github.com/FenixAra/go@v0.0.0-20170127160404-96ea0918e670/src/cmd/link/internal/ld/elf.go (about) 1 // Copyright 2009 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package ld 6 7 import ( 8 "cmd/internal/obj" 9 "cmd/internal/sys" 10 "crypto/sha1" 11 "encoding/binary" 12 "encoding/hex" 13 "io" 14 "path/filepath" 15 "sort" 16 "strings" 17 ) 18 19 /* 20 * Derived from: 21 * $FreeBSD: src/sys/sys/elf32.h,v 1.8.14.1 2005/12/30 22:13:58 marcel Exp $ 22 * $FreeBSD: src/sys/sys/elf64.h,v 1.10.14.1 2005/12/30 22:13:58 marcel Exp $ 23 * $FreeBSD: src/sys/sys/elf_common.h,v 1.15.8.1 2005/12/30 22:13:58 marcel Exp $ 24 * $FreeBSD: src/sys/alpha/include/elf.h,v 1.14 2003/09/25 01:10:22 peter Exp $ 25 * $FreeBSD: src/sys/amd64/include/elf.h,v 1.18 2004/08/03 08:21:48 dfr Exp $ 26 * $FreeBSD: src/sys/arm/include/elf.h,v 1.5.2.1 2006/06/30 21:42:52 cognet Exp $ 27 * $FreeBSD: src/sys/i386/include/elf.h,v 1.16 2004/08/02 19:12:17 dfr Exp $ 28 * $FreeBSD: src/sys/powerpc/include/elf.h,v 1.7 2004/11/02 09:47:01 ssouhlal Exp $ 29 * $FreeBSD: src/sys/sparc64/include/elf.h,v 1.12 2003/09/25 01:10:26 peter Exp $ 30 * 31 * Copyright (c) 1996-1998 John D. Polstra. All rights reserved. 32 * Copyright (c) 2001 David E. O'Brien 33 * Portions Copyright 2009 The Go Authors. All rights reserved. 34 * 35 * Redistribution and use in source and binary forms, with or without 36 * modification, are permitted provided that the following conditions 37 * are met: 38 * 1. Redistributions of source code must retain the above copyright 39 * notice, this list of conditions and the following disclaimer. 40 * 2. Redistributions in binary form must reproduce the above copyright 41 * notice, this list of conditions and the following disclaimer in the 42 * documentation and/or other materials provided with the distribution. 43 * 44 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 45 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 46 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 47 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 48 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 49 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 50 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 51 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 52 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 53 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 54 * SUCH DAMAGE. 55 * 56 */ 57 58 /* 59 * ELF definitions that are independent of architecture or word size. 60 */ 61 62 /* 63 * Note header. The ".note" section contains an array of notes. Each 64 * begins with this header, aligned to a word boundary. Immediately 65 * following the note header is n_namesz bytes of name, padded to the 66 * next word boundary. Then comes n_descsz bytes of descriptor, again 67 * padded to a word boundary. The values of n_namesz and n_descsz do 68 * not include the padding. 69 */ 70 type elfNote struct { 71 nNamesz uint32 72 nDescsz uint32 73 nType uint32 74 } 75 76 const ( 77 EI_MAG0 = 0 78 EI_MAG1 = 1 79 EI_MAG2 = 2 80 EI_MAG3 = 3 81 EI_CLASS = 4 82 EI_DATA = 5 83 EI_VERSION = 6 84 EI_OSABI = 7 85 EI_ABIVERSION = 8 86 OLD_EI_BRAND = 8 87 EI_PAD = 9 88 EI_NIDENT = 16 89 ELFMAG0 = 0x7f 90 ELFMAG1 = 'E' 91 ELFMAG2 = 'L' 92 ELFMAG3 = 'F' 93 SELFMAG = 4 94 EV_NONE = 0 95 EV_CURRENT = 1 96 ELFCLASSNONE = 0 97 ELFCLASS32 = 1 98 ELFCLASS64 = 2 99 ELFDATANONE = 0 100 ELFDATA2LSB = 1 101 ELFDATA2MSB = 2 102 ELFOSABI_NONE = 0 103 ELFOSABI_HPUX = 1 104 ELFOSABI_NETBSD = 2 105 ELFOSABI_LINUX = 3 106 ELFOSABI_HURD = 4 107 ELFOSABI_86OPEN = 5 108 ELFOSABI_SOLARIS = 6 109 ELFOSABI_AIX = 7 110 ELFOSABI_IRIX = 8 111 ELFOSABI_FREEBSD = 9 112 ELFOSABI_TRU64 = 10 113 ELFOSABI_MODESTO = 11 114 ELFOSABI_OPENBSD = 12 115 ELFOSABI_OPENVMS = 13 116 ELFOSABI_NSK = 14 117 ELFOSABI_ARM = 97 118 ELFOSABI_STANDALONE = 255 119 ELFOSABI_SYSV = ELFOSABI_NONE 120 ELFOSABI_MONTEREY = ELFOSABI_AIX 121 ET_NONE = 0 122 ET_REL = 1 123 ET_EXEC = 2 124 ET_DYN = 3 125 ET_CORE = 4 126 ET_LOOS = 0xfe00 127 ET_HIOS = 0xfeff 128 ET_LOPROC = 0xff00 129 ET_HIPROC = 0xffff 130 EM_NONE = 0 131 EM_M32 = 1 132 EM_SPARC = 2 133 EM_386 = 3 134 EM_68K = 4 135 EM_88K = 5 136 EM_860 = 7 137 EM_MIPS = 8 138 EM_S370 = 9 139 EM_MIPS_RS3_LE = 10 140 EM_PARISC = 15 141 EM_VPP500 = 17 142 EM_SPARC32PLUS = 18 143 EM_960 = 19 144 EM_PPC = 20 145 EM_PPC64 = 21 146 EM_S390 = 22 147 EM_V800 = 36 148 EM_FR20 = 37 149 EM_RH32 = 38 150 EM_RCE = 39 151 EM_ARM = 40 152 EM_SH = 42 153 EM_SPARCV9 = 43 154 EM_TRICORE = 44 155 EM_ARC = 45 156 EM_H8_300 = 46 157 EM_H8_300H = 47 158 EM_H8S = 48 159 EM_H8_500 = 49 160 EM_IA_64 = 50 161 EM_MIPS_X = 51 162 EM_COLDFIRE = 52 163 EM_68HC12 = 53 164 EM_MMA = 54 165 EM_PCP = 55 166 EM_NCPU = 56 167 EM_NDR1 = 57 168 EM_STARCORE = 58 169 EM_ME16 = 59 170 EM_ST100 = 60 171 EM_TINYJ = 61 172 EM_X86_64 = 62 173 EM_AARCH64 = 183 174 EM_486 = 6 175 EM_MIPS_RS4_BE = 10 176 EM_ALPHA_STD = 41 177 EM_ALPHA = 0x9026 178 SHN_UNDEF = 0 179 SHN_LORESERVE = 0xff00 180 SHN_LOPROC = 0xff00 181 SHN_HIPROC = 0xff1f 182 SHN_LOOS = 0xff20 183 SHN_HIOS = 0xff3f 184 SHN_ABS = 0xfff1 185 SHN_COMMON = 0xfff2 186 SHN_XINDEX = 0xffff 187 SHN_HIRESERVE = 0xffff 188 SHT_NULL = 0 189 SHT_PROGBITS = 1 190 SHT_SYMTAB = 2 191 SHT_STRTAB = 3 192 SHT_RELA = 4 193 SHT_HASH = 5 194 SHT_DYNAMIC = 6 195 SHT_NOTE = 7 196 SHT_NOBITS = 8 197 SHT_REL = 9 198 SHT_SHLIB = 10 199 SHT_DYNSYM = 11 200 SHT_INIT_ARRAY = 14 201 SHT_FINI_ARRAY = 15 202 SHT_PREINIT_ARRAY = 16 203 SHT_GROUP = 17 204 SHT_SYMTAB_SHNDX = 18 205 SHT_LOOS = 0x60000000 206 SHT_HIOS = 0x6fffffff 207 SHT_GNU_VERDEF = 0x6ffffffd 208 SHT_GNU_VERNEED = 0x6ffffffe 209 SHT_GNU_VERSYM = 0x6fffffff 210 SHT_LOPROC = 0x70000000 211 SHT_ARM_ATTRIBUTES = 0x70000003 212 SHT_HIPROC = 0x7fffffff 213 SHT_LOUSER = 0x80000000 214 SHT_HIUSER = 0xffffffff 215 SHF_WRITE = 0x1 216 SHF_ALLOC = 0x2 217 SHF_EXECINSTR = 0x4 218 SHF_MERGE = 0x10 219 SHF_STRINGS = 0x20 220 SHF_INFO_LINK = 0x40 221 SHF_LINK_ORDER = 0x80 222 SHF_OS_NONCONFORMING = 0x100 223 SHF_GROUP = 0x200 224 SHF_TLS = 0x400 225 SHF_MASKOS = 0x0ff00000 226 SHF_MASKPROC = 0xf0000000 227 PT_NULL = 0 228 PT_LOAD = 1 229 PT_DYNAMIC = 2 230 PT_INTERP = 3 231 PT_NOTE = 4 232 PT_SHLIB = 5 233 PT_PHDR = 6 234 PT_TLS = 7 235 PT_LOOS = 0x60000000 236 PT_HIOS = 0x6fffffff 237 PT_LOPROC = 0x70000000 238 PT_HIPROC = 0x7fffffff 239 PT_GNU_STACK = 0x6474e551 240 PT_GNU_RELRO = 0x6474e552 241 PT_PAX_FLAGS = 0x65041580 242 PT_SUNWSTACK = 0x6ffffffb 243 PF_X = 0x1 244 PF_W = 0x2 245 PF_R = 0x4 246 PF_MASKOS = 0x0ff00000 247 PF_MASKPROC = 0xf0000000 248 DT_NULL = 0 249 DT_NEEDED = 1 250 DT_PLTRELSZ = 2 251 DT_PLTGOT = 3 252 DT_HASH = 4 253 DT_STRTAB = 5 254 DT_SYMTAB = 6 255 DT_RELA = 7 256 DT_RELASZ = 8 257 DT_RELAENT = 9 258 DT_STRSZ = 10 259 DT_SYMENT = 11 260 DT_INIT = 12 261 DT_FINI = 13 262 DT_SONAME = 14 263 DT_RPATH = 15 264 DT_SYMBOLIC = 16 265 DT_REL = 17 266 DT_RELSZ = 18 267 DT_RELENT = 19 268 DT_PLTREL = 20 269 DT_DEBUG = 21 270 DT_TEXTREL = 22 271 DT_JMPREL = 23 272 DT_BIND_NOW = 24 273 DT_INIT_ARRAY = 25 274 DT_FINI_ARRAY = 26 275 DT_INIT_ARRAYSZ = 27 276 DT_FINI_ARRAYSZ = 28 277 DT_RUNPATH = 29 278 DT_FLAGS = 30 279 DT_ENCODING = 32 280 DT_PREINIT_ARRAY = 32 281 DT_PREINIT_ARRAYSZ = 33 282 DT_LOOS = 0x6000000d 283 DT_HIOS = 0x6ffff000 284 DT_LOPROC = 0x70000000 285 DT_HIPROC = 0x7fffffff 286 DT_VERNEED = 0x6ffffffe 287 DT_VERNEEDNUM = 0x6fffffff 288 DT_VERSYM = 0x6ffffff0 289 DT_PPC64_GLINK = DT_LOPROC + 0 290 DT_PPC64_OPT = DT_LOPROC + 3 291 DF_ORIGIN = 0x0001 292 DF_SYMBOLIC = 0x0002 293 DF_TEXTREL = 0x0004 294 DF_BIND_NOW = 0x0008 295 DF_STATIC_TLS = 0x0010 296 NT_PRSTATUS = 1 297 NT_FPREGSET = 2 298 NT_PRPSINFO = 3 299 STB_LOCAL = 0 300 STB_GLOBAL = 1 301 STB_WEAK = 2 302 STB_LOOS = 10 303 STB_HIOS = 12 304 STB_LOPROC = 13 305 STB_HIPROC = 15 306 STT_NOTYPE = 0 307 STT_OBJECT = 1 308 STT_FUNC = 2 309 STT_SECTION = 3 310 STT_FILE = 4 311 STT_COMMON = 5 312 STT_TLS = 6 313 STT_LOOS = 10 314 STT_HIOS = 12 315 STT_LOPROC = 13 316 STT_HIPROC = 15 317 STV_DEFAULT = 0x0 318 STV_INTERNAL = 0x1 319 STV_HIDDEN = 0x2 320 STV_PROTECTED = 0x3 321 STN_UNDEF = 0 322 ) 323 324 /* For accessing the fields of r_info. */ 325 326 /* For constructing r_info from field values. */ 327 328 /* 329 * Relocation types. 