gecko/mozglue/linker/BaseElf.h

102 lines
2.6 KiB
C++

/* 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;
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 { return NULL; };
virtual bool Contains(void *addr) const { return false; };
virtual void *GetBase() const { return GetPtr(0); }
#ifdef __ARM_EABI__
virtual const void *FindExidx(int *pcount) const { return NULL; };
#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. */
mozilla::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;
};
#endif /* BaseElf_h */