====== Executable and Linking Format (ELF) ======

**Executable and Linking Format** (ELF): [[https://de.wikipedia.org/wiki/Executable_and_Linking_Format]] (außerdem: a.out, COFF, COM, ECOFF, ELF, Hunk, Mach-O, MZ, NE, OMF, PE, PEF, XCOFF)

Das **ELF**-Binärformat: [[http://www.linux-kernel.de/appendix/ap05.pdf]] - Doku: Aufbau und Struktur, ELF-Header.

ELF Header: [[http://www.sco.com/developers/gabi/latest/ch4.eheader.html]] - mit ausführlicher Beschreibung von **e_type**, **e_machine**, **EI_OSABI**, etc.

Linux Programmer's Manual:
  * [[http://man7.org/linux/man-pages/man5/elf.5.html|elf(5)]] - Header %%<elf.h>%%
  * [[http://man7.org/linux/man-pages/man1/readelf.1.html|readelf(1)]] - Displays information about ELF files.


===== Datentypen =====

**%%<elf.h>%%**

<code c>
/* 32-bit ELF base types. */
typedef uint16_t	Elf32_Half;
typedef uint32_t	Elf32_Word;
typedef int32_t		Elf32_Sword;
typedef uint64_t	Elf32_Xword;
typedef int64_t		Elf32_Sxword;
typedef uint32_t	Elf32_Addr;
typedef uint32_t	Elf32_Off;
typedef uint16_t	Elf32_Section;
typedef Elf32_Half	Elf32_Versym;

/* 64-bit ELF base types. */
typedef uint16_t	Elf64_Half;
typedef uint32_t	Elf64_Word;
typedef int32_t		Elf64_Sword;
typedef uint64_t	Elf64_Xword;
typedef int64_t		Elf64_Sxword;
typedef uint64_t	Elf64_Addr;
typedef uint64_t	Elf64_Off;
typedef uint16_t	Elf64_Section;
typedef Elf64_Half	Elf64_Versym;
</code>

===== ELF-Header =====

(aus %%<elf.h>%%)

Auf 32-Bit-Architekturen:

<code c>
#define EI_NIDENT 16

typedef struct elf32_hdr
{
	unsigned char	e_ident[EI_NIDENT];
	Elf32_Half	e_type;
	Elf32_Half	e_machine;
	Elf32_Word	e_version;
	Elf32_Addr	e_entry;	/* Entry point */
	Elf32_Off	e_phoff;
	Elf32_Off	e_shoff;
	Elf32_Word	e_flags;
	Elf32_Half	e_ehsize;
	Elf32_Half	e_phentsize;
	Elf32_Half	e_phnum;
	Elf32_Half	e_shentsize;
	Elf32_Half	e_shnum;
	Elf32_Half	e_shstrndx;
} Elf32_Ehdr;
</code>

Auf 64-Bit-Architekturen:

<code c>
#define EI_NIDENT 16

typedef struct elf64_hdr
{
	unsigned char	e_ident[EI_NIDENT];	/* ELF magic number */
	Elf64_Half	e_type;
	Elf64_Half	e_machine;
	Elf64_Word	e_version;
	Elf64_Addr	e_entry;	/* Entry point virtual address */
	Elf64_Off	e_phoff;	/* Program header table file offset */
	Elf64_Off	e_shoff;	/* Section header table file offset */
	Elf64_Word	e_flags;
	Elf64_Half	e_ehsize;
	Elf64_Half	e_phentsize;
	Elf64_Half	e_phnum;
	Elf64_Half	e_shentsize;
	Elf64_Half	e_shnum;
	Elf64_Half	e_shstrndx;
} Elf64_Ehdr;
</code>

===== Weitere Infos =====

Redirecting functions in shared ELF libraries: [[http://www.codeproject.com/Articles/70302/Redirecting-functions-in-shared-ELF-libraries]]

----
Stand: 12.09.2016\\ 
 --- //[[feedback.jk-wiki@kreick.de|: Jürgen Kreick]]//

EOF