330 */ 331 const ( 332 R_X86_64_NONE = 0 333 R_X86_64_64 = 1 334 R_X86_64_PC32 = 2 335 R_X86_64_GOT32 = 3 336 R_X86_64_PLT32 = 4 337 R_X86_64_COPY = 5 338 R_X86_64_GLOB_DAT = 6 339 R_X86_64_JMP_SLOT = 7 340 R_X86_64_RELATIVE = 8 341 R_X86_64_GOTPCREL = 9 342 R_X86_64_32 = 10 343 R_X86_64_32S = 11 344 R_X86_64_16 = 12 345 R_X86_64_PC16 = 13 346 R_X86_64_8 = 14 347 R_X86_64_PC8 = 15 348 R_X86_64_DTPMOD64 = 16 349 R_X86_64_DTPOFF64 = 17 350 R_X86_64_TPOFF64 = 18 351 R_X86_64_TLSGD = 19 352 R_X86_64_TLSLD = 20 353 R_X86_64_DTPOFF32 = 21 354 R_X86_64_GOTTPOFF = 22 355 R_X86_64_TPOFF32 = 23 356 R_X86_64_PC64 = 24 357 R_X86_64_GOTOFF64 = 25 358 R_X86_64_GOTPC32 = 26 359 R_X86_64_GOT64 = 27 360 R_X86_64_GOTPCREL64 = 28 361 R_X86_64_GOTPC64 = 29 362 R_X86_64_GOTPLT64 = 30 363 R_X86_64_PLTOFF64 = 31 364 R_X86_64_SIZE32 = 32 365 R_X86_64_SIZE64 = 33 366 R_X86_64_GOTPC32_TLSDEC = 34 367 R_X86_64_TLSDESC_CALL = 35 368 R_X86_64_TLSDESC = 36 369 R_X86_64_IRELATIVE = 37 370 R_X86_64_PC32_BND = 40 371 R_X86_64_GOTPCRELX = 41 372 R_X86_64_REX_GOTPCRELX = 42 373 374 R_AARCH64_ABS64 = 257 375 R_AARCH64_ABS32 = 258 376 R_AARCH64_CALL26 = 283 377 R_AARCH64_ADR_PREL_PG_HI21 = 275 378 R_AARCH64_ADD_ABS_LO12_NC = 277 379 R_AARCH64_LDST8_ABS_LO12_NC = 278 380 R_AARCH64_LDST16_ABS_LO12_NC = 284 381 R_AARCH64_LDST32_ABS_LO12_NC = 285 382 R_AARCH64_LDST64_ABS_LO12_NC = 286 383 R_AARCH64_ADR_GOT_PAGE = 311 384 R_AARCH64_LD64_GOT_LO12_NC = 312 385 R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21 = 541 386 R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC = 542 387 R_AARCH64_TLSLE_MOVW_TPREL_G0 = 547 388 389 R_ALPHA_NONE = 0 390 R_ALPHA_REFLONG = 1 391 R_ALPHA_REFQUAD = 2 392 R_ALPHA_GPREL32 = 3 393 R_ALPHA_LITERAL = 4 394 R_ALPHA_LITUSE = 5 395 R_ALPHA_GPDISP = 6 396 R_ALPHA_BRADDR = 7 397 R_ALPHA_HINT = 8 398 R_ALPHA_SREL16 = 9 399 R_ALPHA_SREL32 = 10 400 R_ALPHA_SREL64 = 11 401 R_ALPHA_OP_PUSH = 12 402 R_ALPHA_OP_STORE = 13 403 R_ALPHA_OP_PSUB = 14 404 R_ALPHA_OP_PRSHIFT = 15 405 R_ALPHA_GPVALUE = 16 406 R_ALPHA_GPRELHIGH = 17 407 R_ALPHA_GPRELLOW = 18 408 R_ALPHA_IMMED_GP_16 = 19 409 R_ALPHA_IMMED_GP_HI32 = 20 410 R_ALPHA_IMMED_SCN_HI32 = 21 411 R_ALPHA_IMMED_BR_HI32 = 22 412 R_ALPHA_IMMED_LO32 = 23 413 R_ALPHA_COPY = 24 414 R_ALPHA_GLOB_DAT = 25 415 R_ALPHA_JMP_SLOT = 26 416 R_ALPHA_RELATIVE = 27 417 418 R_ARM_NONE = 0 419 R_ARM_PC24 = 1 420 R_ARM_ABS32 = 2 421 R_ARM_REL32 = 3 422 R_ARM_PC13 = 4 423 R_ARM_ABS16 = 5 424 R_ARM_ABS12 = 6 425 R_ARM_THM_ABS5 = 7 426 R_ARM_ABS8 = 8 427 R_ARM_SBREL32 = 9 428 R_ARM_THM_PC22 = 10 429 R_ARM_THM_PC8 = 11 430 R_ARM_AMP_VCALL9 = 12 431 R_ARM_SWI24 = 13 432 R_ARM_THM_SWI8 = 14 433 R_ARM_XPC25 = 15 434 R_ARM_THM_XPC22 = 16 435 R_ARM_COPY = 20 436 R_ARM_GLOB_DAT = 21 437 R_ARM_JUMP_SLOT = 22 438 R_ARM_RELATIVE = 23 439 R_ARM_GOTOFF = 24 440 R_ARM_GOTPC = 25 441 R_ARM_GOT32 = 26 442 R_ARM_PLT32 = 27 443 R_ARM_CALL = 28 444 R_ARM_JUMP24 = 29 445 R_ARM_V4BX = 40 446 R_ARM_GOT_PREL = 96 447 R_ARM_GNU_VTENTRY = 100 448 R_ARM_GNU_VTINHERIT = 101 449 R_ARM_TLS_IE32 = 107 450 R_ARM_TLS_LE32 = 108 451 R_ARM_RSBREL32 = 250 452 R_ARM_THM_RPC22 = 251 453 R_ARM_RREL32 = 252 454 R_ARM_RABS32 = 253 455 R_ARM_RPC24 = 254 456 R_ARM_RBASE = 255 457 458 R_386_NONE = 0 459 R_386_32 = 1 460 R_386_PC32 = 2 461 R_386_GOT32 = 3 462 R_386_PLT32 = 4 463 R_386_COPY = 5 464 R_386_GLOB_DAT = 6 465 R_386_JMP_SLOT = 7 466 R_386_RELATIVE = 8 467 R_386_GOTOFF = 9 468 R_386_GOTPC = 10 469 R_386_TLS_TPOFF = 14 470 R_386_TLS_IE = 15 471 R_386_TLS_GOTIE = 16 472 R_386_TLS_LE = 17 473 R_386_TLS_GD = 18 474 R_386_TLS_LDM = 19 475 R_386_TLS_GD_32 = 24 476 R_386_TLS_GD_PUSH = 25 477 R_386_TLS_GD_CALL = 26 478 R_386_TLS_GD_POP = 27 479 R_386_TLS_LDM_32 = 28 480 R_386_TLS_LDM_PUSH = 29 481 R_386_TLS_LDM_CALL = 30 482 R_386_TLS_LDM_POP = 31 483 R_386_TLS_LDO_32 = 32 484 R_386_TLS_IE_32 = 33 485 R_386_TLS_LE_32 = 34 486 R_386_TLS_DTPMOD32 = 35 487 R_386_TLS_DTPOFF32 = 36 488 R_386_TLS_TPOFF32 = 37 489 R_386_TLS_GOTDESC = 39 490 R_386_TLS_DESC_CALL = 40 491 R_386_TLS_DESC = 41 492 R_386_IRELATIVE = 42 493 R_386_GOT32X = 43 494 495 R_MIPS_NONE = 0 496 R_MIPS_16 = 1 497 R_MIPS_32 = 2 498 R_MIPS_REL32 = 3 499 R_MIPS_26 = 4 500 R_MIPS_HI16 = 5 501 R_MIPS_LO16 = 6 502 R_MIPS_GPREL16 = 7 503 R_MIPS_LITERAL = 8 504 R_MIPS_GOT16 = 9 505 R_MIPS_PC16 = 10 506 R_MIPS_CALL16 = 11 507 R_MIPS_GPREL32 = 12 508 R_MIPS_SHIFT5 = 16 509 R_MIPS_SHIFT6 = 17 510 R_MIPS_64 = 18 511 R_MIPS_GOT_DISP = 19 512 R_MIPS_GOT_PAGE = 20 513 R_MIPS_GOT_OFST = 21 514 R_MIPS_GOT_HI16 = 22 515 R_MIPS_GOT_LO16 = 23 516 R_MIPS_SUB = 24 517 R_MIPS_INSERT_A = 25 518 R_MIPS_INSERT_B = 26 519 R_MIPS_DELETE = 27 520 R_MIPS_HIGHER = 28 521 R_MIPS_HIGHEST = 29 522 R_MIPS_CALL_HI16 = 30 523 R_MIPS_CALL_LO16 = 31 524 R_MIPS_SCN_DISP = 32 525 R_MIPS_REL16 = 33 526 R_MIPS_ADD_IMMEDIATE = 34 527 R_MIPS_PJUMP = 35 528 R_MIPS_RELGOT = 36 529 R_MIPS_JALR = 37 530 R_MIPS_TLS_DTPMOD32 = 38 531 R_MIPS_TLS_DTPREL32 = 39 532 R_MIPS_TLS_DTPMOD64 = 40 533 R_MIPS_TLS_DTPREL64 = 41 534 R_MIPS_TLS_GD = 42 535 R_MIPS_TLS_LDM = 43 536 R_MIPS_TLS_DTPREL_HI16 = 44 537 R_MIPS_TLS_DTPREL_LO16 = 45 538 R_MIPS_TLS_GOTTPREL = 46 539 R_MIPS_TLS_TPREL32 = 47 540 R_MIPS_TLS_TPREL64 = 48 541 R_MIPS_TLS_TPREL_HI16 = 49 542 R_MIPS_TLS_TPREL_LO16 = 50 543 544 R_PPC_NONE = 0 545 R_PPC_ADDR32 = 1 546 R_PPC_ADDR24 = 2 547 R_PPC_ADDR16 = 3 548 R_PPC_ADDR16_LO = 4 549 R_PPC_ADDR16_HI = 5 550 R_PPC_ADDR16_HA = 6 551 R_PPC_ADDR14 = 7 552 R_PPC_ADDR14_BRTAKEN = 8 553 R_PPC_ADDR14_BRNTAKEN = 9 554 R_PPC_REL24 = 10 555 R_PPC_REL14 = 11 556 R_PPC_REL14_BRTAKEN = 12 557 R_PPC_REL14_BRNTAKEN = 13 558 R_PPC_GOT16 = 14 559 R_PPC_GOT16_LO = 15 560 R_PPC_GOT16_HI = 16 561 R_PPC_GOT16_HA = 17 562 R_PPC_PLTREL24 = 18 563 R_PPC_COPY = 19 564 R_PPC_GLOB_DAT = 20 565 R_PPC_JMP_SLOT = 21 566 R_PPC_RELATIVE = 22 567 R_PPC_LOCAL24PC = 23 568 R_PPC_UADDR32 = 24 569 R_PPC_UADDR16 = 25 570 R_PPC_REL32 = 26 571 R_PPC_PLT32 = 27 572 R_PPC_PLTREL32 = 28 573 R_PPC_PLT16_LO = 29 574 R_PPC_PLT16_HI = 30 575 R_PPC_PLT16_HA = 31 576 R_PPC_SDAREL16 = 32 577 R_PPC_SECTOFF = 33 578 R_PPC_SECTOFF_LO = 34 579 R_PPC_SECTOFF_HI = 35 580 R_PPC_SECTOFF_HA = 36 581 R_PPC_TLS = 67 582 R_PPC_DTPMOD32 = 68 583 R_PPC_TPREL16 = 69 584 R_PPC_TPREL16_LO = 70 585 R_PPC_TPREL16_HI = 71 586 R_PPC_TPREL16_HA = 72 587 R_PPC_TPREL32 = 73 588 R_PPC_DTPREL16 = 74 589 R_PPC_DTPREL16_LO = 75 590 R_PPC_DTPREL16_HI = 76 591 R_PPC_DTPREL16_HA = 77 592 R_PPC_DTPREL32 = 78 593 R_PPC_GOT_TLSGD16 = 79 594 R_PPC_GOT_TLSGD16_LO = 80 595 R_PPC_GOT_TLSGD16_HI = 81 596 R_PPC_GOT_TLSGD16_HA = 82 597 R_PPC_GOT_TLSLD16 = 83 598 R_PPC_GOT_TLSLD16_LO = 84 599 R_PPC_GOT_TLSLD16_HI = 85 600 R_PPC_GOT_TLSLD16_HA = 86 601 R_PPC_GOT_TPREL16 = 87 602 R_PPC_GOT_TPREL16_LO = 88 603 R_PPC_GOT_TPREL16_HI = 89 604 R_PPC_GOT_TPREL16_HA = 90 605 R_PPC_EMB_NADDR32 = 101 606 R_PPC_EMB_NADDR16 = 102 607 R_PPC_EMB_NADDR16_LO = 103 608 R_PPC_EMB_NADDR16_HI = 104 609 R_PPC_EMB_NADDR16_HA = 105 610 R_PPC_EMB_SDAI16 = 106 611 R_PPC_EMB_SDA2I16 = 107 612 R_PPC_EMB_SDA2REL = 108 613 R_PPC_EMB_SDA21 = 109 614 R_PPC_EMB_MRKREF = 110 615 R_PPC_EMB_RELSEC16 = 111 616 R_PPC_EMB_RELST_LO = 112 617 R_PPC_EMB_RELST_HI = 113 618 R_PPC_EMB_RELST_HA = 114 619 R_PPC_EMB_BIT_FLD = 115 620 R_PPC_EMB_RELSDA = 116 621 622 R_PPC64_ADDR32 = R_PPC_ADDR32 623 R_PPC64_ADDR16_LO = R_PPC_ADDR16_LO 624 R_PPC64_ADDR16_HA = R_PPC_ADDR16_HA 625 R_PPC64_REL24 = R_PPC_REL24 626 R_PPC64_GOT16_HA = R_PPC_GOT16_HA 627 R_PPC64_JMP_SLOT = R_PPC_JMP_SLOT 628 R_PPC64_TPREL16 = R_PPC_TPREL16 629 R_PPC64_ADDR64 = 38 630 R_PPC64_TOC16 = 47 631 R_PPC64_TOC16_LO = 48 632 R_PPC64_TOC16_HI = 49 633 R_PPC64_TOC16_HA = 50 634 R_PPC64_ADDR16_LO_DS = 57 635 R_PPC64_GOT16_LO_DS = 59 636 R_PPC64_TOC16_DS = 63 637 R_PPC64_TOC16_LO_DS = 64 638 R_PPC64_TLS = 67 639 R_PPC64_GOT_TPREL16_LO_DS = 88 640 R_PPC64_GOT_TPREL16_HA = 90 641 R_PPC64_REL16_LO = 250 642 R_PPC64_REL16_HI = 251 643 R_PPC64_REL16_HA = 252 644 645 R_SPARC_NONE = 0 646 R_SPARC_8 = 1 647 R_SPARC_16 = 2 648 R_SPARC_32 = 3 649 R_SPARC_DISP8 = 4 650 R_SPARC_DISP16 = 5 651 R_SPARC_DISP32 = 6 652 R_SPARC_WDISP30 = 7 653 R_SPARC_WDISP22 = 8 654 R_SPARC_HI22 = 9 655 R_SPARC_22 = 10 656 R_SPARC_13 = 11 657 R_SPARC_LO10 = 12 658 R_SPARC_GOT10 = 13 659 R_SPARC_GOT13 = 14 660 R_SPARC_GOT22 = 15 661 R_SPARC_PC10 = 16 662 R_SPARC_PC22 = 17 663 R_SPARC_WPLT30 = 18 664 R_SPARC_COPY = 19 665 R_SPARC_GLOB_DAT = 20 666 R_SPARC_JMP_SLOT = 21 667 R_SPARC_RELATIVE = 22 668 R_SPARC_UA32 = 23 669 R_SPARC_PLT32 = 24 670 R_SPARC_HIPLT22 = 25 671 R_SPARC_LOPLT10 = 26 672 R_SPARC_PCPLT32 = 27 673 R_SPARC_PCPLT22 = 28 674 R_SPARC_PCPLT10 = 29 675 R_SPARC_10 = 30 676 R_SPARC_11 = 31 677 R_SPARC_64 = 32 678 R_SPARC_OLO10 = 33 679 R_SPARC_HH22 = 34 680 R_SPARC_HM10 = 35 681 R_SPARC_LM22 = 36 682 R_SPARC_PC_HH22 = 37 683 R_SPARC_PC_HM10 = 38 684 R_SPARC_PC_LM22 = 39 685 R_SPARC_WDISP16 = 40 686 R_SPARC_WDISP19 = 41 687 R_SPARC_GLOB_JMP = 42 688 R_SPARC_7 = 43 689 R_SPARC_5 = 44 690 R_SPARC_6 = 45 691 R_SPARC_DISP64 = 46 692 R_SPARC_PLT64 = 47 693 R_SPARC_HIX22 = 48 694 R_SPARC_LOX10 = 49 695 R_SPARC_H44 = 50 696 R_SPARC_M44 = 51 697 R_SPARC_L44 = 52 698 R_SPARC_REGISTER = 53 699 R_SPARC_UA64 = 54 700 R_SPARC_UA16 = 55 701 702 R_390_NONE = 0 703 R_390_8 = 1 704 R_390_12 = 2 705 R_390_16 = 3 706 R_390_32 = 4 707 R_390_PC32 = 5 708 R_390_GOT12 = 6 709 R_390_GOT32 = 7 710 R_390_PLT32 = 8 711 R_390_COPY = 9 712 R_390_GLOB_DAT = 10 713 R_390_JMP_SLOT = 11 714 R_390_RELATIVE = 12 715 R_390_GOTOFF = 13 716 R_390_GOTPC = 14 717 R_390_GOT16 = 15 718 R_390_PC16 = 16 719 R_390_PC16DBL = 17 720 R_390_PLT16DBL = 18 721 R_390_PC32DBL = 19 722 R_390_PLT32DBL = 20 723 R_390_GOTPCDBL = 21 724 R_390_64 = 22 725 R_390_PC64 = 23 726 R_390_GOT64 = 24 727 R_390_PLT64 = 25 728 R_390_GOTENT = 26 729 R_390_GOTOFF16 = 27 730 R_390_GOTOFF64 = 28 731 R_390_GOTPLT12 = 29 732 R_390_GOTPLT16 = 30 733 R_390_GOTPLT32 = 31 734 R_390_GOTPLT64 = 32 735 R_390_GOTPLTENT = 33 736 R_390_GOTPLTOFF16 = 34 737 R_390_GOTPLTOFF32 = 35 738 R_390_GOTPLTOFF64 = 36 739 R_390_TLS_LOAD = 37 740 R_390_TLS_GDCALL = 38 741 R_390_TLS_LDCALL = 39 742 R_390_TLS_GD32 = 40 743 R_390_TLS_GD64 = 41 744 R_390_TLS_GOTIE12 = 42 745 R_390_TLS_GOTIE32 = 43 746 R_390_TLS_GOTIE64 = 44 747 R_390_TLS_LDM32 = 45 748 R_390_TLS_LDM64 = 46 749 R_390_TLS_IE32 = 47 750 R_390_TLS_IE64 = 48 751 R_390_TLS_IEENT = 49 752 R_390_TLS_LE32 = 50 753 R_390_TLS_LE64 = 51 754 R_390_TLS_LDO32 = 52 755 R_390_TLS_LDO64 = 53 756 R_390_TLS_DTPMOD = 54 757 R_390_TLS_DTPOFF = 55 758 R_390_TLS_TPOFF = 56 759 R_390_20 = 57 760 R_390_GOT20 = 58 761 R_390_GOTPLT20 = 59 762 R_390_TLS_GOTIE20 = 60 763 764 ARM_MAGIC_TRAMP_NUMBER = 0x5c000003 765 ) 766 767 /* 768 * Symbol table entries. 