1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/mozglue/linker/Elfxx.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,241 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this file,
1.6 + * You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +#ifndef Elfxx_h
1.9 +#define Elfxx_h
1.10 +
1.11 +/**
1.12 + * Android system headers have two different elf.h file. The one under linux/
1.13 + * is the most complete.
1.14 + */
1.15 +#ifdef ANDROID
1.16 +#include <linux/elf.h>
1.17 +#else
1.18 +#include <elf.h>
1.19 +#endif
1.20 +#include <endian.h>
1.21 +
1.22 +#if defined(__ARM_EABI__) && !defined(PT_ARM_EXIDX)
1.23 +#define PT_ARM_EXIDX 0x70000001
1.24 +#endif
1.25 +
1.26 +/**
1.27 + * Generic ELF macros for the target system
1.28 + */
1.29 +#ifdef __LP64__
1.30 +#define Elf_(type) Elf64_ ## type
1.31 +#define ELFCLASS ELFCLASS64
1.32 +#define ELF_R_TYPE ELF64_R_TYPE
1.33 +#define ELF_R_SYM ELF64_R_SYM
1.34 +#ifndef ELF_ST_BIND
1.35 +#define ELF_ST_BIND ELF64_ST_BIND
1.36 +#endif
1.37 +#else
1.38 +#define Elf_(type) Elf32_ ## type
1.39 +#define ELFCLASS ELFCLASS32
1.40 +#define ELF_R_TYPE ELF32_R_TYPE
1.41 +#define ELF_R_SYM ELF32_R_SYM
1.42 +#ifndef ELF_ST_BIND
1.43 +#define ELF_ST_BIND ELF32_ST_BIND
1.44 +#endif
1.45 +#endif
1.46 +
1.47 +#ifndef __BYTE_ORDER
1.48 +#error Cannot find endianness
1.49 +#endif
1.50 +
1.51 +#if __BYTE_ORDER == __LITTLE_ENDIAN
1.52 +#define ELFDATA ELFDATA2LSB
1.53 +#elif __BYTE_ORDER == __BIG_ENDIAN
1.54 +#define ELFDATA ELFDATA2MSB
1.55 +#endif
1.56 +
1.57 +#ifdef __linux__
1.58 +#define ELFOSABI ELFOSABI_LINUX
1.59 +#ifdef EI_ABIVERSION
1.60 +#define ELFABIVERSION 0
1.61 +#endif
1.62 +#else
1.63 +#error Unknown ELF OSABI
1.64 +#endif
1.65 +
1.66 +#if defined(__i386__)
1.67 +#define ELFMACHINE EM_386
1.68 +
1.69 +// Doing this way probably doesn't scale to other architectures
1.70 +#define R_ABS R_386_32
1.71 +#define R_GLOB_DAT R_386_GLOB_DAT
1.72 +#define R_JMP_SLOT R_386_JMP_SLOT
1.73 +#define R_RELATIVE R_386_RELATIVE
1.74 +#define RELOC(n) DT_REL ## n
1.75 +#define UNSUPPORTED_RELOC(n) DT_RELA ## n
1.76 +#define STR_RELOC(n) "DT_REL" # n
1.77 +#define Reloc Rel
1.78 +
1.79 +#elif defined(__x86_64__)
1.80 +#define ELFMACHINE EM_X86_64
1.81 +
1.82 +#define R_ABS R_X86_64_64
1.83 +#define R_GLOB_DAT R_X86_64_GLOB_DAT
1.84 +#define R_JMP_SLOT R_X86_64_JUMP_SLOT
1.85 +#define R_RELATIVE R_X86_64_RELATIVE
1.86 +#define RELOC(n) DT_RELA ## n
1.87 +#define UNSUPPORTED_RELOC(n) DT_REL ## n
1.88 +#define STR_RELOC(n) "DT_RELA" # n
1.89 +#define Reloc Rela
1.90 +
1.91 +#elif defined(__arm__)
1.92 +#define ELFMACHINE EM_ARM
1.93 +
1.94 +#ifndef R_ARM_ABS32
1.95 +#define R_ARM_ABS32 2
1.96 +#endif
1.97 +#ifndef R_ARM_GLOB_DAT
1.98 +#define R_ARM_GLOB_DAT 21
1.99 +#endif
1.100 +#ifndef R_ARM_JUMP_SLOT
1.101 +#define R_ARM_JUMP_SLOT 22
1.102 +#endif
1.103 +#ifndef R_ARM_RELATIVE
1.104 +#define R_ARM_RELATIVE 23
1.105 +#endif
1.106 +
1.107 +#define R_ABS R_ARM_ABS32
1.108 +#define R_GLOB_DAT R_ARM_GLOB_DAT
1.109 +#define R_JMP_SLOT R_ARM_JUMP_SLOT
1.110 +#define R_RELATIVE R_ARM_RELATIVE
1.111 +#define RELOC(n) DT_REL ## n
1.112 +#define UNSUPPORTED_RELOC(n) DT_RELA ## n
1.113 +#define STR_RELOC(n) "DT_REL" # n
1.114 +#define Reloc Rel
1.115 +
