include/elf/external.h

   1 /* ELF support for BFD.
   2    Copyright (C) 1991-2024 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 externally by the BFD library.
  27    I.E. it describes the in-file 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 /* The 64-bit stuff is kind of random.  Perhaps someone will publish a
  32    spec someday.  */
  33
  34 #ifndef _ELF_EXTERNAL_H
  35 #define _ELF_EXTERNAL_H
  36
  37 /* Special section indices, which may show up in st_shndx fields, among
  38    other places.  */
  39
  40 #define SHN_LORESERVE   0xFF00          /* Begin range of reserved indices */
  41 #define SHN_LOPROC      0xFF00          /* Begin range of appl-specific */
  42 #define SHN_HIPROC      0xFF1F          /* End range of appl-specific */
  43 #define SHN_LOOS        0xFF20          /* OS specific semantics, lo */
  44 #define SHN_HIOS        0xFF3F          /* OS specific semantics, hi */
  45 #define SHN_ABS         0xFFF1          /* Associated symbol is absolute */
  46 #define SHN_COMMON      0xFFF2          /* Associated symbol is in common */
  47 #define SHN_XINDEX      0xFFFF          /* Section index is held elsewhere */
  48 #define SHN_HIRESERVE   0xFFFF          /* End range of reserved indices */
  49
  50 /* ELF Header (32-bit implementations) */
  51
  52 typedef struct {
  53   unsigned char e_ident[16];            /* ELF "magic number" */
  54   unsigned char e_type[2];              /* Identifies object file type */
  55   unsigned char e_machine[2];           /* Specifies required architecture */
  56   unsigned char e_version[4];           /* Identifies object file version */
  57   unsigned char e_entry[4];             /* Entry point virtual address */
  58   unsigned char e_phoff[4];             /* Program header table file offset */
  59   unsigned char e_shoff[4];             /* Section header table file offset */
  60   unsigned char e_flags[4];             /* Processor-specific flags */
  61   unsigned char e_ehsize[2];            /* ELF header size in bytes */
  62   unsigned char e_phentsize[2];         /* Program header table entry size */
  63   unsigned char e_phnum[2];             /* Program header table entry count */
  64   unsigned char e_shentsize[2];         /* Section header table entry size */
  65   unsigned char e_shnum[2];             /* Section header table entry count */
  66   unsigned char e_shstrndx[2];          /* Section header string table index */
  67 } Elf32_External_Ehdr;
  68
  69 typedef struct {
  70   unsigned char e_ident[16];            /* ELF "magic number" */
  71   unsigned char e_type[2];              /* Identifies object file type */
  72   unsigned char e_machine[2];           /* Specifies required architecture */
  73   unsigned char e_version[4];           /* Identifies object file version */
  74   unsigned char e_entry[8];             /* Entry point virtual address */
  75   unsigned char e_phoff[8];             /* Program header table file offset */
  76   unsigned char e_shoff[8];             /* Section header table file offset */
  77   unsigned char e_flags[4];             /* Processor-specific flags */
  78   unsigned char e_ehsize[2];            /* ELF header size in bytes */
  79   unsigned char e_phentsize[2];         /* Program header table entry size */
  80   unsigned char e_phnum[2];             /* Program header table entry count */
  81   unsigned char e_shentsize[2];         /* Section header table entry size */
  82   unsigned char e_shnum[2];             /* Section header table entry count */
  83   unsigned char e_shstrndx[2];          /* Section header string table index */
  84 } Elf64_External_Ehdr;
  85
  86 /* Program header */
  87
  88 typedef struct {
  89   unsigned char p_type[4];              /* Identifies program segment type */
  90   unsigned char p_offset[4];            /* Segment file offset */
  91   unsigned char p_vaddr[4];             /* Segment virtual address */
  92   unsigned char p_paddr[4];             /* Segment physical address */
  93   unsigned char p_filesz[4];            /* Segment size in file */
  94   unsigned char p_memsz[4];             /* Segment size in memory */
  95   unsigned char p_flags[4];             /* Segment flags */
  96   unsigned char p_align[4];             /* Segment alignment, file & memory */
  97 } Elf32_External_Phdr;
  98
  99 typedef struct {
 100   unsigned char p_type[4];              /* Identifies program segment type */
 101   unsigned char p_flags[4];             /* Segment flags */