769 */ 770 771 /* For accessing the fields of st_info. */ 772 773 /* For constructing st_info from field values. */ 774 775 /* For accessing the fields of st_other. */ 776 777 /* 778 * ELF header. 779 */ 780 type ElfEhdr struct { 781 ident [EI_NIDENT]uint8 782 type_ uint16 783 machine uint16 784 version uint32 785 entry uint64 786 phoff uint64 787 shoff uint64 788 flags uint32 789 ehsize uint16 790 phentsize uint16 791 phnum uint16 792 shentsize uint16 793 shnum uint16 794 shstrndx uint16 795 } 796 797 /* 798 * Section header. 799 */ 800 type ElfShdr struct { 801 name uint32 802 type_ uint32 803 flags uint64 804 addr uint64 805 off uint64 806 size uint64 807 link uint32 808 info uint32 809 addralign uint64 810 entsize uint64 811 shnum int 812 secsym *Symbol 813 } 814 815 /* 816 * Program header. 817 */ 818 type ElfPhdr struct { 819 type_ uint32 820 flags uint32 821 off uint64 822 vaddr uint64 823 paddr uint64 824 filesz uint64 825 memsz uint64 826 align uint64 827 } 828 829 /* For accessing the fields of r_info. */ 830 831 /* For constructing r_info from field values. */ 832 833 /* 834 * Symbol table entries. 835 */ 836 837 /* For accessing the fields of st_info. */ 838 839 /* For constructing st_info from field values. */ 840 841 /* For accessing the fields of st_other. */ 842 843 /* 844 * Go linker interface 845 */ 846 const ( 847 ELF64HDRSIZE = 64 848 ELF64PHDRSIZE = 56 849 ELF64SHDRSIZE = 64 850 ELF64RELSIZE = 16 851 ELF64RELASIZE = 24 852 ELF64SYMSIZE = 24 853 ELF32HDRSIZE = 52 854 ELF32PHDRSIZE = 32 855 ELF32SHDRSIZE = 40 856 ELF32SYMSIZE = 16 857 ELF32RELSIZE = 8 858 ) 859 860 /* 861 * The interface uses the 64-bit structures always, 862 * to avoid code duplication. The writers know how to 863 * marshal a 32-bit representation from the 64-bit structure. 864 */ 865 866 var Elfstrdat []byte 867 868 /* 869 * Total amount of space to reserve at the start of the file 870 * for Header, PHeaders, SHeaders, and interp. 871 * May waste some. 872 * On FreeBSD, cannot be larger than a page. 873 */ 874 const ( 875 ELFRESERVE = 4096 876 ) 877 878 /* 879 * We use the 64-bit data structures on both 32- and 64-bit machines 880 * in order to write the code just once. The 64-bit data structure is 881 * written in the 32-bit format on the 32-bit machines. 882 */ 883 const ( 884 NSECT = 400 885 ) 886 887 var ( 888 Iself bool 889 890 Nelfsym int = 1 891 892 elf64 bool 893 // Either ".rel" or ".rela" depending on which type of relocation the 894 // target platform uses. 895 elfRelType string 896 897 ehdr ElfEhdr 898 phdr [NSECT]*ElfPhdr 899 shdr [NSECT]*ElfShdr 900 901 interp string 902 ) 903 904 type Elfstring struct { 905 s string 906 off int 907 } 908 909 var elfstr [100]Elfstring 910 911 var nelfstr int 912 913 var buildinfo []byte 914 915 /* 916 Initialize the global variable that describes the ELF header. It will be updated as 917 we write section and prog headers. 918 */ 919 func Elfinit(ctxt *Link) { 920 Iself = true 921 922 if SysArch.InFamily(sys.AMD64, sys.ARM64, sys.MIPS64, sys.PPC64, sys.S390X) { 923 elfRelType = ".rela" 924 } else { 925 elfRelType = ".rel" 926 } 927 928 switch SysArch.Family { 929 // 64-bit architectures 930 case sys.PPC64, sys.S390X: 931 if ctxt.Arch.ByteOrder == binary.BigEndian { 932 ehdr.flags = 1 /* Version 1 ABI */ 933 } else { 934 ehdr.flags = 2 /* Version 2 ABI */ 935 } 936 fallthrough 937 case sys.AMD64, sys.ARM64, sys.MIPS64: 938 if SysArch.Family == sys.MIPS64 { 939 ehdr.flags = 0x20000000 /* MIPS 3 */ 940 } 941 elf64 = true 942 943 ehdr.phoff = ELF64HDRSIZE /* Must be be ELF64HDRSIZE: first PHdr must follow ELF header */ 944 ehdr.shoff = ELF64HDRSIZE /* Will move as we add PHeaders */ 945 ehdr.ehsize = ELF64HDRSIZE /* Must be ELF64HDRSIZE */ 946 ehdr.phentsize = ELF64PHDRSIZE /* Must be ELF64PHDRSIZE */ 947 ehdr.shentsize = ELF64SHDRSIZE /* Must be ELF64SHDRSIZE */ 948 949 // 32-bit architectures 950 case sys.ARM, sys.MIPS: 951 if SysArch.Family == sys.ARM { 952 // we use EABI on linux/arm, freebsd/arm, netbsd/arm. 953 if Headtype == obj.Hlinux || Headtype == obj.Hfreebsd || Headtype == obj.Hnetbsd { 954 // We set a value here that makes no indication of which 955 // float ABI the object uses, because this is information 956 // used by the dynamic linker to compare executables and 957 // shared libraries -- so it only matters for cgo calls, and 958 // the information properly comes from the object files 959 // produced by the host C compiler. parseArmAttributes in 960 // ldelf.go reads that information and updates this field as 961 // appropriate. 962 ehdr.flags = 0x5000002 // has entry point, Version5 EABI 963 } 964 } else if SysArch.Family == sys.MIPS { 965 ehdr.flags = 0x50001004 /* MIPS 32 CPIC O32*/ 966 } 967 fallthrough 968 default: 969 ehdr.phoff = ELF32HDRSIZE 970 /* Must be be ELF32HDRSIZE: first PHdr must follow ELF header */ 971 ehdr.shoff = ELF32HDRSIZE /* Will move as we add PHeaders */ 972 ehdr.ehsize = ELF32HDRSIZE /* Must be ELF32HDRSIZE */ 973 ehdr.phentsize = ELF32PHDRSIZE /* Must be ELF32PHDRSIZE */ 974 ehdr.shentsize = ELF32SHDRSIZE /* Must be ELF32SHDRSIZE */ 975 } 976 } 977 978 // Make sure PT_LOAD is aligned properly and 979 // that there is no gap, 980 // correct ELF loaders will do this implicitly, 981 // but buggy ELF loaders like the one in some 982 // versions of QEMU and UPX won't. 983 func fixElfPhdr(e *ElfPhdr) { 984 frag := int(e.vaddr & (e.align - 1)) 985 986 e.off -= uint64(frag) 987 e.vaddr -= uint64(frag) 988 e.paddr -= uint64(frag) 989 e.filesz += uint64(frag) 990 e.memsz += uint64(frag) 991 } 992 993 func elf64phdr(e *ElfPhdr) { 994 if e.type_ == PT_LOAD { 995 fixElfPhdr(e) 996 } 997 998 Thearch.Lput(e.type_) 999 Thearch.Lput(e.flags) 1000 Thearch.Vput(e.off) 1001 Thearch.Vput(e.vaddr) 1002 Thearch.Vput(e.paddr) 1003 Thearch.Vput(e.filesz) 1004 Thearch.Vput(e.memsz) 1005 Thearch.Vput(e.align) 1006 } 1007 1008 func elf32phdr(e *ElfPhdr) { 1009 if e.type_ == PT_LOAD { 1010 fixElfPhdr(e) 1011 } 1012 1013 Thearch.Lput(e.type_) 1014 Thearch.Lput(uint32(e.off)) 1015 Thearch.Lput(uint32(e.vaddr)) 1016 Thearch.Lput(uint32(e.paddr)) 1017 Thearch.Lput(uint32(e.filesz)) 1018 Thearch.Lput(uint32(e.memsz)) 1019 Thearch.Lput(e.flags) 1020 Thearch.Lput(uint32(e.align)) 1021 } 1022 1023 func elf64shdr(e *ElfShdr) { 1024 Thearch.Lput(e.name) 1025 Thearch.Lput(e.type_) 1026 Thearch.Vput(e.flags) 1027 Thearch.Vput(e.addr) 1028 Thearch.Vput(e.off) 1029 Thearch.Vput(e.size) 1030 Thearch.Lput(e.link) 1031 Thearch.Lput(e.info) 1032 Thearch.Vput(e.addralign) 1033 Thearch.Vput(e.entsize) 1034 } 1035 1036 func elf32shdr(e *ElfShdr) { 1037 Thearch.Lput(e.name) 1038 Thearch.Lput(e.type_) 1039 Thearch.Lput(uint32(e.flags)) 1040 Thearch.Lput(uint32(e.addr)) 1041 Thearch.Lput(uint32(e.off)) 1042 Thearch.Lput(uint32(e.size)) 1043 Thearch.Lput(e.link) 1044 Thearch.Lput(e.info) 1045 Thearch.Lput(uint32(e.addralign)) 1046 Thearch.Lput(uint32(e.entsize)) 1047 } 1048 1049 func elfwriteshdrs() uint32 { 1050 if elf64 { 1051 for i := 0; i < int(ehdr.shnum); i++ { 1052 elf64shdr(shdr[i]) 1053 } 1054 return uint32(ehdr.shnum) * ELF64SHDRSIZE 1055 } 1056 1057 for i := 0; i < int(ehdr.shnum); i++ { 1058 elf32shdr(shdr[i]) 1059 } 1060 return uint32(ehdr.shnum) * ELF32SHDRSIZE 1061 } 1062 1063 func elfsetstring(s *Symbol, str string, off int) { 1064 if nelfstr >= len(elfstr) { 1065 Errorf(s, "too many elf strings") 1066 errorexit() 1067 } 1068 1069 elfstr[nelfstr].s = str 1070 elfstr[nelfstr].off = off 1071 nelfstr++ 1072 } 1073 1074 func elfwritephdrs() uint32 { 1075 if elf64 { 1076 for i := 0; i < int(ehdr.phnum); i++ { 1077 elf64phdr(phdr[i]) 1078 } 1079 return uint32(ehdr.phnum) * ELF64PHDRSIZE 1080 } 1081 1082 for i := 0; i < int(ehdr.phnum); i++ { 1083 elf32phdr(phdr[i]) 1084 } 1085 return uint32(ehdr.phnum) * ELF32PHDRSIZE 1086 } 1087 1088 func newElfPhdr() *ElfPhdr { 1089 e := new(ElfPhdr) 1090 if ehdr.phnum >= NSECT { 1091 Errorf(nil, "too many phdrs") 1092 } else { 1093 phdr[ehdr.phnum] = e 1094 ehdr.phnum++ 1095 } 1096 if elf64 { 1097 ehdr.shoff += ELF64PHDRSIZE 1098 } else { 1099 ehdr.shoff += ELF32PHDRSIZE 1100 } 1101 return e 1102 } 1103 1104 func newElfShdr(name int64) *ElfShdr { 1105 e := new(ElfShdr) 1106 e.name = uint32(name) 1107 e.shnum = int(ehdr.shnum) 1108 if ehdr.shnum >= NSECT { 1109 Errorf(nil, "too many shdrs") 1110 } else { 1111 shdr[ehdr.shnum] = e 1112 ehdr.shnum++ 1113 } 1114 1115 return e 1116 } 1117 1118 func getElfEhdr() *ElfEhdr { 1119 return &ehdr 1120 } 1121 1122 func elf64writehdr() uint32 { 1123 for i := 0; i < EI_NIDENT; i++ { 1124 Cput(ehdr.ident[i]) 1125 } 1126 Thearch.Wput(ehdr.type_) 1127 Thearch.Wput(ehdr.machine) 1128 Thearch.Lput(ehdr.version) 1129 Thearch.Vput(ehdr.entry) 1130 Thearch.Vput(ehdr.phoff) 1131 Thearch.Vput(ehdr.shoff) 1132 Thearch.Lput(ehdr.flags) 1133 Thearch.Wput(ehdr.ehsize) 1134 Thearch.Wput(ehdr.phentsize) 1135 Thearch.Wput(ehdr.phnum) 1136 Thearch.Wput(ehdr.shentsize) 1137 Thearch.Wput(ehdr.shnum) 1138 Thearch.Wput(ehdr.shstrndx) 1139 