reloc.c revision 1.31
1 /* $NetBSD: reloc.c,v 1.31 2000/07/26 02:07:34 mycroft Exp $ */ 2 3 /* 4 * Copyright 1996 John D. Polstra. 5 * Copyright 1996 Matt Thomas <matt (at) 3am-software.com> 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. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by John Polstra. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 /* 35 * Dynamic linker for ELF. 36 * 37 * John Polstra <jdp (at) polstra.com>. 38 */ 39 40 #include <err.h> 41 #include <errno.h> 42 #include <fcntl.h> 43 #include <stdarg.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include <unistd.h> 48 #include <sys/types.h> 49 #include <sys/mman.h> 50 #include <dirent.h> 51 52 #include "debug.h" 53 #include "rtld.h" 54 55 #ifndef RTLD_INHIBIT_COPY_RELOCS 56 static int _rtld_do_copy_relocation __P((const Obj_Entry *, const Elf_RelA *, 57 bool)); 58 59 /* 60 * XXX: These don't work for the alpha and i386; don't know about powerpc 61 * The alpha and the i386 avoid the problem by compiling everything PIC. 62 * These relocation are supposed to be writing the address of the 63 * function to be called on the bss.rel or bss.rela segment, but: 64 * - st_size == 0 65 * - on the i386 at least the call instruction is a direct call 66 * not an indirect call. 67 */ 68 static int 69 _rtld_do_copy_relocation(dstobj, rela, dodebug) 70 const Obj_Entry *dstobj; 71 const Elf_RelA *rela; 72 bool dodebug; 73 { 74 void *dstaddr = (void *)(dstobj->relocbase + rela->r_offset); 75 const Elf_Sym *dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info); 76 const char *name = dstobj->strtab + dstsym->st_name; 77 unsigned long hash = _rtld_elf_hash(name); 78 size_t size = dstsym->st_size; 79 const void *srcaddr; 80 const Elf_Sym *srcsym; 81 Obj_Entry *srcobj; 82 83 for (srcobj = dstobj->next; srcobj != NULL; srcobj = srcobj->next) 84 if ((srcsym = _rtld_symlook_obj(name, hash, srcobj, 85 false)) != NULL) 86 break; 87 88 if (srcobj == NULL) { 89 _rtld_error("Undefined symbol \"%s\" referenced from COPY" 90 " relocation in %s", name, dstobj->path); 91 return (-1); 92 } 93 srcaddr = (const void *)(srcobj->relocbase + srcsym->st_value); 94 (void)memcpy(dstaddr, srcaddr, size); 95 rdbg(dodebug, ("COPY %s %s %s --> src=%p dst=%p *dst= %p size %ld", 96 dstobj->path, srcobj->path, name, (void *)srcaddr, 97 (void *)dstaddr, (void *)*(long *)dstaddr, (long)size)); 98 return (0); 99 } 100 #endif /* RTLD_INHIBIT_COPY_RELOCS */ 101 102 103 /* 104 * Process the special R_xxx_COPY relocations in the main program. These 105 * copy data from a shared object into a region in the main program's BSS 106 * segment. 107 * 108 * Returns 0 on success, -1 on failure. 