ldso/ldso/mips/elfinterp.c

   1 /* vi: set sw=4 ts=4: */
   2 /* mips/mipsel ELF shared library loader suppport
   3  *
   4    Copyright (C) 2002, Steven J. Hill (sjhill@realitydiluted.com)
   5  *
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. The name of the above contributors may not be
  14  *    used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include "ldso.h"
  31
  32 extern int _dl_runtime_resolve(void);
  33 extern int _dl_runtime_pltresolve(void);
  34
  35 #define OFFSET_GP_GOT 0x7ff0
  36
  37 unsigned long __dl_runtime_resolve(unsigned long sym_index,
  38         unsigned long old_gpreg)
  39 {
  40         unsigned long *got = (unsigned long *) (old_gpreg - OFFSET_GP_GOT);
  41         struct elf_resolve *tpnt = (struct elf_resolve *) got[1];
  42         ElfW(Sym) *sym;
  43         char *strtab;
  44         unsigned long local_gotno;
  45         unsigned long gotsym;
  46         unsigned long new_addr;
  47         unsigned long instr_addr;
  48         char **got_addr;
  49         char *symname;
  50
  51         gotsym = tpnt->dynamic_info[DT_MIPS_GOTSYM_IDX];
  52         local_gotno = tpnt->dynamic_info[DT_MIPS_LOCAL_GOTNO_IDX];
  53
  54         sym = ((ElfW(Sym) *) tpnt->dynamic_info[DT_SYMTAB]) + sym_index;
  55         strtab = (char *) tpnt->dynamic_info[DT_STRTAB];
  56         symname = strtab + sym->st_name;
  57
  58         new_addr = (unsigned long) _dl_find_hash(symname,
  59                         tpnt->symbol_scope, tpnt, ELF_RTYPE_CLASS_PLT, NULL);
  60         if (unlikely(!new_addr)) {
  61                 _dl_dprintf (2, "%s: can't resolve symbol '%s'\n",
  62                                 _dl_progname, symname);
  63                 _dl_exit (1);
  64         }
  65
  66         /* Address of jump instruction to fix up */
  67         instr_addr = (unsigned long) (got + local_gotno + sym_index - gotsym);
  68         got_addr = (char **) instr_addr;
  69
  70 #if defined (__SUPPORT_LD_DEBUG__)
  71         if (_dl_debug_bindings)
  72         {
  73                 _dl_dprintf(_dl_debug_file, "\nresolve function: %s", symname);
  74                 if (_dl_debug_detail) _dl_dprintf(_dl_debug_file,
  75                                 "\n\tpatched %x ==> %x @ %x\n", *got_addr, new_addr, got_addr);
  76         }
  77         if (!_dl_debug_nofixups) {
  78                 *got_addr = (char*)new_addr;
  79         }
  80 #else
  81         *got_addr = (char*)new_addr;
  82 #endif
  83
  84         return new_addr;
  85 }
  86
  87 unsigned long
  88 __dl_runtime_pltresolve(struct elf_resolve *tpnt, int reloc_entry)
  89 {
  90         ELF_RELOC *this_reloc;
  91         char *strtab;
  92         Elf32_Sym *symtab;
  93         int symtab_index;
  94         char *rel_addr;
  95         char *new_addr;
  96         char **got_addr;
  97         unsigned long instr_addr;
  98         char *symname;
  99
 100         rel_addr = (char *)tpnt->dynamic_info[DT_JMPREL];
 101         this_reloc = (ELF_RELOC *)(intptr_t)(rel_addr + reloc_entry);
 102         symtab_index = ELF32_R_SYM(this_reloc->r_info);
 103
 104         symtab = (Elf32_Sym *)(intptr_t)tpnt->dynamic_info[DT_SYMTAB];
 105         strtab = (char *)tpnt->dynamic_info[DT_STRTAB];
 106         symname = strtab + symtab[symtab_index].st_name;
 107
 108         /* Address of the jump instruction to fix up. */
 109         instr_addr = ((unsigned long)this_reloc->r_offset +
 110                       (unsigned long)tpnt->loadaddr);
 111         got_addr = (char **)instr_addr;
 112
 113         /* Get the address of the GOT entry. */
 114         new_addr = _dl_find_hash(symname, tpnt->symbol_scope, tpnt, ELF_RTYPE_CLASS_PLT, NULL);
