diff options
Diffstat (limited to 'lib/include/elf.h')
| -rw-r--r-- | lib/include/elf.h | 156 |
1 files changed, 130 insertions, 26 deletions
diff --git a/lib/include/elf.h b/lib/include/elf.h index a0fe6f7..0317859 100644 --- a/lib/include/elf.h +++ b/lib/include/elf.h @@ -4,6 +4,51 @@ #include <stdint.h> +/// ---------- +/// ELF Header +/// ---------- + +// Index into `ident`. +#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_OSABI 7 + +// indent[EI_CLASS] +#define ELFCLASS32 1 +#define ELFCLASS64 2 + +// indent[EI_CLASS] +#define ELFDATA2LSB 1 +#define ELFDATA2MSB 2 + +// indent[EI_OSABI] +#define ELFOSABI_SYSV 0 + +// Objec file `type`. +#define ET_NONE 0 +#define ET_DYN 3 + +typedef struct { + uint8_t ident[16]; // ELF identification. + uint16_t type; // Object file type. + uint16_t machine; // Machine type. + uint32_t version; // Object file version. + uint64_t entry; // Entrypoint address. + uint64_t phoff; // Program header file offset. + uint64_t shoff; // Section header file offset. + uint32_t flags; // Processor specific flags. + uint16_t ehsize; // ELF header size. + uint16_t phentsize; // Program header entry size. + uint16_t phnum; // Number of program header entries. + uint16_t shentsize; // Section header entry size. + uint16_t shnum; // Number of section header entries. + uint16_t shstrndx; // Section name string table index. +} Elf64Ehdr; + /// -------------- /// Program Header /// -------------- @@ -15,6 +60,7 @@ #define PT_NOTE 4 /* Location of auxiliary information */ #define PT_SHLIB 5 /* Reserved, but unspecified semantic */ #define PT_PHDR 6 /* Location & size of program headers itself */ +#define PT_TLS 7 /* Thread local storage */ #define PT_GNU_EH_FRAME 0x6474e550 /* [x86-64] stack unwinding tables */ #define PT_LOPROC 0x70000000 @@ -39,32 +85,36 @@ typedef struct { /// Dynamic Section /// --------------- -#define DT_NULL 0 /* [ignored] Marks end of dynamic section */ -#define DT_NEEDED 1 /* [val] Name of needed library */ -#define DT_PLTRELSZ 2 /* [val] Size in bytes of PLT relocs */ -#define DT_PLTGOT 3 /* [ptr] Processor defined value */ -#define DT_HASH 4 /* [ptr] Address of symbol hash table */ -#define DT_STRTAB 5 /* [ptr] Address of string table */ -#define DT_SYMTAB 6 /* [ptr] Address of symbol table */ -#define DT_RELA 7 /* [ptr] Address of Rela relocs */ -#define DT_RELASZ 8 /* [val] Total size of Rela relocs */ -#define DT_RELAENT 9 /* [val] Size of one Rela reloc */ -#define DT_STRSZ 10 /* [val] Size of string table */ -#define DT_SYMENT 11 /* [val] Size of one symbol table entry */ -#define DT_INIT 12 /* [ptr] Address of init function */ -#define DT_FINI 13 /* [ptr] Address of termination function */ -#define DT_SONAME 14 /* [val] Name of shared object */ -#define DT_RPATH 15 /* [val] Library search path (deprecated) */ -#define DT_SYMBOLIC 16 /* [ignored] Start symbol search here */ -#define DT_REL 17 /* [ptr] Address of Rel relocs */ -#define DT_RELSZ 18 /* [val] Total size of Rel relocs */ -#define DT_RELENT 19 /* [val] Size of one Rel reloc */ -#define DT_PLTREL 20 /* [val] Type of reloc in PLT */ -#define DT_DEBUG 21 /* [ptr] For debugging; unspecified */ -#define DT_TEXTREL 22 /* [ignored] Reloc might modify .text */ -#define DT_JMPREL 23 /* [ptr] Address of PLT relocs */ -#define DT_BIND_NOW 24 /* [ignored] Process relocations of object */ -#define DT_MAX_CNT 25 +#define DT_NULL 0 /* [ignored] Marks end of dynamic section */ +#define DT_NEEDED 1 /* [val] Name of needed library */ +#define DT_PLTRELSZ 2 /* [val] Size in bytes of PLT relocs */ +#define DT_PLTGOT 3 /* [ptr] Processor defined value */ +#define DT_HASH 4 /* [ptr] Address of symbol hash table */ +#define DT_STRTAB 5 /* [ptr] Address of string table */ +#define DT_SYMTAB 6 /* [ptr] Address of symbol table */ +#define DT_RELA 7 /* [ptr] Address of Rela relocs */ +#define DT_RELASZ 8 /* [val] Total size of Rela relocs */ +#define DT_RELAENT 9 /* [val] Size of one Rela reloc */ +#define DT_STRSZ 10 /* [val] Size of string table */ +#define DT_SYMENT 11 /* [val] Size of one symbol table entry */ +#define DT_INIT 12 /* [ptr] Address of init function */ +#define DT_FINI 13 /* [ptr] Address of termination function */ +#define DT_SONAME 14 /* [val] Name of shared object */ +#define DT_RPATH 15 /* [val] Library search path (deprecated) */ +#define DT_SYMBOLIC 16 /* [ignored] Start symbol search here */ +#define DT_REL 17 /* [ptr] Address of Rel relocs */ +#define DT_RELSZ 18 /* [val] Total size of Rel relocs */ +#define DT_RELENT 19 /* [val] Size of one Rel reloc */ +#define DT_PLTREL 20 /* [val] Type of reloc in PLT */ +#define DT_DEBUG 21 /* [ptr] For debugging; unspecified */ +#define DT_TEXTREL 22 /* [ignored] Reloc might modify .text */ +#define DT_JMPREL 23 /* [ptr] Address of PLT relocs */ +#define DT_BIND_NOW 24 /* [ignored] Process relocations of object */ +#define DT_INIT_ARRAY 25 /* [ptr] Address of array of initialization functions */ +#define DT_FINI_ARRAY 26 /* [ptr] Address of array of termination functions */ +#define DT_INIT_ARRAYSZ 27 /* [val] Size in bytes of the initialization array */ +#define DT_FINI_ARRAYSZ 28 /* [val] Size in bytes of the termination array */ +#define DT_MAX_CNT 29 typedef struct { uint64_t tag; @@ -73,3 +123,57 @@ typedef struct { void* ptr; }; } Elf64Dyn; + +/// ------------ +/// Symbol Entry +/// ------------ + +typedef struct { + uint32_t name; // Symbol name (index into string table). + uint8_t info; // Symbol Binding bits[7..4] + Symbol Type bits[3..0]. + uint8_t other; // Reserved. + uint16_t shndx; // Section table index. + uint64_t value; // + uint64_t size; // +} Elf64Sym; + +#define ELF64_ST_BIND(i) ((i) >> 4) +#define ELF64_ST_TYPE(i) ((i)&0xf) + +// Symbold Bindings. +#define STB_GLOBAL 1 /* Global symbol, visible to all object files. */ +#define STB_WEAK 2 /* Global scope, but with lower precedence than global symbols. */ + +// Symbol Types. +#define STT_NOTYPE 0 /* No type. */ +#define STT_OBJECT 1 /* Data Object. */ +#define STT_FUNC 2 /* Function entry point. */ + +// Special Section Indicies. +#define SHN_UNDEF 0 /* Undefined section. */ +#define SHN_ABS 0xff1 /* Indicates an absolute value. */ + +/// ----------------- +/// Relocations Entry +/// ----------------- + +typedef struct { + uint64_t offset; // Virtual address of the storage unit affected by the relocation. + uint64_t info; // Symbol table index + relocation type. +} Elf64Rel; + +typedef struct { + uint64_t offset; // Virtual address of the storage unit affected by the relocation. + uint64_t info; // Symbol table index + relocation type. + int64_t addend; // Constant value used to compute the relocation value. +} Elf64Rela; + +#define ELF64_R_SYM(i) ((i) >> 32) +#define ELF64_R_TYPE(i) ((i)&0xffffffffL) + +// x86_64 relocation types. +#define R_X86_64_64 1 /* Absolute 64bit address, address affected by relocation: `base + offset` */ +#define R_X86_64_COPY 5 /* Copy content from sym addr to relocation address: `base + offset` */ +#define R_X86_64_GLOB_DAT 6 /* Address affected by relocation: `base + offset` */ +#define R_X86_64_JUMP_SLOT 7 /* Address affected by relocation: `base + offset` */ +#define R_X86_64_RELATIVE 8 /* Relative address *`base + offset` = `base + addend` */ |