/** * @file elf.h * @author K. Lange * * @copyright Copyright in this work is disclaimed under the assertion * that its contents are purely factual and no rights may be reserved * for its use. * * @brief Structures for Elf binary files. * * Based primarily on the Elf and SysV ABI specification documents. * * @see https://uclibc.org/docs/elf-64-gen.pdf * @see https://refspecs.linuxfoundation.org/elf/x86_64-abi-0.99.pdf */ #pragma once #include /** * @typedef Elf64_Addr * @brief Unsigned program address. (uintptr_t) * @typedef Elf64_Off * @brief Unsigned file offset. (size_t) * @typedef Elf64_Half * @brief Unsigned medium integer. (unsigned short) * @typedef Elf64_Word * @brief Unsigned integer. (unsigned int) * @typedef Elf64_Sword * @brief Signed integer. (int) * @typedef Elf64_Xword * @brief Unsigned long integer. (unsigned long long) * @typedef Elf64_Sxword * @brief Signed long integer. (long long) */ typedef uint64_t Elf64_Addr; typedef uint64_t Elf64_Off; 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; /** * Values for e_ident[EI_MAGn] */ #define ELFMAG0 0x7f #define ELFMAG1 'E' #define ELFMAG2 'L' #define ELFMAG3 'F' /** * Values for e_ident[EI_CLASS] */ #define ELFCLASS32 1 #define ELFCLASS64 2 /** * Values for e_ident[EI_DATA] */ #define ELFDATA2LSB 1 #define ELFDATA2MSB 2 /** * Values for e_type */ #define ET_NONE 0 #define ET_REL 1 #define ET_EXEC 2 #define ET_DYN 3 #define ET_CORE 4 /** * e_ident fields */ #define EI_MAG0 0 #define EI_MAG1 1 #define EI_MAG2 2 #define EI_MAG3 3 #define EI_CLASS 4 #define EI_DATA 5 #define EI_VERSION 6 #define EI_OSABI 7 #define EI_ABIVERSION 8 #define EI_PAD 9 #define EI_NIDENT 16 #define EM_X86_64 62 /** * @brief Elf object file header. */ typedef struct Elf64_Header { uint8_t e_ident[EI_NIDENT]; /**< @brief Identifies the layout of the rest of the file. */ Elf64_Half e_type; /**< @brief What kind of file this is, eg. object or executable... */ Elf64_Half e_machine; /**< @brief The architecture this file is for. */ Elf64_Word e_version; /**< @brief The version of the standard this file confirms to. */ Elf64_Addr e_entry; /**< @brief The entry point of an executable. */ Elf64_Off e_phoff; /**< @brief The offset of the program headers. */ Elf64_Off e_shoff; /**< @brief The offset of the section headers. */ Elf64_Word e_flags; /**< @brief Various flags. */ Elf64_Half e_ehsize; /**< @brief Size of this header. */ Elf64_Half e_phentsize; /**< @brief Size of one program header table entry. */ Elf64_Half e_phnum; /**< @brief The number of entries in the program header table. */ Elf64_Half e_shentsize; /**< @brief Size of one section header table entry. */ Elf64_Half e_shnum; /**< @brief The number of entries in the section header table. */ Elf64_Half e_shstrndx; } Elf64_Header; /** * Special section indices */ #define SHN_UNDEF 0 #define SHN_LOPROC 0xFF00 #define SHN_HIPROC 0xFF1F #define SHN_LOOS 0xFF20 #define SHN_HIOS 0xFF3F #define SHN_ABS 0xFFF1 #define SHN_COMMON 0xFFF2 /** * Values for sh_type, sh_link, sh_info */ #define SHT_NULL 0 #define SHT_PROGBITS 1 #define SHT_SYMTAB 2 #define SHT_STRTAB 3 #define SHT_RELA 4 #define SHT_HASH 5 #define SHT_DYNAMIC 6 #define SHT_NOTE 7 #define SHT_NOBITS 8 #define SHT_REL 9 #define SHT_SHLIB 10 #define