ltrace-elf.c revision fe1c171b8988a4e9a882b11291faf9d3fa09e944
1# include "config.h" 2 3#include <endian.h> 4#include <errno.h> 5#include <error.h> 6#include <fcntl.h> 7#include <gelf.h> 8#include <stdint.h> 9#include <stdlib.h> 10#include <string.h> 11#include <unistd.h> 12#include <assert.h> 13 14#include "common.h" 15 16static void do_init_elf(struct ltelf *lte, const char *filename); 17static void do_close_elf(struct ltelf *lte); 18static void add_library_symbol(GElf_Addr addr, const char *name, 19 struct library_symbol **library_symbolspp, 20 enum toplt type_of_plt, int is_weak); 21static int in_load_libraries(const char *name, struct ltelf *lte); 22static GElf_Addr opd2addr(struct ltelf *ltc, GElf_Addr addr); 23 24#ifdef PLT_REINITALISATION_BP 25extern char *PLTs_initialized_by_here; 26#endif 27 28#ifndef DT_PPC_GOT 29# define DT_PPC_GOT (DT_LOPROC + 0) 30#endif 31 32#define PPC_PLT_STUB_SIZE 16 33 34static Elf_Data *loaddata(Elf_Scn *scn, GElf_Shdr *shdr) 35{ 36 Elf_Data *data = elf_getdata(scn, NULL); 37 if (data == NULL || elf_getdata(scn, data) != NULL 38 || data->d_off || data->d_size != shdr->sh_size) 39 return NULL; 40 return data; 41} 42 43static int inside(GElf_Addr addr, GElf_Shdr *shdr) 44{ 45 return addr >= shdr->sh_addr 46 && addr < shdr->sh_addr + shdr->sh_size; 47} 48 49static int maybe_pick_section(GElf_Addr addr, 50 Elf_Scn *in_sec, GElf_Shdr *in_shdr, 51 Elf_Scn **tgt_sec, GElf_Shdr *tgt_shdr) 52{ 53 if (inside (addr, in_shdr)) { 54 *tgt_sec = in_sec; 55 *tgt_shdr = *in_shdr; 56 return 1; 57 } 58 return 0; 59} 60 61static int get_section_covering(struct ltelf *lte, GElf_Addr addr, 62 Elf_Scn **tgt_sec, GElf_Shdr *tgt_shdr) 63{ 64 int i; 65 for (i = 1; i < lte->ehdr.e_shnum; ++i) { 66 Elf_Scn *scn; 67 GElf_Shdr shdr; 68 69 scn = elf_getscn(lte->elf, i); 70 if (scn == NULL || gelf_getshdr(scn, &shdr) == NULL) { 71 debug(1, "Couldn't read section or header."); 72 return 0; 73 } 74 75 if (maybe_pick_section(addr, scn, &shdr, tgt_sec, tgt_shdr)) 76 return 1; 77 } 78 79 return 0; 80} 81 82static GElf_Addr read32be(Elf_Data *data, size_t offset) 83{ 84 if (data->d_size < offset + 4) { 85 debug(1, "Not enough data to read 32bit value at offset %zd.", 86 offset); 87 return 0; 88 } 89 90 unsigned char const *buf = data->d_buf + offset; 91 return ((Elf32_Word)buf[0] << 24) 92 | ((Elf32_Word)buf[1] << 16) 93 | ((Elf32_Word)buf[2] << 8) 94 | ((Elf32_Word)buf[3]); 95} 96 97static GElf_Addr get_glink_vma(struct ltelf *lte, GElf_Addr ppcgot, 98 Elf_Data *plt_data) 99{ 100 Elf_Scn *ppcgot_sec = NULL; 101 GElf_Shdr ppcgot_shdr; 102 if (ppcgot != 0 103 && !get_section_covering(lte, ppcgot, &ppcgot_sec, &ppcgot_shdr)) 104 // xxx should be the log out 105 fprintf(stderr, 106 "DT_PPC_GOT=%#lx, but no such section found.