return ELF64HDRSIZE 1140 } 1141 1142 func elf32writehdr() uint32 { 1143 for i := 0; i < EI_NIDENT; i++ { 1144 Cput(ehdr.ident[i]) 1145 } 1146 Thearch.Wput(ehdr.type_) 1147 Thearch.Wput(ehdr.machine) 1148 Thearch.Lput(ehdr.version) 1149 Thearch.Lput(uint32(ehdr.entry)) 1150 Thearch.Lput(uint32(ehdr.phoff)) 1151 Thearch.Lput(uint32(ehdr.shoff)) 1152 Thearch.Lput(ehdr.flags) 1153 Thearch.Wput(ehdr.ehsize) 1154 Thearch.Wput(ehdr.phentsize) 1155 Thearch.Wput(ehdr.phnum) 1156 Thearch.Wput(ehdr.shentsize) 1157 Thearch.Wput(ehdr.shnum) 1158 Thearch.Wput(ehdr.shstrndx) 1159 return ELF32HDRSIZE 1160 } 1161 1162 func elfwritehdr() uint32 { 1163 if elf64 { 1164 return elf64writehdr() 1165 } 1166 return elf32writehdr() 1167 } 1168 1169 /* Taken directly from the definition document for ELF64 */ 1170 func elfhash(name string) uint32 { 1171 var h uint32 1172 for i := 0; i < len(name); i++ { 1173 h = (h << 4) + uint32(name[i]) 1174 if g := h & 0xf0000000; g != 0 { 1175 h ^= g >> 24 1176 } 1177 h &= 0x0fffffff 1178 } 1179 return h 1180 } 1181 1182 func Elfwritedynent(ctxt *Link, s *Symbol, tag int, val uint64) { 1183 if elf64 { 1184 Adduint64(ctxt, s, uint64(tag)) 1185 Adduint64(ctxt, s, val) 1186 } else { 1187 Adduint32(ctxt, s, uint32(tag)) 1188 Adduint32(ctxt, s, uint32(val)) 1189 } 1190 } 1191 1192 func elfwritedynentsym(ctxt *Link, s *Symbol, tag int, t *Symbol) { 1193 Elfwritedynentsymplus(ctxt, s, tag, t, 0) 1194 } 1195 1196 func Elfwritedynentsymplus(ctxt *Link, s *Symbol, tag int, t *Symbol, add int64) { 1197 if elf64 { 1198 Adduint64(ctxt, s, uint64(tag)) 1199 } else { 1200 Adduint32(ctxt, s, uint32(tag)) 1201 } 1202 Addaddrplus(ctxt, s, t, add) 1203 } 1204 1205 func elfwritedynentsymsize(ctxt *Link, s *Symbol, tag int, t *Symbol) { 1206 if elf64 { 1207 Adduint64(ctxt, s, uint64(tag)) 1208 } else { 1209 Adduint32(ctxt, s, uint32(tag)) 1210 } 1211 addsize(ctxt, s, t) 1212 } 1213 1214 func elfinterp(sh *ElfShdr, startva uint64, resoff uint64, p string) int { 1215 interp = p 1216 n := len(interp) + 1 1217 sh.addr = startva + resoff - uint64(n) 1218 sh.off = resoff - uint64(n) 1219 sh.size = uint64(n) 1220 1221 return n 1222 } 1223 1224 func elfwriteinterp() int { 1225 sh := elfshname(".interp") 1226 Cseek(int64(sh.off)) 1227 coutbuf.WriteString(interp) 1228 Cput(0) 1229 return int(sh.size) 1230 } 1231 1232 func elfnote(sh *ElfShdr, startva uint64, resoff uint64, sz int, alloc bool) int { 1233 n := 3*4 + uint64(sz) + resoff%4 1234 1235 sh.type_ = SHT_NOTE 1236 if alloc { 1237 sh.flags = SHF_ALLOC 1238 } 1239 sh.addralign = 4 1240 sh.addr = startva + resoff - n 1241 sh.off = resoff - n 1242 sh.size = n - resoff%4 1243 1244 return int(n) 1245 } 1246 1247 func elfwritenotehdr(str string, namesz uint32, descsz uint32, tag uint32) *ElfShdr { 1248 sh := elfshname(str) 1249 1250 // Write Elf_Note header. 1251 Cseek(int64(sh.off)) 1252 1253 Thearch.Lput(namesz) 1254 Thearch.Lput(descsz) 1255 Thearch.Lput(tag) 1256 1257 return sh 1258 } 1259 1260 // NetBSD Signature (as per sys/exec_elf.h) 1261 const ( 1262 ELF_NOTE_NETBSD_NAMESZ = 7 1263 ELF_NOTE_NETBSD_DESCSZ = 4 1264 ELF_NOTE_NETBSD_TAG = 1 1265 ELF_NOTE_NETBSD_VERSION = 599000000 /* NetBSD 5.99 */ 1266 ) 1267 1268 var ELF_NOTE_NETBSD_NAME = []byte("NetBSD\x00") 1269 1270 func elfnetbsdsig(sh *ElfShdr, startva uint64, resoff uint64) int { 1271 n := int(Rnd(ELF_NOTE_NETBSD_NAMESZ, 4) + Rnd(ELF_NOTE_NETBSD_DESCSZ, 4)) 1272 return elfnote(sh, startva, resoff, n, true) 1273 } 1274 1275 func elfwritenetbsdsig() int { 1276 // Write Elf_Note header. 1277 sh := elfwritenotehdr(".note.netbsd.ident", ELF_NOTE_NETBSD_NAMESZ, ELF_NOTE_NETBSD_DESCSZ, ELF_NOTE_NETBSD_TAG) 1278 1279 if sh == nil { 1280 return 0 1281 } 1282 1283 // Followed by NetBSD string and version. 1284 Cwrite(ELF_NOTE_NETBSD_NAME) 1285 Cput(0) 1286 1287 Thearch.Lput(ELF_NOTE_NETBSD_VERSION) 1288 1289 return int(sh.size) 1290 } 1291 1292 // OpenBSD Signature 1293 const ( 1294 ELF_NOTE_OPENBSD_NAMESZ = 8 1295 ELF_NOTE_OPENBSD_DESCSZ = 4 1296 ELF_NOTE_OPENBSD_TAG = 1 1297 ELF_NOTE_OPENBSD_VERSION = 0 1298 ) 1299 1300 var ELF_NOTE_OPENBSD_NAME = []byte("OpenBSD\x00") 1301 1302 func elfopenbsdsig(sh *ElfShdr, startva uint64, resoff uint64) int { 1303 n := ELF_NOTE_OPENBSD_NAMESZ + ELF_NOTE_OPENBSD_DESCSZ 1304 return elfnote(sh, startva, resoff, n, true) 1305 } 1306 1307 func elfwriteopenbsdsig() int { 1308 // Write Elf_Note header. 1309 sh := elfwritenotehdr(".note.openbsd.ident", ELF_NOTE_OPENBSD_NAMESZ, ELF_NOTE_OPENBSD_DESCSZ, ELF_NOTE_OPENBSD_TAG) 1310 1311 if sh == nil { 1312 return 0 1313 } 1314 1315 // Followed by OpenBSD string and version. 1316 Cwrite(ELF_NOTE_OPENBSD_NAME) 1317 1318 Thearch.Lput(ELF_NOTE_OPENBSD_VERSION) 1319 1320 return int(sh.size) 1321 } 1322 1323 func addbuildinfo(val string) { 1324 if !strings.HasPrefix(val, "0x") { 1325 Exitf("-B argument must start with 0x: %s", val) 1326 } 1327 1328 ov := val 1329 val = val[2:] 1330 1331 const maxLen = 32 1332 if hex.DecodedLen(len(val)) > maxLen { 1333 Exitf("-B option too long (max %d digits): %s", maxLen, ov) 1334 } 1335 1336 b, err := hex.DecodeString(val) 1337 if err != nil { 1338 if err == hex.ErrLength { 1339 Exitf("-B argument must have even number of digits: %s", ov) 1340 } 1341 if inv, ok := err.(hex.InvalidByteError); ok { 1342 Exitf("-B argument contains invalid hex digit %c: %s", byte(inv), ov) 1343 } 1344 Exitf("-B argument contains invalid hex: %s", ov) 1345 } 1346 1347 buildinfo = b 1348 } 1349 1350 // Build info note 1351 const ( 1352 ELF_NOTE_BUILDINFO_NAMESZ = 4 1353 ELF_NOTE_BUILDINFO_TAG = 3 1354 ) 1355 1356 var ELF_NOTE_BUILDINFO_NAME = []byte("GNU\x00") 1357 1358 func elfbuildinfo(sh *ElfShdr, startva uint64, resoff uint64) int { 1359 n := int(ELF_NOTE_BUILDINFO_NAMESZ + Rnd(int64(len(buildinfo)), 4)) 1360 return elfnote(sh, startva, resoff, n, true) 1361 } 1362 1363 func elfgobuildid(sh *ElfShdr, startva uint64, resoff uint64) int { 1364 n := len(ELF_NOTE_GO_NAME) + int(Rnd(int64(len(*flagBuildid)), 4)) 1365 return elfnote(sh, startva, resoff, n, true) 1366 } 1367 1368 func elfwritebuildinfo() int { 1369 sh := elfwritenotehdr(".note.gnu.build-id", ELF_NOTE_BUILDINFO_NAMESZ, uint32(len(buildinfo)), ELF_NOTE_BUILDINFO_TAG) 1370 if sh == nil { 1371 return 0 1372 } 1373 1374 Cwrite(ELF_NOTE_BUILDINFO_NAME) 1375 Cwrite(buildinfo) 1376 var zero = make([]byte, 4) 1377 Cwrite(zero[:int(Rnd(int64(len(buildinfo)), 4)-int64(len(buildinfo)))]) 1378 1379 return int(sh.size) 1380 } 1381 1382 func elfwritegobuildid() int { 1383 sh := elfwritenotehdr(".note.go.buildid", uint32(len(ELF_NOTE_GO_NAME)), uint32(len(*flagBuildid)), ELF_NOTE_GOBUILDID_TAG) 1384 if sh == nil { 1385 return 0 1386 } 1387 1388 Cwrite(ELF_NOTE_GO_NAME) 1389 Cwrite([]byte(*flagBuildid)) 1390 var zero = make([]byte, 4) 1391 Cwrite(zero[:int(Rnd(int64(len(*flagBuildid)), 4)-int64(len(*flagBuildid)))]) 1392 1393 return int(sh.size) 1394 } 1395 1396 // Go specific notes 1397 const ( 1398 ELF_NOTE_GOPKGLIST_TAG = 1 1399 ELF_NOTE_GOABIHASH_TAG = 2 1400 ELF_NOTE_GODEPS_TAG = 3 1401 ELF_NOTE_GOBUILDID_TAG = 4 1402 ) 1403 1404 var ELF_NOTE_GO_NAME = []byte("Go\x00\x00") 1405 1406 var elfverneed int 1407 1408 type Elfaux struct { 1409 next *Elfaux 1410 num int 1411 vers string 1412 } 1413 1414 type Elflib struct { 1415 next *Elflib 1416 aux *Elfaux 1417 file string 1418 } 1419 1420 func addelflib(list **Elflib, file string, vers string) *Elfaux { 1421 var lib *Elflib 1422 1423 for lib = *list; lib != nil; lib = lib.next { 1424 if lib.file == file { 1425 goto havelib 1426 } 1427 } 1428 lib = new(Elflib) 1429 lib.next = *list 1430 lib.file = file 1431 *list = lib 1432 1433 havelib: 1434 for aux := lib.aux; aux != nil; aux = aux.next { 1435 if aux.vers == vers { 1436 return aux 1437 } 1438 } 1439 aux := new(Elfaux) 1440 aux.next = lib.aux 1441 aux.vers = vers 1442 lib.aux = aux 1443 1444 return aux 1445 } 1446 1447 func elfdynhash(ctxt *Link) { 1448 if !Iself { 1449 return 1450 } 1451 1452 nsym := Nelfsym 1453 s := ctxt.Syms.Lookup(".hash", 0) 1454 s.Type = obj.SELFROSECT 1455 s.Attr |= AttrReachable 1456 1457 i := nsym 1458 nbucket := 1 1459 for i > 0 { 1460 nbucket++ 1461 i >>= 1 1462 } 1463 1464 var needlib *Elflib 1465 need := make([]*Elfaux, nsym) 1466 chain := make([]uint32, nsym) 1467 buckets := make([]uint32, nbucket) 1468 1469 var b int 1470 for _, sy := range ctxt.Syms.Allsym { 1471 if sy.Dynid <= 0 { 1472 continue 1473 } 1474 1475 if sy.Dynimpvers != "" { 1476 need[sy.Dynid] = addelflib(&needlib, sy.Dynimplib, sy.Dynimpvers) 1477 } 1478 1479 name := sy.Extname 1480 hc := elfhash(name) 1481 1482 b = int(hc % uint32(nbucket)) 1483 chain[sy.Dynid] = buckets[b] 1484 buckets[b] = uint32(sy.Dynid) 1485 } 1486 1487 // s390x (ELF64) hash table entries are 8 bytes 1488 if SysArch.Family == sys.S390X { 1489 Adduint64(ctxt, s, uint64(nbucket)) 1490 Adduint64(ctxt, s, uint64(nsym)) 1491 for i := 0; i < nbucket; i++ { 1492 Adduint64(ctxt, s, uint64(buckets[i])) 1493 } 1494 for i := 0; i < nsym; i++ { 1495 Adduint64(ctxt, s, uint64(chain[i])) 1496 } 1497 } else { 1498 Adduint32(ctxt, s, uint32(nbucket)) 1499 Adduint32(ctxt, s, uint32(nsym)) 1500 for i := 0; i < nbucket; i++ { 1501 Adduint32(ctxt, s, buckets[i]) 1502 } 1503 for i := 0; i < nsym; i++ { 1504 Adduint32(ctxt, s, chain[i]) 1505 } 1506 } 1507 1508 // version symbols 1509 dynstr := ctxt.Syms.Lookup(".dynstr", 0) 1510 1511 s = ctxt.Syms.Lookup(".gnu.version_r", 0) 1512 i = 2 1513 nfile := 0 1514 var j int 1515 var x *Elfaux 1516 for l := needlib; l != nil; l = l.next { 1517 nfile++ 1518 1519 // header 1520 Adduint16(ctxt, s, 1) // table version 1521 j = 0 1522 for x = l.aux; x != nil; x = x.next { 1523 j++ 1524 } 1525 Adduint16(ctxt, s, uint16(j)) // aux count 1526 Adduint32(ctxt, s, uint32(Addstring(dynstr, l.file))) // file string offset 1527 Adduint32(ctxt, s, 16) // offset from header to first aux 1528 if l.next != nil { 1529 Adduint32(ctxt, s, 16+uint32(j)*16) // offset from this header to next 1530 } else { 1531 Adduint32(ctxt, s, 0) 1532 } 1533 1534 for x = l.aux; x != nil; x = x.next { 1535 x.num = i 1536 i++ 1537 1538 // aux struct 1539 Adduint32(ctxt, s, elfhash(x.vers)) // hash 1540 Adduint16(ctxt, s, 0) // flags 1541 Adduint16(ctxt, s, uint16(x.num)) // other - index we refer to this by 1542 Adduint32(ctxt, s, uint32(Addstring(dynstr, x.vers))) // version string offset 1543 if x.next != nil { 1544 Adduint32(ctxt, s, 16) // offset from this aux to next 1545 } else { 1546 Adduint32(ctxt, s, 0) 1547 } 1548 } 1549 } 1550 1551 // version references 1552 s = ctxt.Syms.Lookup(".gnu.version", 0) 1553 1554 for i := 0; i < nsym; i++ { 1555 if i == 0 { 1556 Adduint16(ctxt, s, 0) // first entry - no symbol 1557 } else if need[i] == nil { 1558 Adduint16(ctxt, s, 1) // global 1559 } else { 1560 Adduint16(ctxt, s, uint16(need[i].num)) 1561 } 1562 } 1563 1564 s = ctxt.Syms.Lookup(".dynamic", 0) 1565 elfverneed = nfile 1566 if elfverneed != 0 { 1567 elfwritedynentsym(ctxt, s, DT_VERNEED, ctxt.Syms.Lookup(".gnu.version_r", 0)) 1568 Elfwritedynent(ctxt, s, DT_VERNEEDNUM, uint64(nfile)) 1569 elfwritedynentsym(ctxt, s, DT_VERSYM, ctxt.Syms.Lookup(".gnu.version", 0)) 1570 } 1571 1572 sy := ctxt.Syms.Lookup(elfRelType+".plt", 0) 1573 if sy.Size > 0 { 1574 if elfRelType == ".rela" { 1575 Elfwritedynent(ctxt, s, DT_PLTREL, DT_RELA) 1576 } else { 1577 Elfwritedynent(ctxt, s, DT_PLTREL, DT_REL) 1578 } 1579 elfwritedynentsymsize(ctxt, s, DT_PLTRELSZ, sy) 1580 elfwritedynentsym(ctxt, s, DT_JMPREL, sy) 1581 } 1582 1583 Elfwritedynent(ctxt, s, DT_NULL, 0) 1584 } 1585 1586 func elfphload(seg *Segment) *ElfPhdr { 1587 ph := newElfPhdr() 1588 ph.type_ = PT_LOAD 1589 if seg.Rwx&4 != 0 { 1590 ph.flags |= PF_R 1591 } 1592 if seg.Rwx&2 != 0 { 1593 ph.flags |= PF_W 1594 } 1595 if seg.Rwx&1 != 0 { 1596 ph.flags |= PF_X 1597 } 1598 ph.vaddr = seg.Vaddr 1599 ph.paddr = seg.Vaddr 1600 ph.memsz = seg.Length 1601 ph.off = seg.Fileoff 1602 ph.filesz = seg.Filelen 1603 ph.align = uint64(*FlagRound) 1604 1605 return ph 1606 } 1607 1608 func elfphrelro(seg *Segment) { 1609 ph := newElfPhdr() 1610 ph.type_ = PT_GNU_RELRO 1611 ph.vaddr = seg.Vaddr 1612 ph.paddr = seg.Vaddr 1613 ph.memsz = seg.Length 1614 ph.off = seg.Fileoff 1615 ph.filesz = seg.Filelen 1616 ph.align = uint64(*FlagRound) 1617 } 1618 1619 func elfshname(name string) *ElfShdr { 1620 var off int 1621 var sh *ElfShdr 1622 1623 for i := 0; i < nelfstr; i++ { 1624 if name == elfstr[i].s { 1625 off = elfstr[i].off 1626 for i = 0; i < int(ehdr.shnum); i++ { 1627 sh = shdr[i] 1628 if sh.name == uint32(off) { 1629 return sh 1630 } 1631 } 1632 1633 sh = newElfShdr(int64(off)) 1634 return sh 1635 } 1636 } 1637 1638 Exitf("cannot find elf name %s", name) 1639 return nil 1640 } 1641 1642 // Create an ElfShdr for the section with name. 1643 // Create a duplicate if one already exists with that name 1644 func elfshnamedup(name string) *ElfShdr { 1645 var off int 1646 var sh *ElfShdr 1647 1648 for i := 0; i < nelfstr; i++ { 1649 if name == elfstr[i].s { 1650 off = elfstr[i].off 1651 sh = newElfShdr(int64(off)) 1652 return sh 1653 } 1654 } 1655 1656 Errorf(nil, "cannot find elf name %s", name) 1657 errorexit() 1658 return nil 1659 } 1660 1661 func elfshalloc(sect *Section) *ElfShdr { 1662 sh := elfshname(sect.Name) 1663 sect.Elfsect = sh 1664 return sh 1665 } 1666 1667 func elfshbits(sect *Section) *ElfShdr { 1668 var sh *ElfShdr 1669 1670 if sect.Name == ".text" { 1671 if sect.Elfsect == nil { 1672 sect.Elfsect = elfshnamedup(sect.Name) 1673 } 1674 sh = sect.Elfsect 1675 } else { 1676 sh = elfshalloc(sect) 1677 } 1678 1679 // If this section has already been set up as a note, we assume type_ and 1680 // flags are already correct, but the other fields still need filling in. 1681 if sh.type_ == SHT_NOTE { 1682 if Linkmode != LinkExternal { 1683 // TODO(mwhudson): the approach here will work OK when 1684 // linking internally for notes that we want to be included 1685 // in a loadable segment (e.g. the abihash note) but not for 1686 // notes that we do not want to be mapped (e.g. the package 1687 // list note). The real fix is probably to define new values 1688 // for Symbol.Type corresponding to mapped and unmapped notes 1689 // and handle them in dodata(). 1690 Errorf(nil, "sh.type_ == SHT_NOTE in elfshbits when linking internally") 1691 } 1692 sh.addralign = uint64(sect.Align) 1693 sh.size = sect.Length 1694 sh.off = sect.Seg.Fileoff + sect.Vaddr - sect.Seg.Vaddr 1695 return sh 1696 } 1697 if sh.type_ > 0 { 1698 return sh 1699 } 1700 1701 if sect.Vaddr < sect.Seg.Vaddr+sect.Seg.Filelen { 1702 sh.type_ = SHT_PROGBITS 1703 } else { 1704 sh.type_ = SHT_NOBITS 1705 } 1706 sh.flags = SHF_ALLOC 1707 if sect.Rwx&1 != 0 { 1708 sh.flags |= SHF_EXECINSTR 1709 } 1710 if sect.Rwx&2 != 0 { 1711 sh.flags |= SHF_WRITE 1712 } 1713 if sect.Name == ".tbss" { 1714 sh.flags |= SHF_TLS 1715 sh.type_ = SHT_NOBITS 1716 } 1717 if strings.HasPrefix(sect.Name, ".debug") { 1718 sh.flags = 0 1719 } 1720 1721 if Linkmode != LinkExternal { 1722 sh.addr = sect.Vaddr 1723 } 1724 sh.addralign = uint64(sect.Align) 1725 sh.size = sect.Length 1726 if sect.Name != ".tbss" { 1727 sh.off = sect.Seg.Fileoff + sect.Vaddr - sect.Seg.Vaddr 1728 } 1729 1730 return sh 1731 } 1732 1733 func elfshreloc(sect *Section) *ElfShdr { 1734 // If main section is SHT_NOBITS, nothing to relocate. 1735 // Also nothing to relocate in .shstrtab or notes. 1736 if sect.Vaddr >= sect.Seg.Vaddr+sect.Seg.Filelen { 1737 return nil 1738 } 1739 if sect.Name == ".shstrtab" || sect.Name == ".tbss" { 1740 return nil 1741 } 1742 if sect.Elfsect.type_ == SHT_NOTE { 1743 return nil 1744 } 1745 1746 var typ int 1747 if elfRelType == ".rela" { 1748 typ = SHT_RELA 1749 } else { 1750 typ = SHT_REL 1751 } 1752 1753 sh := elfshname(elfRelType + sect.Name) 1754 // There could be multiple text sections but each needs 1755 // its own .rela.text. 1756 1757 if sect.Name == ".text" { 1758 if sh.info != 0 && sh.info != uint32(sect.Elfsect.shnum) { 1759 sh = elfshnamedup(elfRelType + sect.Name) 1760 } 1761 } 1762 1763 sh.type_ = uint32(typ) 1764 sh.entsize = uint64(SysArch.RegSize) * 2 1765 if typ == SHT_RELA { 1766 sh.entsize += uint64(SysArch.RegSize) 1767 } 1768 sh.link = uint32(elfshname(".symtab").shnum) 1769 sh.info = uint32(sect.Elfsect.shnum) 1770 sh.off = sect.Reloff 1771 sh.size = sect.Rellen 1772 sh.addralign = uint64(SysArch.RegSize) 1773 return sh 1774 } 1775 1776 func elfrelocsect(ctxt *Link, sect *Section, syms []*Symbol) { 1777 // If main section is SHT_NOBITS, nothing to relocate. 1778 // Also nothing to relocate in .shstrtab. 1779 if sect.Vaddr >= sect.Seg.Vaddr+sect.Seg.Filelen { 1780 return 1781 } 1782 if sect.Name == ".shstrtab" { 1783 return 1784 } 1785 1786 sect.Reloff = uint64(coutbuf.Offset()) 1787 for i, s := range syms { 1788 if !s.Attr.Reachable() { 1789 continue 1790 } 1791 if uint64(s.Value) >= sect.Vaddr { 1792 syms = syms[i:] 1793 break 1794 } 1795 } 1796 1797 eaddr := int32(sect.Vaddr + sect.Length) 1798 for _, sym := range syms { 1799 if !sym.Attr.Reachable() { 1800 continue 1801 } 1802 if sym.Value >= int64(eaddr) { 1803 break 1804 } 1805 for ri := 0; ri < len(sym.R); ri++ { 1806 r := &sym.R[ri] 1807 if r.Done != 0 { 1808 continue 1809 } 1810 if r.Xsym == nil { 1811 Errorf(sym, "missing xsym in relocation") 1812 continue 1813 } 1814 if r.Xsym.ElfsymForReloc() == 0 { 1815 Errorf(sym, "reloc %d to non-elf symbol %s (outer=%s) %d", r.Type, r.Sym.Name, r.Xsym.Name, r.Sym.Type) 1816 } 1817 if !r.Xsym.Attr.Reachable() { 1818 Errorf(sym, "unreachable reloc %v target %v", r.Type, r.Xsym.Name) 1819 } 1820 if Thearch.Elfreloc1(ctxt, r, int64(uint64(sym.Value+int64(r.Off))-sect.Vaddr)) < 0 { 1821 Errorf(sym, "unsupported obj reloc %d/%d to %s", r.Type, r.Siz, r.Sym.Name) 1822 } 1823 } 1824 } 1825 1826 sect.Rellen = uint64(coutbuf.Offset()) - sect.Reloff 1827 } 1828 1829 func Elfemitreloc(ctxt *Link) { 1830 for coutbuf.Offset()&7 != 0 { 1831 Cput(0) 1832 } 1833 1834 for sect := Segtext.Sect; sect != nil; sect = sect.Next { 1835 if sect.Name == ".text" { 1836 elfrelocsect(ctxt, sect, ctxt.Textp) 1837 } else { 1838 elfrelocsect(ctxt, sect, datap) 1839 } 1840 } 1841 1842 for sect := Segrodata.Sect; sect != nil; sect = sect.Next { 1843 elfrelocsect(ctxt, sect, datap) 1844 } 1845 for sect := Segrelrodata.Sect; sect != nil; sect = sect.Next { 1846 elfrelocsect(ctxt, sect, datap) 1847 } 1848 for sect := Segdata.Sect; sect != nil; sect = sect.Next { 1849 elfrelocsect(ctxt, sect, datap) 1850 } 1851 for sect := Segdwarf.Sect; sect != nil; sect = sect.Next { 1852 elfrelocsect(ctxt, sect, dwarfp) 1853 } 1854 } 1855 1856 func addgonote(ctxt *Link, sectionName string, tag uint32, desc []byte) { 1857 s := ctxt.Syms.Lookup(sectionName, 0) 1858 s.Attr |= AttrReachable 1859 s.Type = obj.SELFROSECT 1860 // namesz 1861 Adduint32(ctxt, s, uint32(len(ELF_NOTE_GO_NAME))) 1862 // descsz 1863 Adduint32(ctxt, s, uint32(len(desc))) 1864 // tag 1865 Adduint32(ctxt, s, tag) 1866 // name + padding 1867 s.P = append(s.P, ELF_NOTE_GO_NAME...) 1868 for len(s.P)%4 != 0 { 1869 s.P = append(s.P, 0) 1870 } 1871 // desc + padding 1872 s.P = append(s.P, desc...) 1873 for len(s.P)%4 != 0 { 1874 s.P = append(s.P, 0) 1875 } 1876 s.Size = int64(len(s.P)) 1877 } 1878 1879 func (ctxt *Link) doelf() { 1880 if !Iself { 1881 return 1882 } 1883 1884 /* predefine strings we need for section headers */ 1885 shstrtab := ctxt.Syms.Lookup(".shstrtab", 0) 1886 1887 shstrtab.Type = obj.SELFROSECT 1888 shstrtab.Attr |= AttrReachable 1889 1890 Addstring(shstrtab, "") 1891 Addstring(shstrtab, ".text") 1892 Addstring(shstrtab, ".noptrdata") 1893 Addstring(shstrtab, ".data") 1894 Addstring(shstrtab, ".bss") 1895 Addstring(shstrtab, ".noptrbss") 1896 1897 // generate .tbss section (except for OpenBSD where it's not supported) 1898 // for dynamic internal linker or external linking, so that various 1899 // binutils could correctly calculate PT_TLS size. 1900 // see https://golang.org/issue/5200. 