SHT_DYNSYM 11 #define SHT_LOOS 0x60000000 #define SHT_HIOS 0x6FFFFFFF #define SHT_LOPROC 0x70000000 #define SHT_HIPROC 0x7FFFFFFF /** * Values for sh_flags */ #define SHF_WRITE 0x00000001 #define SHF_ALLOC 0x00000002 #define SHF_EXECINSTR 0x00000004 #define SHF_MASKOS 0x0F000000 #define SHF_MASKPROC 0xF0000000 /* From the SysV x86-64 ABI */ #define SHF_X86_64_LARGE 0x10000000 #define SHF_X86_64_UNWIND 0x70000001 typedef struct Elf64_Shdr { Elf64_Word sh_name; Elf64_Word sh_type; Elf64_Xword sh_flags; Elf64_Addr sh_addr; Elf64_Off sh_offset; Elf64_Xword sh_size; Elf64_Word sh_link; Elf64_Word sh_info; Elf64_Xword sh_addralign; Elf64_Xword sh_entsize; } Elf64_Shdr; /** * Binding types. * Contained in the high four bits of @p st_info */ #define STB_LOCAL 0 /**< @brief Not visible outside the object file. */ #define STB_GLOBAL 1 /**< @brief Global symbol, visible to all object files. */ #define STB_WEAK 2 /**< @brief Global scope, but with lower precedence than global symbols. */ #define STB_LOOS 10 #define STB_HIOS 12 #define STB_LOPROC 13 #define STB_HIPROC 15 /** * Symbol types. * Contained in the low four bits of @p st_info */ #define STT_NOTYPE 0 /**< @brief No type specified (e.g., an absolute symbol) */ #define STT_OBJECT 1 /**< @brief Data object */ #define STT_FUNC 2 /**< @brief Function entry point */ #define STT_SECTION 3 /**< @brief Symbol is associated with a section */ #define STT_FILE 4 /**< @brief Source file associated with the object */ #define STT_LOOS 10 #define STT_HIOS 12 #define STT_LOPROC 13 #define STT_HIPROC 15 typedef struct Elf64_Sym { Elf64_Word st_name; /**< @brief Symbol name */ unsigned char st_info; /**< @brief Type and binding attributes */ unsigned char st_other; /**< @brief Reserved */ Elf64_Half st_shndx; /**< @brief Section table index */ Elf64_Addr st_value; /**< @brief Symbol value */ Elf64_Xword st_size; /**< @brief Size of object (e.g., common) */ } Elf64_Sym; /** * Relocations */ #define ELF64_R_SYM(i) ((i) >> 32) #define ELF64_R_TYPE(i) ((i) & 0xFFFFFFFFL) #define ELF64_R_INFO(s,t) (((s) << 32) + ((t) & 0xFFFFFFFFL)) typedef struct Elf64_Rel { Elf64_Addr r_offset; /**< @brief Address of reference */ Elf64_Xword r_info; /**< @brief Symbol index and type of relocation */ } Elf64_Rel; typedef struct Elf64_Rela { Elf64_Addr r_offset; /**< @brief Address of reference */ Elf64_Xword r_info; /**< @brief Symbol index and type of relocation */ Elf64_Sxword r_addend; /**< @brief Constant part of expression */ } Elf64_Rela; /** * x86-64 SysV Relocation types */ #define R_X86_64_NONE 0 /**< @brief @p none none */ #define R_X86_64_64 1 /**< @brief @p word64 S + A */ #define R_X86_64_PC32 2 /**< @brief @p word32 S + A - P */ #define R_X86_64_GOT32 3 /**< @brief @p word32 G + A */ #define R_X86_64_PLT32 4 /**< @brief @p word32 L + A - P */ #define R_X86_64_COPY 5 /**< @brief @p none none */ #define R_X86_64_GLOB_DAT 6 /**< @brief @p word64 S */ #define R_X86_64_JUMP_SLOT 7 /**< @brief @p word64 S */ #define R_X86_64_RELATIVE 8 /**< @brief @p word64 B + A */ #define R_X86_64_GOTPCREL 9 /**< @brief @p word32 G + GOT + A - P */ #define R_X86_64_32 10 /**< @brief @p word32 S + A */ #define R_X86_64_32S 11 /**< @brief @p word32 S + A */ /* vvv These should not appear