\n", 107 ppcgot); 108 109 if (ppcgot_sec != NULL) { 110 Elf_Data *data = loaddata(ppcgot_sec, &ppcgot_shdr); 111 if (data == NULL 112 || data->d_size < 8 ) 113 debug(1, "Couldn't read GOT data."); 114 else { 115 // where PPCGOT begins in .got 116 size_t offset = ppcgot - ppcgot_shdr.sh_addr; 117 GElf_Addr glink_vma = read32be(data, offset + 4); 118 if (glink_vma != 0) { 119 debug(1, "PPC GOT glink_vma address: %#lx", 120 glink_vma); 121 return glink_vma; 122 } 123 } 124 } 125 126 if (plt_data != NULL) { 127 GElf_Addr glink_vma = read32be(plt_data, 0); 128 debug(1, ".plt glink_vma address: %#lx", glink_vma); 129 return glink_vma; 130 } 131 132 return 0; 133} 134 135static void 136do_init_elf(struct ltelf *lte, const char *filename) { 137 int i; 138 GElf_Addr relplt_addr = 0; 139 size_t relplt_size = 0; 140 141 debug(DEBUG_FUNCTION, "do_init_elf(filename=%s)", filename); 142 debug(1, "Reading ELF from %s...", filename); 143 144 memset(lte, 0, sizeof(*lte)); 145 lte->fd = open(filename, O_RDONLY); 146 if (lte->fd == -1) 147 error(EXIT_FAILURE, errno, "Can't open \"%s\"", filename); 148 149#ifdef HAVE_ELF_C_READ_MMAP 150 lte->elf = elf_begin(lte->fd, ELF_C_READ_MMAP, NULL); 151#else 152 lte->elf = elf_begin(lte->fd, ELF_C_READ, NULL); 153#endif 154 155 if (lte->elf == NULL || elf_kind(lte->elf) != ELF_K_ELF) 156 error(EXIT_FAILURE, 0, "Can't open ELF file \"%s\"", filename); 157 158 if (gelf_getehdr(lte->elf, <e->ehdr) == NULL) 159 error(EXIT_FAILURE, 0, "Can't read ELF header of \"%s\"", 160 filename); 161 162 if (lte->ehdr.e_type != ET_EXEC && lte->ehdr.e_type != ET_DYN) 163 error(EXIT_FAILURE, 0, 164 "\"%s\" is not an ELF executable nor shared library", 165 filename); 166 167 if ((lte->ehdr.e_ident[EI_CLASS] != LT_ELFCLASS 168 || lte->ehdr.e_machine != LT_ELF_MACHINE) 169#ifdef LT_ELF_MACHINE2 170 && (lte->ehdr.e_ident[EI_CLASS] != LT_ELFCLASS2 171 || lte->ehdr.e_machine != LT_ELF_MACHINE2) 172#endif 173#ifdef LT_ELF_MACHINE3 174 && (lte->ehdr.e_ident[EI_CLASS] != LT_ELFCLASS3 175 || lte->ehdr.e_machine != LT_ELF_MACHINE3) 176#endif 177 ) 178 error(EXIT_FAILURE, 0, 179 "\"%s\" is ELF from incompatible architecture", filename); 180 181 Elf_Data *plt_data = NULL; 182 GElf_Addr ppcgot = 0; 183 184 for (i = 1; i < lte->ehdr.e_shnum; ++i) { 185 Elf_Scn *scn; 186 GElf_Shdr shdr; 187 const char *name; 188 189 scn = elf_getscn(lte->elf, i); 190 if (scn == NULL || gelf_getshdr(scn, &shdr) == NULL) 191 error(EXIT_FAILURE, 0, 192 "Couldn't get section header from \"%s\"", 193 filename); 194 195 name = elf_strptr(lte->elf, lte->ehdr.e_shstrndx, shdr.sh_name); 196 if (name == NULL) 197 error(EXIT_FAILURE, 0, 198 "Couldn't get section header from \"%s\"", 199 filename); 200 201 if (shdr.sh_type == SHT_SYMTAB) { 202 Elf_Data *data; 203 204 lte->symtab = elf_getdata(scn, NULL); 205 lte->symtab_count = shdr.sh_size / shdr.sh_entsize; 206 if ((lte->symtab == NULL 207 || elf_getdata(scn, lte->symtab) != NULL) 208 && opt_x != NULL) 209 error(EXIT_FAILURE, 0, 210 "Couldn't get .symtab data from \"%s\"", 211 filename); 212 213 scn = elf_getscn(lte->elf, shdr.sh_link); 214 if (scn == NULL || gelf_getshdr(scn, &shdr) == NULL) 215 error(EXIT_FAILURE, 0, 216 "Couldn't get section header from \"%s\"", 217 filename); 218 219 data = elf_getdata(scn, NULL); 220 if (data == NULL || elf_getdata(scn, data) != NULL 221 || shdr.sh_size != data->d_size || data->d_off) 222 error(EXIT_FAILURE, 0, 223 "Couldn't get .strtab data from \"%s\"", 224 filename); 225 226 lte->strtab = data->d_buf; 227 } else if (shdr.sh_type == SHT_DYNSYM) { 228 Elf_Data *data; 229 230 lte->dynsym = elf_getdata(scn, NULL); 231 lte->dynsym_count = shdr.sh_size / shdr.sh_entsize; 232 if (lte->dynsym == NULL 233 || elf_getdata(scn, lte->dynsym) != NULL) 234 error(EXIT_FAILURE, 0, 235 "Couldn't get .dynsym data from \"%s\"", 236 filename); 237 238 scn = elf_getscn(lte->elf, shdr.sh_link); 239 if (scn == NULL || gelf_getshdr(scn, &shdr) == NULL) 240 error(EXIT_FAILURE, 0, 241 "Couldn't get section header from \"%s\"", 242 filename); 243 244 data = elf_getdata(scn, NULL); 245 if (data == NULL || elf_getdata(scn, data) != NULL 246 || shdr.sh_size != data->d_size || data->d_off) 247 error(EXIT_FAILURE, 0, 248 "Couldn't get .dynstr data from \"%s\"", 249 filename); 250 251 lte->dynstr = data->d_buf; 252 } else if (shdr.sh_type == SHT_DYNAMIC) { 253 Elf_Data *data; 254 size_t j; 255 256 data = elf_getdata(scn, NULL); 257 if (data == NULL || elf_getdata(scn, data) != NULL) 258 error(EXIT_FAILURE, 0, 259 "Couldn't get .dynamic data from \"%s\"", 260 filename); 261 262 for (j = 0; j < shdr.sh_size / shdr.sh_entsize; ++j) { 263 GElf_Dyn dyn; 264 265 if (gelf_getdyn(data, j, &dyn) == NULL) 266 error(EXIT_FAILURE, 0, 267 "Couldn't get .dynamic data from \"%s\"", 268 filename); 269#ifdef __mips__ 270/** 271 MIPS ABI Supplement: 272 273 DT_PLTGOT This member holds the address of the .got section. 274 275 DT_MIPS_SYMTABNO This member holds the number of entries in the 276 .dynsym section. 277 278 DT_MIPS_LOCAL_GOTNO This member holds the number of local global 279 offset table entries. 280 281 DT_MIPS_GOTSYM This member holds the index of the first dyamic 282 symbol table entry that corresponds to an entry in the gobal offset 283 table. 284 285 */ 286 if(dyn.d_tag==DT_PLTGOT){ 287 lte->pltgot_addr=dyn.d_un.d_ptr; 288 } 289 if(dyn.d_tag==DT_MIPS_LOCAL_GOTNO){ 290 lte->mips_local_gotno=dyn.d_un.d_val; 291 } 292 if(dyn.d_tag==DT_MIPS_GOTSYM){ 293 lte->mips_gotsym=dyn.d_un.d_val; 294 } 295#endif // __mips__ 296 if (dyn.d_tag == DT_JMPREL) 297 relplt_addr = dyn.d_un.d_ptr; 298 else if (dyn.d_tag == DT_PLTRELSZ) 299 relplt_size = dyn.d_un.d_val; 300 else if (dyn.d_tag == DT_PPC_GOT) { 301 ppcgot = dyn.d_un.d_val; 302 debug(1, "ppcgot %#lx", ppcgot); 303 } 304 } 305 } else if (shdr.sh_type == SHT_HASH) { 306 Elf_Data *data; 307 size_t j; 308 309 lte->hash_type = SHT_HASH; 310 311 data = elf_getdata(scn, NULL); 312 if (data == NULL || elf_getdata(scn, data) != NULL 313 || data->d_off || data->d_size != shdr.sh_size) 314 error(EXIT_FAILURE, 0, 315 "Couldn't get .hash data from \"%s\"", 316 filename); 317 318 if (shdr.sh_entsize == 4) { 319 /* Standard conforming ELF. */ 320 if (data->d_type != ELF_T_WORD) 321 error(EXIT_FAILURE, 0, 322 "Couldn't get .hash data from \"%s\"", 323 filename); 324 lte->hash = (Elf32_Word *) data->d_buf; 325 } else if (shdr.sh_entsize == 8) { 326 /* Alpha or s390x. */ 327 Elf32_Word *dst, *src; 