1.116 +#else
1.117 +#error Unknown ELF machine type
1.118 +#endif
1.119 +
1.120 +/**
1.121 + * Android system headers don't have all definitions
1.122 + */
1.123 +#ifndef STN_UNDEF
1.124 +#define STN_UNDEF 0
1.125 +#endif
1.126 +#ifndef DT_INIT_ARRAY
1.127 +#define DT_INIT_ARRAY 25
1.128 +#endif
1.129 +#ifndef DT_FINI_ARRAY
1.130 +#define DT_FINI_ARRAY 26
1.131 +#endif
1.132 +#ifndef DT_INIT_ARRAYSZ
1.133 +#define DT_INIT_ARRAYSZ 27
1.134 +#endif
1.135 +#ifndef DT_FINI_ARRAYSZ
1.136 +#define DT_FINI_ARRAYSZ 28
1.137 +#endif
1.138 +#ifndef DT_RELACOUNT
1.139 +#define DT_RELACOUNT 0x6ffffff9
1.140 +#endif
1.141 +#ifndef DT_RELCOUNT
1.142 +#define DT_RELCOUNT 0x6ffffffa
1.143 +#endif
1.144 +#ifndef DT_VERSYM
1.145 +#define DT_VERSYM 0x6ffffff0
1.146 +#endif
1.147 +#ifndef DT_VERDEF
1.148 +#define DT_VERDEF 0x6ffffffc
1.149 +#endif
1.150 +#ifndef DT_VERDEFNUM
1.151 +#define DT_VERDEFNUM 0x6ffffffd
1.152 +#endif
1.153 +#ifndef DT_VERNEED
1.154 +#define DT_VERNEED 0x6ffffffe
1.155 +#endif
1.156 +#ifndef DT_VERNEEDNUM
1.157 +#define DT_VERNEEDNUM 0x6fffffff
1.158 +#endif
1.159 +#ifndef DT_FLAGS_1
1.160 +#define DT_FLAGS_1 0x6ffffffb
1.161 +#endif
1.162 +#ifndef DT_FLAGS
1.163 +#define DT_FLAGS 30
1.164 +#endif
1.165 +#ifndef DF_SYMBOLIC
1.166 +#define DF_SYMBOLIC 0x00000002
1.167 +#endif
1.168 +#ifndef DF_TEXTREL
1.169 +#define DF_TEXTREL 0x00000004
1.170 +#endif
1.171 +
1.172 +namespace Elf {
1.173 +
1.174 +/**
1.175 + * Define a few basic Elf Types
1.176 + */
1.177 +typedef Elf_(Phdr) Phdr;
1.178 +typedef Elf_(Dyn) Dyn;
1.179 +typedef Elf_(Sym) Sym;
1.180 +typedef Elf_(Addr) Addr;
1.181 +typedef Elf_(Word) Word;
1.182 +typedef Elf_(Half) Half;
1.183 +
1.184 +/**
1.185 + * Helper class around the standard Elf header struct
1.186 + */
1.187 +struct Ehdr: public Elf_(Ehdr)
1.188 +{
1.189 + /**
1.190 + * Equivalent to reinterpret_cast<const Ehdr *>(buf), but additionally
1.191 + * checking that this is indeed an Elf header and that the Elf type
1.192 + * corresponds to that of the system
1.193 + */
1.194 + static const Ehdr *validate(const void *buf);
1.195 +};
1.196 +
1.197 +/**
1.198 + * Elf String table
1.199 + */
1.200 +class Strtab: public UnsizedArray<const char>
1.201 +{
1.202 +public:
1.203 + /**
1.204 + * Returns the string at the given index in the table
1.205 + */
1.206 + const char *GetStringAt(off_t index) const
1.207 + {
1.208 + return &UnsizedArray<const char>::operator[](index);
1.209 + }
1.210 +};
1.211 +
1.212 +/**
1.213 + * Helper class around Elf relocation.
1.214 + */
1.215 +struct Rel: public Elf_(Rel)
1.216 +{
1.217 + /**
1.218 + * Returns the addend for the relocation, which is the value stored
1.219 + * at r_offset.
1.220 + */
1.221 + Addr GetAddend(void *base) const
1.222 + {
1.223 + return *(reinterpret_cast<const Addr *>(
1.224 + reinterpret_cast<const char *>(base) + r_offset));
1.225 + }
1.226 +};
1.227 +
1.228 +/**
1.229 + * Helper class around Elf relocation with addend.
1.230 + */
1.231 +struct Rela: public Elf_(Rela)
1.232 +{
1.233 + /**
1.234 + * Returns the addend for the relocation.
1.235 + */
1.236 + Addr GetAddend(void *base) const
1.237 + {
1.238 + return r_addend;
1.239 + }
1.240 +};
1.241 +
1.242 +} /* namespace Elf */
1.243 +
1.244 +#endif /* Elfxx_h */