in a valid file */ #define R_X86_64_16 12 /**< @brief @p word16 S + A */ #define R_X86_64_PC16 13 /**< @brief @p word16 S + A - P */ #define R_X86_64_8 14 /**< @brief @p word8 S + A */ #define R_X86_64_PC8 15 /**< @brief @p word8 S + A - P */ /* ^^^ These should not appear in a valid file */ #define R_X86_64_DTPMOD64 16 /**< @brief @p word64 */ #define R_X86_64_DTPOFF64 17 /**< @brief @p word64 */ #define R_X86_64_TPOFF64 18 /**< @brief @p word64 */ #define R_X86_64_TLSGD 19 /**< @brief @p word32 */ #define R_X86_64_TLSLD 20 /**< @brief @p word32 */ #define R_X86_64_DTPOFF32 21 /**< @brief @p word32 */ #define R_X86_64_GOTTPOFF 22 /**< @brief @p word32 */ #define R_X86_64_TPOFF32 23 /**< @brief @p word32 */ #define R_X86_64_PC64 24 /**< @brief @p word64 S + A - P */ #define R_X86_64_GOTOFF64 25 /**< @brief @p word64 S + A - GOT */ #define R_X86_64_GOTPC32 26 /**< @brief @p word32 GOT + A - P */ /* Large model */ #define R_X86_64_GOT64 27 /**< @brief @p word64 G + A */ #define R_X86_64_GOTPCREL64 28 /**< @brief @p word64 G + GOT - P + A */ #define R_X86_64_GOTPC64 29 /**< @brief @p word64 GOT - P + A */ #define R_X86_64_GOTPLT64 30 /**< @brief @p word64 G + A */ #define R_X86_64_PLTOFF64 31 /**< @brief @p word64 L - GOT + A */ /* ... */ #define R_X86_64_SIZE32 32 /**< @brief @p word32 Z + A */ #define R_X86_64_SIZE64 33 /**< @brief @p word64 Z + A */ #define R_X86_64_GOTPC32_TLSDESC 34 /**< @brief @p word32 */ #define R_X86_64_TLSDESC_CALL 35 /**< @brief @p none */ #define R_X86_64_TLSDESC 36 /**< @brief @p word64*2 */ #define R_X86_64_IRELATIVE 37 /**< @brief @p word64 indirect (B + A) */ /** * Program header types */ #define PT_NULL 0 #define PT_LOAD 1 #define PT_DYNAMIC 2 #define PT_INTERP 3 #define PT_NOTE 4 #define PT_SHLIB 5 #define PT_PHDR 6 #define PT_TLS 7 #define PT_LOOS 0x60000000 #define PT_HIOS 0x6FFFFFFF #define PT_LOPROC 0x70000000 #define PT_HIPROC 0x7FFFFFFF /* From the SysV x86-64 ABI */ #define PT_GNU_EH_FRAME 0x6474e550 #define PT_SUNW_EH_FRAME 0x6474e550 #define PT_SUNW_UNWIND 0x6464e550 /** * Program header flags */ #define PF_X 0x01 #define PF_W 0x02 #define PF_R 0x04 #define PF_MASKOS 0x00FF0000 #define PF_MAKSPROC 0xFF000000 typedef struct Elf64_Phdr { Elf64_Word p_type; Elf64_Word p_flags; Elf64_Off p_offset; Elf64_Addr p_vaddr; Elf64_Addr p_paddr; Elf64_Xword p_filesz; Elf64_Xword p_memsz; Elf64_Xword p_align; } Elf64_Phdr; /** * Dynamic table */ #define DT_NULL 0 #define DT_NEEDED 1 #define DT_PLTRELSZ 2 #define DT_PLTGOT 3 #define DT_HASH 4 #define DT_STRTAB 5 #define DT_SYMTAB 6 #define DT_RELA 7 #define DT_RELASZ 8 #define DT_RELAENT 9 #define DT_STRSZ 10 #define DT_SYMENT 11 #define DT_INIT 12 #define DT_FINI 13 #define DT_SONAME 14 #define DT_RPATH 15 #define DT_SYMBOLIC 16 #define DT_REL 17 #define DT_RELSZ 18 #define DT_RELENT 19 #define DT_PLTREL 20 #define DT_DEBUG 21 #define DT_TEXTREL 22 #define DT_JMPREL 23 #define DT_BIND_NOW 24 #define DT_INIT_ARRAY 25 #define DT_FINI_ARRAY 26 #define DT_INIT_ARRAYSZ 27 #define DT_FINI_ARRAYSZ 28 #define DT_LOOS 0x60000000 #define DT_HIOS 0x6FFFFFFF #define DT_LOPROC 0x70000000 #define DT_HIPROC 0x7FFFFFFF typedef struct Elf64_Dyn { Elf64_Sxword d_tag; union { Elf64_Xword d_val; Elf64_Addr d_ptr; } d_un; } Elf64_Dyn;