328 size_t hash_count = data->d_size / 8; 329 330 lte->hash = (Elf32_Word *) 331 malloc(hash_count * sizeof(Elf32_Word)); 332 if (lte->hash == NULL) 333 error(EXIT_FAILURE, 0, 334 "Couldn't convert .hash section from \"%s\"", 335 filename); 336 lte->lte_flags |= LTE_HASH_MALLOCED; 337 dst = lte->hash; 338 src = (Elf32_Word *) data->d_buf; 339 if ((data->d_type == ELF_T_WORD 340 && __BYTE_ORDER == __BIG_ENDIAN) 341 || (data->d_type == ELF_T_XWORD 342 && lte->ehdr.e_ident[EI_DATA] == 343 ELFDATA2MSB)) 344 ++src; 345 for (j = 0; j < hash_count; ++j, src += 2) 346 *dst++ = *src; 347 } else 348 error(EXIT_FAILURE, 0, 349 "Unknown .hash sh_entsize in \"%s\"", 350 filename); 351 } else if (shdr.sh_type == SHT_GNU_HASH 352 && lte->hash == NULL) { 353 Elf_Data *data; 354 355 lte->hash_type = SHT_GNU_HASH; 356 357 if (shdr.sh_entsize != 0 358 && shdr.sh_entsize != 4) { 359 error(EXIT_FAILURE, 0, 360 ".gnu.hash sh_entsize in \"%s\" should be 4, but is %llu", 361 filename, shdr.sh_entsize); 362 } 363 364 data = loaddata(scn, &shdr); 365 if (data == NULL) 366 error(EXIT_FAILURE, 0, 367 "Couldn't get .gnu.hash data from \"%s\"", 368 filename); 369 370 lte->hash = (Elf32_Word *) data->d_buf; 371 } else if (shdr.sh_type == SHT_PROGBITS 372 || shdr.sh_type == SHT_NOBITS) { 373 if (strcmp(name, ".plt") == 0) { 374 lte->plt_addr = shdr.sh_addr; 375 lte->plt_size = shdr.sh_size; 376 if (shdr.sh_flags & SHF_EXECINSTR) { 377 lte->lte_flags |= LTE_PLT_EXECUTABLE; 378 } 379 if (lte->ehdr.e_machine == EM_PPC) { 380 plt_data = loaddata(scn, &shdr); 381 if (plt_data == NULL) 382 fprintf(stderr, 383 "Can't load .plt data\n"); 384 } 385 } 386#ifdef ARCH_SUPPORTS_OPD 387 else if (strcmp(name, ".opd") == 0) { 388 lte->opd_addr = (GElf_Addr *) (long) shdr.sh_addr; 389 lte->opd_size = shdr.sh_size; 390 lte->opd = elf_rawdata(scn, NULL); 391 } 392#endif 393 } 394 } 395 396 if (lte->dynsym == NULL || lte->dynstr == NULL) 397 error(EXIT_FAILURE, 0, 398 "Couldn't find .dynsym or .dynstr in \"%s\"", filename); 399 400 if (!relplt_addr || !lte->plt_addr) { 401 debug(1, "%s has no PLT relocations", filename); 402 lte->relplt = NULL; 403 lte->relplt_count = 0; 404 } else if (relplt_size == 0) { 405 debug(1, "%s has unknown PLT size", filename); 406 lte->relplt = NULL; 407 lte->relplt_count = 0; 408 } else { 409 if (lte->ehdr.e_machine == EM_PPC) { 410 GElf_Addr glink_vma 411 = get_glink_vma(lte, ppcgot, plt_data); 412 413 assert (relplt_size % 12 == 0); 414 size_t count = relplt_size / 12; // size of RELA entry 415 lte->plt_stub_vma = glink_vma 416 - (GElf_Addr)count * PPC_PLT_STUB_SIZE; 417 debug(1, "stub_vma is %#lx", lte->plt_stub_vma); 418 } 419 420 for (i = 1; i < lte->ehdr.e_shnum; ++i) { 421 Elf_Scn *scn; 422 GElf_Shdr shdr; 423 424 scn = elf_getscn(lte->elf, i); 425 if (scn == NULL || gelf_getshdr(scn, &shdr) == NULL) 426 error(EXIT_FAILURE, 0, 427 "Couldn't get section header from \"%s\"", 428 filename); 429 if (shdr.sh_addr == relplt_addr 430 && shdr.sh_size == relplt_size) { 431 lte->relplt = elf_getdata(scn, NULL); 432 lte->relplt_count = 433 