        ELF_RELOC *rel_addr;

        int symtab_index;

        char *new_addr;

        char **got_addr;

        unsigned long instr_addr;

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

        this_reloc = rel_addr + (reloc_entry >> 3);

        reloc_type = ELF32_R_TYPE(this_reloc->r_info);

        symtab_index = ELF32_R_SYM(this_reloc->r_info);

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

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

        if (reloc_type != R_ARM_JUMP_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(strtab + symtab[symtab_index].st_name,

                tpnt->symbol_scope, tpnt, resolver);

        if (!new_addr) {

                _dl_dprintf(2, "%s: can't resolve symbol '%s'\n",

                        _dl_progname, strtab + symtab[symtab_index].st_name);

                _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",

                                        strtab + symtab[symtab_index].st_name);

                        if(_dl_debug_detail) _dl_dprintf(_dl_debug_file,

                                        "\tpatch %x ==> %x @ %x", *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))

{

        int i;

        char *strtab;

        int goof = 0;

        Elf32_Sym *symtab;

        ELF_RELOC *rpnt;

        int symtab_index;

        /* Now parse the relocation information */

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

        rel_size = rel_size / sizeof(ELF_RELOC);

        symtab = (Elf32_Sym *) (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");

                        goof += res;

                }

          }

          return goof;

}

static unsigned long

fix_bad_pc24 (unsigned long *const reloc_addr, unsigned long value)

{

  static void *fix_page;

  static unsigned int fix_offset;

  unsigned int *fix_address;

  if (! fix_page)

    {

      fix_page = _dl_mmap (NULL,  PAGE_SIZE   , PROT_READ | PROT_WRITE | PROT_EXEC,

                       MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);

      fix_offset = 0;

    }

  fix_address = (unsigned int *)(fix_page + fix_offset);

  fix_address[0] = 0xe51ff004;  /* ldr pc, [pc, #-4] */

  fix_address[1] = value;

  fix_offset += 8;

  if (fix_offset >= PAGE_SIZE)

    fix_page = NULL;

  return (unsigned long)fix_address;

}

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;

        unsigned long *reloc_addr;

        unsigned long symbol_addr;

        int goof = 0;

        reloc_addr = (unsigned long *) (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;

        if (symtab_index) {

                symbol_addr = (unsigned long) _dl_find_hash(strtab + symtab[symtab_index].st_name,

                                scope, (reloc_type == R_ARM_JUMP_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) {

                        goof++;

                }

        }

#if defined (__SUPPORT_LD_DEBUG__)

        {

                unsigned long old_val = *reloc_addr;

#endif

                switch (reloc_type) {

                        case R_ARM_NONE:

                                break;

                        case R_ARM_ABS32:

                                *reloc_addr += symbol_addr;

                                break;

                        case R_ARM_PC24:

                                {

                                        unsigned long addend;

                                        long newvalue, topbits;

                                        addend = *reloc_addr & 0x00ffffff;

                                        if (addend & 0x00800000) addend |= 0xff000000;

                                        newvalue = symbol_addr - (unsigned long)reloc_addr + (addend << 2);

                                        topbits = newvalue & 0xfe000000;

                                        if (topbits != 0xfe000000 && topbits != 0x00000000)

                                        {

                                                newvalue = fix_bad_pc24(reloc_addr, symbol_addr)

                                                        - (unsigned long)reloc_addr + (addend << 2);

                                                topbits = newvalue & 0xfe000000;

                                                if (topbits != 0xfe000000 && topbits != 0x00000000)

                                                {

                                                        _dl_dprintf(2,"symbol '%s': R_ARM_PC24 relocation out of range.",

                                                                symtab[symtab_index].st_name);

                                                        _dl_exit(1);

                                                }

                                        }

                                        newvalue >>= 2;

                                        symbol_addr = (*reloc_addr & 0xff000000) | (newvalue & 0x00ffffff);

                                        *reloc_addr = symbol_addr;

                                        break;

                                }

                        case R_ARM_GLOB_DAT:

                        case R_ARM_JUMP_SLOT:

                                *reloc_addr = symbol_addr;

                                break;

                        case R_ARM_RELATIVE:

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

                                break;

                        case R_ARM_COPY:

#if 0                                                   

                                /* Do this later */

                                _dl_dprintf(2, "Doing copy for symbol ");

                                if (symtab_index) _dl_dprintf(2, strtab + symtab[symtab_index].st_name);

                                _dl_dprintf(2, "\n");

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

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

#endif

                                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, "\tpatch: %x ==> %x @ %x", old_val, *reloc_addr, reloc_addr);

        }

#endif

        return goof;

}

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;

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

        reloc_type = ELF32_R_TYPE(rpnt->r_info);

#if defined (__SUPPORT_LD_DEBUG__)

        {

                unsigned long old_val = *reloc_addr;

#endif

                switch (reloc_type) {

                        case R_ARM_NONE:

                                break;

                        case R_ARM_JUMP_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, "\tpatch: %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;

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

        reloc_type = ELF32_R_TYPE(rpnt->r_info);

        if (reloc_type != R_ARM_COPY)

                return 0;

        symtab_index = ELF32_R_SYM(rpnt->r_info);

        symbol_addr = 0;

        if (symtab_index) {

                symbol_addr = (unsigned long) _dl_find_hash(strtab +

                        symtab[symtab_index].st_name, 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",

                             strtab + symtab[symtab_index].st_name,

                             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)_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)

{

  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)

{

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

}