include/elf/internal.h

   1 /* ELF support for BFD.
   2    Copyright 1991, 1992, 1993, 1994, 1995, 1997, 1998, 2000, 2001, 2002,
   3    2003, 2006 Free Software Foundation, Inc.
   4
   5    Written by Fred Fish @ Cygnus Support, from information published
   6    in "UNIX System V Release 4, Programmers Guide: ANSI C and
   7    Programming Support Tools".
   8
   9 This file is part of BFD, the Binary File Descriptor library.
  10
  11 This program is free software; you can redistribute it and/or modify
  12 it under the terms of the GNU General Public License as published by
  13 the Free Software Foundation; either version 2 of the License, or
  14 (at your option) any later version.
  15
  16 This program is distributed in the hope that it will be useful,
  17 but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 GNU General Public License for more details.
  20
  21 You should have received a copy of the GNU General Public License
  22 along with this program; if not, write to the Free Software
  23 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
  24
  25
  26 /* This file is part of ELF support for BFD, and contains the portions
  27    that describe how ELF is represented internally in the BFD library.
  28    I.E. it describes the in-memory representation of ELF.  It requires
  29    the elf-common.h file which contains the portions that are common to
  30    both the internal and external representations. */
  31
  32
  33 /* NOTE that these structures are not kept in the same order as they appear
  34    in the object file.  In some cases they've been reordered for more optimal
  35    packing under various circumstances.  */
  36
  37 #ifndef _ELF_INTERNAL_H
  38 #define _ELF_INTERNAL_H
  39
  40 /* ELF Header */
  41
  42 #define EI_NIDENT       16              /* Size of e_ident[] */
  43
  44 typedef struct elf_internal_ehdr {
  45   unsigned char         e_ident[EI_NIDENT]; /* ELF "magic number" */
  46   bfd_vma               e_entry;        /* Entry point virtual address */
  47   bfd_size_type         e_phoff;        /* Program header table file offset */
  48   bfd_size_type         e_shoff;        /* Section header table file offset */
  49   unsigned long         e_version;      /* Identifies object file version */
  50   unsigned long         e_flags;        /* Processor-specific flags */
  51   unsigned short        e_type;         /* Identifies object file type */
  52   unsigned short        e_machine;      /* Specifies required architecture */
  53   unsigned int          e_ehsize;       /* ELF header size in bytes */
  54   unsigned int          e_phentsize;    /* Program header table entry size */
  55   unsigned int          e_phnum;        /* Program header table entry count */
  56   unsigned int          e_shentsize;    /* Section header table entry size */
  57   unsigned int          e_shnum;        /* Section header table entry count */
  58   unsigned int          e_shstrndx;     /* Section header string table index */
  59 } Elf_Internal_Ehdr;
  60
  61 /* Program header */
  62
  63 struct elf_internal_phdr {
  64   unsigned long p_type;                 /* Identifies program segment type */
  65   unsigned long p_flags;                /* Segment flags */
  66   bfd_vma       p_offset;               /* Segment file offset */
  67   bfd_vma       p_vaddr;                /* Segment virtual address */
  68   bfd_vma       p_paddr;                /* Segment physical address */
  69   bfd_vma       p_filesz;               /* Segment size in file */
  70   bfd_vma       p_memsz;                /* Segment size in memory */
  71   bfd_vma       p_align;                /* Segment alignment, file & memory */
  72 };
  73
  74 typedef struct elf_internal_phdr Elf_Internal_Phdr;
  75
  76 /* Section header */
  77
  78 typedef struct elf_internal_shdr {
  79   unsigned int  sh_name;                /* Section name, index in string tbl */
  80   unsigned int  sh_type;                /* Type of section */
  81   bfd_vma       sh_flags;               /* Miscellaneous section attributes */
  82   bfd_vma       sh_addr;                /* Section virtual addr at execution */
  83   bfd_size_type sh_size;                /* Size of section in bytes */
  84   bfd_size_type sh_entsize;             /* Entry size if section holds table */
  85   unsigned long sh_link;                /* Index of another section */
  86   unsigned long sh_info;                /* Additional section information */
  87   file_ptr      sh_offset;              /* Section file offset */
  88   unsigned int  sh_addralign;           /* Section alignment */
  89
  90   /* The internal rep also has some cached info associated with it. */
  91   asection *    bfd_section;            /* Associated BFD section.  */
  92   unsigned char *contents;              /* Section contents.  */
  93 } Elf_Internal_Shdr;
  94
