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-rw-r--r--mozglue/linker/Elfxx.h241
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diff --git a/mozglue/linker/Elfxx.h b/mozglue/linker/Elfxx.h
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+/* 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 */