 115         if (unlikely(!new_addr)) {
 116                 _dl_dprintf(2, "%s: can't resolve symbol '%s' in lib '%s'.\n", _dl_progname, symname, tpnt->libname);
 117                 _dl_exit(1);
 118         }
 119
 120 #if defined (__SUPPORT_LD_DEBUG__)
 121         if ((unsigned long)got_addr < 0x40000000) {
 122                 if (_dl_debug_bindings) {
 123                         _dl_dprintf(_dl_debug_file, "\nresolve function: %s", symname);
 124                         if (_dl_debug_detail)
 125                                 _dl_dprintf(_dl_debug_file,
 126                                             "\n\tpatched: %x ==> %x @ %x",
 127                                             *got_addr, new_addr, got_addr);
 128                 }
 129         }
 130         if (!_dl_debug_nofixups) {
 131                 *got_addr = new_addr;
 132         }
 133 #else
 134         *got_addr = new_addr;
 135 #endif
 136
 137         return (unsigned long)new_addr;
 138 }
 139
 140 void _dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
 141         unsigned long rel_addr, unsigned long rel_size)
 142 {
 143         /* Nothing to do */
 144         return;
 145 }
 146
 147 int _dl_parse_relocation_information(struct dyn_elf *xpnt,
 148         unsigned long rel_addr, unsigned long rel_size)
 149 {
 150         ElfW(Sym) *symtab;
 151         ELF_RELOC *rpnt;
 152         char *strtab;
 153         unsigned long i;
 154         unsigned long *got;
 155         unsigned long *reloc_addr=NULL;
 156         unsigned long symbol_addr;
 157         int reloc_type, symtab_index;
 158         struct elf_resolve *tpnt = xpnt->dyn;
 159         char *symname = NULL;
 160 #if defined (__SUPPORT_LD_DEBUG__)
 161         unsigned long old_val=0;
 162 #endif
 163
 164         /* Now parse the relocation information */
 165         rel_size = rel_size / sizeof(ElfW(Rel));
 166         rpnt = (ELF_RELOC *) rel_addr;
 167
 168         symtab = (ElfW(Sym) *) tpnt->dynamic_info[DT_SYMTAB];
 169         strtab = (char *) tpnt->dynamic_info[DT_STRTAB];
 170         got = (unsigned long *) tpnt->dynamic_info[DT_PLTGOT];
 171
 172         for (i = 0; i < rel_size; i++, rpnt++) {
 173                 reloc_addr = (unsigned long *) (tpnt->loadaddr +
 174                         (unsigned long) rpnt->r_offset);
 175                 reloc_type = ELF_R_TYPE(rpnt->r_info);
 176                 symtab_index = ELF_R_SYM(rpnt->r_info);
 177                 symbol_addr = 0;
 178
 179                 debug_sym(symtab,strtab,symtab_index);
 180                 debug_reloc(symtab,strtab,rpnt);
 181                 symname = strtab + symtab[symtab_index].st_name;
 182 #if defined (__SUPPORT_LD_DEBUG__)
 183                 if (reloc_addr)
 184                         old_val = *reloc_addr;
 185 #endif
 186
 187                 if (reloc_type == R_MIPS_JUMP_SLOT || reloc_type == R_MIPS_COPY) {
 188                         symbol_addr = (unsigned long)_dl_find_hash(symname,
 189                                                                    tpnt->symbol_scope,
 190                                                                    tpnt,
 191                                                                    elf_machine_type_class(reloc_type), NULL);
 192                         if (unlikely(!symbol_addr && ELF32_ST_BIND(symtab[symtab_index].st_info) != STB_WEAK))
 193                                 return 1;
 194                 }
 195                 if (!symtab_index) {
 196                         /* Relocs against STN_UNDEF are usually treated as using a
 197                         * symbol value of zero, and using the module containing the
 198                         * reloc itself.
