1/* ELF support for BFD. 2 Copyright (C) 1991-2020 Free Software Foundation, Inc. 3 4 Written by Fred Fish @ Cygnus Support, from information published 5 in "UNIX System V Release 4, Programmers Guide: ANSI C and 6 Programming Support Tools". 7 8 This file is part of BFD, the Binary File Descriptor library. 9 10 This program is free software; you can redistribute it and/or modify 11 it under the terms of the GNU General Public License as published by 12 the Free Software Foundation; either version 3 of the License, or 13 (at your option) any later version. 14 15 This program is distributed in the hope that it will be useful, 16 but WITHOUT ANY WARRANTY; without even the implied warranty of 17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 GNU General Public License for more details. 19 20 You should have received a copy of the GNU General Public License 21 along with this program; if not, write to the Free Software 22 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 23 MA 02110-1301, USA. */ 24 25/* This file is part of ELF support for BFD, and contains the portions 26 that describe how ELF is represented internally in the BFD library. 27 I.E. it describes the in-memory representation of ELF. It requires 28 the elf-common.h file which contains the portions that are common to 29 both the internal and external representations. */ 30 31/* NOTE that these structures are not kept in the same order as they appear 32 in the object file. In some cases they've been reordered for more optimal 33 packing under various circumstances. */ 34 35#ifndef _ELF_INTERNAL_H 36#define _ELF_INTERNAL_H 37 38/* Special section indices, which may show up in st_shndx fields, among 39 other places. */ 40 41#undef SHN_UNDEF 42#undef SHN_LORESERVE 43#undef SHN_LOPROC 44#undef SHN_HIPROC 45#undef SHN_LOOS 46#undef SHN_HIOS 47#undef SHN_ABS 48#undef SHN_COMMON 49#undef SHN_XINDEX 50#undef SHN_HIRESERVE 51#define SHN_UNDEF 0 /* Undefined section reference */ 52#define SHN_LORESERVE (-0x100u) /* Begin range of reserved indices */ 53#define SHN_LOPROC (-0x100u) /* Begin range of appl-specific */ 54#define SHN_HIPROC (-0xE1u) /* End range of appl-specific */ 55#define SHN_LOOS (-0xE0u) /* OS specific semantics, lo */ 56#define SHN_HIOS (-0xC1u) /* OS specific semantics, hi */ 57#define SHN_ABS (-0xFu) /* Associated symbol is absolute */ 58#define SHN_COMMON (-0xEu) /* Associated symbol is in common */ 59#define SHN_XINDEX (-0x1u) /* Section index is held elsewhere */ 60#define SHN_HIRESERVE (-0x1u) /* End range of reserved indices */ 61#define SHN_BAD (-0x101u) /* Used internally by bfd */ 62 63/* ELF Header */ 64 65#define EI_NIDENT 16 /* Size of e_ident[] */ 66 67typedef struct elf_internal_ehdr { 68 unsigned char e_ident[EI_NIDENT]; /* ELF "magic number" */ 69 bfd_vma e_entry; /* Entry point virtual address */ 70 bfd_size_type e_phoff; /* Program header table file offset */ 71 bfd_size_type e_shoff; /* Section header table file offset */ 72 unsigned long e_version; /* Identifies object file version */ 73 unsigned long e_flags; /* Processor-specific flags */ 74 unsigned short e_type; /* Identifies object file type */ 75 unsigned short e_machine; /* Specifies required architecture */ 76 unsigned int e_ehsize; /* ELF header size in bytes */ 77 unsigned int e_phentsize; /* Program header table entry size */ 78 unsigned int e_phnum; /* Program header table entry count */ 79 unsigned int e_shentsize; /* Section header table entry size */ 80 unsigned int e_shnum; /* Section header table entry count */ 81 unsigned int e_shstrndx; /* Section header string table index */ 82} Elf_Internal_Ehdr; 83 84/* Program header */ 85 86struct elf_internal_phdr { 87 unsigned long p_type; /* Identifies program segment type. */ 88 unsigned long p_flags; /* Segment flags. */ 89 bfd_vma p_offset; /* Segment file offset in octets. */ 90 bfd_vma p_vaddr; /* Segment virtual address in octets. */ 91 bfd_vma p_paddr; /* Segment physical address in octets. */ 92 bfd_vma p_filesz; /* Segment size