elf.h

#pragma once
#include <stdint.h>
#include <ctype.h>
#include <stdio.h>

const int EI_NIDENT = 16;

#define PF_X		(1 << 0)	/* Segment is executable */
#define PF_W		(1 << 1)	/* Segment is writable */
#define PF_R		(1 << 2)	/* Segment is readable */

#define PT_DYNAMIC 2
/*
 * ELF definitions common to all 64-bit architectures.
 */

typedef uint64_t	Elf64_Addr;
typedef uint16_t	Elf64_Half;
typedef uint64_t	Elf64_Off;
typedef int32_t		Elf64_Sword;
typedef int64_t		Elf64_Sxword;
typedef uint32_t	Elf64_Word;
typedef uint64_t	Elf64_Lword;
typedef uint64_t	Elf64_Xword;

/*
 * Types of dynamic symbol hash table bucket and chain elements.
 *
 * This is inconsistent among 64 bit architectures, so a machine dependent
 * typedef is required.
 */

typedef Elf64_Word	Elf64_Hashelt;

/* Non-standard class-dependent datatype used for abstraction. */
typedef Elf64_Xword	Elf64_Size;
typedef Elf64_Sxword	Elf64_Ssize;

typedef struct {
	unsigned char	e_ident[EI_NIDENT];	/* File identification. */
	Elf64_Half	e_type;		/* File type. */
	Elf64_Half	e_machine;	/* Machine architecture. */
	Elf64_Word	e_version;	/* ELF format version. */
	Elf64_Addr	e_entry;	/* Entry point. */
	Elf64_Off	e_phoff;	/* Program header file offset. */
	Elf64_Off	e_shoff;	/* Section header file offset. */
	Elf64_Word	e_flags;	/* Architecture-specific flags. */
	Elf64_Half	e_ehsize;	/* Size of ELF header in bytes. */
	Elf64_Half	e_phentsize;	/* Size of program header entry. */
	Elf64_Half	e_phnum;	/* Number of program header entries. */
	Elf64_Half	e_shentsize;	/* Size of section header entry. */
	Elf64_Half	e_shnum;	/* Number of section header entries. */
	Elf64_Half	e_shstrndx;	/* Section name strings section. */
} Elf64_Ehdr;

typedef struct {
	Elf64_Word	p_type;		/* Entry type. */
	Elf64_Word	p_flags;	/* Access permission flags. */
	Elf64_Off	p_offset;	/* File offset of contents. */
	Elf64_Addr	p_vaddr;	/* Virtual address in memory image. */
	Elf64_Addr	p_paddr;	/* Physical address (not used). */
	Elf64_Xword	p_filesz;	/* Size of contents in file. */
	Elf64_Xword	p_memsz;	/* Size of contents in memory. */
	Elf64_Xword	p_align;	/* Alignment in memory and file. */
} Elf64_Phdr;

typedef struct {
	Elf64_Sxword	d_tag;		/* Entry type. */
	union {
		Elf64_Xword	d_val;	/* Integer value. */
		Elf64_Addr	d_ptr;	/* Address value. */
	} d_un;
} Elf64_Dyn;

struct Elf64_Sym {
  Elf64_Word st_name;     // Symbol name (index into string table)
  unsigned char st_info;  // Symbol's type and binding attributes
  unsigned char st_other; // Must be zero; reserved
  Elf64_Half st_shndx;    // Which section (header tbl index) it's defined in
  Elf64_Addr st_value;    // Value or address associated with the symbol
  Elf64_Xword st_size;    // Size of the symbol
};

// Relocation entry with explicit addend.
struct Elf64_Rela {
  Elf64_Addr r_offset; // Location (file byte offset, or program virtual addr).
  Elf64_Xword r_info;  // Symbol table index and type of relocation to apply.
  Elf64_Sxword r_addend; // Compute value for relocatable field by adding this.

  // These accessors and mutators correspond to the ELF64_R_SYM, ELF64_R_TYPE,
  // and ELF64_R_INFO macros defined in the ELF specification:
  Elf64_Word getSymbol() const { return (r_info >> 32); }
  Elf64_Word getType() const { return (Elf64_Word)(r_info & 0xffffffffL); }
  void setSymbol(Elf64_Word s) { setSymbolAndType(s, getType()); }
  void setType(Elf64_Word t) { setSymbolAndType(getSymbol(), t); }
  void setSymbolAndType(Elf64_Word s, Elf64_Word t) {
    r_info = ((Elf64_Xword)s << 32) + (t & 0xffffffffL);
  }
};