shdr.sh_size / shdr.sh_entsize; 434 if (lte->relplt == NULL 435 || elf_getdata(scn, lte->relplt) != NULL) 436 error(EXIT_FAILURE, 0, 437 "Couldn't get .rel*.plt data from \"%s\"", 438 filename); 439 break; 440 } 441 } 442 443 if (i == lte->ehdr.e_shnum) 444 error(EXIT_FAILURE, 0, 445 "Couldn't find .rel*.plt section in \"%s\"", 446 filename); 447 448 debug(1, "%s %zd PLT relocations", filename, lte->relplt_count); 449 } 450} 451 452static void 453do_close_elf(struct ltelf *lte) { 454 debug(DEBUG_FUNCTION, "do_close_elf()"); 455 if (lte->lte_flags & LTE_HASH_MALLOCED) 456 free((char *)lte->hash); 457 elf_end(lte->elf); 458 close(lte->fd); 459} 460 461static void 462add_library_symbol(GElf_Addr addr, const char *name, 463 struct library_symbol **library_symbolspp, 464 enum toplt type_of_plt, int is_weak) { 465 struct library_symbol *s; 466 467 debug(DEBUG_FUNCTION, "add_library_symbol()"); 468 469 s = malloc(sizeof(struct library_symbol) + strlen(name) + 1); 470 if (s == NULL) 471 error(EXIT_FAILURE, errno, "add_library_symbol failed"); 472 473 s->needs_init = 1; 474 s->is_weak = is_weak; 475 s->plt_type = type_of_plt; 476 s->next = *library_symbolspp; 477 s->enter_addr = (void *)(uintptr_t) addr; 478 s->name = (char *)(s + 1); 479 strcpy(s->name, name); 480 *library_symbolspp = s; 481 482 debug(2, "addr: %p, symbol: \"%s\"", (void *)(uintptr_t) addr, name); 483} 484 485/* stolen from elfutils-0.123 */ 486static unsigned long 487private_elf_gnu_hash(const char *name) { 488 unsigned long h = 5381; 489 const unsigned char *string = (const unsigned char *)name; 490 unsigned char c; 491 for (c = *string; c; c = *++string) 492 h = h * 33 + c; 493 return h & 0xffffffff; 494} 495 496static int 497in_load_libraries(const char *name, struct ltelf *lte) { 498 size_t i; 499 unsigned long hash; 500 unsigned long gnu_hash; 501 502 if (!library_num) 503 return 1; 504 505 hash = elf_hash((const unsigned char *)name); 506 gnu_hash = private_elf_gnu_hash(name); 507 for (i = 1; i <= library_num; ++i) { 508 if (lte[i].hash == NULL) 509 continue; 510 511 if (lte[i].hash_type == SHT_GNU_HASH) { 512 Elf32_Word * hashbase = lte[i].hash; 513 Elf32_Word nbuckets = *hashbase++; 514 Elf32_Word symbias = *hashbase++; 515 Elf32_Word bitmask_nwords = *hashbase++; 516 Elf32_Word * buckets; 517 Elf32_Word * chain_zero; 518 Elf32_Word bucket; 519 520 // +1 for skipped `shift' 521 hashbase += lte[i].ehdr.e_ident[EI_CLASS] * bitmask_nwords + 1; 522 buckets = hashbase; 523 hashbase += nbuckets; 524 chain_zero = hashbase - symbias; 525 bucket = buckets[gnu_hash % nbuckets]; 526 527 if (bucket != 0) { 528 const Elf32_Word *hasharr = &chain_zero[bucket]; 529 do 530 if ((*hasharr & ~1u) == (gnu_hash & ~1u)) { 531 int symidx = hasharr - chain_zero; 532 GElf_Sym sym; 533 534 if (gelf_getsym(lte[i].dynsym, symidx, &sym) == NULL) 535 error(EXIT_FAILURE, 0, 536 "Couldn't get symbol from .dynsym"); 537 538 if (sym.st_value != 0 539 && sym.st_shndx != SHN_UNDEF 540 && strcmp(name, lte[i].dynstr + sym.st_name) == 0) 541 return 1; 542 } 543 while ((*hasharr++ & 1u) == 0); 