1 /* simple-object-elf.c -- routines to manipulate ELF object files. 2 Copyright (C) 2010-2018 Free Software Foundation, Inc. 3 Written by Ian Lance Taylor, Google. 4 5 This program is free software; you can redistribute it and/or modify it 6 under the terms of the GNU General Public License as published by the 7 Free Software Foundation; either version 2, or (at your option) any 8 later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program; if not, write to the Free Software 17 Foundation, 51 Franklin Street - Fifth Floor, 18 Boston, MA 02110-1301, USA. */ 19 20 #include "config.h" 21 #include "libiberty.h" 22 #include "simple-object.h" 23 24 #include <errno.h> 25 /* mingw.org's MinGW doesn't have ENOTSUP. */ 26 #ifndef ENOTSUP 27 # define ENOTSUP ENOSYS 28 #endif 29 #include <stddef.h> 30 31 #ifdef HAVE_STDLIB_H 32 #include <stdlib.h> 33 #endif 34 35 #ifdef HAVE_STDINT_H 36 #include <stdint.h> 37 #endif 38 39 #ifdef HAVE_STRING_H 40 #include <string.h> 41 #endif 42 43 #ifdef HAVE_INTTYPES_H 44 #include <inttypes.h> 45 #endif 46 47 #include "simple-object-common.h" 48 49 /* ELF structures and constants. */ 50 51 /* 32-bit ELF file header. */ 52 53 typedef struct { 54 unsigned char e_ident[16]; /* ELF "magic number" */ 55 unsigned char e_type[2]; /* Identifies object file type */ 56 unsigned char e_machine[2]; /* Specifies required architecture */ 57 unsigned char e_version[4]; /* Identifies object file version */ 58 unsigned char e_entry[4]; /* Entry point virtual address */ 59 unsigned char e_phoff[4]; /* Program header table file offset */ 60 unsigned char e_shoff[4]; /* Section header table file offset */ 61 unsigned char e_flags[4]; /* Processor-specific flags */ 62 unsigned char e_ehsize[2]; /* ELF header size in bytes */ 63 unsigned char e_phentsize[2]; /* Program header table entry size */ 64 unsigned char e_phnum[2]; /* Program header table entry count */ 65 unsigned char e_shentsize[2]; /* Section header table entry size */ 66 unsigned char e_shnum[2]; /* Section header table entry count */ 67 unsigned char e_shstrndx[2]; /* Section header string table index */ 68 } Elf32_External_Ehdr; 69 70 /* 64-bit ELF file header. */ 71 72 typedef struct { 73 unsigned char e_ident[16]; /* ELF "magic number" */ 74 unsigned char e_type[2]; /* Identifies object file type */ 75 unsigned char e_machine[2]; /* Specifies required architecture */ 76 unsigned char e_version[4]; /* Identifies object file version */ 77 unsigned char e_entry[8]; /* Entry point virtual address */ 78 unsigned char e_phoff[8]; /* Program header table file offset */ 79 unsigned char e_shoff[8]; /* Section header table file offset */ 80 unsigned char e_flags[4]; /* Processor-specific flags */ 81 unsigned char e_ehsize[2]; /* ELF header size in bytes */ 82 unsigned char e_phentsize[2]; /* Program header table entry size */ 83 unsigned char e_phnum[2]; /* Program header table entry count */ 84 unsigned char e_shentsize[2]; /* Section header table entry size */ 85 unsigned char e_shnum[2]; /* Section header table entry count */ 86 unsigned char e_shstrndx[2]; /* Section header string table index */ 87 } Elf64_External_Ehdr; 88 89 /* Indexes and values in e_ident field of Ehdr. */ 90 91 #define EI_MAG0 0 /* File identification byte 0 index */ 92 #define ELFMAG0 0x7F /* Magic number byte 0 */ 93 94 #define EI_MAG1 1 /* File identification byte 1 index */ 95 #define ELFMAG1 'E' /* Magic number byte 1 */ 96 97 #define EI_MAG2 2 /* File identification byte 2 index */ 98 #define ELFMAG2 'L' /* Magic number byte 2 */ 99 100 #define EI_MAG3 3 /* File identification byte 3 index */ 101 #define ELFMAG3 'F' /* Magic number byte 3 */ 102 103 #define EI_CLASS 4 /* File class */ 104 #define ELFCLASSNONE 0 /* Invalid class */ 105 #define ELFCLASS32 1 /* 32-bit objects */ 106 #define ELFCLASS64 2 /* 64-bit objects */ 107 108 #define EI_DATA 5 /* Data encoding */ 109 #define ELFDATANONE 0 /* Invalid data encoding */ 110 #define ELFDATA2LSB 1 /* 2's complement, little endian */ 111 #define ELFDATA2MSB 2 /* 2's complement, big endian */ 112 113 #define EI_VERSION 6 /* File version */ 114 #define EV_CURRENT 1 /* Current version */ 115 116 #define EI_OSABI 7 /* Operating System/ABI indication */ 117 118 /* Values for e_type field of Ehdr. */ 119 120 #define ET_REL 1 /* Relocatable file */ 121 122 /* Values for e_machine field of Ehdr. */ 123 124 #define EM_SPARC 2 /* SUN SPARC */ 125 #define EM_SPARC32PLUS 18 /* Sun's "v8plus" */ 126 127 /* Special section index values. */ 128 129 #define SHN_UNDEF 0 /* Undefined section */ 130 #define SHN_LORESERVE 0xFF00 /* Begin range of reserved indices */ 131 #define SHN_COMMON 0xFFF2 /* Associated symbol is in common */ 132 #define SHN_XINDEX 0xFFFF /* Section index is held elsewhere */ 133 #define SHN_HIRESERVE 0xffff /* End of reserved indices */ 134 135 136 /* 32-bit ELF program header. */ 137 138 typedef struct { 139 unsigned char p_type[4]; /* Identifies program segment type */ 140 unsigned char p_offset[4]; /* Segment file offset */ 141 unsigned char p_vaddr[4]; /* Segment virtual address */ 142 unsigned char p_paddr[4]; /* Segment physical address */ 143 unsigned char p_filesz[4]; /* Segment size in file */ 144 unsigned char p_memsz[4]; /* Segment size in memory */ 145 unsigned char p_flags[4]; /* Segment flags */ 146 unsigned char p_align[4]; /* Segment alignment, file & memory */ 147 } Elf32_External_Phdr; 148 149 /* 64-bit ELF program header. */ 150 151 typedef struct { 152 unsigned char p_type[4]; /* Identifies program segment type */ 153 unsigned char p_flags[4]; /* Segment flags */ 154 unsigned char p_offset[8]; /* Segment file offset */ 155 unsigned char p_vaddr[8]; /* Segment virtual address */ 156 unsigned char p_paddr[8]; /* Segment physical address */ 157 unsigned char p_filesz[8]; /* Segment size in file */ 158 unsigned char p_memsz[8]; /* Segment size in memory */ 159 unsigned char p_align[8]; /* Segment alignment, file & memory */ 160 } Elf64_External_Phdr; 161 162 /* 32-bit ELF section header */ 163 164 typedef struct { 165 unsigned char sh_name[4]; /* Section name, index in string tbl */ 166 unsigned char sh_type[4]; /* Type of section */ 167 unsigned char sh_flags[4]; /* Miscellaneous section attributes */ 168 unsigned char sh_addr[4]; /* Section virtual addr at