| 1 | /* ELF support for BFD. |
| 2 | Copyright (C) 1991-2018 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 */ |