/* ELF support for BFD. Copyright (C) 1991-2026 Free Software Foundation, Inc. Written by Fred Fish @ Cygnus Support, from information published in "UNIX System V Release 4, Programmers Guide: ANSI C and Programming Support Tools". This file is part of BFD, the Binary File Descriptor library. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. *//* This file is part of ELF support for BFD, and contains the portions that describe how ELF is represented externally by the BFD library. I.E. it describes the in-file representation of ELF. It requires the elf/common.h file which contains the portions that are common to both the internal and external representations. *//* The 64-bit stuff is kind of random. Perhaps someone will publish a spec someday. */#ifndef _ELF_EXTERNAL_H#define _ELF_EXTERNAL_H/* Special section indices, which may show up in st_shndx fields, among other places. */#define SHN_LORESERVE 0xFF00 /* Begin range of reserved indices */#define SHN_LOPROC 0xFF00 /* Begin range of appl-specific */#define SHN_HIPROC 0xFF1F /* End range of appl-specific */#define SHN_LOOS 0xFF20 /* OS specific semantics, lo */#define SHN_HIOS 0xFF3F /* OS specific semantics, hi */#define SHN_ABS 0xFFF1 /* Associated symbol is absolute */#define SHN_COMMON 0xFFF2 /* Associated symbol is in common */#define SHN_XINDEX 0xFFFF /* Section index is held elsewhere */#define SHN_HIRESERVE 0xFFFF /* End range of reserved indices *//* ELF Header (32-bit implementations) */typedef struct { unsigned char e_ident[16]; /* ELF "magic number" */ unsigned char e_type[2]; /* Identifies object file type */ unsigned char e_machine[2]; /* Specifies required architecture */ unsigned char e_version[4]; /* Identifies object file version */ unsigned char e_entry[4]; /* Entry point virtual address */ unsigned char e_phoff[4]; /* Program header table file offset */ unsigned char e_shoff[4]; /* Section header table file offset */ unsigned char e_flags[4]; /* Processor-specific flags */ unsigned char e_ehsize[2]; /* ELF header size in bytes */ unsigned char e_phentsize[2]; /* Program header table entry size */ unsigned char e_phnum[2]; /* Program header table entry count */ unsigned char e_shentsize[2]; /* Section header table entry size */ unsigned char e_shnum[2]; /* Section header table entry count */ unsigned char e_shstrndx[2]; /* Section header string table index */} Elf32_External_Ehdr;typedef struct { unsigned char e_ident[16]; /* ELF "magic number" */ unsigned char e_type[2]; /* Identifies object file type */ unsigned char e_machine[2]; /* Specifies required architecture */ unsigned char e_version[4]; /* Identifies object file version */ unsigned char e_entry[8]; /* Entry point virtual address */ unsigned char e_phoff[8]; /* Program header table file offset */ unsigned char e_shoff[8]; /* Section header table file offset */ unsigned char e_flags[4]; /* Processor-specific flags */ unsigned char e_ehsize[2]; /* ELF header size in bytes */ unsigned char e_phentsize[2]; /* Program header table entry size */ unsigned char e_phnum[2]; /* Program header table entry count */ unsigned char e_shentsize[2]; /* Section header table entry size */ unsigned char e_shnum[2]; /* Section header table entry count */ unsigned char e_shstrndx[2]; /* Section header string table index */} Elf64_External_Ehdr;/* Program header */typedef struct { unsigned char p_type[4]; /* Identifies program segment type */ unsigned char p_offset[4]; /* Segment file offset */ unsigned char p_vaddr[4]; /* Segment virtual address */ unsigned char p_paddr[4]; /* Segment physical address */ unsigned char p_filesz[4]; /* Segment size in file */ unsigned char p_memsz[4]; /* Segment size in memory */ unsigned char