544 } 545 } else { 546 Elf32_Word nbuckets, symndx; 547 Elf32_Word *buckets, *chain; 548 nbuckets = lte[i].hash[0]; 549 buckets = <e[i].hash[2]; 550 chain = <e[i].hash[2 + nbuckets]; 551 552 for (symndx = buckets[hash % nbuckets]; 553 symndx != STN_UNDEF; symndx = chain[symndx]) { 554 GElf_Sym sym; 555 556 if (gelf_getsym(lte[i].dynsym, symndx, &sym) == NULL) 557 error(EXIT_FAILURE, 0, 558 "Couldn't get symbol from .dynsym"); 559 560 if (sym.st_value != 0 561 && sym.st_shndx != SHN_UNDEF 562 && strcmp(name, lte[i].dynstr + sym.st_name) == 0) 563 return 1; 564 } 565 } 566 } 567 return 0; 568} 569 570static GElf_Addr 571opd2addr(struct ltelf *lte, GElf_Addr addr) { 572#ifdef ARCH_SUPPORTS_OPD 573 unsigned long base, offset; 574 575 if (!lte->opd) 576 return addr; 577 578 base = (unsigned long)lte->opd->d_buf; 579 offset = (unsigned long)addr - (unsigned long)lte->opd_addr; 580 if (offset > lte->opd_size) 581 error(EXIT_FAILURE, 0, "static plt not in .opd"); 582 583 return *(GElf_Addr*)(base + offset); 584#else //!ARCH_SUPPORTS_OPD 585 return addr; 586#endif 587} 588 589struct library_symbol * 590read_elf(Process *proc) { 591 struct library_symbol *library_symbols = NULL; 592 struct ltelf lte[MAX_LIBRARIES + 1]; 593 size_t i; 594 struct opt_x_t *xptr; 595 struct library_symbol **lib_tail = NULL; 596 int exit_out = 0; 597 598 debug(DEBUG_FUNCTION, "read_elf(file=%s)", proc->filename); 599 600 elf_version(EV_CURRENT); 601 602 do_init_elf(lte, proc->filename); 603 proc->e_machine = lte->ehdr.e_machine; 604 for (i = 0; i < library_num; ++i) 605 do_init_elf(<e[i + 1], library[i]); 606 607 if (!options.no_plt) { 608#ifdef __mips__ 609 // MIPS doesn't use the PLT and the GOT entries get changed 610 // on startup. 611 proc->need_to_reinitialize_breakpoints = 1; 612 for(i=lte->mips_gotsym; i<lte->dynsym_count;i++){ 613 GElf_Sym sym; 614 const char *name; 615 GElf_Addr addr = arch_plt_sym_val(lte, i, 0); 616 if (gelf_getsym(lte->dynsym, i, &sym) == NULL){ 617 error(EXIT_FAILURE, 0, 618 "Couldn't get relocation from \"%s\"", 619 proc->filename); 620 } 621 name=lte->dynstr+sym.st_name; 622 if(ELF64_ST_TYPE(sym.st_info) != STT_FUNC){ 623 debug(2,"sym %s not a function",name); 624 continue; 625 } 626 add_library_symbol(addr, name, &library_symbols, 0, 627 ELF64_ST_BIND(sym.st_info) != 0); 628 if (!lib_tail) 629 lib_tail = &(library_symbols->next); 630 } 631#else 632 for (i = 0; i < lte->relplt_count; ++i) { 633 GElf_Rel rel; 634 GElf_Rela rela; 635 GElf_Sym sym; 636 GElf_Addr addr; 637 void *ret; 638 const char *name; 639 640 if (lte->relplt->d_type == ELF_T_REL) { 641 ret = gelf_getrel(lte->relplt, i, &rel); 642 rela.r_offset = rel.r_offset; 643 rela.r_info = rel.r_info; 644 rela.r_addend = 0; 645 } else 646 ret = gelf_getrela(lte->relplt, i, &rela); 647 648 if (ret == NULL 649 || ELF64_R_SYM(rela.r_info) >= lte->dynsym_count 650 || gelf_getsym(lte->dynsym, ELF64_R_SYM(rela.r_info), 651 &sym) == NULL) 652 error(EXIT_FAILURE, 0, 653 "Couldn't get relocation from \"%s\"", 654 proc->filename); 655 656#ifdef PLT_REINITALISATION_BP 657 if (!sym.st_value && PLTs_initialized_by_here) 658 proc->need_to_reinitialize_breakpoints = 1; 659#endif 660 661 name = lte->dynstr + sym.st_name; 662 if (in_load_libraries(name, lte)) { 663 enum toplt pltt; 664 if (sym.st_value == 0 && lte->plt_stub_vma != 0) { 665 pltt = LS_TOPLT_EXEC; 666 addr = lte->plt_stub_vma + PPC_PLT_STUB_SIZE * i; 667 printf ("%s %#lx\n", name, addr); 668 } 669 else { 670 pltt = PLTS_ARE_EXECUTABLE(lte) 671 ? LS_TOPLT_EXEC : LS_TOPLT_POINT; 672 addr = arch_plt_sym_val(lte, i, &rela); 673 } 674 675 add_library_symbol(addr, name, &library_symbols, pltt, 676 ELF64_ST_BIND(sym.st_info) == STB_WEAK); 677 if (!lib_tail) 678 lib_tail = &(library_symbols->next); 679 } 680 } 681#endif // !__mips__ 682#ifdef PLT_REINITALISATION_BP 683 struct opt_x_t *main_cheat; 684 685 if (proc->need_to_reinitialize_breakpoints) { 686 /* Add "PLTs_initialized_by_here" to opt_x list, if not 687 already there. */ 688 main_cheat = (struct opt_x_t *)malloc(sizeof(struct opt_x_t)); 689 if (main_cheat == NULL) 690 error(EXIT_FAILURE, 0, "Couldn't allocate memory"); 691 main_cheat->next = opt_x; 692 main_cheat->found = 0; 693 main_cheat->name = PLTs_initialized_by_here; 694 695 for (xptr = opt_x; xptr; xptr = xptr->next) 696 if (strcmp(xptr->name, PLTs_initialized_by_here) == 0 697 && main_cheat) { 698 free(main_cheat); 699 main_cheat = NULL; 700 break; 701 } 702 if (main_cheat) 703 opt_x = main_cheat; 704 } 705#endif 706 } else { 707 lib_tail = &library_symbols; 708 } 709 710 for (i = 0; i < lte->symtab_count; ++i) { 711 GElf_Sym sym; 712 GElf_Addr addr; 713 const char *name; 714 715 if (gelf_getsym(lte->symtab, i, &sym) == NULL) 716 error(EXIT_FAILURE, 0, 717 "Couldn't get symbol from \"%s\"", 718 proc->filename); 719 720 name = lte->strtab + sym.st_name; 721 addr = sym.st_value; 722 if (!addr) 723 continue; 724 725 for (xptr = opt_x; xptr; xptr = xptr->next) 726 if (xptr->name && strcmp(xptr->name, name) == 0) { 727 /* FIXME: Should be able to use &library_symbols as above. But 728 when you do, none of the real library symbols cause breaks. */ 729 add_library_symbol(opd2addr(lte, addr), 730 name, lib_tail, LS_TOPLT_NONE, 0); 731 xptr->found = 1; 732 break; 733 } 734 } 735 for (xptr = opt_x; xptr; xptr = xptr->next) 736 if ( ! xptr->found) { 737 char *badthing = "WARNING"; 738#ifdef PLT_REINITALISATION_BP 739 if (strcmp(xptr->name, PLTs_initialized_by_here) == 0) { 740 if (lte->ehdr.e_entry) { 741 add_library_symbol ( 742 opd2addr (lte, lte->ehdr.e_entry), 743 PLTs_initialized_by_here, 744 lib_tail, 1, 0); 745 fprintf (stderr, "WARNING: Using e_ent" 746 "ry from elf header (%p) for " 747 "address of \"%s\"\n", (void*) 748 (long) lte->ehdr.e_entry, 749 PLTs_initialized_by_here); 750 continue; 751 } 752 badthing = "ERROR"; 753 exit_out = 1; 754 } 755#endif 756 fprintf (stderr, 757 "%s: Couldn't find symbol \"%s\" in file \"%s" 758 "\"\n", badthing, xptr->name, proc->filename); 759 } 760 if (exit_out) { 761 exit (1); 762 } 763 764 for (i = 0; i < library_num + 1; ++i) 765 do_close_elf(<e[i]); 766 767 return library_symbols; 768} 769