execution */ 169 unsigned char sh_offset[4]; /* Section file offset */ 170 unsigned char sh_size[4]; /* Size of section in bytes */ 171 unsigned char sh_link[4]; /* Index of another section */ 172 unsigned char sh_info[4]; /* Additional section information */ 173 unsigned char sh_addralign[4]; /* Section alignment */ 174 unsigned char sh_entsize[4]; /* Entry size if section holds table */ 175 } Elf32_External_Shdr; 176 177 /* 64-bit ELF section header. */ 178 179 typedef struct { 180 unsigned char sh_name[4]; /* Section name, index in string tbl */ 181 unsigned char sh_type[4]; /* Type of section */ 182 unsigned char sh_flags[8]; /* Miscellaneous section attributes */ 183 unsigned char sh_addr[8]; /* Section virtual addr at execution */ 184 unsigned char sh_offset[8]; /* Section file offset */ 185 unsigned char sh_size[8]; /* Size of section in bytes */ 186 unsigned char sh_link[4]; /* Index of another section */ 187 unsigned char sh_info[4]; /* Additional section information */ 188 unsigned char sh_addralign[8]; /* Section alignment */ 189 unsigned char sh_entsize[8]; /* Entry size if section holds table */ 190 } Elf64_External_Shdr; 191 192 /* Values for sh_type field. */ 193 194 #define SHT_NULL 0 /* Section header table entry unused */ 195 #define SHT_PROGBITS 1 /* Program data */ 196 #define SHT_SYMTAB 2 /* Link editing symbol table */ 197 #define SHT_STRTAB 3 /* A string table */ 198 #define SHT_RELA 4 /* Relocation entries with addends */ 199 #define SHT_REL 9 /* Relocation entries, no addends */ 200 #define SHT_GROUP 17 /* Section contains a section group */ 201 #define SHT_SYMTAB_SHNDX 18 /* Extended section indeces */ 202 203 /* Values for sh_flags field. */ 204 205 #define SHF_INFO_LINK 0x00000040 /* `sh_info' contains SHT index */ 206 #define SHF_EXECINSTR 0x00000004 /* Executable section. */ 207 #define SHF_EXCLUDE 0x80000000 /* Link editor is to exclude this 208 section from executable and 209 shared library that it builds 210 when those objects are not to be 211 further relocated. */ 212 /* Symbol table entry. */ 213 214 typedef struct 215 { 216 unsigned char st_name[4]; /* Symbol name (string tbl index) */ 217 unsigned char st_value[4]; /* Symbol value */ 218 unsigned char st_size[4]; /* Symbol size */ 219 unsigned char st_info; /* Symbol type and binding */ 220 unsigned char st_other; /* Symbol visibility */ 221 unsigned char st_shndx[2]; /* Section index */ 222 } Elf32_External_Sym; 223 224 typedef struct 225 { 226 unsigned char st_name[4]; /* Symbol name (string tbl index) */ 227 unsigned char st_info; /* Symbol type and binding */ 228 unsigned char st_other; /* Symbol visibility */ 229 unsigned char st_shndx[2]; /* Section index */ 230 unsigned char st_value[8]; /* Symbol value */ 231 unsigned char st_size[8]; /* Symbol size */ 232 } Elf64_External_Sym; 233 234 #define ELF_ST_BIND(val) (((unsigned char) (val)) >> 4) 235 #define ELF_ST_TYPE(val) ((val) & 0xf) 236 #define ELF_ST_INFO(bind, type) (((bind) << 4) + ((type) & 0xf)) 237 238 #define STT_NOTYPE 0 /* Symbol type is unspecified */ 239 #define STT_OBJECT 1 /* Symbol is a data object */ 240 #define STT_FUNC 2 /* Symbol is a code object */ 241 #define STT_TLS 6 /* Thread local data object */ 242 #define STT_GNU_IFUNC 10 /* Symbol is an indirect code object */ 243 244 #define STB_LOCAL 0 /* Local symbol */ 245 #define STB_GLOBAL 1 /* Global symbol */ 246 #define STB_WEAK 2 /* Weak global */ 247 248 #define STV_DEFAULT 0 /* Visibility is specified by binding type */ 249 #define STV_HIDDEN 2 /* Can only be seen inside currect component */ 250 251 /* Functions to fetch and store different ELF types, depending on the 252 endianness and size. */ 253 254 struct elf_type_functions 255 { 256 unsigned short (*fetch_Elf_Half) (const unsigned char *); 257 unsigned int (*fetch_Elf_Word) (const unsigned char *); 258 ulong_type (*fetch_Elf_Addr) (const unsigned char *); 259 void (*set_Elf_Half) (unsigned char *, unsigned short); 260 void (*set_Elf_Word) (unsigned char *, unsigned int); 261 void (*set_Elf_Addr) (unsigned char *, ulong_type); 262 }; 263 264 static const struct elf_type_functions elf_big_32_functions = 265 { 266 simple_object_fetch_big_16, 267 simple_object_fetch_big_32, 268 simple_object_fetch_big_32_ulong, 269 simple_object_set_big_16, 270 simple_object_set_big_32, 271 simple_object_set_big_32_ulong 272 }; 273 274 static const struct elf_type_functions elf_little_32_functions = 275 { 276 simple_object_fetch_little_16, 277 simple_object_fetch_little_32, 278 simple_object_fetch_little_32_ulong, 279 simple_object_set_little_16, 280 simple_object_set_little_32, 281 simple_object_set_little_32_ulong 282 }; 283 284 #ifdef UNSIGNED_64BIT_TYPE 285 286 static const struct elf_type_functions elf_big_64_functions = 287 { 288 simple_object_fetch_big_16, 289 simple_object_fetch_big_32, 290 simple_object_fetch_big_64, 291 simple_object_set_big_16, 292 simple_object_set_big_32, 293 simple_object_set_big_64 294 }; 295 296 static const struct elf_type_functions elf_little_64_functions = 297 { 298 simple_object_fetch_little_16, 299 simple_object_fetch_little_32, 300 simple_object_fetch_little_64, 301 simple_object_set_little_16, 302 simple_object_set_little_32, 303 simple_object_set_little_64 304 }; 305 306 #endif 307 308 /* Hideous macro to fetch the value of a field from an external ELF 309 struct of some sort. TYPEFUNCS is the set of type functions. 310 BUFFER points to the external data. STRUCTTYPE is the appropriate 311 struct type. FIELD is a field within the struct. TYPE is the type 312 of the field in the struct: Elf_Half, Elf_Word, or Elf_Addr. */ 313 314 #define ELF_FETCH_STRUCT_FIELD(TYPEFUNCS, STRUCTTYPE, FIELD, BUFFER, TYPE) \ 315 ((TYPEFUNCS)->fetch_ ## TYPE ((BUFFER) + offsetof (STRUCTTYPE, FIELD))) 316 317 /* Even more hideous macro to fetch the value of FIELD from BUFFER. 