1901 if Headtype != obj.Hopenbsd { 1902 if !*FlagD || Linkmode == LinkExternal { 1903 Addstring(shstrtab, ".tbss") 1904 } 1905 } 1906 if Headtype == obj.Hnetbsd { 1907 Addstring(shstrtab, ".note.netbsd.ident") 1908 } 1909 if Headtype == obj.Hopenbsd { 1910 Addstring(shstrtab, ".note.openbsd.ident") 1911 } 1912 if len(buildinfo) > 0 { 1913 Addstring(shstrtab, ".note.gnu.build-id") 1914 } 1915 if *flagBuildid != "" { 1916 Addstring(shstrtab, ".note.go.buildid") 1917 } 1918 Addstring(shstrtab, ".elfdata") 1919 Addstring(shstrtab, ".rodata") 1920 // See the comment about data.rel.ro.FOO section names in data.go. 1921 relro_prefix := "" 1922 if UseRelro() { 1923 Addstring(shstrtab, ".data.rel.ro") 1924 relro_prefix = ".data.rel.ro" 1925 } 1926 Addstring(shstrtab, relro_prefix+".typelink") 1927 Addstring(shstrtab, relro_prefix+".itablink") 1928 Addstring(shstrtab, relro_prefix+".gosymtab") 1929 Addstring(shstrtab, relro_prefix+".gopclntab") 1930 1931 if Linkmode == LinkExternal { 1932 *FlagD = true 1933 1934 Addstring(shstrtab, elfRelType+".text") 1935 Addstring(shstrtab, elfRelType+".rodata") 1936 Addstring(shstrtab, elfRelType+relro_prefix+".typelink") 1937 Addstring(shstrtab, elfRelType+relro_prefix+".itablink") 1938 Addstring(shstrtab, elfRelType+relro_prefix+".gosymtab") 1939 Addstring(shstrtab, elfRelType+relro_prefix+".gopclntab") 1940 Addstring(shstrtab, elfRelType+".noptrdata") 1941 Addstring(shstrtab, elfRelType+".data") 1942 if UseRelro() { 1943 Addstring(shstrtab, elfRelType+".data.rel.ro") 1944 } 1945 1946 // add a .note.GNU-stack section to mark the stack as non-executable 1947 Addstring(shstrtab, ".note.GNU-stack") 1948 1949 if Buildmode == BuildmodeShared { 1950 Addstring(shstrtab, ".note.go.abihash") 1951 Addstring(shstrtab, ".note.go.pkg-list") 1952 Addstring(shstrtab, ".note.go.deps") 1953 } 1954 } 1955 1956 hasinitarr := *FlagLinkshared 1957 1958 /* shared library initializer */ 1959 switch Buildmode { 1960 case BuildmodeCArchive, BuildmodeCShared, BuildmodeShared, BuildmodePlugin: 1961 hasinitarr = true 1962 } 1963 1964 if hasinitarr { 1965 Addstring(shstrtab, ".init_array") 1966 Addstring(shstrtab, elfRelType+".init_array") 1967 } 1968 1969 if !*FlagS { 1970 Addstring(shstrtab, ".symtab") 1971 Addstring(shstrtab, ".strtab") 1972 dwarfaddshstrings(ctxt, shstrtab) 1973 } 1974 1975 Addstring(shstrtab, ".shstrtab") 1976 1977 if !*FlagD { /* -d suppresses dynamic loader format */ 1978 Addstring(shstrtab, ".interp") 1979 Addstring(shstrtab, ".hash") 1980 Addstring(shstrtab, ".got") 1981 if SysArch.Family == sys.PPC64 { 1982 Addstring(shstrtab, ".glink") 1983 } 1984 Addstring(shstrtab, ".got.plt") 1985 Addstring(shstrtab, ".dynamic") 1986 Addstring(shstrtab, ".dynsym") 1987 Addstring(shstrtab, ".dynstr") 1988 Addstring(shstrtab, elfRelType) 1989 Addstring(shstrtab, elfRelType+".plt") 1990 1991 Addstring(shstrtab, ".plt") 1992 Addstring(shstrtab, ".gnu.version") 1993 Addstring(shstrtab, ".gnu.version_r") 1994 1995 /* dynamic symbol table - first entry all zeros */ 1996 s := ctxt.Syms.Lookup(".dynsym", 0) 1997 1998 s.Type = obj.SELFROSECT 1999 s.Attr |= AttrReachable 2000 if elf64 { 2001 s.Size += ELF64SYMSIZE 2002 } else { 2003 s.Size += ELF32SYMSIZE 2004 } 2005 2006 /* dynamic string table */ 2007 s = ctxt.Syms.Lookup(".dynstr", 0) 2008 2009 s.Type = obj.SELFROSECT 2010 s.Attr |= AttrReachable 2011 if s.Size == 0 { 2012 Addstring(s, "") 2013 } 2014 dynstr := s 2015 2016 /* relocation table */ 2017 s = ctxt.Syms.Lookup(elfRelType, 0) 2018 s.Attr |= AttrReachable 2019 s.Type = obj.SELFROSECT 2020 2021 /* global offset table */ 2022 s = ctxt.Syms.Lookup(".got", 0) 2023 2024 s.Attr |= AttrReachable 2025 s.Type = obj.SELFGOT // writable 2026 2027 /* ppc64 glink resolver */ 2028 if SysArch.Family == sys.PPC64 { 2029 s := ctxt.Syms.Lookup(".glink", 0) 2030 s.Attr |= AttrReachable 2031 s.Type = obj.SELFRXSECT 2032 } 2033 2034 /* hash */ 2035 s = ctxt.Syms.Lookup(".hash", 0) 2036 2037 s.Attr |= AttrReachable 2038 s.Type = obj.SELFROSECT 2039 2040 s = ctxt.Syms.Lookup(".got.plt", 0) 2041 s.Attr |= AttrReachable 2042 s.Type = obj.SELFSECT // writable 2043 2044 s = ctxt.Syms.Lookup(".plt", 0) 2045 2046 s.Attr |= AttrReachable 2047 if SysArch.Family == sys.PPC64 { 2048 // In the ppc64 ABI, .plt is a data section 2049 // written by the dynamic linker. 2050 s.Type = obj.SELFSECT 2051 } else { 2052 s.Type = obj.SELFRXSECT 2053 } 2054 2055 Thearch.Elfsetupplt(ctxt) 2056 2057 s = ctxt.Syms.Lookup(elfRelType+".plt", 0) 2058 s.Attr |= AttrReachable 2059 s.Type = obj.SELFROSECT 2060 2061 s = ctxt.Syms.Lookup(".gnu.version", 0) 2062 s.Attr |= AttrReachable 2063 s.Type = obj.SELFROSECT 2064 2065 s = ctxt.Syms.Lookup(".gnu.version_r", 0) 2066 s.Attr |= AttrReachable 2067 s.Type = obj.SELFROSECT 2068 2069 /* define dynamic elf table */ 2070 s = ctxt.Syms.Lookup(".dynamic", 0) 2071 2072 s.Attr |= AttrReachable 2073 s.Type = obj.SELFSECT // writable 2074 2075 /* 2076 * .dynamic table 2077 */ 2078 elfwritedynentsym(ctxt, s, DT_HASH, ctxt.Syms.Lookup(".hash", 0)) 2079 2080 elfwritedynentsym(ctxt, s, DT_SYMTAB, ctxt.Syms.Lookup(".dynsym", 0)) 2081 if elf64 { 2082 Elfwritedynent(ctxt, s, DT_SYMENT, ELF64SYMSIZE) 2083 } else { 2084 Elfwritedynent(ctxt, s, DT_SYMENT, ELF32SYMSIZE) 2085 } 2086 elfwritedynentsym(ctxt, s, DT_STRTAB, ctxt.Syms.Lookup(".dynstr", 0)) 2087 elfwritedynentsymsize(ctxt, s, DT_STRSZ, ctxt.Syms.Lookup(".dynstr", 0)) 2088 if elfRelType == ".rela" { 2089 elfwritedynentsym(ctxt, s, DT_RELA, ctxt.Syms.Lookup(".rela", 0)) 2090 elfwritedynentsymsize(ctxt, s, DT_RELASZ, ctxt.Syms.Lookup(".rela", 0)) 2091 Elfwritedynent(ctxt, s, DT_RELAENT, ELF64RELASIZE) 2092 } else { 2093 elfwritedynentsym(ctxt, s, DT_REL, ctxt.Syms.Lookup(".rel", 0)) 2094 elfwritedynentsymsize(ctxt, s, DT_RELSZ, ctxt.Syms.Lookup(".rel", 0)) 2095 Elfwritedynent(ctxt, s, DT_RELENT, ELF32RELSIZE) 2096 } 2097 2098 if rpath.val != "" { 2099 Elfwritedynent(ctxt, s, DT_RUNPATH, uint64(Addstring(dynstr, rpath.val))) 2100 } 2101 2102 if SysArch.Family == sys.PPC64 { 2103 elfwritedynentsym(ctxt, s, DT_PLTGOT, ctxt.Syms.Lookup(".plt", 0)) 2104 } else if SysArch.Family == sys.S390X { 2105 elfwritedynentsym(ctxt, s, DT_PLTGOT, ctxt.Syms.Lookup(".got", 0)) 2106 } else { 2107 elfwritedynentsym(ctxt, s, DT_PLTGOT, ctxt.Syms.Lookup(".got.plt", 0)) 2108 } 2109 2110 if SysArch.Family == sys.PPC64 { 2111 Elfwritedynent(ctxt, s, DT_PPC64_OPT, 0) 2112 } 2113 2114 // Solaris dynamic linker can't handle an empty .rela.plt if 2115 // DT_JMPREL is emitted so we have to defer generation of DT_PLTREL, 2116 // DT_PLTRELSZ, and DT_JMPREL dynamic entries until after we know the 2117 // size of .rel(a).plt section. 2118 Elfwritedynent(ctxt, s, DT_DEBUG, 0) 2119 } 2120 2121 if Buildmode == BuildmodeShared { 2122 // The go.link.abihashbytes symbol will be pointed at the appropriate 2123 // part of the .note.go.abihash section in data.go:func address(). 