p_flags[4]; /* Segment flags */ unsigned char p_align[4]; /* Segment alignment, file & memory */} Elf32_External_Phdr;typedef struct { unsigned char p_type[4]; /* Identifies program segment type */ unsigned char p_flags[4]; /* Segment flags */ unsigned char p_offset[8]; /* Segment file offset */ unsigned char p_vaddr[8]; /* Segment virtual address */ unsigned char p_paddr[8]; /* Segment physical address */ unsigned char p_filesz[8]; /* Segment size in file */ unsigned char p_memsz[8]; /* Segment size in memory */ unsigned char p_align[8]; /* Segment alignment, file & memory */} Elf64_External_Phdr;/* Section header */typedef struct { unsigned char sh_name[4]; /* Section name, index in string tbl */ unsigned char sh_type[4]; /* Type of section */ unsigned char sh_flags[4]; /* Miscellaneous section attributes */ unsigned char sh_addr[4]; /* Section virtual addr at execution */ unsigned char sh_offset[4]; /* Section file offset */ unsigned char sh_size[4]; /* Size of section in bytes */ unsigned char sh_link[4]; /* Index of another section */ unsigned char sh_info[4]; /* Additional section information */ unsigned char sh_addralign[4]; /* Section alignment */ unsigned char sh_entsize[4]; /* Entry size if section holds table */} Elf32_External_Shdr;typedef struct { unsigned char sh_name[4]; /* Section name, index in string tbl */ unsigned char sh_type[4]; /* Type of section */ unsigned char sh_flags[8]; /* Miscellaneous section attributes */ unsigned char sh_addr[8]; /* Section virtual addr at execution */ unsigned char sh_offset[8]; /* Section file offset */ unsigned char sh_size[8]; /* Size of section in bytes */ unsigned char sh_link[4]; /* Index of another section */ unsigned char sh_info[4]; /* Additional section information */ unsigned char sh_addralign[8]; /* Section alignment */ unsigned char sh_entsize[8]; /* Entry size if section holds table */} Elf64_External_Shdr;/* Compression header */typedef struct { unsigned char ch_type[4]; /* Type of compression */ unsigned char ch_size[4]; /* Size of uncompressed data in bytes */ unsigned char ch_addralign[4]; /* Alignment of uncompressed data */} Elf32_External_Chdr;typedef struct { unsigned char ch_type[4]; /* Type of compression */ unsigned char ch_reserved[4]; /* Padding */ unsigned char ch_size[8]; /* Size of uncompressed data in bytes */ unsigned char ch_addralign[8]; /* Alignment of uncompressed data */} Elf64_External_Chdr;/* Symbol table entry */typedef struct { unsigned char st_name[4]; /* Symbol name, index in string tbl */ unsigned char st_value[4]; /* Value of the symbol */ unsigned char st_size[4]; /* Associated symbol size */ unsigned char st_info[1]; /* Type and binding attributes */ unsigned char st_other[1]; /* No defined meaning, 0 */ unsigned char st_shndx[2]; /* Associated section index */} Elf32_External_Sym;typedef struct { unsigned char st_name[4]; /* Symbol name, index in string tbl */ unsigned char st_info[1]; /* Type and binding attributes */ unsigned char st_other[1]; /* No defined meaning, 0 */ unsigned char st_shndx[2]; /* Associated section index */ unsigned char st_value[8]; /* Value of the symbol */ unsigned char st_size[8]; /* Associated symbol size */} Elf64_External_Sym;typedef struct { unsigned char est_shndx[4]; /* Section index */} Elf_External_Sym_Shndx;/* Note segments */typedef struct { unsigned char namesz[4]; /* Size of entry's owner string */ unsigned char descsz[4]; /* Size of the note descriptor */ unsigned char type[4]; /* Interpretation of the descriptor */ char name[1]; /* Start of the name+desc data */} Elf_External_Note;/* Align an address upward to a boundary, expressed as a number of bytes. E.g. align to an 8-byte boundary with argument of 8. */#define