318 SIZE is 32 or 64. STRUCTTYPE is the name of the struct from 319 elf/external.h: Ehdr, Shdr, etc. FIELD is the name of a field in 320 the struct. TYPE is the type of the field in the struct: Elf_Half, 321 Elf_Word, or Elf_Addr. */ 322 323 #define ELF_FETCH_SIZED_FIELD(TYPEFUNCS, SIZE, STRUCTTYPE, BUFFER, \ 324 FIELD, TYPE) \ 325 ELF_FETCH_STRUCT_FIELD (TYPEFUNCS, \ 326 Elf ## SIZE ## _External_ ## STRUCTTYPE, \ 327 FIELD, BUFFER, TYPE) 328 329 /* Like ELF_FETCH_SIZED_FIELD but taking an ELFCLASS value. */ 330 331 #define ELF_FETCH_FIELD(TYPEFUNCS, CLASS, STRUCTTYPE, BUFFER, \ 332 FIELD, TYPE) \ 333 ((CLASS) == ELFCLASS32 \ 334 ? ELF_FETCH_SIZED_FIELD (TYPEFUNCS, 32, STRUCTTYPE, BUFFER, FIELD, \ 335 TYPE) \ 336 : ELF_FETCH_SIZED_FIELD (TYPEFUNCS, 64, STRUCTTYPE, BUFFER, FIELD, \ 337 TYPE)) 338 339 /* Hideous macro to set the value of a field in an external ELF 340 structure to VAL. TYPEFUNCS is the set of type functions. BUFFER 341 points to the external data. STRUCTTYPE is the appropriate 342 structure type. FIELD is a field within the struct. TYPE is the 343 type of the field in the struct: Elf_Half, Elf_Word, or 344 Elf_Addr. */ 345 346 #define ELF_SET_STRUCT_FIELD(TYPEFUNCS, STRUCTTYPE, FIELD, BUFFER, TYPE, VAL) \ 347 (TYPEFUNCS)->set_ ## TYPE ((BUFFER) + offsetof (STRUCTTYPE, FIELD), (VAL)) 348 349 /* Even more hideous macro to set the value of FIELD in BUFFER to VAL. 350 SIZE is 32 or 64. STRUCTTYPE is the name of the struct from 351 elf/external.h: Ehdr, Shdr, etc. FIELD is the name of a field in 352 the struct. TYPE is the type of the field in the struct: Elf_Half, 353 Elf_Word, or Elf_Addr. */ 354 355 #define ELF_SET_SIZED_FIELD(TYPEFUNCS, SIZE, STRUCTTYPE, BUFFER, FIELD, \ 356 TYPE, VAL) \ 357 ELF_SET_STRUCT_FIELD (TYPEFUNCS, \ 358 Elf ## SIZE ## _External_ ## STRUCTTYPE, \ 359 FIELD, BUFFER, TYPE, VAL) 360 361 /* Like ELF_SET_SIZED_FIELD but taking an ELFCLASS value. */ 362 363 #define ELF_SET_FIELD(TYPEFUNCS, CLASS, STRUCTTYPE, BUFFER, FIELD, \ 364 TYPE, VAL) \ 365 ((CLASS) == ELFCLASS32 \ 366 ? ELF_SET_SIZED_FIELD (TYPEFUNCS, 32, STRUCTTYPE, BUFFER, FIELD, \ 367 TYPE, VAL) \ 368 : ELF_SET_SIZED_FIELD (TYPEFUNCS, 64, STRUCTTYPE, BUFFER, FIELD, \ 369 TYPE, VAL)) 370 371 /* Private data for an simple_object_read. */ 372 373 struct simple_object_elf_read 374 { 375 /* Type functions. */ 376 const struct elf_type_functions* type_functions; 377 /* Elf data. */ 378 unsigned char ei_data; 379 /* Elf class. */ 380 unsigned char ei_class; 381 /* ELF OS ABI. */ 382 unsigned char ei_osabi; 383 /* Elf machine number. */ 384 unsigned short machine; 385 /* Processor specific flags. */ 386 unsigned int flags; 387 /* File offset of section headers. */ 388 ulong_type shoff; 389 /* Number of sections. */ 390 unsigned int shnum; 391 /* Index of string table section header. */ 392 unsigned int shstrndx; 393 }; 394 395 /* Private data for an simple_object_attributes. */ 396 397 struct simple_object_elf_attributes 398 { 399 /* Type functions. */ 400 const struct elf_type_functions* type_functions; 401 /* Elf data. */ 402 unsigned char ei_data; 403 /* Elf class. */ 404 unsigned char ei_class; 405 /* ELF OS ABI. */ 406 unsigned char ei_osabi; 407 /* Elf machine number. */ 408 unsigned short machine; 409 /* Processor specific flags. */ 410 unsigned int flags; 411 }; 412 413 /* Private data for an simple_object_write. */ 414 415 struct simple_object_elf_write 416 { 417 struct simple_object_elf_attributes attrs; 418 unsigned char *shdrs; 419 }; 420 421 /* See if we have an ELF file. */ 422 423 static void * 424 simple_object_elf_match (unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN], 425 int descriptor, off_t offset, 426 const char *segment_name ATTRIBUTE_UNUSED, 427 const char **errmsg, int *err) 428 { 429 unsigned char ei_data; 430 unsigned char ei_class; 431 const struct elf_type_functions *type_functions; 432 unsigned char ehdr[sizeof (Elf64_External_Ehdr)]; 433 struct simple_object_elf_read *eor; 434 435 if (header[EI_MAG0] != ELFMAG0 436 || header[EI_MAG1] != ELFMAG1 437 || header[EI_MAG2] != ELFMAG2 438 || header[EI_MAG3] != ELFMAG3 439 || header[EI_VERSION] != EV_CURRENT) 440 { 441 *errmsg = NULL; 442 *err = 0; 443 return NULL; 444 } 445 446 ei_data = header[EI_DATA]; 447 if (ei_data != ELFDATA2LSB && ei_data != ELFDATA2MSB) 448 { 449 *errmsg = "unknown ELF endianness"; 450 *err = 0; 451 return NULL; 452 } 453 454 ei_class = header[EI_CLASS]; 455 switch (ei_class) 456 { 457 case ELFCLASS32: 458 type_functions = (ei_data == ELFDATA2LSB 459 ? &elf_little_32_functions 460 : &elf_big_32_functions); 461 break; 462 463 case ELFCLASS64: 464 #ifndef UNSIGNED_64BIT_TYPE 465 *errmsg = "64-bit ELF objects not supported"; 466 *err = 0; 467 return NULL; 468 #else 469 type_functions = (ei_data == ELFDATA2LSB 470 ? &elf_little_64_functions 471 : &elf_big_64_functions); 472 break; 473 #endif 474 475 default: 476 *errmsg = "unrecognized ELF size"; 477 *err = 0; 478 return NULL; 479 } 480 481 if (!simple_object_internal_read (descriptor, offset, ehdr, sizeof ehdr, 482 errmsg, err)) 483 return NULL; 484 485 eor = XNEW (struct simple_object_elf_read); 486 eor->type_functions = type_functions; 487 eor->ei_data = ei_data; 488 eor->ei_class = ei_class; 489 eor->ei_osabi = header[EI_OSABI]; 490 eor->machine = ELF_FETCH_FIELD (type_functions, ei_class, Ehdr, ehdr, 491 e_machine, Elf_Half); 492 eor->flags = ELF_FETCH_FIELD (type_functions, ei_class, Ehdr, ehdr, 493 e_flags, Elf_Word); 494 eor->shoff = ELF_FETCH_FIELD (type_functions, ei_class, Ehdr, ehdr, 495 e_shoff, Elf_Addr); 496 eor->shnum = ELF_FETCH_FIELD (type_functions, ei_class, Ehdr, ehdr, 497 e_shnum, Elf_Half); 498 eor->shstrndx = ELF_FETCH_FIELD (type_functions, ei_class, Ehdr, ehdr, 499 e_shstrndx, Elf_Half); 500 501 if ((eor->shnum == 0 || eor->shstrndx == SHN_XINDEX) 502 && eor->shoff != 0) 503 { 504 unsigned char shdr[sizeof (Elf64_External_Shdr)]; 505 506 /* Object file has more than 0xffff sections. */ 507 508 if (!simple_object_internal_read (descriptor, offset + eor->shoff, shdr, 509 (ei_class == ELFCLASS32 510 ? sizeof (Elf32_External_Shdr) 511 : sizeof (Elf64_External_Shdr)), 512 errmsg, err)) 513 { 514 XDELETE (eor); 515 return NULL; 516 } 517 518 if (eor->shnum == 0) 519 eor->shnum = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 520 shdr, sh_size, Elf_Addr); 521 522 if (eor->shstrndx == SHN_XINDEX) 523 { 524 eor->shstrndx = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 525 shdr, sh_link, Elf_Word); 526 527 /* Versions of the GNU binutils between 2.12 and 2.18 did 528 not handle objects with more than SHN_LORESERVE sections 529 correctly. All large section indexes were offset by 530 0x100. There is more information at 531 http://sourceware.org/bugzilla/show_bug.cgi?id-5900 . 