michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef CustomElf_h
michael@0: #define CustomElf_h
michael@0: 
michael@0: #include "ElfLoader.h"
michael@0: #include "Logging.h"
michael@0: #include "Elfxx.h"
michael@0: 
michael@0: /**
michael@0:  * Library Handle class for ELF libraries we don't let the system linker
michael@0:  * handle.
michael@0:  */
michael@0: class CustomElf: public LibHandle, private ElfLoader::link_map
michael@0: {
michael@0:   friend class ElfLoader;
michael@0:   friend class SEGVHandler;
michael@0: public:
michael@0:   /**
michael@0:    * Returns a new CustomElf using the given file descriptor to map ELF
michael@0:    * content. The file descriptor ownership is stolen, and it will be closed
michael@0:    * in CustomElf's destructor if an instance is created, or by the Load
michael@0:    * method otherwise. The path corresponds to the file descriptor, and flags
michael@0:    * are the same kind of flags that would be given to dlopen(), though
michael@0:    * currently, none are supported and the behaviour is more or less that of
michael@0:    * RTLD_GLOBAL | RTLD_BIND_NOW.
michael@0:    */
michael@0:   static mozilla::TemporaryRef<LibHandle> Load(Mappable *mappable,
michael@0:                                                const char *path, int flags);
michael@0: 
michael@0:   /**
michael@0:    * Inherited from LibHandle
michael@0:    */
michael@0:   virtual ~CustomElf();
michael@0:   virtual void *GetSymbolPtr(const char *symbol) const;
michael@0:   virtual bool Contains(void *addr) const;
michael@0: 
michael@0: #ifdef __ARM_EABI__
michael@0:   virtual const void *FindExidx(int *pcount) const;
michael@0: #endif
michael@0: 
michael@0: protected:
michael@0:   virtual Mappable *GetMappable() const;
michael@0: 
michael@0: public:
michael@0:   /**
michael@0:    * Shows some stats about the Mappable instance. The when argument is to be
michael@0:    * used by the caller to give an identifier of the when the stats call is
michael@0:    * made.
michael@0:    */
michael@0:   void stats(const char *when) const;
michael@0: 
michael@0: private:
michael@0:   /**
michael@0:    * Returns a pointer to the Elf Symbol in the Dynamic Symbol table
michael@0:    * corresponding to the given symbol name (with a pre-computed hash).
michael@0:    */
michael@0:   const Elf::Sym *GetSymbol(const char *symbol, unsigned long hash) const;
michael@0: 
michael@0:   /**
michael@0:    * Returns the address corresponding to the given symbol name (with a
michael@0:    * pre-computed hash).
michael@0:    */
michael@0:   void *GetSymbolPtr(const char *symbol, unsigned long hash) const;
michael@0: 
michael@0:   /**
michael@0:    * Scan dependent libraries to find the address corresponding to the
michael@0:    * given symbol name. This is used to find symbols that are undefined
michael@0:    * in the Elf object.
michael@0:    */
michael@0:   void *GetSymbolPtrInDeps(const char *symbol) const;
michael@0: 
michael@0:   /**
michael@0:    * Private constructor
michael@0:    */
michael@0:   CustomElf(Mappable *mappable, const char *path)
michael@0:   : LibHandle(path)
michael@0:   , mappable(mappable)
michael@0:   , init(0)
michael@0:   , fini(0)
michael@0:   , initialized(false)
michael@0:   , has_text_relocs(false)
michael@0:   { }
michael@0: 
michael@0:   /**
michael@0:    * Returns a pointer relative to the base address where the library is
michael@0:    * loaded.
michael@0:    */
michael@0:   void *GetPtr(const Elf::Addr offset) const
michael@0:   {
michael@0:     return base + offset;
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Like the above, but returns a typed (const) pointer
michael@0:    */
michael@0:   template <typename T>
michael@0:   const T *GetPtr(const Elf::Addr offset) const
michael@0:   {
michael@0:     return reinterpret_cast<const T *>(base + offset);
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Loads an Elf segment defined by the given PT_LOAD header.