ELF_ALIGN_UP(addr, boundary) \ (((bfd_vma) (addr) + ((boundary) - 1)) & ~ (bfd_vma) ((boundary) -1))/* Compute the offset of the note descriptor from size of note entry's owner string and note alignment. */#define ELF_NOTE_DESC_OFFSET(namesz, align) \ ELF_ALIGN_UP (offsetof (Elf_External_Note, name) + (namesz), (align))/* Compute the offset of the next note entry from size of note entry's owner string, size of the note descriptor and note alignment. */#define ELF_NOTE_NEXT_OFFSET(namesz, descsz, align) \ ELF_ALIGN_UP (ELF_NOTE_DESC_OFFSET ((namesz), (align)) + (descsz), \ (align))/* Relocation Entries */typedef struct { unsigned char r_offset[4]; /* Location at which to apply the action */ unsigned char r_info[4]; /* index and type of relocation */} Elf32_External_Rel;typedef struct { unsigned char r_offset[4]; /* Location at which to apply the action */ unsigned char r_info[4]; /* index and type of relocation */ unsigned char r_addend[4]; /* Constant addend used to compute value */} Elf32_External_Rela;typedef struct { unsigned char r_data[4]; /* RELR entry */} Elf32_External_Relr;typedef struct { unsigned char r_offset[8]; /* Location at which to apply the action */ unsigned char r_info[8]; /* index and type of relocation */} Elf64_External_Rel;typedef struct { unsigned char r_offset[8]; /* Location at which to apply the action */ unsigned char r_info[8]; /* index and type of relocation */ unsigned char r_addend[8]; /* Constant addend used to compute value */} Elf64_External_Rela;typedef struct { unsigned char r_data[8]; /* RELR entry */} Elf64_External_Relr;/* dynamic section structure */typedef struct { unsigned char d_tag[4]; /* entry tag value */ union { unsigned char d_val[4]; unsigned char d_ptr[4]; } d_un;} Elf32_External_Dyn;typedef struct { unsigned char d_tag[8]; /* entry tag value */ union { unsigned char d_val[8]; unsigned char d_ptr[8]; } d_un;} Elf64_External_Dyn;/* The version structures are currently size independent. They are named without a 32 or 64. If that ever changes, these structures will need to be renamed. *//* This structure appears in a SHT_GNU_verdef section. */typedef struct { unsigned char vd_version[2]; unsigned char vd_flags[2]; unsigned char vd_ndx[2]; unsigned char vd_cnt[2]; unsigned char vd_hash[4]; unsigned char vd_aux[4]; unsigned char vd_next[4];} Elf_External_Verdef;/* This structure appears in a SHT_GNU_verdef section. */typedef struct { unsigned char vda_name[4]; unsigned char vda_next[4];} Elf_External_Verdaux;/* This structure appears in a SHT_GNU_verneed section. */typedef struct { unsigned char vn_version[2]; unsigned char vn_cnt[2]; unsigned char vn_file[4]; unsigned char vn_aux[4]; unsigned char vn_next[4];} Elf_External_Verneed;/* This structure appears in a SHT_GNU_verneed section. */typedef struct { unsigned char vna_hash[4]; unsigned char vna_flags[2]; unsigned char vna_other[2]; unsigned char vna_name[4]; unsigned char vna_next[4];} Elf_External_Vernaux;/* This structure appears in a SHT_GNU_versym section. This is not a standard ELF structure; ELF just uses Elf32_Half. */typedef struct { unsigned char vs_vers[2];} ATTRIBUTE_PACKED Elf_External_Versym;/* Structure for syminfo section. */typedef struct{ unsigned char si_boundto[2]; unsigned char si_flags[2];} Elf_External_Syminfo;/* This structure appears on the stack and in NT_AUXV core file notes. */typedef struct{ unsigned char a_type[4]; unsigned char a_val[4];} Elf32_External_Auxv;typedef struct{ unsigned char a_type[8]; unsigned char a_val[8];} Elf64_External_Auxv;/* Size of SHT_GROUP section entry. */#define GRP_ENTRY_SIZE 4#endif /* _ELF_EXTERNAL_H */
/* ELF support for BFD.
Copyright (C) 1991-2026 Free Software Foundation, Inc.