109 */ 110 int 111 _rtld_do_copy_relocations(dstobj, dodebug) 112 const Obj_Entry *dstobj; 113 bool dodebug; 114 { 115 #ifndef RTLD_INHIBIT_COPY_RELOCS 116 117 /* COPY relocations are invalid elsewhere */ 118 assert(dstobj->mainprog); 119 120 if (dstobj->rel != NULL) { 121 const Elf_Rel *rel; 122 for (rel = dstobj->rel; rel < dstobj->rellim; ++rel) { 123 if (ELF_R_TYPE(rel->r_info) == R_TYPE(COPY)) { 124 Elf_RelA ourrela; 125 ourrela.r_info = rel->r_info; 126 ourrela.r_offset = rel->r_offset; 127 ourrela.r_addend = 0; 128 if (_rtld_do_copy_relocation(dstobj, 129 &ourrela, dodebug) < 0) 130 return (-1); 131 } 132 } 133 } 134 if (dstobj->rela != NULL) { 135 const Elf_RelA *rela; 136 for (rela = dstobj->rela; rela < dstobj->relalim; ++rela) { 137 if (ELF_R_TYPE(rela->r_info) == R_TYPE(COPY)) { 138 if (_rtld_do_copy_relocation(dstobj, rela, 139 dodebug) < 0) 140 return (-1); 141 } 142 } 143 } 144 #endif /* RTLD_INHIBIT_COPY_RELOCS */ 145 146 return (0); 147 } 148 149 150 #ifndef __sparc__ 151 int 152 _rtld_relocate_nonplt_object(obj, rela, dodebug) 153 Obj_Entry *obj; 154 const Elf_RelA *rela; 155 bool dodebug; 156 { 157 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 158 const Elf_Sym *def; 159 const Obj_Entry *defobj; 160 #if defined(__alpha__) || defined(__i386__) || defined(__m68k__) 161 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 162 extern Elf_Dyn _DYNAMIC; 163 #endif 164 #if defined(__alpha__) || defined(__i386__) || defined(__m68k__) || \ 165 defined(__powerpc__) || defined(__vax__) 166 Elf_Addr tmp; 167 #endif 168 169 switch (ELF_R_TYPE(rela->r_info)) { 170 171 case R_TYPE(NONE): 172 break; 173 174 #if defined(__i386__) 175 case R_TYPE(GOT32): 176 177 def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, 178 &defobj, false); 179 if (def == NULL) 180 return -1; 181 182 tmp = (Elf_Addr)(defobj->relocbase + def->st_value); 183 if (*where != tmp) 184 *where = tmp; 185 rdbg(dodebug, ("GOT32 %s in %s --> %p in %s", 186 defobj->strtab + def->st_name, obj->path, 187 (void *)*where, defobj->path)); 188 break; 189 190 case R_TYPE(PC32): 191 /* 192 * I don't think the dynamic linker should ever see this 193 * type of relocation. But the binutils-2.6 tools sometimes 194 * generate it. 195 */ 196 197 def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, 198 &defobj, false); 199 if (def == NULL) 200 return -1; 201 202 *where += (Elf_Addr)(defobj->relocbase + def->st_value) - 203 (Elf_Addr)where; 204 rdbg(dodebug, ("PC32 %s in %s --> %p in %s", 205 defobj->strtab + def->st_name, obj->path, 206 (void *)*where, defobj->path)); 207 break; 208 209 case R_TYPE(32): 210 def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, 211 &defobj, false); 212 if (def == NULL) 213 return -1; 214 215 *where += (Elf_Addr)(defobj->relocbase + def->st_value); 216 rdbg(dodebug, ("32 %s in %s --> %p in %s", 217 defobj->strtab + def->st_name, obj->path, 218 (void *)*where, defobj->path)); 219 break; 220 #endif /* __i386__ */ 221 222 #if defined(__m68k__) 223 case R_TYPE(GOT32): 224 def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, 225 &defobj, false); 226 if (def == NULL) 227 return -1; 228 229 tmp = (Elf_Addr)(defobj->relocbase + def->st_value + 230 rela->r_addend); 231 if (*where != tmp) 232 *where = tmp; 233 rdbg(dodebug, ("GOT32 %s in %s --> %p in %s", 234 defobj->strtab + def->st_name, obj->path, 235 (void *)*where, defobj->path)); 236 break; 237 238 case R_TYPE(PC32): 239 def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, 240 &defobj, false); 241 if (def == NULL) 242 return -1; 243 244 tmp = (Elf_Addr)(defobj->relocbase + def->st_value + 245 rela->r_addend) - (Elf_Addr)where; 246 if (*where != tmp) 247 *where = tmp; 248 rdbg(dodebug, ("PC32 %s in %s --> %p in %s", 249 defobj->strtab + def->st_name, obj->path, 250 (void *)*where, defobj->path)); 251 break; 252 253 case R_TYPE(32): 254 def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, 255 &defobj, false); 256 if (def == NULL) 257 return -1; 258 259 tmp = (Elf_Addr)(defobj->relocbase + def->st_value + 260 rela->r_addend); 261 if (*where != tmp) 262 *where = tmp; 263 rdbg(dodebug, ("32 %s in %s --> %p in %s", 264 defobj->strtab + def->st_name, obj->path, 265 (void *)*where, defobj->path)); 266 break; 267 #endif /* __m68k__ */ 268 269 #if defined(__alpha__) 270 case R_TYPE(REFQUAD): 271 def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, 272 &defobj, false); 273 if (def == NULL) 274 return -1; 275 276 tmp = (Elf_Addr)(defobj->relocbase + def->st_value) + 277 *where + rela->r_addend; 278 if (*where != tmp) 279 *where = tmp; 280 rdbg(dodebug, ("REFQUAD %s in %s --> %p in %s", 281 defobj->strtab + def->st_name, obj->path, 282 (void *)*where, defobj->path)); 283 break; 284 #endif /* __alpha__ */ 285 286 #if defined(__alpha__) || defined(__i386__) || defined(__m68k__) 287 case R_TYPE(GLOB_DAT): 288 def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, 289 &defobj, false); 290 if (def == NULL) 291 return -1; 292 293 if (*where != (Elf_Addr)(defobj->relocbase + def->st_value)) 294 *where = (Elf_Addr)(defobj->relocbase + def->st_value); 295 rdbg(dodebug, ("GLOB_DAT %s in %s --> %p in %s", 296 defobj->strtab + def->st_name, obj->path, 297 (void *)*where, defobj->path)); 298 break; 299 300 case R_TYPE(RELATIVE): 301 if (!dodebug || 302 (caddr_t)where < (caddr_t)_GLOBAL_OFFSET_TABLE_ || 303 (caddr_t)where >= (caddr_t)&_DYNAMIC) { 304 *where += (Elf_Addr)obj->relocbase; 305 rdbg(dodebug, ("RELATIVE in %s --> %p", obj->path, 306 (void *)*where)); 307 } 308 else 309 rdbg(dodebug, ("RELATIVE in %s stays at %p", 310 obj->path, (void *)*where)); 311 break; 312 313 case R_TYPE(COPY): 314 /* 315 * These are deferred until all other relocations have 316 * been done. All we do here is make sure that the COPY 317 * relocation is not in a shared library. They are allowed 318 * only in executable files. 