  95 /* Symbol table entry */
  96
  97 struct elf_internal_sym {
  98   bfd_vma       st_value;               /* Value of the symbol */
  99   bfd_vma       st_size;                /* Associated symbol size */
 100   unsigned long st_name;                /* Symbol name, index in string tbl */
 101   unsigned char st_info;                /* Type and binding attributes */
 102   unsigned char st_other;               /* Visibilty, and target specific */
 103   unsigned int  st_shndx;               /* Associated section index */
 104 };
 105
 106 typedef struct elf_internal_sym Elf_Internal_Sym;
 107
 108 /* Note segments */
 109
 110 typedef struct elf_internal_note {
 111   unsigned long namesz;                 /* Size of entry's owner string */
 112   unsigned long descsz;                 /* Size of the note descriptor */
 113   unsigned long type;                   /* Interpretation of the descriptor */
 114   char *        namedata;               /* Start of the name+desc data */
 115   char *        descdata;               /* Start of the desc data */
 116   bfd_vma       descpos;                /* File offset of the descdata */
 117 } Elf_Internal_Note;
 118
 119 /* Relocation Entries */
 120
 121 typedef struct elf_internal_rela {
 122   bfd_vma       r_offset;       /* Location at which to apply the action */
 123   bfd_vma       r_info;         /* Index and Type of relocation */
 124   bfd_vma       r_addend;       /* Constant addend used to compute value */
 125 } Elf_Internal_Rela;
 126
 127 /* dynamic section structure */
 128
 129 typedef struct elf_internal_dyn {
 130   /* This needs to support 64-bit values in elf64.  */
 131   bfd_vma d_tag;                /* entry tag value */
 132   union {
 133     /* This needs to support 64-bit values in elf64.  */
 134     bfd_vma     d_val;
 135     bfd_vma     d_ptr;
 136   } d_un;
 137 } Elf_Internal_Dyn;
 138
 139 /* This structure appears in a SHT_GNU_verdef section.  */
 140
 141 typedef struct elf_internal_verdef {
 142   unsigned short vd_version;    /* Version number of structure.  */
 143   unsigned short vd_flags;      /* Flags (VER_FLG_*).  */
 144   unsigned short vd_ndx;        /* Version index.  */
 145   unsigned short vd_cnt;        /* Number of verdaux entries.  */
 146   unsigned long  vd_hash;       /* Hash of name.  */
 147   unsigned long  vd_aux;        /* Offset to verdaux entries.  */
 148   unsigned long  vd_next;       /* Offset to next verdef.  */
 149
 150   /* These fields are set up when BFD reads in the structure.  FIXME:
 151      It would be cleaner to store these in a different structure.  */
 152   bfd                         *vd_bfd;          /* BFD.  */
 153   const char                  *vd_nodename;     /* Version name.  */
 154   struct elf_internal_verdef  *vd_nextdef;      /* vd_next as pointer.  */
 155   struct elf_internal_verdaux *vd_auxptr;       /* vd_aux as pointer.  */
 156   unsigned int                 vd_exp_refno;    /* Used by the linker.  */
 157 } Elf_Internal_Verdef;
 158
 159 /* This structure appears in a SHT_GNU_verdef section.  */
 160
 161 typedef struct elf_internal_verdaux {
 162   unsigned long vda_name;       /* String table offset of name.  */
 163   unsigned long vda_next;       /* Offset to next verdaux.  */
 164
 165   /* These fields are set up when BFD reads in the structure.  FIXME:
 166      It would be cleaner to store these in a different structure.  */
 167   const char *vda_nodename;                     /* vda_name as pointer.  */
 168   struct elf_internal_verdaux *vda_nextptr;     /* vda_next as pointer.  */
 169 } Elf_Internal_Verdaux;
 170
 171 /* This structure appears in a SHT_GNU_verneed section.  */
 172
 173 typedef struct elf_internal_verneed {
 174   unsigned short vn_version;    /* Version number of structure.  */
 175   unsigned short vn_cnt;        /* Number of vernaux entries.  */
 176   unsigned long  vn_file;       /* String table offset of library name.  */
 177   unsigned long  vn_aux;        /* Offset to vernaux entries.  */
 178   unsigned long  vn_next;       /* Offset to next verneed.  */
 179
 180   /* These fields are set up when BFD reads in the structure.  FIXME:
 181      It would be cleaner to store these in a different structure.  */
 182   bfd                         *vn_bfd;          /* BFD.  */
 183   const char                  *vn_filename;     /* vn_file as pointer.  */
 184   struct elf_internal_vernaux *vn_auxptr;       /* vn_aux as pointer.  */
 185   struct elf_internal_verneed *vn_nextref;      /* vn_nextref as pointer.  */
 186 } Elf_Internal_Verneed;
 187
 188 /* This structure appears in a SHT_GNU_verneed section.  */
 189
 190 typedef struct elf_internal_vernaux {
 191   unsigned long  vna_hash;      /* Hash of dependency name.  */
 192   unsigned short vna_flags;     /* Flags (VER_FLG_*).  */
 193   unsigned short vna_other;     /* Unused.  */
