354 lines
11 KiB
C
354 lines
11 KiB
C
/**
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* @file elf.h
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* @author K. Lange
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*
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* @copyright Copyright in this work is disclaimed under the assertion
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* that its contents are purely factual and no rights may be reserved
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* for its use.
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*
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* @brief Structures for Elf binary files.
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*
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* Based primarily on the Elf and SysV ABI specification documents.
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*
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* @see https://uclibc.org/docs/elf-64-gen.pdf
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* @see https://refspecs.linuxfoundation.org/elf/x86_64-abi-0.99.pdf
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*/
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#pragma once
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#include <stdint.h>
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/**
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* @typedef Elf64_Addr
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* @brief Unsigned program address. (uintptr_t)
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* @typedef Elf64_Off
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* @brief Unsigned file offset. (size_t)
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* @typedef Elf64_Half
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* @brief Unsigned medium integer. (unsigned short)
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* @typedef Elf64_Word
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* @brief Unsigned integer. (unsigned int)
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* @typedef Elf64_Sword
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* @brief Signed integer. (int)
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* @typedef Elf64_Xword
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* @brief Unsigned long integer. (unsigned long long)
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* @typedef Elf64_Sxword
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* @brief Signed long integer. (long long)
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*/
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typedef uint64_t Elf64_Addr;
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typedef uint64_t Elf64_Off;
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typedef uint16_t Elf64_Half;
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typedef uint32_t Elf64_Word;
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typedef int32_t Elf64_Sword;
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typedef uint64_t Elf64_Xword;
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typedef int64_t Elf64_Sxword;
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/**
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* Values for e_ident[EI_MAGn]
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*/
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#define ELFMAG0 0x7f
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#define ELFMAG1 'E'
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#define ELFMAG2 'L'
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#define ELFMAG3 'F'
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/**
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* Values for e_ident[EI_CLASS]
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*/
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#define ELFCLASS32 1
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#define ELFCLASS64 2
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/**
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* Values for e_ident[EI_DATA]
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*/
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#define ELFDATA2LSB 1
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#define ELFDATA2MSB 2
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/**
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* Values for e_type
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*/
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#define ET_NONE 0
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#define ET_REL 1
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#define ET_EXEC 2
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#define ET_DYN 3
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#define ET_CORE 4
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/**
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* e_ident fields
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*/
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#define EI_MAG0 0
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#define EI_MAG1 1
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#define EI_MAG2 2
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#define EI_MAG3 3
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#define EI_CLASS 4
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#define EI_DATA 5
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#define EI_VERSION 6
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#define EI_OSABI 7
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#define EI_ABIVERSION 8
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#define EI_PAD 9
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#define EI_NIDENT 16
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#define EM_X86_64 62
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/**
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* @brief Elf object file header.
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*/
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typedef struct Elf64_Header {
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uint8_t e_ident[EI_NIDENT]; /**< @brief Identifies the layout of the rest of the file. */
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Elf64_Half e_type; /**< @brief What kind of file this is, eg. object or executable... */
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Elf64_Half e_machine; /**< @brief The architecture this file is for. */
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Elf64_Word e_version; /**< @brief The version of the standard this file confirms to. */
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Elf64_Addr e_entry; /**< @brief The entry point of an executable. */
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Elf64_Off e_phoff; /**< @brief The offset of the program headers. */
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Elf64_Off e_shoff; /**< @brief The offset of the section headers. */
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Elf64_Word e_flags; /**< @brief Various flags. */
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Elf64_Half e_ehsize; /**< @brief Size of this header. */
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Elf64_Half e_phentsize; /**< @brief Size of one program header table entry. */
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Elf64_Half e_phnum; /**< @brief The number of entries in the program header table. */
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Elf64_Half e_shentsize; /**< @brief Size of one section header table entry. */
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Elf64_Half e_shnum; /**< @brief The number of entries in the section header table. */
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Elf64_Half e_shstrndx;
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} Elf64_Header;
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/**
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* Special section indices
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*/
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#define SHN_UNDEF 0
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#define SHN_LOPROC 0xFF00
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#define SHN_HIPROC 0xFF1F
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#define SHN_LOOS 0xFF20
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#define SHN_HIOS 0xFF3F
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#define SHN_ABS 0xFFF1
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#define SHN_COMMON 0xFFF2
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/**
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* Values for sh_type, sh_link, sh_info
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*/
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#define SHT_NULL 0
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#define SHT_PROGBITS 1
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#define SHT_SYMTAB 2
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#define SHT_STRTAB 3
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#define SHT_RELA 4
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#define SHT_HASH 5
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#define SHT_DYNAMIC 6
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#define SHT_NOTE 7
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#define SHT_NOBITS 8
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#define SHT_REL 9
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#define SHT_SHLIB 10
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#define SHT_DYNSYM 11
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#define SHT_LOOS 0x60000000
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#define SHT_HIOS 0x6FFFFFFF
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#define SHT_LOPROC 0x70000000
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#define SHT_HIPROC 0x7FFFFFFF
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/**
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* Values for sh_flags
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*/
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#define SHF_WRITE 0x00000001
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#define SHF_ALLOC 0x00000002
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#define SHF_EXECINSTR 0x00000004
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#define SHF_MASKOS 0x0F000000
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#define SHF_MASKPROC 0xF0000000
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/* From the SysV x86-64 ABI */
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#define SHF_X86_64_LARGE 0x10000000
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#define SHF_X86_64_UNWIND 0x70000001
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typedef struct Elf64_Shdr {
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Elf64_Word sh_name;
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Elf64_Word sh_type;
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Elf64_Xword sh_flags;
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Elf64_Addr sh_addr;
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Elf64_Off sh_offset;
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Elf64_Xword sh_size;
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Elf64_Word sh_link;
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Elf64_Word sh_info;
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Elf64_Xword sh_addralign;
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Elf64_Xword sh_entsize;
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} Elf64_Shdr;
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/**
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* Binding types.