2124 s := ctxt.Syms.Lookup("go.link.abihashbytes", 0) 2125 s.Attr |= AttrLocal 2126 s.Type = obj.SRODATA 2127 s.Attr |= AttrSpecial 2128 s.Attr |= AttrReachable 2129 s.Size = int64(sha1.Size) 2130 2131 sort.Sort(byPkg(ctxt.Library)) 2132 h := sha1.New() 2133 for _, l := range ctxt.Library { 2134 io.WriteString(h, l.hash) 2135 } 2136 addgonote(ctxt, ".note.go.abihash", ELF_NOTE_GOABIHASH_TAG, h.Sum([]byte{})) 2137 addgonote(ctxt, ".note.go.pkg-list", ELF_NOTE_GOPKGLIST_TAG, pkglistfornote) 2138 var deplist []string 2139 for _, shlib := range ctxt.Shlibs { 2140 deplist = append(deplist, filepath.Base(shlib.Path)) 2141 } 2142 addgonote(ctxt, ".note.go.deps", ELF_NOTE_GODEPS_TAG, []byte(strings.Join(deplist, "\n"))) 2143 } 2144 2145 if Linkmode == LinkExternal && *flagBuildid != "" { 2146 addgonote(ctxt, ".note.go.buildid", ELF_NOTE_GOBUILDID_TAG, []byte(*flagBuildid)) 2147 } 2148 } 2149 2150 // Do not write DT_NULL. elfdynhash will finish it. 2151 func shsym(sh *ElfShdr, s *Symbol) { 2152 addr := Symaddr(s) 2153 if sh.flags&SHF_ALLOC != 0 { 2154 sh.addr = uint64(addr) 2155 } 2156 sh.off = uint64(datoff(s, addr)) 2157 sh.size = uint64(s.Size) 2158 } 2159 2160 func phsh(ph *ElfPhdr, sh *ElfShdr) { 2161 ph.vaddr = sh.addr 2162 ph.paddr = ph.vaddr 2163 ph.off = sh.off 2164 ph.filesz = sh.size 2165 ph.memsz = sh.size 2166 ph.align = sh.addralign 2167 } 2168 2169 func Asmbelfsetup() { 2170 /* This null SHdr must appear before all others */ 2171 elfshname("") 2172 2173 for sect := Segtext.Sect; sect != nil; sect = sect.Next { 2174 // There could be multiple .text sections. Instead check the Elfsect 2175 // field to determine if already has an ElfShdr and if not, create one. 2176 if sect.Name == ".text" { 2177 if sect.Elfsect == nil { 2178 sect.Elfsect = elfshnamedup(sect.Name) 2179 } 2180 } else { 2181 elfshalloc(sect) 2182 } 2183 } 2184 for sect := Segrodata.Sect; sect != nil; sect = sect.Next { 2185 elfshalloc(sect) 2186 } 2187 for sect := Segrelrodata.Sect; sect != nil; sect = sect.Next { 2188 elfshalloc(sect) 2189 } 2190 for sect := Segdata.Sect; sect != nil; sect = sect.Next { 2191 elfshalloc(sect) 2192 } 2193 for sect := Segdwarf.Sect; sect != nil; sect = sect.Next { 2194 elfshalloc(sect) 2195 } 2196 } 2197 2198 func Asmbelf(ctxt *Link, symo int64) { 2199 eh := getElfEhdr() 2200 switch SysArch.Family { 2201 default: 2202 Exitf("unknown architecture in asmbelf: %v", SysArch.Family) 2203 case sys.MIPS, sys.MIPS64: 2204 eh.machine = EM_MIPS 2205 case sys.ARM: 2206 eh.machine = EM_ARM 2207 case sys.AMD64: 2208 eh.machine = EM_X86_64 2209 case sys.ARM64: 2210 eh.machine = EM_AARCH64 2211 case sys.I386: 2212 eh.machine = EM_386 2213 case sys.PPC64: 2214 eh.machine = EM_PPC64 2215 case sys.S390X: 2216 eh.machine = EM_S390 2217 } 2218 2219 elfreserve := int64(ELFRESERVE) 2220 2221 numtext := int64(0) 2222 for sect := Segtext.Sect; sect != nil; sect = sect.Next { 2223 if sect.Name == ".text" { 2224 numtext++ 2225 } 2226 } 2227 2228 // If there are multiple text sections, extra space is needed 2229 // in the elfreserve for the additional .text and .rela.text 2230 // section headers. It can handle 4 extra now. Headers are 2231 // 64 bytes. 2232 2233 if numtext > 4 { 2234 elfreserve += elfreserve + numtext*64*2 2235 } 2236 2237 startva := *FlagTextAddr - int64(HEADR) 2238 resoff := elfreserve 2239 2240 var pph *ElfPhdr 2241 var pnote *ElfPhdr 2242 if Linkmode == LinkExternal { 2243 /* skip program headers */ 2244 eh.phoff = 0 2245 2246 eh.phentsize = 0 2247 2248 if Buildmode == BuildmodeShared { 2249 sh := elfshname(".note.go.pkg-list") 2250 sh.type_ = SHT_NOTE 2251 sh = elfshname(".note.go.abihash") 2252 sh.type_ = SHT_NOTE 2253 sh.flags = SHF_ALLOC 2254 sh = elfshname(".note.go.deps") 2255 sh.type_ = SHT_NOTE 2256 } 2257 2258 if *flagBuildid != "" { 2259 sh := elfshname(".note.go.buildid") 2260 sh.type_ = SHT_NOTE 2261 sh.flags = SHF_ALLOC 2262 } 2263 2264 goto elfobj 2265 } 2266 2267 /* program header info */ 2268 pph = newElfPhdr() 2269 2270 pph.type_ = PT_PHDR 2271 pph.flags = PF_R 2272 pph.off = uint64(eh.ehsize) 2273 pph.vaddr = uint64(*FlagTextAddr) - uint64(HEADR) + pph.off 2274 pph.paddr = uint64(*FlagTextAddr) - uint64(HEADR) + pph.off 2275 pph.align = uint64(*FlagRound) 2276 2277 /* 2278 * PHDR must be in a loaded segment. Adjust the text 2279 * segment boundaries downwards to include it. 2280 * Except on NaCl where it must not be loaded. 2281 */ 2282 if Headtype != obj.Hnacl { 2283 o := int64(Segtext.Vaddr - pph.vaddr) 2284 Segtext.Vaddr -= uint64(o) 2285 Segtext.Length += uint64(o) 2286 o = int64(Segtext.Fileoff - pph.off) 2287 Segtext.Fileoff -= uint64(o) 2288 Segtext.Filelen += uint64(o) 2289 } 2290 2291 if !*FlagD { /* -d suppresses dynamic loader format */ 2292 /* interpreter */ 2293 sh := elfshname(".interp") 2294 2295 sh.type_ = SHT_PROGBITS 2296 sh.flags = SHF_ALLOC 2297 sh.addralign = 1 2298 if interpreter == "" { 2299 switch Headtype { 2300 case obj.Hlinux: 2301 interpreter = Thearch.Linuxdynld 2302 2303 case obj.Hfreebsd: 2304 interpreter = Thearch.Freebsddynld 2305 2306 case obj.Hnetbsd: 2307 interpreter = Thearch.Netbsddynld 2308 2309 case obj.Hopenbsd: 2310 interpreter = Thearch.Openbsddynld 2311 2312 case obj.Hdragonfly: 2313 interpreter = Thearch.Dragonflydynld 2314 2315 case obj.Hsolaris: 2316 interpreter = Thearch.Solarisdynld 2317 } 2318 } 2319 2320 resoff -= int64(elfinterp(sh, uint64(startva), uint64(resoff), interpreter)) 2321 2322 ph := newElfPhdr() 2323 ph.type_ = PT_INTERP 2324 ph.flags = PF_R 2325 phsh(ph, sh) 2326 } 2327 2328 pnote = nil 2329 if Headtype == obj.Hnetbsd || Headtype == obj.Hopenbsd { 2330 var sh *ElfShdr 2331 switch Headtype { 2332 case obj.Hnetbsd: 2333 sh = elfshname(".note.netbsd.ident") 2334 resoff -= int64(elfnetbsdsig(sh, uint64(startva), uint64(resoff))) 2335 2336 case obj.Hopenbsd: 2337 sh = elfshname(".note.openbsd.ident") 2338 resoff -= int64(elfopenbsdsig(sh, uint64(startva), uint64(resoff))) 2339 } 2340 2341 pnote = newElfPhdr() 2342 pnote.type_ = PT_NOTE 2343 pnote.flags = PF_R 2344 phsh(pnote, sh) 2345 } 2346 2347 if len(buildinfo) > 0 { 2348 sh := elfshname(".note.gnu.build-id") 2349 resoff -= int64(elfbuildinfo(sh, uint64(startva), uint64(resoff))) 2350 2351 if pnote == nil { 2352 pnote = newElfPhdr() 2353 pnote.type_ = PT_NOTE 2354 pnote.flags = PF_R 2355 } 2356 2357 phsh(pnote, sh) 2358 } 2359 2360 if *flagBuildid != "" { 2361 sh := elfshname(".note.go.buildid") 2362 resoff -= int64(elfgobuildid(sh, uint64(startva), uint64(resoff))) 2363 2364 pnote := newElfPhdr() 2365 pnote.type_ = PT_NOTE 2366 pnote.flags = PF_R 2367 phsh(pnote, sh) 2368 } 2369 2370 // Additions to the reserved area must be above this line. 2371 2372 elfphload(&Segtext) 2373 if Segrodata.Sect != nil { 2374 elfphload(&Segrodata) 2375 } 2376 if Segrelrodata.Sect != nil { 2377 elfphload(&Segrelrodata) 2378 elfphrelro(&Segrelrodata) 2379 } 2380 elfphload(&Segdata) 2381 2382 /* Dynamic linking sections */ 2383 if !*FlagD { 2384 sh := elfshname(".dynsym") 2385 sh.type_ = SHT_DYNSYM 2386 sh.flags = SHF_ALLOC 2387 if elf64 { 2388 sh.entsize = ELF64SYMSIZE 2389 } else { 2390 sh.entsize = ELF32SYMSIZE 2391 } 2392 sh.addralign = uint64(SysArch.RegSize) 2393 sh.link = uint32(elfshname(".dynstr").shnum) 2394 2395 // sh->info = index of first non-local symbol (number of local symbols) 2396 shsym(sh, ctxt.Syms.Lookup(".dynsym", 0)) 2397 2398 sh = elfshname(".dynstr") 2399 sh.type_ = SHT_STRTAB 2400 sh.flags = SHF_ALLOC 2401 sh.addralign = 1 2402 shsym(sh, ctxt.Syms.Lookup(".dynstr", 0)) 2403 2404 if elfverneed != 0 { 2405 sh := elfshname(".gnu.version") 2406 sh.type_ = SHT_GNU_VERSYM 2407 sh.flags = SHF_ALLOC 2408 sh.addralign = 2 2409 sh.link = uint32(elfshname(".dynsym").shnum) 2410 sh.entsize = 2 2411 shsym(sh, ctxt.Syms.Lookup(".gnu.version", 0)) 2412 2413 sh = elfshname(".gnu.version_r") 2414 sh.type_ = SHT_GNU_VERNEED 2415 sh.flags = SHF_ALLOC 2416 sh.addralign = uint64(SysArch.RegSize) 2417 sh.info = uint32(elfverneed) 2418 sh.link = uint32(elfshname(".dynstr").shnum) 2419 shsym(sh, ctxt.Syms.Lookup(".gnu.version_r", 0)) 2420 } 2421 2422 if elfRelType == ".rela" { 2423 sh := elfshname(".rela.plt") 2424 sh.type_ = SHT_RELA 2425 sh.flags = SHF_ALLOC 2426 sh.entsize = ELF64RELASIZE 2427 sh.addralign = uint64(SysArch.RegSize) 2428 sh.link = uint32(elfshname(".dynsym").shnum) 2429 sh.info = uint32(elfshname(".plt").shnum) 2430 shsym(sh, ctxt.Syms.Lookup(".rela.plt", 0)) 2431 2432 sh = elfshname(".rela") 2433 sh.type_ = SHT_RELA 2434 sh.flags = SHF_ALLOC 2435 sh.entsize = ELF64RELASIZE 2436 sh.addralign = 8 2437 sh.link = uint32(elfshname(".dynsym").shnum) 2438 shsym(sh, ctxt.Syms.Lookup(".rela", 0)) 2439 } else { 2440 sh := elfshname(".rel.plt") 2441 sh.type_ = SHT_REL 2442 sh.flags = SHF_ALLOC 2443 sh.entsize = ELF32RELSIZE 2444 sh.addralign = 4 2445 sh.link = uint32(elfshname(".dynsym").shnum) 2446 shsym(sh, ctxt.Syms.Lookup(".rel.plt", 0)) 2447 2448 sh = elfshname(".rel") 2449 sh.type_ = SHT_REL 2450 sh.flags = SHF_ALLOC 2451 sh.entsize = ELF32RELSIZE 2452 sh.addralign = 4 2453 sh.link = uint32(elfshname(".dynsym").shnum) 2454 shsym(sh, ctxt.Syms.Lookup(".rel", 0)) 2455 } 2456 2457 if eh.machine == EM_PPC64 { 2458 sh := elfshname(".glink") 2459 sh.type_ = SHT_PROGBITS 2460 sh.flags = SHF_ALLOC + SHF_EXECINSTR 2461 sh.addralign = 4 2462 shsym(sh, ctxt.Syms.Lookup(".glink", 0)) 2463 } 2464 2465 sh = elfshname(".plt") 2466 sh.type_ = SHT_PROGBITS 2467 sh.flags = SHF_ALLOC + SHF_EXECINSTR 2468 if eh.machine == EM_X86_64 { 2469 sh.entsize = 16 2470 } else if eh.machine == EM_S390 { 2471 sh.entsize = 32 2472 } else if eh.machine == EM_PPC64 { 2473 // On ppc64, this is just a table of addresses 2474 // filled by the dynamic linker 2475 sh.type_ = SHT_NOBITS 2476 2477 sh.flags = SHF_ALLOC + SHF_WRITE 2478 sh.entsize = 8 2479 } else { 2480 sh.entsize = 4 2481 } 2482 sh.addralign = sh.entsize 2483 shsym(sh, ctxt.Syms.Lookup(".plt", 0)) 2484 2485 // On ppc64, .got comes from the input files, so don't 2486 // create it here, and .got.plt is not used. 2487 if eh.machine != EM_PPC64 { 2488 sh := elfshname(".got") 2489 sh.type_ = SHT_PROGBITS 2490 sh.flags = SHF_ALLOC + SHF_WRITE 2491 sh.entsize = uint64(SysArch.RegSize) 2492 sh.addralign = uint64(SysArch.RegSize) 2493 shsym(sh, ctxt.Syms.Lookup(".got", 0)) 2494 2495 sh = elfshname(".got.plt") 2496 sh.type_ = SHT_PROGBITS 2497 sh.flags = SHF_ALLOC + SHF_WRITE 2498 sh.entsize = uint64(SysArch.RegSize) 2499 sh.addralign = uint64(SysArch.RegSize) 2500 shsym(sh, ctxt.Syms.Lookup(".got.plt", 0)) 2501 } 2502 2503 sh = elfshname(".hash") 2504 sh.type_ = SHT_HASH 2505 sh.flags = SHF_ALLOC 2506 sh.entsize = 4 2507 sh.addralign = uint64(SysArch.RegSize) 2508 sh.link = uint32(elfshname(".dynsym").shnum) 2509 shsym(sh, ctxt.Syms.Lookup(".hash", 0)) 2510 2511 /* sh and PT_DYNAMIC for .dynamic section */ 2512 sh = elfshname(".dynamic") 2513 2514 sh.type_ = SHT_DYNAMIC 2515 sh.flags = SHF_ALLOC + SHF_WRITE 2516 sh.entsize = 2 * uint64(SysArch.RegSize) 2517 sh.addralign = uint64(SysArch.RegSize) 2518 sh.link = uint32(elfshname(".dynstr").shnum) 2519 shsym(sh, ctxt.Syms.Lookup(".dynamic", 0)) 2520 ph := newElfPhdr() 2521 ph.type_ = PT_DYNAMIC 2522 ph.flags = PF_R + PF_W 2523 phsh(ph, sh) 2524 2525 /* 2526 * Thread-local storage segment (really just size). 