sdcc/support/sdbinutils/include/elf/internal.h

   1 /* ELF support for BFD.
   2    Copyright (C) 1991-2022 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 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
  98 typedef struct elf_internal_phdr Elf_Internal_Phdr;
  99
 100 /* Section header */
 101
 102 typedef 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
 122 typedef 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
 130 struct 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
 140 typedef struct elf_internal_sym Elf_Internal_Sym;
 141
 142 /* Note segments */
 143
 144 typedef 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
 155 typedef 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
 163 typedef 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
 175 typedef 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
 195 typedef 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
 207 typedef 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
 224 typedef 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
 240 typedef struct elf_internal_versym {
 241   unsigned short vs_vers;
 242 } Elf_Internal_Versym;
 243
 244 /* Structure for syminfo section.  */
 245 typedef 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.  */
 252 typedef 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
 262 struct 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 */