 102   unsigned char p_offset[8];            /* Segment file offset */
 103   unsigned char p_vaddr[8];             /* Segment virtual address */
 104   unsigned char p_paddr[8];             /* Segment physical address */
 105   unsigned char p_filesz[8];            /* Segment size in file */
 106   unsigned char p_memsz[8];             /* Segment size in memory */
 107   unsigned char p_align[8];             /* Segment alignment, file & memory */
 108 } Elf64_External_Phdr;
 109
 110 /* Section header */
 111
 112 typedef struct {
 113   unsigned char sh_name[4];             /* Section name, index in string tbl */
 114   unsigned char sh_type[4];             /* Type of section */
 115   unsigned char sh_flags[4];            /* Miscellaneous section attributes */
 116   unsigned char sh_addr[4];             /* Section virtual addr at execution */
 117   unsigned char sh_offset[4];           /* Section file offset */
 118   unsigned char sh_size[4];             /* Size of section in bytes */
 119   unsigned char sh_link[4];             /* Index of another section */
 120   unsigned char sh_info[4];             /* Additional section information */
 121   unsigned char sh_addralign[4];        /* Section alignment */
 122   unsigned char sh_entsize[4];          /* Entry size if section holds table */
 123 } Elf32_External_Shdr;
 124
 125 typedef struct {
 126   unsigned char sh_name[4];             /* Section name, index in string tbl */
 127   unsigned char sh_type[4];             /* Type of section */
 128   unsigned char sh_flags[8];            /* Miscellaneous section attributes */
 129   unsigned char sh_addr[8];             /* Section virtual addr at execution */
 130   unsigned char sh_offset[8];           /* Section file offset */
 131   unsigned char sh_size[8];             /* Size of section in bytes */
 132   unsigned char sh_link[4];             /* Index of another section */
 133   unsigned char sh_info[4];             /* Additional section information */
 134   unsigned char sh_addralign[8];        /* Section alignment */
 135   unsigned char sh_entsize[8];          /* Entry size if section holds table */
 136 } Elf64_External_Shdr;
 137
 138 /* Compression header */
 139
 140 typedef struct {
 141   unsigned char ch_type[4];             /* Type of compression */
 142   unsigned char ch_size[4];             /* Size of uncompressed data in bytes */
 143   unsigned char ch_addralign[4];        /* Alignment of uncompressed data  */
 144 } Elf32_External_Chdr;
 145
 146 typedef struct {
 147   unsigned char ch_type[4];             /* Type of compression */
 148   unsigned char ch_reserved[4];         /* Padding */
 149   unsigned char ch_size[8];             /* Size of uncompressed data in bytes */
 150   unsigned char ch_addralign[8];        /* Alignment of uncompressed data  */
 151 } Elf64_External_Chdr;
 152
 153 /* Symbol table entry */
 154
 155 typedef struct {
 156   unsigned char st_name[4];             /* Symbol name, index in string tbl */
 157   unsigned char st_value[4];            /* Value of the symbol */
 158   unsigned char st_size[4];             /* Associated symbol size */
 159   unsigned char st_info[1];             /* Type and binding attributes */
 160   unsigned char st_other[1];            /* No defined meaning, 0 */
 161   unsigned char st_shndx[2];            /* Associated section index */
 162 } Elf32_External_Sym;
 163
 164 typedef struct {
 165   unsigned char st_name[4];             /* Symbol name, index in string tbl */
 166   unsigned char st_info[1];             /* Type and binding attributes */
 167   unsigned char st_other[1];            /* No defined meaning, 0 */
 168   unsigned char st_shndx[2];            /* Associated section index */
 169   unsigned char st_value[8];            /* Value of the symbol */
 170   unsigned char st_size[8];             /* Associated symbol size */
 171 } Elf64_External_Sym;
 172
 173 typedef struct {
 174   unsigned char est_shndx[4];           /* Section index */
 175 } Elf_External_Sym_Shndx;
 176
 177 /* Note segments */
 178
 179 typedef struct {
 180   unsigned char namesz[4];              /* Size of entry's owner string */
 181   unsigned char descsz[4];              /* Size of the note descriptor */
 182   unsigned char type[4];                /* Interpretation of the descriptor */
 183   char          name[1];                /* Start of the name+desc data */
 184 } Elf_External_Note;
 185
 186 /* Align an address upward to a boundary, expressed as a number of bytes.