Written by Fred Fish @ Cygnus Support, from information published
in "UNIX System V Release 4, Programmers Guide: ANSI C and
Programming Support Tools".
This file is part of BFD, the Binary File Descriptor library.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
/* This file is part of ELF support for BFD, and contains the portions
that describe how ELF is represented externally by the BFD library.
I.E. it describes the in-file representation of ELF. It requires
the elf/common.h file which contains the portions that are common to
both the internal and external representations. */
/* The 64-bit stuff is kind of random. Perhaps someone will publish a
spec someday. */
#ifndef _ELF_EXTERNAL_H
#define _ELF_EXTERNAL_H
/* Special section indices, which may show up in st_shndx fields, among
other places. */
#define SHN_LORESERVE 0xFF00 /* Begin range of reserved indices */
#define SHN_LOPROC 0xFF00 /* Begin range of appl-specific */
#define SHN_HIPROC 0xFF1F /* End range of appl-specific */
#define SHN_LOOS 0xFF20 /* OS specific semantics, lo */
#define SHN_HIOS 0xFF3F /* OS specific semantics, hi */
#define SHN_ABS 0xFFF1 /* Associated symbol is absolute */
#define SHN_COMMON 0xFFF2 /* Associated symbol is in common */
#define SHN_XINDEX 0xFFFF /* Section index is held elsewhere */
#define SHN_HIRESERVE 0xFFFF /* End range of reserved indices */
/* ELF Header (32-bit implementations) */
typedef struct {
unsigned char e_ident[16]; /* ELF "magic number" */
unsigned char e_type[2]; /* Identifies object file type */
unsigned char e_machine[2]; /* Specifies required architecture */
unsigned char e_version[4]; /* Identifies object file version */
unsigned char e_entry[4]; /* Entry point virtual address */
unsigned char e_phoff[4]; /* Program header table file offset */
unsigned char e_shoff[4]; /* Section header table file offset */
unsigned char e_flags[4]; /* Processor-specific flags */
unsigned char e_ehsize[2]; /* ELF header size in bytes */
unsigned char e_phentsize[2]; /* Program header table entry size */
unsigned char e_phnum[2]; /* Program header table entry count */
unsigned char e_shentsize[2]; /* Section header table entry size */
unsigned char e_shnum[2]; /* Section header table entry count */
unsigned char e_shstrndx[2]; /* Section header string table index */
} Elf32_External_Ehdr;
typedef struct {
unsigned char e_ident[16]; /* ELF "magic number" */
unsigned char e_type[2]; /* Identifies object file type */
unsigned char e_machine[2]; /* Specifies required architecture */
unsigned char e_version[4]; /* Identifies object file version */
unsigned char e_entry[8]; /* Entry point virtual address */
unsigned char e_phoff[8]; /* Program header table file offset */
unsigned char e_shoff[8]; /* Section header table file offset */
unsigned char e_flags[4]; /* Processor-specific flags */
unsigned char e_ehsize[2]; /* ELF header size in bytes */
unsigned char e_phentsize[2]; /* Program header table entry size */
unsigned char e_phnum[2]; /* Program header table entry count */
unsigned char e_shentsize[2]; /* Section header table entry size */
unsigned char e_shnum[2]; /* Section header table entry count */
unsigned char e_shstrndx[2]; /* Section header string table index */
} Elf64_External_Ehdr;
/* Program header */
typedef struct {
unsigned char p_type[4]; /* Identifies program segment type */
unsigned char p_offset[4]; /* Segment file offset */
unsigned char p_vaddr[4]; /* Segment virtual address */
unsigned char p_paddr[4]; /* Segment physical address */
unsigned char p_filesz[4]; /* Segment size in file */
unsigned char p_memsz[4]; /* Segment size in memory */
unsigned char p_flags[4]; /* Segment flags */