2527 */ 2528 // Do not emit PT_TLS for OpenBSD since ld.so(1) does 2529 // not currently support it. This is handled 2530 // appropriately in runtime/cgo. 2531 if Headtype != obj.Hopenbsd { 2532 tlssize := uint64(0) 2533 for sect := Segdata.Sect; sect != nil; sect = sect.Next { 2534 if sect.Name == ".tbss" { 2535 tlssize = sect.Length 2536 } 2537 } 2538 if tlssize != 0 { 2539 ph := newElfPhdr() 2540 ph.type_ = PT_TLS 2541 ph.flags = PF_R 2542 ph.memsz = tlssize 2543 ph.align = uint64(SysArch.RegSize) 2544 } 2545 } 2546 } 2547 2548 if Headtype == obj.Hlinux { 2549 ph := newElfPhdr() 2550 ph.type_ = PT_GNU_STACK 2551 ph.flags = PF_W + PF_R 2552 ph.align = uint64(SysArch.RegSize) 2553 2554 ph = newElfPhdr() 2555 ph.type_ = PT_PAX_FLAGS 2556 ph.flags = 0x2a00 // mprotect, randexec, emutramp disabled 2557 ph.align = uint64(SysArch.RegSize) 2558 } else if Headtype == obj.Hsolaris { 2559 ph := newElfPhdr() 2560 ph.type_ = PT_SUNWSTACK 2561 ph.flags = PF_W + PF_R 2562 } 2563 2564 elfobj: 2565 sh := elfshname(".shstrtab") 2566 sh.type_ = SHT_STRTAB 2567 sh.addralign = 1 2568 shsym(sh, ctxt.Syms.Lookup(".shstrtab", 0)) 2569 eh.shstrndx = uint16(sh.shnum) 2570 2571 // put these sections early in the list 2572 if !*FlagS { 2573 elfshname(".symtab") 2574 elfshname(".strtab") 2575 } 2576 2577 for sect := Segtext.Sect; sect != nil; sect = sect.Next { 2578 elfshbits(sect) 2579 } 2580 for sect := Segrodata.Sect; sect != nil; sect = sect.Next { 2581 elfshbits(sect) 2582 } 2583 for sect := Segrelrodata.Sect; sect != nil; sect = sect.Next { 2584 elfshbits(sect) 2585 } 2586 for sect := Segdata.Sect; sect != nil; sect = sect.Next { 2587 elfshbits(sect) 2588 } 2589 for sect := Segdwarf.Sect; sect != nil; sect = sect.Next { 2590 elfshbits(sect) 2591 } 2592 2593 if Linkmode == LinkExternal { 2594 for sect := Segtext.Sect; sect != nil; sect = sect.Next { 2595 elfshreloc(sect) 2596 } 2597 for sect := Segrodata.Sect; sect != nil; sect = sect.Next { 2598 elfshreloc(sect) 2599 } 2600 for sect := Segrelrodata.Sect; sect != nil; sect = sect.Next { 2601 elfshreloc(sect) 2602 } 2603 for sect := Segdata.Sect; sect != nil; sect = sect.Next { 2604 elfshreloc(sect) 2605 } 2606 for _, s := range dwarfp { 2607 if len(s.R) > 0 || s.Type == obj.SDWARFINFO { 2608 elfshreloc(s.Sect) 2609 } 2610 if s.Type == obj.SDWARFINFO { 2611 break 2612 } 2613 } 2614 // add a .note.GNU-stack section to mark the stack as non-executable 2615 sh := elfshname(".note.GNU-stack") 2616 2617 sh.type_ = SHT_PROGBITS 2618 sh.addralign = 1 2619 sh.flags = 0 2620 } 2621 2622 if !*FlagS { 2623 sh := elfshname(".symtab") 2624 sh.type_ = SHT_SYMTAB 2625 sh.off = uint64(symo) 2626 sh.size = uint64(Symsize) 2627 sh.addralign = uint64(SysArch.RegSize) 2628 sh.entsize = 8 + 2*uint64(SysArch.RegSize) 2629 sh.link = uint32(elfshname(".strtab").shnum) 2630 sh.info = uint32(elfglobalsymndx) 2631 2632 sh = elfshname(".strtab") 2633 sh.type_ = SHT_STRTAB 2634 sh.off = uint64(symo) + uint64(Symsize) 2635 sh.size = uint64(len(Elfstrdat)) 2636 sh.addralign = 1 2637 } 2638 2639 /* Main header */ 2640 eh.ident[EI_MAG0] = '\177' 2641 2642 eh.ident[EI_MAG1] = 'E' 2643 eh.ident[EI_MAG2] = 'L' 2644 eh.ident[EI_MAG3] = 'F' 2645 if Headtype == obj.Hfreebsd { 2646 eh.ident[EI_OSABI] = ELFOSABI_FREEBSD 2647 } else if Headtype == obj.Hnetbsd { 2648 eh.ident[EI_OSABI] = ELFOSABI_NETBSD 2649 } else if Headtype == obj.Hopenbsd { 2650 eh.ident[EI_OSABI] = ELFOSABI_OPENBSD 2651 } else if Headtype == obj.Hdragonfly { 2652 eh.ident[EI_OSABI] = ELFOSABI_NONE 2653 } 2654 if elf64 { 2655 eh.ident[EI_CLASS] = ELFCLASS64 2656 } else { 2657 eh.ident[EI_CLASS] = ELFCLASS32 2658 } 2659 if ctxt.Arch.ByteOrder == binary.BigEndian { 2660 eh.ident[EI_DATA] = ELFDATA2MSB 2661 } else { 2662 eh.ident[EI_DATA] = ELFDATA2LSB 2663 } 2664 eh.ident[EI_VERSION] = EV_CURRENT 2665 2666 if Linkmode == LinkExternal { 2667 eh.type_ = ET_REL 2668 } else if Buildmode == BuildmodePIE { 2669 eh.type_ = ET_DYN 2670 } else { 2671 eh.type_ = ET_EXEC 2672 } 2673 2674 if Linkmode != LinkExternal { 2675 eh.entry = uint64(Entryvalue(ctxt)) 2676 } 2677 2678 eh.version = EV_CURRENT 2679 2680 if pph != nil { 2681 pph.filesz = uint64(eh.phnum) * uint64(eh.phentsize) 2682 pph.memsz = pph.filesz 2683 } 2684 2685 Cseek(0) 2686 a := int64(0) 2687 a += int64(elfwritehdr()) 2688 a += int64(elfwritephdrs()) 2689 a += int64(elfwriteshdrs()) 2690 if !*FlagD { 2691 a += int64(elfwriteinterp()) 2692 } 2693 if Linkmode != LinkExternal { 2694 if Headtype == obj.Hnetbsd { 2695 a += int64(elfwritenetbsdsig()) 2696 } 2697 if Headtype == obj.Hopenbsd { 2698 a += int64(elfwriteopenbsdsig()) 2699 } 2700 if len(buildinfo) > 0 { 2701 a += int64(elfwritebuildinfo()) 2702 } 2703 if *flagBuildid != "" { 2704 a += int64(elfwritegobuildid()) 2705 } 2706 } 2707 2708 if a > elfreserve { 2709 Errorf(nil, "ELFRESERVE too small: %d > %d with %d text sections", a, elfreserve, numtext) 2710 } 2711 } 2712 2713 func Elfadddynsym(ctxt *Link, s *Symbol) { 2714 if elf64 { 2715 s.Dynid = int32(Nelfsym) 2716 Nelfsym++ 2717 2718 d := ctxt.Syms.Lookup(".dynsym", 0) 2719 2720 name := s.Extname 2721 Adduint32(ctxt, d, uint32(Addstring(ctxt.Syms.Lookup(".dynstr", 0), name))) 2722 2723 /* type */ 2724 t := STB_GLOBAL << 4 2725 2726 if s.Attr.CgoExport() && s.Type&obj.SMASK == obj.STEXT { 2727 t |= STT_FUNC 2728 } else { 2729 t |= STT_OBJECT 2730 } 2731 Adduint8(ctxt, d, uint8(t)) 2732 2733 /* reserved */ 2734 Adduint8(ctxt, d, 0) 2735 2736 /* section where symbol is defined */ 2737 if s.Type == obj.SDYNIMPORT { 2738 Adduint16(ctxt, d, SHN_UNDEF) 2739 } else { 2740 Adduint16(ctxt, d, 1) 2741 } 2742 2743 /* value */ 2744 if s.Type == obj.SDYNIMPORT { 2745 Adduint64(ctxt, d, 0) 2746 } else { 2747 Addaddr(ctxt, d, s) 2748 } 2749 2750 /* size of object */ 2751 Adduint64(ctxt, d, uint64(s.Size)) 2752 2753 if SysArch.Family == sys.AMD64 && !s.Attr.CgoExportDynamic() && s.Dynimplib != "" && !seenlib[s.Dynimplib] { 2754 Elfwritedynent(ctxt, ctxt.Syms.Lookup(".dynamic", 0), DT_NEEDED, uint64(Addstring(ctxt.Syms.Lookup(".dynstr", 0), s.Dynimplib))) 2755 } 2756 } else { 2757 s.Dynid = int32(Nelfsym) 2758 Nelfsym++ 2759 2760 d := ctxt.Syms.Lookup(".dynsym", 0) 2761 2762 /* name */ 2763 name := s.Extname 2764 2765 Adduint32(ctxt, d, uint32(Addstring(ctxt.Syms.Lookup(".dynstr", 0), name))) 2766 2767 /* value */ 2768 if s.Type == obj.SDYNIMPORT { 2769 Adduint32(ctxt, d, 0) 2770 } else { 2771 Addaddr(ctxt, d, s) 2772 } 2773 2774 /* size of object */ 2775 Adduint32(ctxt, d, uint32(s.Size)) 2776 2777 /* type */ 2778 t := STB_GLOBAL << 4 2779 2780 // TODO(mwhudson): presumably the behavior should actually be the same on both arm and 386. 2781 if SysArch.Family == sys.I386 && s.Attr.CgoExport() && s.Type&obj.SMASK == obj.STEXT { 2782 t |= STT_FUNC 2783 } else if SysArch.Family == sys.ARM && s.Attr.CgoExportDynamic() && s.Type&obj.SMASK == obj.STEXT { 2784 t |= STT_FUNC 2785 } else { 2786 t |= STT_OBJECT 2787 } 2788 Adduint8(ctxt, d, uint8(t)) 2789 Adduint8(ctxt, d, 0) 2790 2791 /* shndx */ 2792 if s.Type == obj.SDYNIMPORT { 2793 Adduint16(ctxt, d, SHN_UNDEF) 2794 } else { 2795 Adduint16(ctxt, d, 1) 2796 } 2797 } 2798 } 2799 2800 func ELF32_R_SYM(info uint32) uint32 { 2801 return info >> 8 2802 } 2803 2804 func ELF32_R_TYPE(info uint32) uint32 { 2805 return uint32(uint8(info)) 2806 } 2807 2808 func ELF32_R_INFO(sym uint32, type_ uint32) uint32 { 2809 return sym<<8 | type_ 2810 } 2811 2812 func ELF32_ST_BIND(info uint8) uint8 { 2813 return info >> 4 2814 } 2815 2816 func ELF32_ST_TYPE(info uint8) uint8 { 2817 return info & 0xf 2818 } 2819 2820 func ELF32_ST_INFO(bind uint8, type_ uint8) uint8 { 2821 return bind<<4 | type_&0xf 2822 } 2823 2824 func ELF32_ST_VISIBILITY(oth uint8) uint8 { 2825 return oth & 3 2826 } 2827 2828 func ELF64_R_SYM(info uint64) uint32 { 2829 return uint32(info >> 32) 2830 } 2831 2832 func ELF64_R_TYPE(info uint64) uint32 { 2833 return uint32(info) 2834 } 2835 2836 func ELF64_R_INFO(sym uint32, type_ uint32) uint64 { 2837 return uint64(sym)<<32 | uint64(type_) 2838 } 2839 2840 func ELF64_ST_BIND(info uint8) uint8 { 2841 return info >> 4 2842 } 2843 2844 func ELF64_ST_TYPE(info uint8) uint8 { 2845 return info & 0xf 2846 } 2847 2848 func ELF64_ST_INFO(bind uint8, type_ uint8) uint8 { 2849 return bind<<4 | type_&0xf 2850 } 2851 2852 func ELF64_ST_VISIBILITY(oth uint8) uint8 { 2853 return oth & 3 2854 }