зеркало из https://github.com/mozilla/gecko-dev.git
148 строки
3.8 KiB
C++
148 строки
3.8 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef CustomElf_h
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#define CustomElf_h
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#include "ElfLoader.h"
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#include "BaseElf.h"
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#include "Logging.h"
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#include "Elfxx.h"
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/**
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* Library Handle class for ELF libraries we don't let the system linker
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* handle.
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*/
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class CustomElf : public BaseElf, private ElfLoader::link_map {
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friend class ElfLoader;
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friend class SEGVHandler;
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public:
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/**
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* Returns a new CustomElf using the given file descriptor to map ELF
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* content. The file descriptor ownership is stolen, and it will be closed
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* in CustomElf's destructor if an instance is created, or by the Load
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* method otherwise. The path corresponds to the file descriptor, and flags
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* are the same kind of flags that would be given to dlopen(), though
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* currently, none are supported and the behaviour is more or less that of
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* RTLD_GLOBAL | RTLD_BIND_NOW.
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*/
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static already_AddRefed<LibHandle> Load(Mappable* mappable, const char* path,
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int flags);
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/**
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* Inherited from LibHandle/BaseElf
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*/
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virtual ~CustomElf();
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protected:
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virtual Mappable* GetMappable() const;
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public:
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/**
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* Returns the instance, casted as BaseElf. (short of a better way to do
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* this without RTTI)
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*/
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virtual BaseElf* AsBaseElf() { return this; }
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private:
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/**
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* Scan dependent libraries to find the address corresponding to the
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* given symbol name. This is used to find symbols that are undefined
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* in the Elf object.
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*/
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void* GetSymbolPtrInDeps(const char* symbol) const;
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/**
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* Private constructor
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*/
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CustomElf(Mappable* mappable, const char* path)
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: BaseElf(path, mappable),
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link_map(),
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init(0),
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fini(0),
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initialized(false),
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has_text_relocs(false) {}
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/**
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* Loads an Elf segment defined by the given PT_LOAD header.
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* Returns whether this succeeded or failed.
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*/
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bool LoadSegment(const Elf::Phdr* pt_load) const;
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/**
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* Initializes the library according to information found in the given
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* PT_DYNAMIC header.
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* Returns whether this succeeded or failed.
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*/
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bool InitDyn(const Elf::Phdr* pt_dyn);
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/**
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* Apply .rel.dyn/.rela.dyn relocations.
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* Returns whether this succeeded or failed.
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*/
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bool Relocate();
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/**
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* Apply .rel.plt/.rela.plt relocations.
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* Returns whether this succeeded or failed.
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*/
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bool RelocateJumps();
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/**
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* Call initialization functions (.init/.init_array)
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* Returns true;
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*/
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bool CallInit();
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/**
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* Call destructor functions (.fini_array/.fini)
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* Returns whether this succeeded or failed.
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*/
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void CallFini();
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/**
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* Call a function given a pointer to its location.
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*/
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void CallFunction(void* ptr) const {
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/* C++ doesn't allow direct conversion between pointer-to-object
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* and pointer-to-function. */
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union {
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void* ptr;
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void (*func)(void);
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} f;
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f.ptr = ptr;
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DEBUG_LOG("%s: Calling function @%p", GetPath(), ptr);
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f.func();
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}
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/**
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* Call a function given a an address relative to the library base
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*/
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void CallFunction(Elf::Addr addr) const { return CallFunction(GetPtr(addr)); }
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/* List of dependent libraries */
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std::vector<RefPtr<LibHandle> > dependencies;
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/* List of .rel.dyn/.rela.dyn relocations */
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Array<Elf::Reloc> relocations;
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/* List of .rel.plt/.rela.plt relocation */
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Array<Elf::Reloc> jumprels;
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/* Relative address of the initialization and destruction functions
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* (.init/.fini) */
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Elf::Addr init, fini;
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/* List of initialization and destruction functions
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* (.init_array/.fini_array) */
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Array<void*> init_array, fini_array;
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bool initialized;
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bool has_text_relocs;
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};
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#endif /* CustomElf_h */
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