unsigned char p_align[4]; /* Segment alignment, file & memory */
} Elf32_External_Phdr;
typedef struct {
unsigned char p_type[4]; /* Identifies program segment type */
unsigned char p_flags[4]; /* Segment flags */
unsigned char p_offset[8]; /* Segment file offset */
unsigned char p_vaddr[8]; /* Segment virtual address */
unsigned char p_paddr[8]; /* Segment physical address */
unsigned char p_filesz[8]; /* Segment size in file */
unsigned char p_memsz[8]; /* Segment size in memory */
unsigned char p_align[8]; /* Segment alignment, file & memory */
} Elf64_External_Phdr;
/* Section header */
typedef struct {
unsigned char sh_name[4]; /* Section name, index in string tbl */
unsigned char sh_type[4]; /* Type of section */
unsigned char sh_flags[4]; /* Miscellaneous section attributes */
unsigned char sh_addr[4]; /* Section virtual addr at execution */
unsigned char sh_offset[4]; /* Section file offset */
unsigned char sh_size[4]; /* Size of section in bytes */
unsigned char sh_link[4]; /* Index of another section */
unsigned char sh_info[4]; /* Additional section information */
unsigned char sh_addralign[4]; /* Section alignment */
unsigned char sh_entsize[4]; /* Entry size if section holds table */
} Elf32_External_Shdr;
typedef struct {
unsigned char sh_name[4]; /* Section name, index in string tbl */
unsigned char sh_type[4]; /* Type of section */
unsigned char sh_flags[8]; /* Miscellaneous section attributes */
unsigned char sh_addr[8]; /* Section virtual addr at execution */
unsigned char sh_offset[8]; /* Section file offset */
unsigned char sh_size[8]; /* Size of section in bytes */
unsigned char sh_link[4]; /* Index of another section */
unsigned char sh_info[4]; /* Additional section information */
unsigned char sh_addralign[8]; /* Section alignment */
unsigned char sh_entsize[8]; /* Entry size if section holds table */
} Elf64_External_Shdr;
/* Compression header */
typedef struct {
unsigned char ch_type[4]; /* Type of compression */
unsigned char ch_size[4]; /* Size of uncompressed data in bytes */
unsigned char ch_addralign[4]; /* Alignment of uncompressed data */
} Elf32_External_Chdr;
typedef struct {
unsigned char ch_type[4]; /* Type of compression */
unsigned char ch_reserved[4]; /* Padding */
unsigned char ch_size[8]; /* Size of uncompressed data in bytes */
unsigned char ch_addralign[8]; /* Alignment of uncompressed data */
} Elf64_External_Chdr;
/* Symbol table entry */
typedef struct {
unsigned char st_name[4]; /* Symbol name, index in string tbl */
unsigned char st_value[4]; /* Value of the symbol */
unsigned char st_size[4]; /* Associated symbol size */
unsigned char st_info[1]; /* Type and binding attributes */
unsigned char st_other[1]; /* No defined meaning, 0 */
unsigned char st_shndx[2]; /* Associated section index */
} Elf32_External_Sym;
typedef struct {
unsigned char st_name[4]; /* Symbol name, index in string tbl */
unsigned char st_info[1]; /* Type and binding attributes */
unsigned char st_other[1]; /* No defined meaning, 0 */
unsigned char st_shndx[2]; /* Associated section index */
unsigned char st_value[8]; /* Value of the symbol */
unsigned char st_size[8]; /* Associated symbol size */
} Elf64_External_Sym;
typedef struct {
unsigned char est_shndx[4]; /* Section index */
} Elf_External_Sym_Shndx;
/* Note segments */
typedef struct {
unsigned char namesz[4]; /* Size of entry's owner string */
unsigned char descsz[4]; /* Size of the note descriptor */
unsigned char type[4]; /* Interpretation of the descriptor */
char name[1]; /* Start of the name+desc data */
} Elf_External_Note;
/* Align an address upward to a boundary, expressed as a number of bytes.