in file in octets. */ 93 bfd_vma p_memsz; /* Segment size in memory in octets. */ 94 bfd_vma p_align; /* Segment alignment in bytes, file 95 & memory */ 96}; 97 98typedef struct elf_internal_phdr Elf_Internal_Phdr; 99 100/* Section header */ 101 102typedef struct elf_internal_shdr { 103 unsigned int sh_name; /* Section name, index in string tbl */ 104 unsigned int sh_type; /* Type of section */ 105 bfd_vma sh_flags; /* Miscellaneous section attributes */ 106 bfd_vma sh_addr; /* Section virtual addr at execution in 107 octets. */ 108 file_ptr sh_offset; /* Section file offset in octets. */ 109 bfd_size_type sh_size; /* Size of section in octets. */ 110 unsigned int sh_link; /* Index of another section */ 111 unsigned int sh_info; /* Additional section information */ 112 bfd_vma sh_addralign; /* Section alignment */ 113 bfd_size_type sh_entsize; /* Entry size if section holds table */ 114 115 /* The internal rep also has some cached info associated with it. */ 116 asection * bfd_section; /* Associated BFD section. */ 117 unsigned char *contents; /* Section contents. */ 118} Elf_Internal_Shdr; 119 120/* Compression header */ 121 122typedef struct elf_internal_chdr { 123 unsigned int ch_type; /* Type of compression */ 124 bfd_size_type ch_size; /* Size of uncompressed data in bytes */ 125 bfd_vma ch_addralign; /* Alignment of uncompressed data */ 126} Elf_Internal_Chdr; 127 128/* Symbol table entry */ 129 130struct elf_internal_sym { 131 bfd_vma st_value; /* Value of the symbol */ 132 bfd_vma st_size; /* Associated symbol size */ 133 unsigned long st_name; /* Symbol name, index in string tbl */ 134 unsigned char st_info; /* Type and binding attributes */ 135 unsigned char st_other; /* Visibilty, and target specific */ 136 unsigned char st_target_internal; /* Internal-only information */ 137 unsigned int st_shndx; /* Associated section index */ 138}; 139 140typedef struct elf_internal_sym Elf_Internal_Sym; 141 142/* Note segments */ 143 144typedef struct elf_internal_note { 145 unsigned long namesz; /* Size of entry's owner string */ 146 unsigned long descsz; /* Size of the note descriptor */ 147 unsigned long type; /* Interpretation of the descriptor */ 148 char * namedata; /* Start of the name+desc data */ 149 char * descdata; /* Start of the desc data */ 150 bfd_vma descpos; /* File offset of the descdata */ 151} Elf_Internal_Note; 152 153/* Relocation Entries */ 154 155typedef struct elf_internal_rela { 156 bfd_vma r_offset; /* Location at which to apply the action */ 157 bfd_vma r_info; /* Index and Type of relocation */ 158 bfd_vma r_addend; /* Constant addend used to compute value */ 159} Elf_Internal_Rela; 160 161/* dynamic section structure */ 162 163typedef struct elf_internal_dyn { 164 /* This needs to support 64-bit values in elf64. */ 165 bfd_vma d_tag; /* entry tag value */ 166 union { 167 /* This needs to support 64-bit values in elf64. */ 168 bfd_vma d_val; 169 bfd_vma d_ptr; 170 } d_un; 171} Elf_Internal_Dyn; 172 173/* This structure appears in a SHT_GNU_verdef section. */ 174 175typedef struct elf_internal_verdef { 176 unsigned short vd_version; /* Version number of structure. */ 177 unsigned short vd_flags; /* Flags (VER_FLG_*). */ 178 unsigned short vd_ndx; /* Version index. */ 179 unsigned short vd_cnt; /* Number of verdaux entries. */ 180 unsigned long vd_hash; /* Hash of name. */ 181 unsigned long vd_aux; /* Offset to verdaux entries. */ 182 unsigned long vd_next; /* Offset to next verdef. */ 183 184 /* These fields are set up when BFD reads in the structure. FIXME: 185 It would be cleaner to store these in a different structure. */ 186 bfd *vd_bfd; /* BFD. */ 187 const char *vd_nodename; /* Version name. */ 188 struct elf_internal_verdef *vd_nextdef; /* vd_next as pointer. */ 189 struct elf_internal_verdaux *vd_auxptr; /* vd_aux as pointer. */ 190 unsigned int vd_exp_refno; /* Used by the linker. */ 191} Elf_Internal_Verdef; 192 193/* This structure appears in a SHT_GNU_verdef section. */ 194 195typedef struct elf_internal_verdaux { 196 unsigned long vda_name; /* String table offset of name. */ 197 unsigned long vda_next; /* Offset to next verdaux. */ 198 199 /* These fields are set up when BFD reads in the structure. FIXME: 200 It would be cleaner to store these in a different structure. */ 201 const char *vda_nodename; /* vda_name as pointer. */ 202 struct elf_internal_verdaux *vda_nextptr; /* vda_next as pointer. */ 203} Elf_Internal_Verdaux; 204 205/* This structure appears in a SHT_GNU_verneed section. */ 206 207typedef struct elf_internal_verneed { 208 unsigned short vn_version; /* Version number of structure. */ 209 unsigned short vn_cnt; /* Number of vernaux entries. */ 210 unsigned long vn_file; /* String table offset of library name. */ 211 unsigned long vn_aux; /* Offset to vernaux entries. */ 212 unsigned long vn_next; /* Offset to next verneed. */ 213 214 /* These fields are set up when BFD reads in the structure. FIXME: 215 It would be cleaner to store these in a different structure. */ 216 bfd *vn_bfd; /* BFD. */ 217 const char *vn_filename; /* vn_file as pointer. */ 218 struct elf_internal_vernaux *vn_auxptr; /* vn_aux as pointer. */ 219 struct elf_internal_verneed *vn_nextref; /* vn_nextref as pointer. */ 220} Elf_Internal_Verneed; 221 222/* This structure appears in a SHT_GNU_verneed section. */ 223 224typedef struct elf_internal_vernaux { 225 unsigned long vna_hash; /* Hash of dependency name. */ 226 unsigned short vna_flags; /* Flags (VER_FLG_*). */ 227 unsigned short vna_other; /* Unused. */ 228 unsigned long vna_name; /* String table offset to version name. */ 229 unsigned long vna_next; /* Offset to next vernaux. */ 230 231 /* These fields are set up when BFD reads in the structure. FIXME: 232 It would be cleaner to store these in a different structure. */ 233 const char *vna_nodename; /* vna_name as pointer. */ 234 struct elf_internal_vernaux *vna_nextptr; /* vna_next as pointer. */ 235} Elf_Internal_Vernaux; 236 237/* This structure appears in a SHT_GNU_versym section. This is not a 238 standard ELF structure; ELF just uses Elf32_Half. */ 239 240typedef struct elf_internal_versym { 241 unsigned short vs_vers; 242} Elf_Internal_Versym; 243 244/* Structure for syminfo section. */ 245typedef struct 246{ 247 unsigned short int si_boundto; 248 unsigned short int si_flags; 249} Elf_Internal_Syminfo; 250 251/* This structure appears on the stack and in NT_AUXV core file notes. */ 252typedef struct 253{ 254 bfd_vma a_type; 255 bfd_vma a_val; 256} Elf_Internal_Auxv; 257 258 259/* This structure is used to describe how sections should be assigned 260 to program segments. */ 261 262struct elf_segment_map 263{ 264 /* Next program segment. */ 265 struct elf_segment_map *next; 266 /* Program segment type. */ 267 unsigned long p_type; 268 /* Program segment flags. */ 269 unsigned long p_flags; 270 /* Program segment physical address in octets. */ 271 bfd_vma p_paddr; 272 /* Program segment virtual address offset from section vma in bytes. */ 273 bfd_vma p_vaddr_offset; 274 /* Program segment alignment. */ 275 bfd_vma p_align; 276 /* Segment size in file and memory in octets. */ 277 bfd_vma p_size; 278 /* Whether the p_flags field is valid; if not, the flags are based 279 on the section flags. */ 280 unsigned int p_flags_valid : 1; 281 /* Whether the p_paddr field is valid; if not, the physical address 282 is based on the section lma values. */ 283 unsigned int p_paddr_valid : 1; 284 /* Whether the p_align field is valid; if not, PT_LOAD segment 285 alignment is based on the default maximum page size. */ 286 unsigned int p_align_valid : 1; 287 /* Whether the p_size field is valid; if not, the size are based 288 on the section sizes. */ 289 unsigned int p_size_valid : 1; 290 /* Whether this segment includes the file header. */ 291 unsigned int includes_filehdr : 1; 292 /* Whether this segment includes the program headers. */ 293 unsigned int includes_phdrs : 1; 294 /* Assume this PT_LOAD header has an lma of zero when sorting 295 headers before assigning