532 Fortunately these object files are easy to detect, as the 533 GNU binutils always put the section header string table 534 near the end of the list of sections. Thus if the 535 section header string table index is larger than the 536 number of sections, then we know we have to subtract 537 0x100 to get the real section index. */ 538 if (eor->shstrndx >= eor->shnum 539 && eor->shstrndx >= SHN_LORESERVE + 0x100) 540 eor->shstrndx -= 0x100; 541 } 542 } 543 544 if (eor->shstrndx >= eor->shnum) 545 { 546 *errmsg = "invalid ELF shstrndx >= shnum"; 547 *err = 0; 548 XDELETE (eor); 549 return NULL; 550 } 551 552 return (void *) eor; 553 } 554 555 /* Find all sections in an ELF file. */ 556 557 static const char * 558 simple_object_elf_find_sections (simple_object_read *sobj, 559 int (*pfn) (void *, const char *, 560 off_t offset, off_t length), 561 void *data, 562 int *err) 563 { 564 struct simple_object_elf_read *eor = 565 (struct simple_object_elf_read *) sobj->data; 566 const struct elf_type_functions *type_functions = eor->type_functions; 567 unsigned char ei_class = eor->ei_class; 568 size_t shdr_size; 569 unsigned int shnum; 570 unsigned char *shdrs; 571 const char *errmsg; 572 unsigned char *shstrhdr; 573 size_t name_size; 574 off_t shstroff; 575 unsigned char *names; 576 unsigned int i; 577 578 shdr_size = (ei_class == ELFCLASS32 579 ? sizeof (Elf32_External_Shdr) 580 : sizeof (Elf64_External_Shdr)); 581 582 /* Read the section headers. We skip section 0, which is not a 583 useful section. */ 584 585 shnum = eor->shnum; 586 shdrs = XNEWVEC (unsigned char, shdr_size * (shnum - 1)); 587 588 if (!simple_object_internal_read (sobj->descriptor, 589 sobj->offset + eor->shoff + shdr_size, 590 shdrs, 591 shdr_size * (shnum - 1), 592 &errmsg, err)) 593 { 594 XDELETEVEC (shdrs); 595 return errmsg; 596 } 597 598 /* Read the section names. */ 599 600 shstrhdr = shdrs + (eor->shstrndx - 1) * shdr_size; 601 name_size = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 602 shstrhdr, sh_size, Elf_Addr); 603 shstroff = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 604 shstrhdr, sh_offset, Elf_Addr); 605 names = XNEWVEC (unsigned char, name_size); 606 if (!simple_object_internal_read (sobj->descriptor, 607 sobj->offset + shstroff, 608 names, name_size, &errmsg, err)) 609 { 610 XDELETEVEC (names); 611 XDELETEVEC (shdrs); 612 return errmsg; 613 } 614 615 for (i = 1; i < shnum; ++i) 616 { 617 unsigned char *shdr; 618 unsigned int sh_name; 619 const char *name; 620 off_t offset; 621 off_t length; 622 623 shdr = shdrs + (i - 1) * shdr_size; 624 sh_name = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 625 shdr, sh_name, Elf_Word); 626 if (sh_name >= name_size) 627 { 628 *err = 0; 629 XDELETEVEC (names); 630 XDELETEVEC (shdrs); 631 return "ELF section name out of range"; 632 } 633 634 name = (const char *) names + sh_name; 635 offset = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 636 shdr, sh_offset, Elf_Addr); 637 length = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 638 shdr, sh_size, Elf_Addr); 639 640 if (!(*pfn) (data, name, offset, length)) 641 break; 642 } 643 644 XDELETEVEC (names); 645 XDELETEVEC (shdrs); 646 647 return NULL; 648 } 649 650 /* Fetch the attributes for an simple_object_read. */ 651 652 static void * 653 simple_object_elf_fetch_attributes (simple_object_read *sobj, 654 const char **errmsg ATTRIBUTE_UNUSED, 655 int *err ATTRIBUTE_UNUSED) 656 { 657 struct simple_object_elf_read *eor = 658 (struct simple_object_elf_read *) sobj->data; 659 struct simple_object_elf_attributes *ret; 660 661 ret = XNEW (struct simple_object_elf_attributes); 662 ret->type_functions = eor->type_functions; 663 ret->ei_data = eor->ei_data; 664 ret->ei_class = eor->ei_class; 665 ret->ei_osabi = eor->ei_osabi; 666 ret->machine = eor->machine; 667 ret->flags = eor->flags; 668 return ret; 669 } 670 671 /* Release the privata data for an simple_object_read. */ 672 673 static void 674 simple_object_elf_release_read (void *data) 675 { 676 XDELETE (data); 677 } 678 679 /* Compare two attributes structures. */ 680 681 static const char * 682 simple_object_elf_attributes_merge (void *todata, void *fromdata, int *err) 683 { 684 struct simple_object_elf_attributes *to = 685 (struct simple_object_elf_attributes *) todata; 686 struct simple_object_elf_attributes *from = 687 (struct simple_object_elf_attributes *) fromdata; 688 689 if (to->ei_data != from->ei_data || to->ei_class != from->ei_class) 690 { 691 *err = 0; 692 return "ELF object format mismatch"; 693 } 694 695 if (to->machine != from->machine) 696 { 697 int ok; 698 699 /* EM_SPARC and EM_SPARC32PLUS are compatible and force an 700 output of EM_SPARC32PLUS. */ 701 ok = 0; 702 switch (to->machine) 703 { 704 case EM_SPARC: 705 if (from->machine == EM_SPARC32PLUS) 706 { 707 to->machine = from->machine; 708 ok = 1; 709 } 710 break; 711 712 case EM_SPARC32PLUS: 713 if (from->machine == EM_SPARC) 714 ok = 1; 715 break; 716 717 default: 718 break; 719 } 720 721 if (!ok) 722 { 723 *err = 0; 724 return "ELF machine number mismatch"; 725 } 726 } 727 728 return NULL; 729 } 730 731 /* Release the private data for an attributes structure. */ 732 733 static void 734 simple_object_elf_release_attributes (void *data) 735 { 736 XDELETE (data); 737 } 738 739 /* Prepare to write out a file. */ 740 741 static void * 742 simple_object_elf_start_write (void *attributes_data, 743 const char **errmsg ATTRIBUTE_UNUSED, 744 int *err ATTRIBUTE_UNUSED) 745 { 746 struct simple_object_elf_attributes *attrs = 747 (struct simple_object_elf_attributes *) attributes_data; 748 struct simple_object_elf_write *ret; 749 750 /* We're just going to record the attributes, but we need to make a 751 copy because the user may delete them. */ 752 ret = XNEW (struct simple_object_elf_write); 753 ret->attrs = *attrs; 754 ret->shdrs = NULL; 755 return ret; 756 } 757 758 /* Write out an ELF ehdr. */ 759 760 static int 761 simple_object_elf_write_ehdr (simple_object_write *sobj, int descriptor, 762 const char **errmsg, int *err) 763 { 764 struct simple_object_elf_attributes *attrs = 765 (struct simple_object_elf_attributes *) sobj->data; 766 const struct elf_type_functions* fns; 767 unsigned char cl; 768 size_t ehdr_size; 769 unsigned char buf[sizeof (Elf64_External_Ehdr)]; 770 simple_object_write_section *section; 771 unsigned int shnum; 772 unsigned int shstrndx; 773 774 fns = attrs->type_functions; 775 cl = attrs->ei_class; 776 777 shnum = 0; 778 for (section = sobj->sections; section != NULL; section = section->next) 779 ++shnum; 780 if (shnum > 0) 781 { 782 /* Add a section header for the dummy section and one for 783 .shstrtab. */ 784 shnum += 2; 785 } 786 787 ehdr_size = (cl == ELFCLASS32 788 ? sizeof (Elf32_External_Ehdr) 789 : sizeof (Elf64_External_Ehdr)); 790 memset (buf, 0, sizeof (Elf64_External_Ehdr)); 791 792 buf[EI_MAG0] = ELFMAG0; 793 buf[EI_MAG1] = ELFMAG1; 794 buf[EI_MAG2] = ELFMAG2; 795 buf[EI_MAG3] = ELFMAG3; 796 buf[EI_CLASS] = cl; 797 buf[EI_DATA] = attrs->ei_data; 798 buf[EI_VERSION] = EV_CURRENT; 799 buf[EI_OSABI] = attrs->ei_osabi; 800 801 ELF_SET_FIELD (fns, cl, Ehdr, buf, e_type, Elf_Half, ET_REL); 802 ELF_SET_FIELD (fns, cl, Ehdr, buf, e_machine, Elf_Half, attrs->machine); 803 ELF_SET_FIELD (fns, cl, Ehdr, buf, e_version, Elf_Word, EV_CURRENT); 804 /* e_entry left as zero. */ 805 /* e_phoff left as zero. */ 806 ELF_SET_FIELD (fns, cl, Ehdr, buf, e_shoff, Elf_Addr, ehdr_size); 807 ELF_SET_FIELD (fns, cl, Ehdr, buf, e_flags, Elf_Word, attrs->flags); 808 ELF_SET_FIELD (fns, cl, Ehdr, buf, e_ehsize, Elf_Half, ehdr_size); 809 ELF_SET_FIELD (fns, cl, Ehdr, buf, e_phentsize, Elf_Half, 810 (cl == ELFCLASS32 811 ? sizeof (Elf32_External_Phdr) 812 : sizeof (Elf64_External_Phdr))); 813 /* e_phnum left as zero. */ 814 ELF_SET_FIELD (fns, cl, Ehdr, buf, e_shentsize, Elf_Half, 815 (cl == ELFCLASS32 816 ? sizeof (Elf32_External_Shdr) 817 : sizeof (Elf64_External_Shdr))); 818 ELF_SET_FIELD (fns, cl, Ehdr, buf, e_shnum, Elf_Half, 819 shnum >= SHN_LORESERVE ? 0 : shnum); 820 if (shnum == 0) 821 shstrndx = 0; 822 else 823 { 824 shstrndx = shnum - 1; 825 if (shstrndx >= SHN_LORESERVE) 826 shstrndx = SHN_XINDEX; 827 } 828 ELF_SET_FIELD (fns, cl, Ehdr, buf, e_shstrndx, Elf_Half, shstrndx); 829 830 return simple_object_internal_write (descriptor, 0, buf, ehdr_size, 831 errmsg, err); 832 } 833 834 /* Write out an ELF shdr. */ 835 836 static int 837 simple_object_elf_write_shdr (simple_object_write *sobj, int descriptor, 838 off_t offset, unsigned int sh_name, 839 unsigned int sh_type, unsigned int sh_flags, 840 off_t sh_addr, 841 unsigned int sh_offset, unsigned int sh_size, 842 unsigned int sh_link, unsigned int sh_info, 843 size_t sh_addralign, 844 size_t sh_entsize, 845 const char **errmsg, int *err) 846 { 847 struct simple_object_elf_attributes *attrs = 848 (struct simple_object_elf_attributes *) sobj->data; 849 const struct elf_type_functions* fns; 850 unsigned char cl; 851 size_t shdr_size; 852 unsigned char buf[sizeof (Elf64_External_Shdr)]; 853 854 fns = attrs->type_functions; 855 cl = attrs->ei_class; 856 857 shdr_size = (cl == ELFCLASS32 858 ? sizeof (Elf32_External_Shdr) 859 : sizeof (Elf64_External_Shdr)); 860 memset (buf, 0, sizeof (Elf64_External_Shdr)); 861 862 ELF_SET_FIELD (fns, cl, Shdr, buf, sh_name, Elf_Word, sh_name); 863 ELF_SET_FIELD (fns, cl, Shdr, buf, sh_type, Elf_Word, sh_type); 864 ELF_SET_FIELD (fns, cl, Shdr, buf, sh_flags, Elf_Addr, sh_flags); 865 ELF_SET_FIELD (fns, cl, Shdr, buf, sh_addr, Elf_Addr, sh_addr); 866 ELF_SET_FIELD (fns, cl, Shdr, buf, sh_offset, Elf_Addr, sh_offset); 867 ELF_SET_FIELD (fns, cl, Shdr, buf, sh_size, Elf_Addr, sh_size); 868 ELF_SET_FIELD (fns, cl, Shdr, buf, sh_link, Elf_Word, sh_link); 869 ELF_SET_FIELD (fns, cl, Shdr, buf, sh_info, Elf_Word, sh_info); 870 ELF_SET_FIELD (fns, cl, Shdr, buf, sh_addralign, Elf_Addr, sh_addralign); 871 ELF_SET_FIELD (fns, cl, Shdr, buf, sh_entsize, Elf_Addr, sh_entsize); 872 873 return simple_object_internal_write (descriptor, offset, buf, shdr_size, 874 errmsg, err); 875 } 876 877 /* Write out a complete ELF file. 878 Ehdr 879 initial dummy Shdr 880 user-created Shdrs 881 .shstrtab Shdr 882 user-created section data 883 .shstrtab data */ 884 885 static const char * 886 simple_object_elf_write_to_file (simple_object_write *sobj, int descriptor, 887 int *err) 888 { 889 struct simple_object_elf_write *eow = 890 (struct simple_object_elf_write *) sobj->data; 891 struct simple_object_elf_attributes *attrs = &eow->attrs; 892 unsigned char cl; 893 size_t ehdr_size; 894 size_t shdr_size; 895 const char *errmsg; 896 simple_object_write_section *section; 897 unsigned int shnum; 898 size_t shdr_offset; 899 size_t sh_offset; 900 unsigned int first_sh_size; 901 unsigned int first_sh_link; 902 size_t sh_name; 903 unsigned char zero; 904 unsigned secnum; 905 906 if (!simple_object_elf_write_ehdr (sobj, descriptor, &errmsg, err)) 907 return errmsg; 908 909 cl = attrs->ei_class; 910 if (cl == ELFCLASS32) 911 { 912 ehdr_size = sizeof (Elf32_External_Ehdr); 913 shdr_size = sizeof (Elf32_External_Shdr); 914 } 915 else 916 { 917 ehdr_size = sizeof (Elf64_External_Ehdr); 918 shdr_size = sizeof (Elf64_External_Shdr); 919 } 920 921 shnum = 0; 922 for (section = sobj->sections; section != NULL; section = section->next) 923 ++shnum; 924 if (shnum == 0) 925 return NULL; 926 927 /* Add initial dummy Shdr and .shstrtab. */ 928 shnum += 2; 929 930 shdr_offset = ehdr_size; 931 sh_offset = shdr_offset + shnum * shdr_size; 932 933 if (shnum < SHN_LORESERVE) 934 first_sh_size = 0; 935 else 936 first_sh_size = shnum; 937 if (shnum - 1 < SHN_LORESERVE) 938 first_sh_link = 0; 939 else 940 first_sh_link = shnum - 1; 941 if (!simple_object_elf_write_shdr (sobj, descriptor, shdr_offset, 942 0, 0, 0, 0, 0, first_sh_size, first_sh_link, 943 0, 0, 0, &errmsg, err)) 944 return errmsg; 945 946 shdr_offset += shdr_size; 947 948 sh_name = 1; 949 secnum = 0; 950 for (section = sobj->sections; section != NULL; section = section->next) 951 { 952 size_t mask; 953 size_t new_sh_offset; 954 size_t sh_size; 955 struct simple_object_write_section_buffer *buffer; 956 unsigned int sh_type = SHT_PROGBITS; 957 unsigned int sh_flags = 0; 958 off_t sh_addr = 0; 959 unsigned int sh_link = 0; 960 unsigned int sh_info = 0; 961 size_t sh_addralign = 1U << section->align; 962 size_t sh_entsize = 0; 963 if (eow->shdrs) 964 { 965 sh_type = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, 966 eow->shdrs + secnum * shdr_size, 967 sh_type, Elf_Word); 968 sh_flags = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, 969 eow->shdrs + secnum * shdr_size, 970 sh_flags, Elf_Addr); 971 sh_addr = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, 972 eow->shdrs + secnum * shdr_size, 973 sh_addr, Elf_Addr); 974 sh_link = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, 975 eow->shdrs + secnum * shdr_size, 976 sh_link, Elf_Word); 977 sh_info = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, 978 eow->shdrs + secnum * shdr_size, 979 sh_info, Elf_Word); 980 sh_addralign = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, 981 eow->shdrs + secnum * shdr_size, 982 sh_addralign, Elf_Addr); 983 sh_entsize = ELF_FETCH_FIELD (attrs->type_functions, attrs->ei_class, Shdr, 984 eow->shdrs + secnum * shdr_size, 985 sh_entsize, Elf_Addr); 986 secnum++; 987 } 988 989 mask = sh_addralign - 1; 990 new_sh_offset = sh_offset + mask; 991 new_sh_offset &= ~ mask; 992 while (new_sh_offset > sh_offset) 993 { 994 unsigned char zeroes[16]; 995 size_t write; 996 997 memset (zeroes, 0, sizeof zeroes); 998 write = new_sh_offset - sh_offset; 999 if (write > sizeof zeroes) 1000 write = sizeof zeroes; 1001 if (!simple_object_internal_write (descriptor, sh_offset, zeroes, 1002 write, &errmsg, err)) 1003 return errmsg; 1004 sh_offset += write; 1005 } 1006 1007 sh_size = 0; 1008 for (buffer = section->buffers; buffer != NULL; buffer = buffer->next) 1009 { 1010 if (!simple_object_internal_write (descriptor, sh_offset + sh_size, 1011 ((const unsigned char *) 1012 buffer->buffer), 1013 buffer->size, &errmsg, err)) 1014 return errmsg; 1015 sh_size += buffer->size; 1016 } 1017 1018 if (!simple_object_elf_write_shdr (sobj, descriptor, shdr_offset, 1019 sh_name, sh_type, sh_flags, 1020 sh_addr, sh_offset, 1021 sh_size, sh_link, sh_info, 1022 sh_addralign, sh_entsize, 1023 &errmsg, err)) 1024 return errmsg; 1025 1026 shdr_offset += shdr_size; 1027 sh_name += strlen (section->name) + 1; 1028 sh_offset += sh_size; 1029 } 1030 1031 if (!simple_object_elf_write_shdr (sobj, descriptor, shdr_offset, 1032 sh_name, SHT_STRTAB, 0, 0, sh_offset, 1033 sh_name + strlen (".shstrtab") + 1, 0, 0, 1034 1, 0, &errmsg, err)) 1035 return errmsg; 1036 1037 /* .shstrtab has a leading zero byte. */ 1038 zero = 0; 1039 if (!simple_object_internal_write (descriptor, sh_offset, &zero, 1, 1040 &errmsg, err)) 1041 return errmsg; 1042 ++sh_offset; 1043 1044 for (section = sobj->sections; section != NULL; section = section->next) 1045 { 1046 size_t len; 1047 1048 len = strlen (section->name) + 1; 1049 if (!simple_object_internal_write (descriptor, sh_offset, 1050 (const unsigned char *) section->name, 1051 len, &errmsg, err)) 1052 return errmsg; 1053 sh_offset += len; 1054 } 1055 1056 if (!simple_object_internal_write (descriptor, sh_offset, 1057 (const unsigned char *) ".shstrtab", 1058 strlen (".shstrtab") + 1, &errmsg, err)) 1059 return errmsg; 1060 1061 return NULL; 1062 } 1063 1064 /* Release the private data for an simple_object_write structure. */ 1065 1066 static void 1067 simple_object_elf_release_write (void *data) 1068 { 1069 struct simple_object_elf_write *eow = (struct simple_object_elf_write *) data; 1070 if (eow->shdrs) 1071 XDELETE (eow->shdrs); 1072 XDELETE (data); 1073 } 1074 1075 /* Copy all sections in an ELF file. */ 1076 1077 static const char * 1078 simple_object_elf_copy_lto_debug_sections (simple_object_read *sobj, 1079 simple_object_write *dobj, 1080 char *(*pfn) (const char *), 1081 int *err) 1082 { 1083 struct simple_object_elf_read *eor = 1084 (struct simple_object_elf_read *) sobj->data; 1085 const struct elf_type_functions *type_functions = eor->type_functions; 1086 struct simple_object_elf_write *eow = 1087 (struct simple_object_elf_write *) dobj->data; 1088 unsigned char ei_class = eor->ei_class; 1089 size_t shdr_size; 1090 unsigned int shnum; 1091 unsigned char *shdrs; 1092 const char *errmsg; 1093 unsigned char *shstrhdr; 1094 size_t name_size; 1095 off_t shstroff; 1096 unsigned char *names; 1097 unsigned int i; 1098 int changed; 1099 int *pfnret; 1100 const char **pfnname; 1101 unsigned new_i; 1102 unsigned *sh_map; 1103 unsigned first_shndx = 0; 1104 unsigned int *symtab_indices_shndx; 1105 1106 shdr_size = (ei_class == ELFCLASS32 1107 ? sizeof (Elf32_External_Shdr) 1108 : sizeof (Elf64_External_Shdr)); 1109 1110 /* Read the section headers. We skip section 0, which is not a 1111 useful section. */ 1112 1113 shnum = eor->shnum; 1114 shdrs = XNEWVEC (unsigned char, shdr_size * (shnum - 1)); 1115 1116 if (!simple_object_internal_read (sobj->descriptor, 1117 sobj->offset + eor->shoff + shdr_size, 1118 shdrs, 1119 shdr_size * (shnum - 1), 1120 &errmsg, err)) 1121 { 1122 XDELETEVEC (shdrs); 1123 return errmsg; 1124 } 1125 1126 /* Read the section names. */ 1127 1128 shstrhdr = shdrs + (eor->shstrndx - 1) * shdr_size; 1129 name_size = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1130 shstrhdr, sh_size, Elf_Addr); 1131 shstroff = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1132 shstrhdr, sh_offset, Elf_Addr); 1133 names = XNEWVEC (unsigned char, name_size); 1134 if (!simple_object_internal_read (sobj->descriptor, 1135 sobj->offset + shstroff, 1136 names, name_size, &errmsg, err)) 1137 { 1138 XDELETEVEC (names); 1139 XDELETEVEC (shdrs); 1140 return errmsg; 1141 } 1142 1143 pfnret = XNEWVEC (int, shnum); 1144 pfnname = XNEWVEC (const char *, shnum); 1145 1146 /* Map of symtab to index section. */ 1147 symtab_indices_shndx = XCNEWVEC (unsigned int, shnum - 1); 1148 1149 /* First perform the callbacks to know which sections to preserve and 1150 what name to use for those. */ 1151 for (i = 1; i < shnum; ++i) 1152 { 1153 unsigned char *shdr; 1154 unsigned int sh_name, sh_type; 1155 const char *name; 1156 char *ret; 1157 1158 shdr = shdrs + (i - 1) * shdr_size; 1159 sh_name = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1160 shdr, sh_name, Elf_Word); 1161 if (sh_name >= name_size) 1162 { 1163 *err = 0; 1164 XDELETEVEC (names); 1165 XDELETEVEC (shdrs); 1166 return "ELF section name out of range"; 1167 } 1168 1169 name = (const char *) names + sh_name; 1170 1171 ret = (*pfn) (name); 1172 pfnret[i - 1] = ret == NULL ? -1 : 0; 1173 pfnname[i - 1] = ret == NULL ? name : ret; 1174 if (first_shndx == 0 1175 && pfnret[i - 1] == 0) 1176 first_shndx = i; 1177 1178 /* Remember the indexes