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* Contained in the high four bits of @p st_info
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*/
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#define STB_LOCAL 0 /**< @brief Not visible outside the object file. */
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#define STB_GLOBAL 1 /**< @brief Global symbol, visible to all object files. */
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#define STB_WEAK 2 /**< @brief Global scope, but with lower precedence than global symbols. */
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#define STB_LOOS 10
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#define STB_HIOS 12
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#define STB_LOPROC 13
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#define STB_HIPROC 15
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/**
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* Symbol types.
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* Contained in the low four bits of @p st_info
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*/
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#define STT_NOTYPE 0 /**< @brief No type specified (e.g., an absolute symbol) */
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#define STT_OBJECT 1 /**< @brief Data object */
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#define STT_FUNC 2 /**< @brief Function entry point */
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#define STT_SECTION 3 /**< @brief Symbol is associated with a section */
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#define STT_FILE 4 /**< @brief Source file associated with the object */
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#define STT_LOOS 10
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#define STT_HIOS 12
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#define STT_LOPROC 13
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#define STT_HIPROC 15
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typedef struct Elf64_Sym {
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Elf64_Word st_name; /**< @brief Symbol name */
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unsigned char st_info; /**< @brief Type and binding attributes */
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unsigned char st_other; /**< @brief Reserved */
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Elf64_Half st_shndx; /**< @brief Section table index */
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Elf64_Addr st_value; /**< @brief Symbol value */
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Elf64_Xword st_size; /**< @brief Size of object (e.g., common) */
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} Elf64_Sym;
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/**
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* Relocations
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*/
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#define ELF64_R_SYM(i) ((i) >> 32)
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#define ELF64_R_TYPE(i) ((i) & 0xFFFFFFFFL)
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#define ELF64_R_INFO(s,t) (((s) << 32) + ((t) & 0xFFFFFFFFL))
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typedef struct Elf64_Rel {
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Elf64_Addr r_offset; /**< @brief Address of reference */
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Elf64_Xword r_info; /**< @brief Symbol index and type of relocation */
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} Elf64_Rel;
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typedef struct Elf64_Rela {
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Elf64_Addr r_offset; /**< @brief Address of reference */
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Elf64_Xword r_info; /**< @brief Symbol index and type of relocation */
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Elf64_Sxword r_addend; /**< @brief Constant part of expression */
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} Elf64_Rela;
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/**
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* x86-64 SysV Relocation types
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*/
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#define R_X86_64_NONE 0 /**< @brief @p none none */
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#define R_X86_64_64 1 /**< @brief @p word64 S + A */
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#define R_X86_64_PC32 2 /**< @brief @p word32 S + A - P */
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#define R_X86_64_GOT32 3 /**< @brief @p word32 G + A */
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#define R_X86_64_PLT32 4 /**< @brief @p word32 L + A - P */
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#define R_X86_64_COPY 5 /**< @brief @p none none */
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#define R_X86_64_GLOB_DAT 6 /**< @brief @p word64 S */
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#define R_X86_64_JUMP_SLOT 7 /**< @brief @p word64 S */
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#define R_X86_64_RELATIVE 8 /**< @brief @p word64 B + A */
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#define R_X86_64_GOTPCREL 9 /**< @brief @p word32 G + GOT + A - P */
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#define R_X86_64_32 10 /**< @brief @p word32 S + A */
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#define R_X86_64_32S 11 /**< @brief @p word32 S + A */
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/* vvv These should not appear in a valid file */
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#define R_X86_64_16 12 /**< @brief @p word16 S + A */
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#define R_X86_64_PC16 13 /**< @brief @p word16 S + A - P */
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#define R_X86_64_8 14 /**< @brief @p word8 S + A */
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#define R_X86_64_PC8 15 /**< @brief @p word8 S + A - P */
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/* ^^^ These should not appear in a valid file */
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#define R_X86_64_DTPMOD64 16 /**< @brief @p word64 */
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#define R_X86_64_DTPOFF64 17 /**< @brief @p word64 */
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#define R_X86_64_TPOFF64 18 /**< @brief @p word64 */
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#define R_X86_64_TLSGD 19 /**< @brief @p word32 */
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#define R_X86_64_TLSLD 20 /**< @brief @p word32 */
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#define R_X86_64_DTPOFF32 21 /**< @brief @p word32 */
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#define R_X86_64_GOTTPOFF 22 /**< @brief @p word32 */
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#define R_X86_64_TPOFF32 23 /**< @brief @p word32 */
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#define R_X86_64_PC64 24 /**< @brief @p word64 S + A - P */
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#define R_X86_64_GOTOFF64 25 /**< @brief @p word64 S + A - GOT */