 199                         */
 200                         symbol_addr = symtab[symtab_index].st_value;
 201                 }
 202
 203                 switch (reloc_type) {
 204 #if defined USE_TLS && USE_TLS
 205 # if _MIPS_SIM == _MIPS_SIM_ABI64
 206                 case R_MIPS_TLS_DTPMOD64:
 207                 case R_MIPS_TLS_DTPREL64:
 208                 case R_MIPS_TLS_TPREL64:
 209 # else
 210                 case R_MIPS_TLS_DTPMOD32:
 211                 case R_MIPS_TLS_DTPREL32:
 212                 case R_MIPS_TLS_TPREL32:
 213 # endif
 214                         {
 215                                 struct elf_resolve *tls_tpnt = NULL;
 216                                 struct symbol_ref sym_ref;
 217                                 sym_ref.sym =  &symtab[symtab_index];
 218                                 sym_ref.tpnt =  NULL;
 219
 220                                 if (ELF32_ST_BIND(symtab[symtab_index].st_info) != STB_LOCAL) {
 221                                         symbol_addr = (unsigned long) _dl_find_hash(symname, tpnt->symbol_scope,
 222                                                 tpnt, elf_machine_type_class(reloc_type), &sym_ref);
 223                                         tls_tpnt = sym_ref.tpnt;
 224                                 }
 225                             /* In case of a TLS reloc, tls_tpnt NULL means we have an 'anonymous'
 226                                symbol.  This is the case for a static tls variable, so the lookup
 227                                module is just that one is referencing the tls variable. */
 228                             if (!tls_tpnt)
 229                                 tls_tpnt = tpnt;
 230
 231                                 switch (reloc_type) {
 232                                         case R_MIPS_TLS_DTPMOD64:
 233                                         case R_MIPS_TLS_DTPMOD32:
 234                                                 if (tls_tpnt)
 235                                                         *(ElfW(Word) *)reloc_addr = tls_tpnt->l_tls_modid;
 236 #ifdef __SUPPORT_LD_DEBUG__
 237                                                 _dl_dprintf(2, "TLS_DTPMOD : %s, %d, %d\n",
 238                                                         symname, old_val, *((unsigned int *)reloc_addr));
 239 #endif
 240                                                 break;
 241
 242                                         case R_MIPS_TLS_DTPREL64:
 243                                         case R_MIPS_TLS_DTPREL32:
 244                                                 *(ElfW(Word) *)reloc_addr +=
 245                                                         TLS_DTPREL_VALUE (symbol_addr);
 246 #ifdef __SUPPORT_LD_DEBUG__
 247                                                 _dl_dprintf(2, "TLS_DTPREL : %s, %x, %x\n",
 248                                                         symname, old_val, *((unsigned int *)reloc_addr));
 249 #endif
 250                                                 break;
 251
 252                                         case R_MIPS_TLS_TPREL32:
 253                                         case R_MIPS_TLS_TPREL64:
 254                                                 CHECK_STATIC_TLS((struct link_map *)tls_tpnt);
 255                                                 *(ElfW(Word) *)reloc_addr +=
 256                                                         TLS_TPREL_VALUE (tls_tpnt, symbol_addr);
 257 #ifdef __SUPPORT_LD_DEBUG__
 258                                                 _dl_dprintf(2, "TLS_TPREL  : %s, %x, %x\n",
 259                                                         symname, old_val, *((unsigned int *)reloc_addr));
 260 #endif
 261                                                 break;
 262                                 }
 263
 264                                 break;
 265                         }
 266 #endif /* USE_TLS */
 267 #if _MIPS_SIM == _MIPS_SIM_ABI64
 268                 case (R_MIPS_64 << 8) | R_MIPS_REL32:
 269 #else   /* O32 || N32 */
 270                 case R_MIPS_REL32:
 271 #endif  /* O32 || N32 */
 272                         if (symtab_index) {
 273                                 if (symtab_index < tpnt->dynamic_info[DT_MIPS_GOTSYM_IDX])
 274                                         *reloc_addr +=
 275                                                 symtab[symtab_index].st_value +
 276                                                 (unsigned long) tpnt->loadaddr;
 277                                 else {
 278                                         *reloc_addr += got[symtab_index + tpnt->dynamic_info[DT_MIPS_LOCAL_GOTNO_IDX] -
 279                                                 tpnt->dynamic_info[DT_MIPS_GOTSYM_IDX]];
 280                                 }
 281                         }
 282                         else {
 283                                 *reloc_addr += (unsigned long) tpnt->loadaddr;
 284                         }
 285                         break;
 286                 case R_MIPS_JUMP_SLOT:
 287                         *reloc_addr = symbol_addr;
 288                         break;
 289                 case R_MIPS_COPY:
 290                         if (symbol_addr) {
 291 #if defined (__SUPPORT_LD_DEBUG__)
 292                                 if (_dl_debug_move)
 293                                         _dl_dprintf(_dl_debug_file,
 294                                                     "\n%s move %d bytes from %x to %x",
 295                                                     symname, symtab[symtab_index].st_size,
 296                                                     symbol_addr, reloc_addr);
 297 #endif
 298
 299                                 _dl_memcpy((char *)reloc_addr,
 300                                            (char *)symbol_addr,
 301                                            symtab[symtab_index].st_size);
 302                         }
 303                         break;
 304                 case R_MIPS_NONE:
 305                         break;
 306                 default:
 307                         {
 308                                 _dl_dprintf(2, "\n%s: ",_dl_progname);
 309
 310                                 if (symtab_index)
 311                                         _dl_dprintf(2, "symbol '%s': ", symname);
 312
 313 #if defined (__SUPPORT_LD_DEBUG__)
 314                                 _dl_dprintf(2, "can't handle reloc type '%s' in lib '%s'\n", _dl_reltypes(reloc_type), tpnt->libname);
 315 #else
 316                                 _dl_dprintf(2, "can't handle reloc type %x in lib '%s'\n", reloc_type, tpnt->libname);
 317 #endif
 318                                 _dl_exit(1);
 319                         }
 320                 }
 321
 322         }
 323 #if defined (__SUPPORT_LD_DEBUG__)
 324         if (_dl_debug_reloc && _dl_debug_detail && reloc_addr)
 325                 _dl_dprintf(_dl_debug_file, "\tpatched: %x ==> %x @ %x\n", old_val, *reloc_addr, reloc_addr);
 326 #endif
 327
 328         return 0;
 329 }
 330
 331 /* Relocate the global GOT entries for the object */
 332 void _dl_perform_mips_global_got_relocations(struct elf_resolve *tpnt, int lazy)
 333 {
 334         ElfW(Sym) *sym;
 335         char *strtab;
 336         unsigned long i, tmp_lazy;
 337         unsigned long *got_entry;
 338
 339         for (; tpnt ; tpnt = tpnt->next) {
 340
 341                 /* We don't touch the dynamic linker */
 342                 if (tpnt->libtype == program_interpreter)
 343                         continue;
 344
 345                 /* Setup the loop variables */
 346                 got_entry = (unsigned long *) (tpnt->dynamic_info[DT_PLTGOT])
 347                         + tpnt->dynamic_info[DT_MIPS_LOCAL_GOTNO_IDX];
 348                 sym = (ElfW(Sym) *) tpnt->dynamic_info[DT_SYMTAB] + tpnt->dynamic_info[DT_MIPS_GOTSYM_IDX];
 349                 strtab = (char *) tpnt->dynamic_info[DT_STRTAB];
 350                 i = tpnt->dynamic_info[DT_MIPS_SYMTABNO_IDX] - tpnt->dynamic_info[DT_MIPS_GOTSYM_IDX];
 351
 352 #if defined (__SUPPORT_LD_DEBUG__)
 353                 if (_dl_debug_reloc)
 354                         _dl_dprintf(2, "_dl_perform_mips_global_got_relocations for '%s'\n", tpnt->libname);
 355 #endif
 356                 tmp_lazy = lazy && !tpnt->dynamic_info[DT_BIND_NOW];
 357                 /* Relocate the global GOT entries for the object */
 358                 while (i--) {
 359                         if (sym->st_shndx == SHN_UNDEF) {
 360                                 if (ELF_ST_TYPE(sym->st_info) == STT_FUNC && sym->st_value && tmp_lazy) {
 361                                         *got_entry = sym->st_value + (unsigned long) tpnt->loadaddr;
 362                                 }
 363                                 else {
 364                                         *got_entry = (unsigned long) _dl_find_hash(strtab +
 365                                                 sym->st_name, tpnt->symbol_scope, tpnt, ELF_RTYPE_CLASS_PLT, NULL);
 366                                 }
 367                         }
 368                         else if (sym->st_shndx == SHN_COMMON) {
 369                                 *got_entry = (unsigned long) _dl_find_hash(strtab +
 370                                         sym->st_name, tpnt->symbol_scope, tpnt, ELF_RTYPE_CLASS_PLT, NULL);
 371                         }
 372                         else if (ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
 373                                 *got_entry != sym->st_value && tmp_lazy) {
 374                                 *got_entry += (unsigned long) tpnt->loadaddr;
 375                         }
 376                         else if (ELF_ST_TYPE(sym->st_info) == STT_SECTION) {
 377                                 if (sym->st_other == 0)
 378                                         *got_entry += (unsigned long) tpnt->loadaddr;
 379                         }
 380                         else {
 381                                 *got_entry = (unsigned long) _dl_find_hash(strtab +
 382                                         sym->st_name, tpnt->symbol_scope, tpnt, ELF_RTYPE_CLASS_PLT, NULL);
 383                         }
 384
 385                         got_entry++;
 386                         sym++;
 387                 }
 388         }
 389 }
 390