319 */ 320 if (!obj->mainprog) { 321 _rtld_error( 322 "%s: Unexpected R_COPY relocation in shared library", 323 obj->path); 324 return -1; 325 } 326 rdbg(dodebug, ("COPY (avoid in main)")); 327 break; 328 #endif /* __i386__ || __alpha__ || __m68k__ */ 329 330 #if defined(__mips__) 331 case R_TYPE(REL32): 332 /* 32-bit PC-relative reference */ 333 def = obj->symtab + ELF_R_SYM(rela->r_info); 334 335 if (ELFDEFNNAME(ST_BIND)(def->st_info) == STB_LOCAL && 336 (ELFDEFNNAME(ST_TYPE)(def->st_info) == STT_SECTION || 337 ELFDEFNNAME(ST_TYPE)(def->st_info) == STT_NOTYPE)) { 338 *where += (Elf_Addr)obj->relocbase; 339 rdbg(dodebug, ("REL32 in %s --> %p", obj->path, 340 (void *)*where)); 341 } else { 342 /* XXX maybe do something re: bootstrapping? */ 343 def = _rtld_find_symdef(_rtld_objlist, rela->r_info, 344 NULL, obj, &defobj, false); 345 if (def == NULL) 346 return -1; 347 *where += (Elf_Addr)(defobj->relocbase + def->st_value); 348 rdbg(dodebug, ("REL32 %s in %s --> %p in %s", 349 defobj->strtab + def->st_name, obj->path, 350 (void *)*where, defobj->path)); 351 } 352 break; 353 354 #endif /* __mips__ */ 355 356 #if defined(__powerpc__) || defined(__vax__) 357 case R_TYPE(32): /* word32 S + A */ 358 case R_TYPE(GLOB_DAT): /* word32 S + A */ 359 def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, 360 &defobj, false); 361 if (def == NULL) 362 return -1; 363 364 tmp = (Elf_Addr)(defobj->relocbase + def->st_value + 365 rela->r_addend); 366 367 if (*where != tmp) 368 *where = tmp; 369 rdbg(dodebug, ("32/GLOB_DAT %s in %s --> %p in %s", 370 defobj->strtab + def->st_name, obj->path, 371 (void *)*where, defobj->path)); 372 break; 373 374 case R_TYPE(COPY): 375 rdbg(dodebug, ("COPY")); 376 break; 377 378 case R_TYPE(JMP_SLOT): 379 rdbg(dodebug, ("JMP_SLOT")); 380 break; 381 382 case R_TYPE(RELATIVE): /* word32 B + A */ 383 tmp = (Elf_Addr)(obj->relocbase + rela->r_addend); 384 if (*where != tmp) 385 *where = tmp; 386 rdbg(dodebug, ("RELATIVE in %s --> %p", obj->path, 387 (void *)*where)); 388 break; 389 #endif /* __powerpc__ || __vax__ */ 390 391 #if defined(__powerpc__) 392 case R_TYPE(16_LO): /* #lo(S + A) */ 393 tmp = (Elf_Addr)(obj->relocbase + rela->r_addend); 394 if (*(Elf32_Half *)where != tmp) 395 *(Elf32_Half *)where = tmp; 396 rdbg(dodebug, ("16_LO in %s --> %p", obj->path, 397 (void *)*where)); 398 break; 399 400 case R_TYPE(16_HI): /* #hi(S + A) */ 401 tmp = (Elf_Addr)(obj->relocbase + rela->r_addend) >> 16; 402 if (*(Elf32_Half *)where != tmp) 403 *(Elf32_Half *)where = tmp; 404 rdbg(dodebug, ("16_HI in %s --> %p", obj->path, 405 (void *)*where)); 406 break; 407 408 case R_TYPE(16_HA): /* #ha(S + A) */ 409 tmp = (Elf_Addr)(obj->relocbase + rela->r_addend + 0x8000) 410 >> 16; 411 if (*(Elf32_Half *)where != tmp) 412 *(Elf32_Half *)where = tmp; 413 rdbg(dodebug, ("16_HA in %s --> %p", obj->path, 414 (void *)*where)); 415 break; 416 #endif /* __powerpc__ */ 417 418 default: 419 def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, 420 &defobj, true); 421 rdbg(dodebug, ("sym = %lu, type = %lu, offset = %p, " 422 "addend = %p, contents = %p, symbol = %s", 423 (u_long)ELF_R_SYM(rela->r_info), 424 (u_long)ELF_R_TYPE(rela->r_info), 425 (void *)rela->r_offset, (void *)rela->r_addend, 426 (void *)*where, 427 def ? defobj->strtab + def->st_name : "??")); 