michael@0:    * Returns whether this succeeded or failed.
michael@0:    */
michael@0:   bool LoadSegment(const Elf::Phdr *pt_load) const;
michael@0: 
michael@0:   /**
michael@0:    * Initializes the library according to information found in the given
michael@0:    * PT_DYNAMIC header.
michael@0:    * Returns whether this succeeded or failed.
michael@0:    */
michael@0:   bool InitDyn(const Elf::Phdr *pt_dyn);
michael@0: 
michael@0:   /**
michael@0:    * Apply .rel.dyn/.rela.dyn relocations.
michael@0:    * Returns whether this succeeded or failed.
michael@0:    */
michael@0:   bool Relocate();
michael@0: 
michael@0:   /**
michael@0:    * Apply .rel.plt/.rela.plt relocations.
michael@0:    * Returns whether this succeeded or failed.
michael@0:    */
michael@0:   bool RelocateJumps();
michael@0: 
michael@0:   /**
michael@0:    * Call initialization functions (.init/.init_array)
michael@0:    * Returns true;
michael@0:    */
michael@0:   bool CallInit();
michael@0: 
michael@0:   /**
michael@0:    * Call destructor functions (.fini_array/.fini)
michael@0:    * Returns whether this succeeded or failed.
michael@0:    */
michael@0:   void CallFini();
michael@0: 
michael@0:   /**
michael@0:    * Call a function given a pointer to its location.
michael@0:    */
michael@0:   void CallFunction(void *ptr) const
michael@0:   {
michael@0:     /* C++ doesn't allow direct conversion between pointer-to-object
michael@0:      * and pointer-to-function. */
michael@0:     union {
michael@0:       void *ptr;
michael@0:       void (*func)(void);
michael@0:     } f;
michael@0:     f.ptr = ptr;
michael@0:     DEBUG_LOG("%s: Calling function @%p", GetPath(), ptr);
michael@0:     f.func();
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Call a function given a an address relative to the library base
michael@0:    */
michael@0:   void CallFunction(Elf::Addr addr) const
michael@0:   {
michael@0:     return CallFunction(GetPtr(addr));
michael@0:   }
michael@0: 
michael@0:   /* Appropriated Mappable */
michael@0:   mozilla::RefPtr<Mappable> mappable;
michael@0: 
michael@0:   /* Base address where the library is loaded */
michael@0:   MappedPtr base;
michael@0: 
michael@0:   /* String table */
michael@0:   Elf::Strtab strtab;
michael@0: 
michael@0:   /* Symbol table */
michael@0:   UnsizedArray<Elf::Sym> symtab;
michael@0: 
michael@0:   /* Buckets and chains for the System V symbol hash table */
michael@0:   Array<Elf::Word> buckets;
michael@0:   UnsizedArray<Elf::Word> chains;
michael@0: 
michael@0:   /* List of dependent libraries */
michael@0:   std::vector<mozilla::RefPtr<LibHandle> > dependencies;
michael@0: 
michael@0:   /* List of .rel.dyn/.rela.dyn relocations */
michael@0:   Array<Elf::Reloc> relocations;
michael@0: 
michael@0:   /* List of .rel.plt/.rela.plt relocation */
michael@0:   Array<Elf::Reloc> jumprels;
michael@0: 
michael@0:   /* Relative address of the initialization and destruction functions
michael@0:    * (.init/.fini) */
michael@0:   Elf::Addr init, fini;
michael@0: 
michael@0:   /* List of initialization and destruction functions
michael@0:    * (.init_array/.fini_array) */
michael@0:   Array<void *> init_array, fini_array;
michael@0: 
michael@0:   bool initialized;
michael@0: 
michael@0:   bool has_text_relocs;
michael@0: 
michael@0: #ifdef __ARM_EABI__
michael@0:   /* ARM.exidx information used by FindExidx */
michael@0:   Array<uint32_t[2]> arm_exidx;
michael@0: #endif
michael@0: };
michael@0: 
michael@0: #endif /* CustomElf_h */