file offsets. PT_LOAD headers with this 296 flag set are placed after one with includes_filehdr set, and 297 before PT_LOAD headers without this flag set. */ 298 unsigned int no_sort_lma : 1; 299 /* Index holding original order before sorting segments. */ 300 unsigned int idx; 301 /* Number of sections (may be 0). */ 302 unsigned int count; 303 /* Sections. Actual number of elements is in count field. */ 304 asection *sections[1]; 305}; 306 307/* .tbss is special. It doesn't contribute memory space to normal 308 segments and it doesn't take file space in normal segments. */ 309#define ELF_TBSS_SPECIAL(sec_hdr, segment) \ 310 (((sec_hdr)->sh_flags & SHF_TLS) != 0 \ 311 && (sec_hdr)->sh_type == SHT_NOBITS \ 312 && (segment)->p_type != PT_TLS) 313 314#define ELF_SECTION_SIZE(sec_hdr, segment) \ 315 (ELF_TBSS_SPECIAL(sec_hdr, segment) ? 0 : (sec_hdr)->sh_size) 316 317/* Decide if the section SEC_HDR is in SEGMENT. If CHECK_VMA, then 318 VMAs are checked for alloc sections. If STRICT, then a zero size 319 section won't match at the end of a segment, unless the segment 320 is also zero size. Regardless of STRICT and CHECK_VMA, zero size 321 sections won't match at the start or end of PT_DYNAMIC nor PT_NOTE, 322 unless PT_DYNAMIC and PT_NOTE are themselves zero sized. */ 323#define ELF_SECTION_IN_SEGMENT_1(sec_hdr, segment, check_vma, strict) \ 324 ((/* Only PT_LOAD, PT_GNU_RELRO and PT_TLS segments can contain \ 325 SHF_TLS sections. */ \ 326 ((((sec_hdr)->sh_flags & SHF_TLS) != 0) \ 327 && ((segment)->p_type == PT_TLS \ 328 || (segment)->p_type == PT_GNU_RELRO \ 329 || (segment)->p_type == PT_LOAD)) \ 330 /* PT_TLS segment contains only SHF_TLS sections, PT_PHDR no \ 331 sections at all. */ \ 332 || (((sec_hdr)->sh_flags & SHF_TLS) == 0 \ 333 && (segment)->p_type != PT_TLS \ 334 && (segment)->p_type != PT_PHDR)) \ 335 /* PT_LOAD and similar segments only have SHF_ALLOC sections. */ \ 336 && !(((sec_hdr)->sh_flags & SHF_ALLOC) == 0 \ 337 && ((segment)->p_type == PT_LOAD \ 338 || (segment)->p_type == PT_DYNAMIC \ 339 || (segment)->p_type == PT_GNU_EH_FRAME \ 340 || (segment)->p_type == PT_GNU_STACK \ 341 || (segment)->p_type == PT_GNU_RELRO \ 342 || ((segment)->p_type >= PT_GNU_MBIND_LO \ 343 && (segment)->p_type <= PT_GNU_MBIND_HI))) \ 344 /* Any section besides one of type SHT_NOBITS must have file \ 345 offsets within the segment. */ \ 346 && ((sec_hdr)->sh_type == SHT_NOBITS \ 347 || ((bfd_vma) (sec_hdr)->sh_offset >= (segment)->p_offset \ 348 && (!(strict) \ 349 || ((sec_hdr)->sh_offset - (segment)->p_offset \ 350 <= (segment)->p_filesz - 1)) \ 351 && (((sec_hdr)->sh_offset - (segment)->p_offset \ 352 + ELF_SECTION_SIZE(sec_hdr, segment)) \ 353 <= (segment)->p_filesz))) \ 354 /* SHF_ALLOC sections must have VMAs within the segment. */ \ 355 && (!(check_vma) \ 356 || ((sec_hdr)->sh_flags & SHF_ALLOC) == 0 \ 357 || ((sec_hdr)->sh_addr >= (segment)->p_vaddr \ 358 && (!(strict) \ 359 || ((sec_hdr)->sh_addr - (segment)->p_vaddr \ 360 <= (segment)->p_memsz - 1)) \ 361 && (((sec_hdr)->sh_addr - (segment)->p_vaddr \ 362 + ELF_SECTION_SIZE(sec_hdr, segment)) \ 363 <= (segment)->p_memsz))) \ 364 /* No zero size sections at start or end of PT_DYNAMIC nor \ 365 PT_NOTE. */ \ 366 && (((segment)->p_type != PT_DYNAMIC \ 367 && (segment)->p_type != PT_NOTE) \ 368 || (sec_hdr)->sh_size != 0 \ 369 || (segment)->p_memsz == 0 \ 370 || (((sec_hdr)->sh_type == SHT_NOBITS \ 371 || ((bfd_vma) (sec_hdr)->sh_offset > (segment)->p_offset \ 372 && ((sec_hdr)->sh_offset - (segment)->p_offset \ 373 < (segment)->p_filesz))) \ 374 && (((sec_hdr)->sh_flags & SHF_ALLOC) == 0 \ 375 || ((sec_hdr)->sh_addr > (segment)->p_vaddr \ 376 && ((sec_hdr)->sh_addr - (segment)->p_vaddr \ 377 < (segment)->p_memsz)))))) 378 379#define ELF_SECTION_IN_SEGMENT(sec_hdr, segment) \ 380 (ELF_SECTION_IN_SEGMENT_1 (sec_hdr, segment, 1, 0)) 381 382#define ELF_SECTION_IN_SEGMENT_STRICT(sec_hdr, segment) \ 383 (ELF_SECTION_IN_SEGMENT_1 (sec_hdr, segment, 1, 1)) 384 385#endif /* _ELF_INTERNAL_H */ 386