E.g. align to an 8-byte boundary with argument of 8. */
#define ELF_ALIGN_UP(addr, boundary) \
(((bfd_vma) (addr) + ((boundary) - 1)) & ~ (bfd_vma) ((boundary) -1))
/* Compute the offset of the note descriptor from size of note entry's
owner string and note alignment. */
#define ELF_NOTE_DESC_OFFSET(namesz, align) \
ELF_ALIGN_UP (offsetof (Elf_External_Note, name) + (namesz), (align))
/* Compute the offset of the next note entry from size of note entry's
owner string, size of the note descriptor and note alignment. */
#define ELF_NOTE_NEXT_OFFSET(namesz, descsz, align) \
ELF_ALIGN_UP (ELF_NOTE_DESC_OFFSET ((namesz), (align)) + (descsz), \
(align))
/* Relocation Entries */
typedef struct {
unsigned char r_offset[4]; /* Location at which to apply the action */
unsigned char r_info[4]; /* index and type of relocation */
} Elf32_External_Rel;
typedef struct {
unsigned char r_offset[4]; /* Location at which to apply the action */
unsigned char r_info[4]; /* index and type of relocation */
unsigned char r_addend[4]; /* Constant addend used to compute value */
} Elf32_External_Rela;
typedef struct {
unsigned char r_data[4]; /* RELR entry */
} Elf32_External_Relr;
typedef struct {
unsigned char r_offset[8]; /* Location at which to apply the action */
unsigned char r_info[8]; /* index and type of relocation */
} Elf64_External_Rel;
typedef struct {
unsigned char r_offset[8]; /* Location at which to apply the action */
unsigned char r_info[8]; /* index and type of relocation */
unsigned char r_addend[8]; /* Constant addend used to compute value */
} Elf64_External_Rela;
typedef struct {
unsigned char r_data[8]; /* RELR entry */
} Elf64_External_Relr;
/* dynamic section structure */
typedef struct {
unsigned char d_tag[4]; /* entry tag value */
union {
unsigned char d_val[4];
unsigned char d_ptr[4];
} d_un;
} Elf32_External_Dyn;
typedef struct {
unsigned char d_tag[8]; /* entry tag value */
union {
unsigned char d_val[8];
unsigned char d_ptr[8];
} d_un;
} Elf64_External_Dyn;
/* The version structures are currently size independent. They are
named without a 32 or 64. If that ever changes, these structures
will need to be renamed. */
/* This structure appears in a SHT_GNU_verdef section. */
typedef struct {
unsigned char vd_version[2];
unsigned char vd_flags[2];
unsigned char vd_ndx[2];
unsigned char vd_cnt[2];
unsigned char vd_hash[4];
unsigned char vd_aux[4];
unsigned char vd_next[4];
} Elf_External_Verdef;
/* This structure appears in a SHT_GNU_verdef section. */
typedef struct {
unsigned char vda_name[4];
unsigned char vda_next[4];
} Elf_External_Verdaux;
/* This structure appears in a SHT_GNU_verneed section. */
typedef struct {
unsigned char vn_version[2];
unsigned char vn_cnt[2];
unsigned char vn_file[4];
unsigned char vn_aux[4];
unsigned char vn_next[4];
} Elf_External_Verneed;
/* This structure appears in a SHT_GNU_verneed section. */
typedef struct {
unsigned char vna_hash[4];
unsigned char vna_flags[2];
unsigned char vna_other[2];
unsigned char vna_name[4];
unsigned char vna_next[4];
} Elf_External_Vernaux;
/* This structure appears in a SHT_GNU_versym section. This is not a
standard ELF structure; ELF just uses Elf32_Half. */
typedef struct {
unsigned char vs_vers[2];
} ATTRIBUTE_PACKED Elf_External_Versym;
/* Structure for syminfo section. */
typedef struct
{
unsigned char si_boundto[2];
unsigned char si_flags[2];
} Elf_External_Syminfo;
/* This structure appears on the stack and in NT_AUXV core file notes. */
typedef struct
{
unsigned char a_type[4];
unsigned char a_val[4];
} Elf32_External_Auxv;
typedef struct
{
unsigned char a_type[8];
unsigned char a_val[8];
} Elf64_External_Auxv;
/* Size of SHT_GROUP section entry. */
#define GRP_ENTRY_SIZE 4
#endif /* _ELF_EXTERNAL_H */