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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 BaseElf_h
#define BaseElf_h
#include "ElfLoader.h"
#include "Elfxx.h"
/**
* Base class for ELF libraries. This class includes things that will be
* common between SystemElfs and CustomElfs.
*/
class BaseElf : public LibHandle {
public:
/**
* Hash function for symbol lookup, as defined in ELF standard for System V.
*/
static unsigned long Hash(const char* symbol);
/**
* Returns the address corresponding to the given symbol name (with a
* pre-computed hash).
*/
void* GetSymbolPtr(const char* symbol, unsigned long hash) const;
/**
* Returns a pointer to the Elf Symbol in the Dynamic Symbol table
* corresponding to the given symbol name (with a pre-computed hash).
*/
const Elf::Sym* GetSymbol(const char* symbol, unsigned long hash) const;
explicit BaseElf(const char* path, Mappable* mappable = nullptr)
: LibHandle(path), mappable(mappable) {}
protected:
/**
* Inherited from LibHandle. Those are temporary and are not supposed to
* be used.
*/
virtual void* GetSymbolPtr(const char* symbol) const;
virtual bool Contains(void* addr) const;
virtual void* GetBase() const { return GetPtr(0); }
#ifdef __ARM_EABI__
virtual const void* FindExidx(int* pcount) const;
#endif
virtual Mappable* GetMappable() const { return NULL; };
public:
/* private: */
/**
* Returns a pointer relative to the base address where the library is
* loaded.
*/
void* GetPtr(const Elf::Addr offset) const {
if (reinterpret_cast<void*>(offset) > base)
return reinterpret_cast<void*>(offset);
return base + offset;
}
/**
* Like the above, but returns a typed (const) pointer
*/
template <typename T>
const T* GetPtr(const Elf::Addr offset) const {
if (reinterpret_cast<void*>(offset) > base)
return reinterpret_cast<const T*>(offset);
return reinterpret_cast<const T*>(base + offset);
}
/* Appropriated Mappable */
/* /!\ we rely on this being nullptr for BaseElf instances, but not
* CustomElf instances. */
RefPtr<Mappable> mappable;
/* Base address where the library is loaded */
MappedPtr base;
/* Buckets and chains for the System V symbol hash table */
Array<Elf::Word> buckets;
UnsizedArray<Elf::Word> chains;
/* protected: */
/* String table */
Elf::Strtab strtab;
/* Symbol table */
UnsizedArray<Elf::Sym> symtab;
#ifdef __ARM_EABI__
/* ARM.exidx information used by FindExidx */
Array<uint32_t[2]> arm_exidx;
#endif
};
/**
* Class for ELF libraries that already loaded in memory.
*/
class LoadedElf : public BaseElf {
public:
/**
* Returns a LoadedElf corresponding to the already loaded ELF
* at the given base address.
*/
static already_AddRefed<LibHandle> Create(const char* path, void* base_addr);
private:
explicit LoadedElf(const char* path) : BaseElf(path) {}
~LoadedElf() {
/* Avoid base's destructor unmapping something that doesn't actually
* belong to it. */
base.release();
ElfLoader::Singleton.Forget(this);
}
/**
* Initializes the library according to information found in the given
* PT_DYNAMIC header.
* Returns whether this succeeded or failed.
*/
bool InitDyn(const Elf::Phdr* pt_dyn);
};
#endif /* BaseElf_h */