From 26a029d407be480d791972afb5975cf62c9360a6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 02:47:55 +0200 Subject: Adding upstream version 124.0.1. Signed-off-by: Daniel Baumann --- mozglue/linker/CustomElf.h | 144 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 144 insertions(+) create mode 100644 mozglue/linker/CustomElf.h (limited to 'mozglue/linker/CustomElf.h') diff --git a/mozglue/linker/CustomElf.h b/mozglue/linker/CustomElf.h new file mode 100644 index 0000000000..12cff4ce5a --- /dev/null +++ b/mozglue/linker/CustomElf.h @@ -0,0 +1,144 @@ +/* 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 CustomElf_h +#define CustomElf_h + +#include "ElfLoader.h" +#include "BaseElf.h" +#include "Logging.h" +#include "Elfxx.h" + +/** + * Library Handle class for ELF libraries we don't let the system linker + * handle. + */ +class CustomElf : public BaseElf, private ElfLoader::link_map { + friend class ElfLoader; + friend class SEGVHandler; + + public: + /** + * Returns a new CustomElf using the given file descriptor to map ELF + * content. The file descriptor ownership is stolen, and it will be closed + * in CustomElf's destructor if an instance is created, or by the Load + * method otherwise. The path corresponds to the file descriptor, and flags + * are the same kind of flags that would be given to dlopen(), though + * currently, none are supported and the behaviour is more or less that of + * RTLD_GLOBAL | RTLD_BIND_NOW. + */ + static already_AddRefed Load(Mappable* mappable, const char* path, + int flags); + + /** + * Inherited from LibHandle/BaseElf + */ + virtual ~CustomElf(); + + public: + /** + * Returns the instance, casted as BaseElf. (short of a better way to do + * this without RTTI) + */ + virtual BaseElf* AsBaseElf() { return this; } + + private: + /** + * Scan dependent libraries to find the address corresponding to the + * given symbol name. This is used to find symbols that are undefined + * in the Elf object. + */ + void* GetSymbolPtrInDeps(const char* symbol) const; + + /** + * Private constructor + */ + CustomElf(Mappable* mappable, const char* path) + : BaseElf(path, mappable), + link_map(), + init(0), + fini(0), + initialized(false), + has_text_relocs(false) {} + + /** + * Loads an Elf segment defined by the given PT_LOAD header. + * Returns whether this succeeded or failed. + */ + bool LoadSegment(const Elf::Phdr* pt_load) const; + + /** + * 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); + + /** + * Apply .rel.dyn/.rela.dyn relocations. + * Returns whether this succeeded or failed. + */ + bool Relocate(); + + /** + * Apply .rel.plt/.rela.plt relocations. + * Returns whether this succeeded or failed. + */ + bool RelocateJumps(); + + /** + * Call initialization functions (.init/.init_array) + * Returns true; + */ + bool CallInit(); + + /** + * Call destructor functions (.fini_array/.fini) + * Returns whether this succeeded or failed. + */ + void CallFini(); + + /** + * Call a function given a pointer to its location. + */ + void CallFunction(void* ptr) const { + /* C++ doesn't allow direct conversion between pointer-to-object + * and pointer-to-function. */ + union { + void* ptr; + void (*func)(void); + } f; + f.ptr = ptr; + DEBUG_LOG("%s: Calling function @%p", GetPath(), ptr); + f.func(); + } + + /** + * Call a function given a an address relative to the library base + */ + void CallFunction(Elf::Addr addr) const { return CallFunction(GetPtr(addr)); } + + /* List of dependent libraries */ + std::vector > dependencies; + + /* List of .rel.dyn/.rela.dyn relocations */ + Array relocations; + + /* List of .rel.plt/.rela.plt relocation */ + Array jumprels; + + /* Relative address of the initialization and destruction functions + * (.init/.fini) */ + Elf::Addr init, fini; + + /* List of initialization and destruction functions + * (.init_array/.fini_array) */ + Array init_array, fini_array; + + bool initialized; + + bool has_text_relocs; +}; + +#endif /* CustomElf_h */ -- cgit v1.2.3