1 /* ELF support for BFD. 2 Copyright (C) 1991-2016 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 67 typedef 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 86 struct 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 */ 90 bfd_vma p_vaddr; /* Segment virtual address */ 91 bfd_vma p_paddr; /* Segment physical address */ 92 bfd_vma p_filesz; /* Segment size in file */ 93 bfd_vma p_memsz; /* Segment size in memory */ 94 bfd_vma p_align; /* Segment alignment, file & memory */ 95 }; 96 97 typedef struct elf_internal_phdr Elf_Internal_Phdr; 98 99 /* Section header */ 100 101 typedef struct elf_internal_shdr { 102 unsigned int sh_name; /* Section name, index in string tbl */ 103 unsigned int sh_type; /* Type of section */ 104 bfd_vma sh_flags; /* Miscellaneous section attributes */ 105 bfd_vma sh_addr; /* Section virtual addr at execution */ 106 file_ptr sh_offset; /* Section file offset */ 107 bfd_size_type sh_size; /* Size of section in bytes */ 108 unsigned int sh_link; /* Index of another section */ 109 unsigned int sh_info; /* Additional section information */ 110 bfd_vma sh_addralign; /* Section alignment */ 111 bfd_size_type sh_entsize; /* Entry size if section holds table */ 112 113 /* The internal rep also has some cached info associated with it. */ 114 asection * bfd_section; /* Associated BFD section. */ 115 unsigned char *contents; /* Section contents. */ 116 } Elf_Internal_Shdr; 117 118 /* Compression header */ 119 120 typedef struct elf_internal_chdr { 121 unsigned int ch_type; /* Type of compression */ 122 bfd_size_type ch_size; /* Size of uncompressed data in bytes */ 123 bfd_vma ch_addralign; /* Alignment of uncompressed data */ 124 } Elf_Internal_Chdr; 125 126 /* Symbol table entry */ 127 128 struct elf_internal_sym { 129 bfd_vma st_value; /* Value of the symbol */ 130 bfd_vma st_size; /* Associated symbol size */ 131 unsigned long st_name; /* Symbol name, index in string tbl */ 132 unsigned char st_info; /* Type and binding attributes */ 133 unsigned char st_other; /* Visibilty, and target specific */ 134 unsigned char st_target_internal; /* Internal-only information */ 135 unsigned int st_shndx; /* Associated section index */ 136 }; 137 138 typedef struct elf_internal_sym Elf_Internal_Sym; 139 140 /* Note segments */ 141 142 typedef struct elf_internal_note { 143 unsigned long namesz; /* Size of entry's owner string */ 144 unsigned long descsz; /* Size of the note descriptor */ 145 unsigned long type; /* Interpretation of the descriptor */ 146 char * namedata; /* Start of the name+desc data */ 147 char * descdata; /* Start of the desc data */ 148 bfd_vma descpos; /* File offset of the descdata */ 149 } Elf_Internal_Note; 150 151 /* Relocation Entries */ 152 153 typedef struct elf_internal_rela { 154 bfd_vma r_offset; /* Location at which to apply the action */ 155 bfd_vma r_info; /* Index and Type of relocation */ 156 bfd_vma r_addend; /* Constant addend used to compute value */ 157 } Elf_Internal_Rela; 158 159 /* dynamic section structure */ 160 161 typedef struct elf_internal_dyn { 162 /* This needs to support 64-bit values in elf64. */ 163 bfd_vma d_tag; /* entry tag value */ 164 union { 165 /* This needs to support 64-bit values in elf64. */ 166 bfd_vma d_val; 167 bfd_vma d_ptr; 168 } d_un; 169 } Elf_Internal_Dyn; 170 171 /* This structure appears in a SHT_GNU_verdef section. */ 172 173 typedef struct elf_internal_verdef { 174 unsigned short vd_version; /* Version number of structure. */ 175 unsigned short vd_flags; /* Flags (VER_FLG_*). */ 176 unsigned short vd_ndx; /* Version index. */ 177 unsigned short vd_cnt; /* Number of verdaux entries. */ 178 unsigned long vd_hash; /* Hash of name. */ 179 unsigned long vd_aux; /* Offset