 187    E.g. align to an 8-byte boundary with argument of 8.  */
 188 #define ELF_ALIGN_UP(addr, boundary) \
 189   (((bfd_vma) (addr) + ((boundary) - 1)) & ~ (bfd_vma) ((boundary) -1))
 190
 191 /* Compute the offset of the note descriptor from size of note entry's
 192    owner string and note alignment.  */
 193 #define ELF_NOTE_DESC_OFFSET(namesz, align) \
 194   ELF_ALIGN_UP (offsetof (Elf_External_Note, name) + (namesz), (align))
 195
 196 /* Compute the offset of the next note entry from size of note entry's
 197    owner string, size of the note descriptor and note alignment.  */
 198 #define ELF_NOTE_NEXT_OFFSET(namesz, descsz, align) \
 199   ELF_ALIGN_UP (ELF_NOTE_DESC_OFFSET ((namesz), (align)) + (descsz), \
 200                 (align))
 201
 202 /* Relocation Entries */
 203 typedef struct {
 204   unsigned char r_offset[4];    /* Location at which to apply the action */
 205   unsigned char r_info[4];      /* index and type of relocation */
 206 } Elf32_External_Rel;
 207
 208 typedef struct {
 209   unsigned char r_offset[4];    /* Location at which to apply the action */
 210   unsigned char r_info[4];      /* index and type of relocation */
 211   unsigned char r_addend[4];    /* Constant addend used to compute value */
 212 } Elf32_External_Rela;
 213
 214 typedef struct {
 215   unsigned char r_data[4];      /* RELR entry */
 216 } Elf32_External_Relr;
 217
 218 typedef struct {
 219   unsigned char r_offset[8];    /* Location at which to apply the action */
 220   unsigned char r_info[8];      /* index and type of relocation */
 221 } Elf64_External_Rel;
 222
 223 typedef struct {
 224   unsigned char r_offset[8];    /* Location at which to apply the action */
 225   unsigned char r_info[8];      /* index and type of relocation */
 226   unsigned char r_addend[8];    /* Constant addend used to compute value */
 227 } Elf64_External_Rela;
 228
 229 typedef struct {
 230   unsigned char r_data[8];      /* RELR entry */
 231 } Elf64_External_Relr;
 232
 233 /* dynamic section structure */
 234
 235 typedef struct {
 236   unsigned char d_tag[4];               /* entry tag value */
 237   union {
 238     unsigned char       d_val[4];
 239     unsigned char       d_ptr[4];
 240   } d_un;
 241 } Elf32_External_Dyn;
 242
 243 typedef struct {
 244   unsigned char d_tag[8];               /* entry tag value */
 245   union {
 246     unsigned char       d_val[8];
 247     unsigned char       d_ptr[8];
 248   } d_un;
 249 } Elf64_External_Dyn;
 250
 251 /* The version structures are currently size independent.  They are
 252    named without a 32 or 64.  If that ever changes, these structures
 253    will need to be renamed.  */
 254
 255 /* This structure appears in a SHT_GNU_verdef section.  */
 256
 257 typedef struct {
 258   unsigned char         vd_version[2];
 259   unsigned char         vd_flags[2];
 260   unsigned char         vd_ndx[2];
 261   unsigned char         vd_cnt[2];
 262   unsigned char         vd_hash[4];
 263   unsigned char         vd_aux[4];
 264   unsigned char         vd_next[4];
 265 } Elf_External_Verdef;
 266
 267 /* This structure appears in a SHT_GNU_verdef section.  */
 268
 269 typedef struct {
 270   unsigned char         vda_name[4];
 271   unsigned char         vda_next[4];
 272 } Elf_External_Verdaux;
 273
 274 /* This structure appears in a SHT_GNU_verneed section.  */
 275
 276 typedef struct {
 277   unsigned char         vn_version[2];
 278   unsigned char         vn_cnt[2];
 279   unsigned char         vn_file[4];
 280   unsigned char         vn_aux[4];
 281   unsigned char         vn_next[4];
 282 } Elf_External_Verneed;
 283
 284 /* This structure appears in a SHT_GNU_verneed section.  */
 285
 286 typedef struct {
 287   unsigned char         vna_hash[4];
 288   unsigned char         vna_flags[2];
 289   unsigned char         vna_other[2];
 290   unsigned char         vna_name[4];
 291   unsigned char         vna_next[4];
 292 } Elf_External_Vernaux;
 293
 294 /* This structure appears in a SHT_GNU_versym section.  This is not a
 295    standard ELF structure; ELF just uses Elf32_Half.  */
 296
 297 typedef struct {
 298   unsigned char         vs_vers[2];
 299 } ATTRIBUTE_PACKED  Elf_External_Versym;
 300
 301 /* Structure for syminfo section.  */
 302 typedef struct
 303 {
 304   unsigned char         si_boundto[2];
 305   unsigned char         si_flags[2];
 306 } Elf_External_Syminfo;
 307
 308
 309 /* This structure appears on the stack and in NT_AUXV core file notes.  */
 310 typedef struct
 311 {
 312   unsigned char         a_type[4];
 313   unsigned char         a_val[4];
 314 } Elf32_External_Auxv;
 315
 316 typedef struct
 317 {
 318   unsigned char         a_type[8];
 319   unsigned char         a_val[8];
 320 } Elf64_External_Auxv;
 321
 322 /* Size of SHT_GROUP section entry.  */
 323
 324 #define GRP_ENTRY_SIZE          4
 325
 326 #endif /* _ELF_EXTERNAL_H */