428 _rtld_error("%s: Unsupported relocation type %d " 429 "in non-PLT relocations\n", 430 obj->path, ELF_R_TYPE(rela->r_info)); 431 return -1; 432 } 433 return 0; 434 } 435 436 437 438 int 439 _rtld_relocate_plt_object(obj, rela, addrp, bind_now, dodebug) 440 Obj_Entry *obj; 441 const Elf_RelA *rela; 442 caddr_t *addrp; 443 bool bind_now; 444 bool dodebug; 445 { 446 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 447 Elf_Addr new_value; 448 449 /* Fully resolve procedure addresses now */ 450 451 #if defined(__powerpc__) 452 return _rtld_reloc_powerpc_plt(obj, rela, bind_now); 453 #endif 454 455 #if defined(__alpha__) || defined(__i386__) || defined(__m68k__) || \ 456 defined(__vax__) 457 if (bind_now || obj->pltgot == NULL) { 458 const Elf_Sym *def; 459 const Obj_Entry *defobj; 460 461 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT)); 462 463 def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, 464 &defobj, true); 465 if (def == NULL) 466 return -1; 467 468 new_value = (Elf_Addr)(defobj->relocbase + def->st_value); 469 #if defined(__vax__) 470 new_value += rela->r_addend; 471 #endif 472 rdbg(dodebug, ("bind now %d/fixup in %s --> old=%p new=%p", 473 (int)bind_now, 474 defobj->strtab + def->st_name, 475 (void *)*where, (void *)new_value)); 476 } else 477 #endif /* __alpha__ || __i386__ || __m68k__ || __vax__ */ 478 if (!obj->mainprog) { 479 /* Just relocate the GOT slots pointing into the PLT */ 480 new_value = *where + (Elf_Addr)(obj->relocbase); 481 rdbg(dodebug, ("fixup !main in %s --> %p", obj->path, 482 (void *)*where)); 483 } else { 484 return 0; 485 } 486 /* 487 * Since this page is probably copy-on-write, let's not write 488 * it unless we really really have to. 489 */ 490 if (*where != new_value) 491 *where = new_value; 492 if (addrp != NULL) { 493 *addrp = *(caddr_t *)(obj->relocbase + rela->r_offset); 494 #if defined(__vax__) 495 *addrp -= rela->r_addend; 496 #endif 497 } 498 return 0; 499 } 500 #endif /* __sparc__ */ 501 502 caddr_t 503 _rtld_bind(obj, reloff) 504 Obj_Entry *obj; 505 Elf_Word reloff; 506 { 507 const Elf_RelA *rela; 508 Elf_RelA ourrela; 509 caddr_t addr; 510 511 if (obj->pltrel != NULL) { 512 const Elf_Rel *rel; 513 514 rel = (const Elf_Rel *)((caddr_t) obj->pltrel + reloff); 515 ourrela.r_info = rel->r_info; 516 ourrela.r_offset = rel->r_offset; 517 ourrela.r_addend = 0; 518 rela = &ourrela; 519 } else { 520 rela = (const Elf_RelA *)((caddr_t) obj->pltrela + reloff); 521 } 522 523 if (_rtld_relocate_plt_object(obj, rela, &addr, true, true) < 0) 524 _rtld_die(); 525 526 return addr; 527 } 528 529 /* 530 * Relocate newly-loaded shared objects. The argument is a pointer to 531 * the Obj_Entry for the first such object. All objects from the first 532 * to the end of the list of objects are relocated. Returns 0 on success, 533 * or -1 on failure. 