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#define R_X86_64_GOTPC32 26 /**< @brief @p word32 GOT + A - P */
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/* Large model */
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#define R_X86_64_GOT64 27 /**< @brief @p word64 G + A */
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#define R_X86_64_GOTPCREL64 28 /**< @brief @p word64 G + GOT - P + A */
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#define R_X86_64_GOTPC64 29 /**< @brief @p word64 GOT - P + A */
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#define R_X86_64_GOTPLT64 30 /**< @brief @p word64 G + A */
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#define R_X86_64_PLTOFF64 31 /**< @brief @p word64 L - GOT + A */
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/* ... */
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#define R_X86_64_SIZE32 32 /**< @brief @p word32 Z + A */
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#define R_X86_64_SIZE64 33 /**< @brief @p word64 Z + A */
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#define R_X86_64_GOTPC32_TLSDESC 34 /**< @brief @p word32 */
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#define R_X86_64_TLSDESC_CALL 35 /**< @brief @p none */
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#define R_X86_64_TLSDESC 36 /**< @brief @p word64*2 */
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#define R_X86_64_IRELATIVE 37 /**< @brief @p word64 indirect (B + A) */
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/**
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* Program header types
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*/
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#define PT_NULL 0
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#define PT_LOAD 1
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#define PT_DYNAMIC 2
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#define PT_INTERP 3
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#define PT_NOTE 4
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#define PT_SHLIB 5
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#define PT_PHDR 6
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#define PT_TLS 7
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#define PT_LOOS 0x60000000
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#define PT_HIOS 0x6FFFFFFF
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#define PT_LOPROC 0x70000000
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#define PT_HIPROC 0x7FFFFFFF
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/* From the SysV x86-64 ABI */
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#define PT_GNU_EH_FRAME 0x6474e550
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#define PT_SUNW_EH_FRAME 0x6474e550
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#define PT_SUNW_UNWIND 0x6464e550
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/**
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* Program header flags
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*/
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#define PF_X 0x01
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#define PF_W 0x02
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#define PF_R 0x04
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#define PF_MASKOS 0x00FF0000
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#define PF_MAKSPROC 0xFF000000
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typedef struct Elf64_Phdr {
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Elf64_Word p_type;
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Elf64_Word p_flags;
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Elf64_Off p_offset;
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Elf64_Addr p_vaddr;
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Elf64_Addr p_paddr;
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Elf64_Xword p_filesz;
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Elf64_Xword p_memsz;
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Elf64_Xword p_align;
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} Elf64_Phdr;
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/**
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* Dynamic table
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*/
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#define DT_NULL 0
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#define DT_NEEDED 1
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#define DT_PLTRELSZ 2
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#define DT_PLTGOT 3
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#define DT_HASH 4
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#define DT_STRTAB 5
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#define DT_SYMTAB 6
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#define DT_RELA 7
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#define DT_RELASZ 8
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#define DT_RELAENT 9
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#define DT_STRSZ 10
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#define DT_SYMENT 11
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#define DT_INIT 12
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#define DT_FINI 13
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#define DT_SONAME 14
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#define DT_RPATH 15
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#define DT_SYMBOLIC 16
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#define DT_REL 17
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#define DT_RELSZ 18
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#define DT_RELENT 19
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#define DT_PLTREL 20
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#define DT_DEBUG 21
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#define DT_TEXTREL 22
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#define DT_JMPREL 23
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#define DT_BIND_NOW 24
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#define DT_INIT_ARRAY 25
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#define DT_FINI_ARRAY 26
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#define DT_INIT_ARRAYSZ 27
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#define DT_FINI_ARRAYSZ 28
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#define DT_LOOS 0x60000000
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#define DT_HIOS 0x6FFFFFFF
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#define DT_LOPROC 0x70000000
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#define DT_HIPROC 0x7FFFFFFF
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typedef struct Elf64_Dyn {
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Elf64_Sxword d_tag;
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union {
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Elf64_Xword d_val;
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Elf64_Addr d_ptr;
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} d_un;
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} Elf64_Dyn;
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