to verdaux entries. */ 180 unsigned long vd_next; /* Offset to next verdef. */ 181 182 /* These fields are set up when BFD reads in the structure. FIXME: 183 It would be cleaner to store these in a different structure. */ 184 bfd *vd_bfd; /* BFD. */ 185 const char *vd_nodename; /* Version name. */ 186 struct elf_internal_verdef *vd_nextdef; /* vd_next as pointer. */ 187 struct elf_internal_verdaux *vd_auxptr; /* vd_aux as pointer. */ 188 unsigned int vd_exp_refno; /* Used by the linker. */ 189 } Elf_Internal_Verdef; 190 191 /* This structure appears in a SHT_GNU_verdef section. */ 192 193 typedef struct elf_internal_verdaux { 194 unsigned long vda_name; /* String table offset of name. */ 195 unsigned long vda_next; /* Offset to next verdaux. */ 196 197 /* These fields are set up when BFD reads in the structure. FIXME: 198 It would be cleaner to store these in a different structure. */ 199 const char *vda_nodename; /* vda_name as pointer. */ 200 struct elf_internal_verdaux *vda_nextptr; /* vda_next as pointer. */ 201 } Elf_Internal_Verdaux; 202 203 /* This structure appears in a SHT_GNU_verneed section. */ 204 205 typedef struct elf_internal_verneed { 206 unsigned short vn_version; /* Version number of structure. */ 207 unsigned short vn_cnt; /* Number of vernaux entries. */ 208 unsigned long vn_file; /* String table offset of library name. */ 209 unsigned long vn_aux; /* Offset to vernaux entries. */ 210 unsigned long vn_next; /* Offset to next verneed. */ 211 212 /* These fields are set up when BFD reads in the structure. FIXME: 213 It would be cleaner to store these in a different structure. */ 214 bfd *vn_bfd; /* BFD. */ 215 const char *vn_filename; /* vn_file as pointer. */ 216 struct elf_internal_vernaux *vn_auxptr; /* vn_aux as pointer. */ 217 struct elf_internal_verneed *vn_nextref; /* vn_nextref as pointer. */ 218 } Elf_Internal_Verneed; 219 220 /* This structure appears in a SHT_GNU_verneed section. */ 221 222 typedef struct elf_internal_vernaux { 223 unsigned long vna_hash; /* Hash of dependency name. */ 224 unsigned short vna_flags; /* Flags (VER_FLG_*). */ 225 unsigned short vna_other; /* Unused. */ 226 unsigned long vna_name; /* String table offset to version name. */ 227 unsigned long vna_next; /* Offset to next vernaux. */ 228 229 /* These fields are set up when BFD reads in the structure. FIXME: 230 It would be cleaner to store these in a different structure. */ 231 const char *vna_nodename; /* vna_name as pointer. */ 232 struct elf_internal_vernaux *vna_nextptr; /* vna_next as pointer. */ 233 } Elf_Internal_Vernaux; 234 235 /* This structure appears in a SHT_GNU_versym section. This is not a 236 standard ELF structure; ELF just uses Elf32_Half. */ 237 238 typedef struct elf_internal_versym { 239 unsigned short vs_vers; 240 } Elf_Internal_Versym; 241 242 /* Structure for syminfo section. */ 243 typedef struct 244 { 245 unsigned short int si_boundto; 246 unsigned short int si_flags; 247 } Elf_Internal_Syminfo; 248 249 /* This structure appears on the stack and in NT_AUXV core file notes. */ 250 typedef struct 251 { 252 bfd_vma a_type; 253 bfd_vma a_val; 254 } Elf_Internal_Auxv; 255 256 257 /* This structure is used to describe how sections should be assigned 258 to program segments. */ 259 260 struct elf_segment_map 261 { 262 /* Next program segment. */ 263 struct elf_segment_map *next; 264 /* Program segment type. */ 265 unsigned long p_type; 266 /* Program segment flags. */ 267 unsigned long p_flags; 268 /* Program segment physical address. */ 269 bfd_vma p_paddr; 270 /* Program segment virtual address offset from section vma. */ 271 bfd_vma p_vaddr_offset; 272 /* Program segment alignment. */ 273 bfd_vma p_align; 274 /* Segment size in