534 */ 535 int 536 _rtld_relocate_objects(first, bind_now, dodebug) 537 Obj_Entry *first; 538 bool bind_now; 539 bool dodebug; 540 { 541 Obj_Entry *obj; 542 int ok = 1; 543 544 for (obj = first; obj != NULL; obj = obj->next) { 545 if (obj->nbuckets == 0 || obj->nchains == 0 || 546 obj->buckets == NULL || obj->symtab == NULL || 547 obj->strtab == NULL) { 548 _rtld_error("%s: Shared object has no run-time" 549 " symbol table", obj->path); 550 return -1; 551 } 552 rdbg(dodebug, (" relocating %s (%ld/%ld rel/rela, " 553 "%ld/%ld plt rel/rela)", 554 obj->path, 555 (long)(obj->rellim - obj->rel), 556 (long)(obj->relalim - obj->rela), 557 (long)(obj->pltrellim - obj->pltrel), 558 (long)(obj->pltrelalim - obj->pltrela))); 559 560 if (obj->textrel) { 561 /* 562 * There are relocations to the write-protected text 563 * segment. 564 */ 565 if (mprotect(obj->mapbase, obj->textsize, 566 PROT_READ | PROT_WRITE | PROT_EXEC) == -1) { 567 _rtld_error("%s: Cannot write-enable text " 568 "segment: %s", obj->path, xstrerror(errno)); 569 return -1; 570 } 571 } 572 if (obj->rel != NULL) { 573 /* Process the non-PLT relocations. */ 574 const Elf_Rel *rel; 575 for (rel = obj->rel; rel < obj->rellim; ++rel) { 576 Elf_RelA ourrela; 577 ourrela.r_info = rel->r_info; 578 ourrela.r_offset = rel->r_offset; 579 #if defined(__mips__) 580 /* rel->r_offset is not valid on mips? */ 581 if (ELF_R_TYPE(ourrela.r_info) == R_TYPE(NONE)) 582 ourrela.r_addend = 0; 583 else 584 #endif 585 ourrela.r_addend = 586 *(Elf_Word *)(obj->relocbase + 587 rel->r_offset); 588 589 if (_rtld_relocate_nonplt_object(obj, &ourrela, 590 dodebug) < 0) 591 ok = 0; 592 } 593 } 594 if (obj->rela != NULL) { 595 /* Process the non-PLT relocations. */ 596 const Elf_RelA *rela; 597 for (rela = obj->rela; rela < obj->relalim; ++rela) { 598 if (_rtld_relocate_nonplt_object(obj, rela, 599 dodebug) < 0) 600 ok = 0; 601 } 602 } 603 if (obj->textrel) { /* Re-protected the text segment. */ 604 if (mprotect(obj->mapbase, obj->textsize, 605 PROT_READ | PROT_EXEC) == -1) { 606 _rtld_error("%s: Cannot write-protect text " 607 "segment: %s", obj->path, xstrerror(errno)); 608 return -1; 609 } 610 } 611 /* Process the PLT relocations. */ 612 if (obj->pltrel != NULL) { 613 const Elf_Rel *rel; 614 for (rel = obj->pltrel; rel < obj->pltrellim; ++rel) { 615 Elf_RelA ourrela; 616 ourrela.r_info = rel->r_info; 617 ourrela.r_offset = rel->r_offset; 618 ourrela.r_addend = 619 *(Elf_Word *)(obj->relocbase + 620 rel->r_offset); 621 if (_rtld_relocate_plt_object(obj, &ourrela, 622 NULL, bind_now, dodebug) < 0) 623 ok = 0; 624 } 625 } 626 if (obj->pltrela != NULL) { 627 const Elf_RelA *rela; 628 for (rela = obj->pltrela; rela < obj->pltrelalim; 629 ++rela) { 630 if (_rtld_relocate_plt_object(obj, rela, 631 NULL, bind_now, dodebug) < 0) 632 ok = 0; 633 } 634 } 635 if (!ok) 636 return -1; 637 638 639 /* Set some sanity-checking numbers in the Obj_Entry. */ 640 obj->magic = RTLD_MAGIC; 641 obj->version = RTLD_VERSION; 642 643 /* Fill in the dynamic linker entry points. */ 644 obj->dlopen = _rtld_dlopen; 645 obj->dlsym = _rtld_dlsym; 646 obj->dlerror = _rtld_dlerror; 647 obj->dlclose = _rtld_dlclose; 648 obj->dladdr = _rtld_dladdr; 649 650 /* Set the special PLTGOT entries. */ 651 if (obj->pltgot != NULL) { 652 #if defined(__i386__) || defined(__m68k__) 653 obj->pltgot[1] = (Elf_Addr) obj; 654 obj->pltgot[2] = (Elf_Addr) & _rtld_bind_start; 655 #endif 656 #if defined(__alpha__) 657 /* 658 * This function will be called to perform the 659 * relocation. 