 194   unsigned long  vna_name;      /* String table offset to version name.  */
 195   unsigned long  vna_next;      /* Offset to next vernaux.  */
 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                  *vna_nodename;    /* vna_name as pointer.  */
 200   struct elf_internal_vernaux *vna_nextptr;     /* vna_next as pointer.  */
 201 } Elf_Internal_Vernaux;
 202
 203 /* This structure appears in a SHT_GNU_versym section.  This is not a
 204    standard ELF structure; ELF just uses Elf32_Half.  */
 205
 206 typedef struct elf_internal_versym {
 207   unsigned short vs_vers;
 208 } Elf_Internal_Versym;
 209
 210 /* Structure for syminfo section.  */
 211 typedef struct
 212 {
 213   unsigned short int    si_boundto;
 214   unsigned short int    si_flags;
 215 } Elf_Internal_Syminfo;
 216
 217 /* This structure appears on the stack and in NT_AUXV core file notes.  */
 218 typedef struct
 219 {
 220   bfd_vma a_type;
 221   bfd_vma a_val;
 222 } Elf_Internal_Auxv;
 223
 224
 225 /* This structure is used to describe how sections should be assigned
 226    to program segments.  */
 227
 228 struct elf_segment_map
 229 {
 230   /* Next program segment.  */
 231   struct elf_segment_map *next;
 232   /* Program segment type.  */
 233   unsigned long p_type;
 234   /* Program segment flags.  */
 235   unsigned long p_flags;
 236   /* Program segment physical address.  */
 237   bfd_vma p_paddr;
 238   /* Program segment virtual address offset from section vma.  */
 239   bfd_vma p_vaddr_offset;
 240   /* Program segment alignment.  */
 241   bfd_vma p_align;
 242   /* Whether the p_flags field is valid; if not, the flags are based
 243      on the section flags.  */
 244   unsigned int p_flags_valid : 1;
 245   /* Whether the p_paddr field is valid; if not, the physical address
 246      is based on the section lma values.  */
 247   unsigned int p_paddr_valid : 1;
 248   /* Whether the p_align field is valid; if not, PT_LOAD segment
 249      alignment is based on the default maximum page size.  */
 250   unsigned int p_align_valid : 1;
 251   /* Whether this segment includes the file header.  */
 252   unsigned int includes_filehdr : 1;
 253   /* Whether this segment includes the program headers.  */
 254   unsigned int includes_phdrs : 1;
 255   /* Number of sections (may be 0).  */
 256   unsigned int count;
 257   /* Sections.  Actual number of elements is in count field.  */
 258   asection *sections[1];
 259 };
 260
 261 /* .tbss is special.  It doesn't contribute memory space to normal
 262    segments and it doesn't take file space in normal segments.  */
 263 #define ELF_SECTION_SIZE(sec_hdr, segment)                      \
 264    (((sec_hdr->sh_flags & SHF_TLS) == 0                         \
 265      || sec_hdr->sh_type != SHT_NOBITS                          \
 266      || segment->p_type == PT_TLS) ? sec_hdr->sh_size : 0)
 267
 268 /* Decide if the given sec_hdr is in the given segment.  PT_TLS segment
 269    contains only SHF_TLS sections.  Only PT_LOAD and PT_TLS segments
 270    can contain SHF_TLS sections.  */
 271 #define ELF_IS_SECTION_IN_SEGMENT(sec_hdr, segment)             \
 272   (((((sec_hdr->sh_flags & SHF_TLS) != 0)                       \
 273      && (segment->p_type == PT_TLS                              \
 274          || segment->p_type == PT_LOAD))                        \
 275     || ((sec_hdr->sh_flags & SHF_TLS) == 0                      \
 276         && segment->p_type != PT_TLS))                          \
 277    /* Compare allocated sec_hdrs by VMA, unallocated sec_hdrs   \
 278       by file offset.  */                                       \
 279    && (sec_hdr->sh_flags & SHF_ALLOC                            \
 280        ? (sec_hdr->sh_addr >= segment->p_vaddr                  \
 281           && (sec_hdr->sh_addr                                  \
 282               + ELF_SECTION_SIZE(sec_hdr, segment)              \
 283               <= segment->p_vaddr + segment->p_memsz))          \
 284        : ((bfd_vma) sec_hdr->sh_offset >= segment->p_offset     \
 285           && (sec_hdr->sh_offset                                \
 286               + ELF_SECTION_SIZE(sec_hdr, segment)              \
 287               <= segment->p_offset + segment->p_filesz))))
 288
 289 /* Decide if the given sec_hdr is in the given segment in file.  */
 290 #define ELF_IS_SECTION_IN_SEGMENT_FILE(sec_hdr, segment)        \
 291   (sec_hdr->sh_size > 0                                         \
 292    && ELF_IS_SECTION_IN_SEGMENT (sec_hdr, segment))
 293
 294 /* Decide if the given sec_hdr is in the given segment in memory.  */
 295 #define ELF_IS_SECTION_IN_SEGMENT_MEMORY(sec_hdr, segment)      \
 296   (ELF_SECTION_SIZE(sec_hdr, segment) > 0                       \
 297    && ELF_IS_SECTION_IN_SEGMENT (sec_hdr, segment))
 298
 299 #endif /* _ELF_INTERNAL_H */