/* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this file, * You can obtain one at http://mozilla.org/MPL/2.0/. */ #ifndef Elfxx_h #define Elfxx_h /** * Android system headers have two different elf.h file. The one under linux/ * is the most complete on older android API versions. */ #if defined(ANDROID) && __ANDROID_API__ < 21 #include <linux/elf.h> #else #include <elf.h> #endif #include <endian.h> #if defined(__ARM_EABI__) && !defined(PT_ARM_EXIDX) #define PT_ARM_EXIDX 0x70000001 #endif /** * Generic ELF macros for the target system */ #ifdef __LP64__ #define Elf_(type) Elf64_ ## type #define ELFCLASS ELFCLASS64 #define ELF_R_TYPE ELF64_R_TYPE #define ELF_R_SYM ELF64_R_SYM #ifndef ELF_ST_BIND #define ELF_ST_BIND ELF64_ST_BIND #endif #else #define Elf_(type) Elf32_ ## type #define ELFCLASS ELFCLASS32 #define ELF_R_TYPE ELF32_R_TYPE #define ELF_R_SYM ELF32_R_SYM #ifndef ELF_ST_BIND #define ELF_ST_BIND ELF32_ST_BIND #endif #endif #ifndef __BYTE_ORDER #error Cannot find endianness #endif #if __BYTE_ORDER == __LITTLE_ENDIAN #define ELFDATA ELFDATA2LSB #elif __BYTE_ORDER == __BIG_ENDIAN #define ELFDATA ELFDATA2MSB #endif #ifdef __linux__ #define ELFOSABI ELFOSABI_LINUX #ifdef EI_ABIVERSION #define ELFABIVERSION 0 #endif #else #error Unknown ELF OSABI #endif #if defined(__i386__) #define ELFMACHINE EM_386 // Doing this way probably doesn't scale to other architectures #define R_ABS R_386_32 #define R_GLOB_DAT R_386_GLOB_DAT #define R_JMP_SLOT R_386_JMP_SLOT #define R_RELATIVE R_386_RELATIVE #define RELOC(n) DT_REL ## n #define UNSUPPORTED_RELOC(n) DT_RELA ## n #define STR_RELOC(n) "DT_REL" # n #define Reloc Rel #elif defined(__x86_64__) #define ELFMACHINE EM_X86_64 #define R_ABS R_X86_64_64 #define R_GLOB_DAT R_X86_64_GLOB_DAT #define R_JMP_SLOT R_X86_64_JUMP_SLOT #define R_RELATIVE R_X86_64_RELATIVE #define RELOC(n) DT_RELA ## n #define UNSUPPORTED_RELOC(n) DT_REL ## n #define STR_RELOC(n) "DT_RELA" # n #define Reloc Rela #elif defined(__arm__) #define ELFMACHINE EM_ARM #ifndef R_ARM_ABS32 #define R_ARM_ABS32 2 #endif #ifndef R_ARM_GLOB_DAT #define R_ARM_GLOB_DAT 21 #endif #ifndef R_ARM_JUMP_SLOT #define R_ARM_JUMP_SLOT 22 #endif #ifndef R_ARM_RELATIVE #define R_ARM_RELATIVE 23 #endif #define R_ABS R_ARM_ABS32 #define R_GLOB_DAT R_ARM_GLOB_DAT #define R_JMP_SLOT R_ARM_JUMP_SLOT #define R_RELATIVE R_ARM_RELATIVE #define RELOC(n) DT_REL ## n #define UNSUPPORTED_RELOC(n) DT_RELA ## n #define STR_RELOC(n) "DT_REL" # n #define Reloc Rel #else #error Unknown ELF machine type #endif /** * Android system headers don't have all definitions */ #ifndef STN_UNDEF #define STN_UNDEF 0 #endif #ifndef DT_INIT_ARRAY #define DT_INIT_ARRAY 25 #endif #ifndef DT_FINI_ARRAY #define DT_FINI_ARRAY 26 #endif #ifndef DT_INIT_ARRAYSZ #define DT_INIT_ARRAYSZ 27 #endif #ifndef DT_FINI_ARRAYSZ #define DT_FINI_ARRAYSZ 28 #endif #ifndef DT_RELACOUNT #define DT_RELACOUNT 0x6ffffff9 #endif #ifndef DT_RELCOUNT #define DT_RELCOUNT 0x6ffffffa #endif #ifndef DT_VERSYM #define DT_VERSYM 0x6ffffff0 #endif #ifndef DT_VERDEF #define DT_VERDEF 0x6ffffffc #endif #ifndef DT_VERDEFNUM #define DT_VERDEFNUM 0x6ffffffd #endif #ifndef DT_VERNEED #define DT_VERNEED 0x6ffffffe #endif #ifndef DT_VERNEEDNUM #define DT_VERNEEDNUM 0x6fffffff #endif #ifndef DT_FLAGS_1 #define DT_FLAGS_1 0x6ffffffb #endif #ifndef DT_FLAGS #define DT_FLAGS 30 #endif #ifndef DF_SYMBOLIC #define DF_SYMBOLIC 0x00000002 #endif #ifndef DF_TEXTREL #define DF_TEXTREL 0x00000004 #endif namespace Elf { /** * Define a few basic Elf Types */ typedef Elf_(Phdr) Phdr; typedef Elf_(Dyn) Dyn; typedef Elf_(Sym) Sym; typedef Elf_(Addr) Addr; typedef Elf_(Word) Word; typedef Elf_(Half) Half; /** * Helper class around the standard Elf header struct */ struct Ehdr: public Elf_(Ehdr) { /** * Equivalent to reinterpret_cast<const Ehdr *>(buf), but additionally * checking that this is indeed an Elf header and that the Elf type * corresponds to that of the system */ static const Ehdr *validate(const void *buf); }; /** * Elf String table */ class Strtab: public UnsizedArray<const char> { public: /** * Returns the string at the given index in the table */ const char *GetStringAt(off_t index) const { return &UnsizedArray<const char>::operator[](index); } }; /** * Helper class around Elf relocation. */ struct Rel: public Elf_(Rel) { /** * Returns the addend for the relocation, which is the value stored * at r_offset. */ Addr GetAddend(void *base) const { return *(reinterpret_cast<const Addr *>( reinterpret_cast<const char *>(base) + r_offset)); } }; /** * Helper class around Elf relocation with addend. */ struct Rela: public Elf_(Rela) { /** * Returns the addend for the relocation. */ Addr GetAddend(void *base) const { return r_addend; } }; } /* namespace Elf */ #endif /* Elfxx_h */