660 */ 661 obj->pltgot[2] = (Elf_Addr) & _rtld_bind_start; 662 /* Identify this shared object */ 663 obj->pltgot[3] = (Elf_Addr) obj; 664 #endif 665 #if defined(__mips__) 666 _rtld_relocate_mips_got(obj); 667 668 obj->pltgot[0] = (Elf_Addr) & _rtld_bind_start; 669 /* XXX only if obj->pltgot[1] & 0x80000000 ?? */ 670 obj->pltgot[1] |= (Elf_Addr) obj; 671 #endif 672 #if defined(__powerpc__) 673 _rtld_setup_powerpc_plt(obj); 674 #endif 675 #if defined(__sparc__) 676 #if defined(__arch64__) || defined(__sparc_v9__) 677 /* 678 * On sparc64 we got troubles. 679 * 680 * Instructions are 4 bytes long. 681 * Elf[64]_Addr is 8 bytes long, so are our pltglot[] 682 * array entries. 683 * Each PLT entry jumps to PLT0 to enter the dynamic 684 * linker. 685 * Loading an arbitrary 64-bit pointer takes 6 686 * instructions and 2 registers. 687 * 688 * Somehow we need to issue a save to get a new stack 689 * frame, load the address of the dynamic linker, and 690 * jump there, in 8 instructions or less. 691 * 692 * Oh, we need to fill out both PLT0 and PLT1. 693 */ 694 { 695 Elf_Word *entry = (Elf_Word *)obj->pltgot; 696 extern void _rtld_install_plt __P((Elf_Word *, 697 Elf_Addr)); 698 extern void _rtld_bind_start_0 __P((long, 699 long)); 700 extern void _rtld_bind_start_1 __P((long, 701 long)); 702 703 /* Install in entries 0 and 1 */ 704 _rtld_install_plt(&entry[0], 705 (Elf_Addr)&_rtld_bind_start_0); 706 _rtld_install_plt(&entry[8], 707 (Elf_Addr)&_rtld_bind_start_1); 708 709 /* 710 * Install the object reference in first slot 711 * of entry 2. 712 */ 713 obj->pltgot[8] = (Elf_Addr) obj; 714 } 715 #else 716 /* 717 * PLTGOT is the PLT on the sparc. 718 * The first entry holds the call the dynamic linker. 719 * We construct a `call' sequence that transfers 720 * to `_rtld_bind_start()'. 721 * The second entry holds the object identification. 722 * Note: each PLT entry is three words long. 723 */ 724 #define SAVE 0x9de3bfc0 /* i.e. `save %sp,-64,%sp' */ 725 #define CALL 0x40000000 726 #define NOP 0x01000000 727 obj->pltgot[0] = SAVE; 728 obj->pltgot[1] = CALL | 729 ((Elf_Addr)&_rtld_bind_start - 730 (Elf_Addr)&obj->pltgot[1]) >> 2; 731 obj->pltgot[2] = NOP; 732 733 obj->pltgot[3] = (Elf_Addr) obj; 734 #endif /* __arch64__ */ 735 #endif /* __sparc__ */ 736 #if defined(__vax__) 737 obj->pltgot[1] = (Elf_Addr) obj->pltgot; 738 obj->pltgot[2] = (Elf_Addr) & _rtld_bind_start; 739 obj->pltgot[3] = (Elf_Addr) obj; 740 #endif 741 } 742 } 743 744 return 0; 745 } 746
Indexes created Tue Sep 30 11:09:46 GMT 2025