file and memory */ 275 bfd_vma p_size; 276 /* Required size of filehdr + phdrs, if non-zero */ 277 bfd_vma header_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 /* Number of sections (may be 0). */ 295 unsigned int count; 296 /* Sections. Actual number of elements is in count field. */ 297 asection *sections[1]; 298 }; 299 300 /* .tbss is special. It doesn't contribute memory space to normal 301 segments and it doesn't take file space in normal segments. */ 302 #define ELF_TBSS_SPECIAL(sec_hdr, segment) \ 303 (((sec_hdr)->sh_flags & SHF_TLS) != 0 \ 304 && (sec_hdr)->sh_type == SHT_NOBITS \ 305 && (segment)->p_type != PT_TLS) 306 307 #define ELF_SECTION_SIZE(sec_hdr, segment) \ 308 (ELF_TBSS_SPECIAL(sec_hdr, segment) ? 0 : (sec_hdr)->sh_size) 309 310 /* Decide if the section SEC_HDR is in SEGMENT. If CHECK_VMA, then 311 VMAs are checked for alloc sections. If STRICT, then a zero size 312 section won't match at the end of a segment, unless the segment 313 is also zero size. Regardless of STRICT and CHECK_VMA, zero size 314 sections won't match at the start or end of PT_DYNAMIC, unless 315 PT_DYNAMIC is itself zero sized. */ 316 #define ELF_SECTION_IN_SEGMENT_1(sec_hdr, segment, check_vma, strict) \ 317 ((/* Only PT_LOAD, PT_GNU_RELRO and PT_TLS segments can contain \ 318 SHF_TLS sections. */ \ 319 ((((sec_hdr)->sh_flags & SHF_TLS) != 0) \ 320 && ((segment)->p_type == PT_TLS \ 321 || (segment)->p_type == PT_GNU_RELRO \ 322 || (segment)->p_type == PT_LOAD)) \ 323 /* PT_TLS segment contains only SHF_TLS sections, PT_PHDR no \ 324 sections at all. */ \ 325 || (((sec_hdr)->sh_flags & SHF_TLS) == 0 \ 326 && (segment)->p_type != PT_TLS \ 327 && (segment)->p_type != PT_PHDR)) \ 328 /* PT_LOAD and similar segments only have SHF_ALLOC sections. */ \ 329 && !(((sec_hdr)->sh_flags & SHF_ALLOC) == 0 \ 330 && ((segment)->p_type == PT_LOAD \ 331 || (segment)->p_type == PT_DYNAMIC \ 332 || (segment)->p_type == PT_GNU_EH_FRAME \ 333 || (segment)->p_type == PT_GNU_RELRO \ 334 || (segment)->p_type == PT_GNU_STACK)) \ 335 /* Any section besides one of type SHT_NOBITS must have file \ 336 offsets within the segment. */ \ 337 && ((sec_hdr)->sh_type == SHT_NOBITS \ 338 || ((bfd_vma) (sec_hdr)->sh_offset >= (segment)->p_offset \ 339 && (!(strict) \ 340 || ((sec_hdr)->sh_offset - (segment)->p_offset \ 341 <= (segment)->p_filesz - 1)) \ 342 && (((sec_hdr)->sh_offset - (segment)->p_offset \ 343 + ELF_SECTION_SIZE(sec_hdr, segment)) \ 344 <= (segment)->p_filesz))) \ 345 /* SHF_ALLOC sections must have VMAs within the segment. */ \ 346 && (!(check_vma) \ 347 || ((sec_hdr)->sh_flags & SHF_ALLOC) == 0 \ 348 || ((sec_hdr)->sh_addr >= (segment)->p_vaddr \ 349 && (!(strict) \ 350 || ((sec_hdr)->sh_addr - (segment)->p_vaddr \ 351 <= (segment)->p_memsz - 1)) \ 352 && (((sec_hdr)->sh_addr - (segment)->p_vaddr \ 353 + ELF_SECTION_SIZE(sec_hdr, segment)) \ 354 <= (segment)->p_memsz))) \ 355 /* No zero size sections at start or end of PT_DYNAMIC. */ \ 356 && ((segment)->p_type != PT_DYNAMIC \ 357 || (sec_hdr)->sh_size != 0 \ 358 || (segment)->p_memsz == 0 \ 359 || (((sec_hdr)->sh_type == SHT_NOBITS \ 360 || ((bfd_vma) (sec_hdr)->sh_offset > (segment)->p_offset \ 361 && ((sec_hdr)->sh_offset - (segment)->p_offset \ 362 < (segment)->p_filesz))) \ 363 && (((sec_hdr)->sh_flags & SHF_ALLOC) == 0 \ 364 || ((sec_hdr)->sh_addr > (segment)->p_vaddr \ 365 && ((sec_hdr)->sh_addr - (segment)->p_vaddr \ 366 < (segment)->p_memsz)))))) 367 368 #define ELF_SECTION_IN_SEGMENT(sec_hdr, segment) \ 369 (ELF_SECTION_IN_SEGMENT_1 (sec_hdr, segment, 1, 0)) 370 371 #define ELF_SECTION_IN_SEGMENT_STRICT(sec_hdr, segment) \ 372 (ELF_SECTION_IN_SEGMENT_1 (sec_hdr, segment, 1, 1)) 373 374 #endif /* _ELF_INTERNAL_H */ 375