of existing SHT_SYMTAB_SHNDX sections. */ 1179 sh_type = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1180 shdr, sh_type, Elf_Word); 1181 if (sh_type == SHT_SYMTAB_SHNDX) 1182 { 1183 unsigned int sh_link; 1184 sh_link = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1185 shdr, sh_link, Elf_Word); 1186 symtab_indices_shndx[sh_link - 1] = i; 1187 /* Always discard the extended index sections, after 1188 copying it will not be needed. This way we don't need to 1189 update it and deal with the ordering constraints of 1190 processing the existing symtab and changing the index. */ 1191 pfnret[i - 1] = -1; 1192 } 1193 } 1194 1195 /* Mark sections as preserved that are required by to be preserved 1196 sections. */ 1197 do 1198 { 1199 changed = 0; 1200 for (i = 1; i < shnum; ++i) 1201 { 1202 unsigned char *shdr; 1203 unsigned int sh_type, sh_info, sh_link; 1204 off_t offset; 1205 off_t length; 1206 1207 shdr = shdrs + (i - 1) * shdr_size; 1208 sh_type = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1209 shdr, sh_type, Elf_Word); 1210 sh_info = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1211 shdr, sh_info, Elf_Word); 1212 sh_link = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1213 shdr, sh_link, Elf_Word); 1214 if (sh_type == SHT_GROUP) 1215 { 1216 /* Mark groups containing copied sections. */ 1217 unsigned entsize = ELF_FETCH_FIELD (type_functions, ei_class, 1218 Shdr, shdr, sh_entsize, 1219 Elf_Addr); 1220 unsigned char *ent, *buf; 1221 int keep = 0; 1222 offset = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1223 shdr, sh_offset, Elf_Addr); 1224 length = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1225 shdr, sh_size, Elf_Addr); 1226 buf = XNEWVEC (unsigned char, length); 1227 if (!simple_object_internal_read (sobj->descriptor, 1228 sobj->offset + offset, buf, 1229 (size_t) length, &errmsg, err)) 1230 { 1231 XDELETEVEC (buf); 1232 XDELETEVEC (names); 1233 XDELETEVEC (shdrs); 1234 return errmsg; 1235 } 1236 for (ent = buf + entsize; ent < buf + length; ent += entsize) 1237 { 1238 unsigned sec = type_functions->fetch_Elf_Word (ent); 1239 if (pfnret[sec - 1] == 0) 1240 keep = 1; 1241 } 1242 if (keep) 1243 { 1244 changed |= (pfnret[sh_link - 1] == -1 1245 || pfnret[i - 1] == -1); 1246 pfnret[sh_link - 1] = 0; 1247 pfnret[i - 1] = 0; 1248 } 1249 } 1250 if (sh_type == SHT_RELA 1251 || sh_type == SHT_REL) 1252 { 1253 /* Mark relocation sections and symtab of copied sections. */ 1254 if (pfnret[sh_info - 1] == 0) 1255 { 1256 changed |= (pfnret[sh_link - 1] == -1 1257 || pfnret[i - 1] == -1); 1258 pfnret[sh_link - 1] = 0; 1259 pfnret[i - 1] = 0; 1260 } 1261 } 1262 if (sh_type == SHT_SYMTAB) 1263 { 1264 /* Mark strings sections of copied symtabs. */ 1265 if (pfnret[i - 1] == 0) 1266 { 1267 changed |= pfnret[sh_link - 1] == -1; 1268 pfnret[sh_link - 1] = 0; 1269 } 1270 } 1271 } 1272 } 1273 while (changed); 1274 1275 /* Compute a mapping of old -> new section numbers. */ 1276 sh_map = XNEWVEC (unsigned, shnum); 1277 sh_map[0] = 0; 1278 new_i = 1; 1279 for (i = 1; i < shnum; ++i) 1280 { 1281 if (pfnret[i - 1] == -1) 1282 sh_map[i] = 0; 1283 else 1284 sh_map[i] = new_i++; 1285 } 1286 if (new_i - 1 >= SHN_LORESERVE) 1287 { 1288 *err = ENOTSUP; 1289 return "Too many copied sections"; 1290 } 1291 eow->shdrs = XNEWVEC (unsigned char, shdr_size * (new_i - 1)); 1292 1293 /* Then perform the actual copying. */ 1294 new_i = 0; 1295 for (i = 1; i < shnum; ++i) 1296 { 1297 unsigned char *shdr; 1298 unsigned int sh_name, sh_type; 1299 const char *name; 1300 off_t offset; 1301 off_t length; 1302 simple_object_write_section *dest; 1303 off_t flags; 1304 unsigned char *buf; 1305 1306 if (pfnret[i - 1]) 1307 continue; 1308 1309 new_i++; 1310 shdr = shdrs + (i - 1) * shdr_size; 1311 sh_name = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1312 shdr, sh_name, Elf_Word); 1313 if (sh_name >= name_size) 1314 { 1315 *err = 0; 1316 XDELETEVEC (names); 1317 XDELETEVEC (shdrs); 1318 XDELETEVEC (symtab_indices_shndx); 1319 return "ELF section name out of range"; 1320 } 1321 1322 name = pfnname[i - 1]; 1323 offset = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1324 shdr, sh_offset, Elf_Addr); 1325 length = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1326 shdr, sh_size, Elf_Addr); 1327 sh_type = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1328 shdr, sh_type, Elf_Word); 1329 1330 dest = simple_object_write_create_section (dobj, pfnname[i - 1], 1331 0, &errmsg, err); 1332 if (dest == NULL) 1333 { 1334 XDELETEVEC (names); 1335 XDELETEVEC (shdrs); 1336 XDELETEVEC (symtab_indices_shndx); 1337 return errmsg; 1338 } 1339 1340 /* Record the SHDR of the source. */ 1341 memcpy (eow->shdrs + (new_i - 1) * shdr_size, shdr, shdr_size); 1342 shdr = eow->shdrs + (new_i - 1) * shdr_size; 1343 1344 /* Copy the data. 1345 ??? This is quite wasteful and ideally would be delayed until 1346 write_to_file (). Thus it questions the interfacing 1347 which eventually should contain destination creation plus 1348 writing. */ 1349 buf = XNEWVEC (unsigned char, length); 1350 if (!simple_object_internal_read (sobj->descriptor, 1351 sobj->offset + offset, buf, 1352 (size_t) length, &errmsg, err)) 1353 { 1354 XDELETEVEC (buf); 1355 XDELETEVEC (names); 1356 XDELETEVEC (shdrs); 1357 XDELETEVEC (symtab_indices_shndx); 1358 return errmsg; 1359 } 1360 1361 /* If we are processing .symtab purge __gnu_lto_v1 and 1362 __gnu_lto_slim symbols from it and any symbols in discarded 1363 sections. */ 1364 if (sh_type == SHT_SYMTAB) 1365 { 1366 unsigned entsize = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1367 shdr, sh_entsize, Elf_Addr); 1368 unsigned strtab = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1369 shdr, sh_link, Elf_Word); 1370 unsigned char *strshdr = shdrs + (strtab - 1) * shdr_size; 1371 off_t stroff = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1372 strshdr, sh_offset, Elf_Addr); 1373 size_t strsz = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1374 strshdr, sh_size, Elf_Addr); 1375 char *strings = XNEWVEC (char, strsz); 1376 char *gnu_lto = strings; 1377 unsigned char *ent; 1378 unsigned *shndx_table = NULL; 1379 simple_object_internal_read (sobj->descriptor, 1380 sobj->offset + stroff, 1381 (unsigned char *)strings, 1382 strsz, &errmsg, err); 1383 /* Find gnu_lto_ in strings. */ 1384 while ((gnu_lto = (char *) memchr (gnu_lto, 'g', 1385 strings + strsz - gnu_lto))) 1386 if (strncmp (gnu_lto, "gnu_lto_v1", 1387 strings + strsz - gnu_lto) == 0) 1388 break; 1389 else 1390 gnu_lto++; 1391 /* Read the section index table if present. */ 1392 if (symtab_indices_shndx[i - 1] != 0) 1393 { 1394 unsigned char *sidxhdr = shdrs + (strtab - 1) * shdr_size; 1395 off_t sidxoff = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1396 sidxhdr, sh_offset, Elf_Addr); 1397 size_t sidxsz = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1398 sidxhdr, sh_size, Elf_Addr); 1399 shndx_table = (unsigned *)XNEWVEC (char, sidxsz); 1400 simple_object_internal_read (sobj->descriptor, 1401 sobj->offset + sidxoff, 1402 (unsigned char *)shndx_table, 1403 sidxsz, &errmsg, err); 1404 } 1405 for (ent = buf; ent < buf + length; ent += entsize) 1406 { 1407 unsigned st_shndx = ELF_FETCH_FIELD (type_functions, ei_class, 1408 Sym, ent, 1409 st_shndx, Elf_Half); 1410 unsigned raw_st_shndx = st_shndx; 1411 unsigned char *st_info; 1412 unsigned char *st_other; 1413 int discard = 0; 1414 if (ei_class == ELFCLASS32) 1415 { 1416 st_info = &((Elf32_External_Sym *)ent)->st_info; 1417 st_other = &((Elf32_External_Sym *)ent)->st_other; 1418 } 1419 else 1420 { 1421 st_info = &((Elf64_External_Sym *)ent)->st_info; 1422 st_other = &((Elf64_External_Sym *)ent)->st_other; 1423 } 1424 if (st_shndx == SHN_XINDEX) 1425 st_shndx = type_functions->fetch_Elf_Word 1426 ((unsigned char *)(shndx_table + (ent - buf) / entsize)); 1427 /* Eliminate all COMMONs - this includes __gnu_lto_v1 1428 and __gnu_lto_slim which otherwise cause endless 1429 LTO plugin invocation. */ 1430 if (st_shndx == SHN_COMMON) 1431 discard = 1; 1432 /* We also need to remove symbols refering to sections 1433 we'll eventually remove as with fat LTO objects 1434 we otherwise get duplicate symbols at final link 1435 (with GNU ld, gold is fine and ignores symbols in 1436 sections marked as EXCLUDE). ld/20513 */ 1437 else if (st_shndx != SHN_UNDEF 1438 && st_shndx < shnum 1439 && pfnret[st_shndx - 1] == -1) 1440 discard = 1; 1441 1442 if (discard) 1443 { 1444 /* Make discarded symbols undefined and unnamed 1445 in case it is local. */ 1446 int bind = ELF_ST_BIND (*st_info); 1447 int other = STV_DEFAULT; 1448 if (bind == STB_LOCAL) 1449 { 1450 /* Make discarded local symbols unnamed and 1451 defined in the first prevailing section. */ 1452 ELF_SET_FIELD (type_functions, ei_class, Sym, 1453 ent, st_name, Elf_Word, 0); 1454 ELF_SET_FIELD (type_functions, ei_class, Sym, 1455 ent, st_shndx, Elf_Half, 1456 sh_map[first_shndx]); 1457 } 1458 else 1459 { 1460 /* Make discarded global symbols hidden weak 1461 undefined and sharing the gnu_lto_ name. */ 1462 bind = STB_WEAK; 1463 other = STV_HIDDEN; 1464 if (gnu_lto) 1465 ELF_SET_FIELD (type_functions, ei_class, Sym, 1466 ent, st_name, Elf_Word, 1467 gnu_lto - strings); 1468 ELF_SET_FIELD (type_functions, ei_class, Sym, 1469 ent, st_shndx, Elf_Half, SHN_UNDEF); 1470 } 1471 *st_other = other; 1472 *st_info = ELF_ST_INFO (bind, STT_NOTYPE); 1473 ELF_SET_FIELD (type_functions, ei_class, Sym, 1474 ent, st_value, Elf_Addr, 0); 1475 ELF_SET_FIELD (type_functions, ei_class, Sym, 1476 ent, st_size, Elf_Word, 0); 1477 } 1478 else if (raw_st_shndx < SHN_LORESERVE 1479 || raw_st_shndx == SHN_XINDEX) 1480 /* Remap the section reference. */ 1481 ELF_SET_FIELD (type_functions, ei_class, Sym, 1482 ent, st_shndx, Elf_Half, sh_map[st_shndx]); 1483 } 1484 XDELETEVEC (strings); 1485 XDELETEVEC (shndx_table); 1486 } 1487 else if (sh_type == SHT_GROUP) 1488 { 1489 /* Remap section indices in groups and remove removed members. */ 1490 unsigned char *ent, *dst; 1491 for (dst = ent = buf + 4; ent < buf + length; ent += 4) 1492 { 1493 unsigned shndx = type_functions->fetch_Elf_Word (ent); 1494 if (pfnret[shndx - 1] == -1) 1495 ; 1496 else 1497 { 1498 type_functions->set_Elf_Word (dst, sh_map[shndx]); 1499 dst += 4; 1500 } 1501 } 1502 /* Adjust the length. */ 1503 length = dst - buf; 1504 } 1505 1506 errmsg = simple_object_write_add_data (dobj, dest, 1507 buf, length, 1, err); 1508 XDELETEVEC (buf); 1509 if (errmsg) 1510 { 1511 XDELETEVEC (names); 1512 XDELETEVEC (shdrs); 1513 XDELETEVEC (symtab_indices_shndx); 1514 return errmsg; 1515 } 1516 1517 flags = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1518 shdr, sh_flags, Elf_Addr); 1519 /* Remap the section references. */ 1520 { 1521 unsigned int sh_info, sh_link; 1522 if (flags & SHF_INFO_LINK || sh_type == SHT_REL || sh_type == SHT_RELA) 1523 { 1524 sh_info = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1525 shdr, sh_info, Elf_Word); 1526 if (sh_info < SHN_LORESERVE 1527 || sh_info > SHN_HIRESERVE) 1528 sh_info = sh_map[sh_info]; 1529 ELF_SET_FIELD (type_functions, ei_class, Shdr, 1530 shdr, sh_info, Elf_Word, sh_info); 1531 } 1532 sh_link = ELF_FETCH_FIELD (type_functions, ei_class, Shdr, 1533 shdr, sh_link, Elf_Word); 1534 if (sh_link < SHN_LORESERVE 1535 || sh_link > SHN_HIRESERVE) 1536 sh_link = sh_map[sh_link]; 1537 ELF_SET_FIELD (type_functions, ei_class, Shdr, 1538 shdr, sh_link, Elf_Word, sh_link); 1539 } 1540 /* The debugobj doesn't contain any code, thus no trampolines. 1541 Even when the original object needs trampolines, debugobj 1542 doesn't. */ 1543 if (strcmp (name, ".note.GNU-stack") == 0) 1544 flags &= ~SHF_EXECINSTR; 1545 /* Clear SHF_EXCLUDE on to be preserved sections. */ 1546 flags &= ~SHF_EXCLUDE; 1547 ELF_SET_FIELD (type_functions, ei_class, Shdr, 1548 shdr, sh_flags, Elf_Addr, flags); 1549 } 1550 1551 XDELETEVEC (names); 1552 XDELETEVEC (shdrs); 1553 XDELETEVEC (pfnret); 1554 XDELETEVEC (pfnname); 1555 XDELETEVEC (symtab_indices_shndx); 1556 XDELETEVEC (sh_map); 1557 1558 return NULL; 1559 } 1560 1561 1562 /* The ELF functions. */ 1563 1564 const struct simple_object_functions simple_object_elf_functions = 1565 { 1566 simple_object_elf_match, 1567 simple_object_elf_find_sections, 1568 simple_object_elf_fetch_attributes, 1569 simple_object_elf_release_read, 1570 simple_object_elf_attributes_merge, 1571 simple_object_elf_release_attributes, 1572 simple_object_elf_start_write, 1573 simple_object_elf_write_to_file, 1574 simple_object_elf_release_write, 1575 simple_object_elf_copy_lto_debug_sections 1576 }; 1577