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All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ #include "mega-dylib-utils.h" #include "MachOFileAbstraction.hpp" #include "Logging.h" #include <dirent.h> #include <sys/errno.h> #include <sys/fcntl.h> #include <mach-o/loader.h> #include <mach-o/fat.h> #include <assert.h> #include <fstream> #include <iostream> #include <string> #include <algorithm> #include <unordered_map> #include <unordered_set> #include "dyld_cache_config.h" #include "Trie.hpp" #if !NEW_CACHE_FILE_FORMAT #include "CacheFileAbstraction.hpp" #endif #define ALIGN_AS_TYPE(value, type) \ ((value + alignof(type) - 1) & (-alignof(type))) namespace { template <typename P> class SortedStringPool { public: // add a string and symbol table entry index to be updated later void add(uint32_t symbolIndex, const char* symbolName) { _map[symbolName].push_back(symbolIndex); } // copy sorted strings to buffer and update all symbol's string offsets uint32_t copyPoolAndUpdateOffsets(char* dstStringPool, macho_nlist<P>* symbolTable) { // make sorted list of strings std::vector<std::string> allStrings; allStrings.reserve(_map.size()); for (auto& entry : _map) { allStrings.push_back(entry.first); } std::sort(allStrings.begin(), allStrings.end()); // walk sorted list of strings dstStringPool[0] = '\0'; // tradition for start of pool to be empty string uint32_t poolOffset = 1; for (const std::string& symName : allStrings) { // append string to pool strcpy(&dstStringPool[poolOffset], symName.c_str()); // set each string offset of each symbol using it for (uint32_t symbolIndex : _map[symName]) { symbolTable[symbolIndex].set_n_strx(poolOffset); } poolOffset += symName.size() + 1; } // return size of pool return poolOffset; } private: std::unordered_map<std::string, std::vector<uint32_t>> _map; }; struct LocalSymbolInfo { uint32_t dylibOffset; uint32_t nlistStartIndex; uint32_t nlistCount; }; template <typename P> class LinkeditOptimizer { public: LinkeditOptimizer(void* cacheBuffer, macho_header<P>* mh); uint32_t linkeditSize() { return _linkeditSize; } uint32_t linkeditOffset() { return _linkeditCacheOffset; } uint64_t linkeditAddr() { return _linkeditAddr; } const char* installName() { return _installName; } void copyWeakBindingInfo(uint8_t* newLinkEditContent, uint32_t& offset); void copyLazyBindingInfo(uint8_t* newLinkEditContent, uint32_t& offset); void copyBindingInfo(uint8_t* newLinkEditContent, uint32_t& offset); void copyExportInfo(uint8_t* newLinkEditContent, uint32_t& offset); void copyExportedSymbols(uint8_t* newLinkEditContent, SortedStringPool<P>& stringPool, uint32_t& offset, uint32_t& symbolIndex); void copyImportedSymbols(uint8_t* newLinkEditContent, SortedStringPool<P>& stringPool, uint32_t& offset, uint32_t& symbolIndex); void copyLocalSymbols(uint8_t* newLinkEditContent, SortedStringPool<P>& stringPool, uint32_t& offset, uint32_t& symbolIndex, bool redact, std::vector<LocalSymbolInfo>& localSymbolInfos, std::vector<macho_nlist<P>>& unmappedLocalSymbols, SortedStringPool<P>& localSymbolsStringPool); void copyFunctionStarts(uint8_t* newLinkEditContent, uint32_t& offset); void copyDataInCode(uint8_t* newLinkEditContent, uint32_t& offset); void copyIndirectSymbolTable(uint8_t* newLinkEditContent, uint32_t& offset); void updateLoadCommands(uint32_t linkeditStartOffset, uint64_t mergedLinkeditAddr, uint64_t newLinkeditSize, uint32_t sharedSymbolTableStartOffset, uint32_t sharedSymbolTableCount, uint32_t sharedSymbolStringsOffset, uint32_t sharedSymbolStringsSize); macho_header<P>* machHeader() { return _mh; } const std::vector<const char*> getDownwardDependents() { return _downDependentPaths; } const std::vector<const char*> getAllDependents() { return _allDependentPaths; } const std::vector<const char*> getReExportPaths() { return _reExportPaths; } const std::vector<uint64_t> initializerAddresses() { return _initializerAddresses; } const std::vector<macho_section<P>*> dofSections() { return _dofSections; } uint32_t exportsTrieLinkEditOffset() { return _newExportInfoOffset; } uint32_t exportsTrieLinkEditSize() { return _exportInfoSize; } uint32_t weakBindingLinkEditOffset() { return _newWeakBindingInfoOffset; } uint32_t weakBindingLinkEditSize() { return _newWeakBindingSize; } uint64_t dyldSectionAddress() { return _dyldSectionAddr; } const std::vector<macho_segment_command<P>*>& segCmds() { return _segCmds; } private: typedef typename P::uint_t pint_t; typedef typename P::E E; macho_header<P>* _mh; void* _cacheBuffer; uint32_t _linkeditSize = 0; uint32_t _linkeditCacheOffset = 0; uint64_t _linkeditAddr = 0; const uint8_t* _linkeditBias = nullptr; const char* _installName = nullptr; macho_symtab_command<P>* _symTabCmd = nullptr; macho_dysymtab_command<P>* _dynSymTabCmd = nullptr; macho_dyld_info_command<P>* _dyldInfo = nullptr; macho_linkedit_data_command<P>* _functionStartsCmd = nullptr; macho_linkedit_data_command<P>* _dataInCodeCmd = nullptr; std::vector<macho_segment_command<P>*> _segCmds; std::unordered_map<uint32_t,uint32_t> _oldToNewSymbolIndexes; std::vector<const char*> _reExportPaths; std::vector<const char*> _downDependentPaths; std::vector<const char*> _allDependentPaths; std::vector<uint64_t> _initializerAddresses; std::vector<macho_section<P>*> _dofSections; uint32_t _newWeakBindingInfoOffset = 0; uint32_t _newLazyBindingInfoOffset = 0; uint32_t _newBindingInfoOffset = 0; uint32_t _newExportInfoOffset = 0; uint32_t _exportInfoSize = 0; uint32_t _newWeakBindingSize = 0; uint32_t _newExportedSymbolsStartIndex = 0; uint32_t _newExportedSymbolCount = 0; uint32_t _newImportedSymbolsStartIndex = 0; uint32_t _newImportedSymbolCount = 0; uint32_t _newLocalSymbolsStartIndex = 0; uint32_t _newLocalSymbolCount = 0; uint32_t _newFunctionStartsOffset = 0; uint32_t _newDataInCodeOffset = 0; uint32_t _newIndirectSymbolTableOffset = 0; uint64_t _dyldSectionAddr = 0; }; template <typename P> class AcceleratorTables { public: AcceleratorTables(void* cacheBuffer, uint64_t linkeditStartAddr, const std::vector<LinkeditOptimizer<P>*>& optimizers); uint32_t totalSize() const; void copyTo(uint8_t* buffer); private: typedef typename P::E E; struct NodeChain; struct DepNode { std::vector<DepNode*> _dependents; unsigned _depth; const char* _installName; DepNode() : _depth(0), _installName(nullptr) { } void computeDepth(); static void verifyUnreachable(DepNode* target, NodeChain& chain, std::unordered_set<DepNode*>& visitedNodes, const std::vector<DepNode*>& from); }; struct NodeChain { NodeChain* prev; DepNode* node; }; std::unordered_map<macho_header<P>*, DepNode> _depDAG; std::vector<dyldCacheImageInfoExtra<E>> _extraInfo; std::vector<uint8_t> _trieBytes; std::vector<uint16_t> _reExportArray; std::vector<uint16_t> _dependencyArray; std::vector<uint16_t> _bottomUpArray; std::vector<dyldCacheAcceleratorInitializer<E>> _initializers; std::vector<dyldCacheAcceleratorDOFEntry<E>> _dofSections; std::vector<dyldCacheAcceleratorRangeEntry<E>> _rangeTable; std::unordered_map<macho_header<P>*, uint32_t> _machHeaderToImageIndex; std::unordered_map<std::string, macho_header<P>*> _dylibPathToMachHeader; std::unordered_map<macho_header<P>*, LinkeditOptimizer<P>*> _machHeaderToOptimizer; dyldCacheAcceleratorInfo<E> _acceleratorInfoHeader; }; template <typename P> void AcceleratorTables<P>::AcceleratorTables::DepNode::verifyUnreachable(AcceleratorTables<P>::DepNode* target, struct AcceleratorTables<P>::NodeChain& chain, std::unordered_set<DepNode*>& visitedNodes, const std::vector<AcceleratorTables<P>::DepNode*>& from) { for (DepNode* node : from) { bool foundCycle = (node == target); for (NodeChain* c = &chain; c->prev != nullptr; c = c->prev) { if ( c->node == node ) foundCycle = true; } if ( foundCycle ) { NodeChain* chp = &chain; std::string msg = std::string("found cycle for ") + target->_installName; while (chp != nullptr) { msg = msg + "\n " + chp->node->_installName; chp = chp->prev; } warning("%s", msg.c_str()); return; } if ( visitedNodes.count(node) ) continue; NodeChain nextChain; nextChain.prev = &chain; nextChain.node = node; verifyUnreachable(target, nextChain, visitedNodes, node->_dependents); visitedNodes.insert(node); } } const uint16_t kBranchIslandDylibIndex = 0x7FFF; template <typename P> AcceleratorTables<P>::AcceleratorTables(void* cacheBuffer, uint64_t linkeditStartAddr, const std::vector<LinkeditOptimizer<P>*>& optimizers) { // build table mapping tables to map between mach_header, index, and optimizer for ( LinkeditOptimizer<P>* op : optimizers ) { _machHeaderToOptimizer[op->machHeader()] = op; } uint64_t cacheStartAddress; #if NEW_CACHE_FILE_FORMAT #error new format support not implemented #else typedef typename P::E E; const dyldCacheHeader<E>* header = (dyldCacheHeader<E>*)cacheBuffer; const dyldCacheFileMapping<E>* mappings = (dyldCacheFileMapping<E>*)((uint8_t*)cacheBuffer + header->mappingOffset()); cacheStartAddress = mappings[0].address(); const dyldCacheImageInfo<E>* images = (dyldCacheImageInfo<E>*)((uint8_t*)cacheBuffer + header->imagesOffset()); const unsigned imageCount = header->imagesCount(); for (unsigned i=0; i < imageCount; ++i) { uint64_t segCacheFileOffset = images[i].address() - cacheStartAddress; macho_header<P>* mhMapped = (macho_header<P>*)((uint8_t*)cacheBuffer+segCacheFileOffset); const char* path = (char*)cacheBuffer + images[i].pathFileOffset(); _dylibPathToMachHeader[path] = mhMapped; // don't add alias entries (path offset in pool near start of cache) to header->index map if ( images[i].pathFileOffset() > segCacheFileOffset ) _machHeaderToImageIndex[mhMapped] = i; } #endif // build DAG of image dependencies for (LinkeditOptimizer<P>* op : optimizers) { _depDAG[op->machHeader()]._installName = op->installName(); } for (LinkeditOptimizer<P>* op : optimizers) { DepNode& node = _depDAG[op->machHeader()]; for (const char* depPath : op->getDownwardDependents()) { macho_header<P>* depMH = _dylibPathToMachHeader[depPath]; assert(depMH != NULL); DepNode* depNode = &_depDAG[depMH]; node._dependents.push_back(depNode); } } // check for cycles in DAG for (auto& entry : _depDAG) { DepNode* node = &entry.second; NodeChain chain; chain.prev = nullptr; chain.node = node; std::unordered_set<DepNode*> visitedNodes; DepNode::verifyUnreachable(node, chain, visitedNodes, node->_dependents); } // compute depth for each DAG node for (auto& entry : _depDAG) { entry.second.computeDepth(); } // build sorted (bottom up) list of images std::vector<macho_header<P>*> sortedMachHeaders; sortedMachHeaders.reserve(optimizers.size()); for (LinkeditOptimizer<P>* op : optimizers) { if ( strcmp(op->installName(), "dyld_shared_cache_branch_islands") != 0 ) sortedMachHeaders.push_back(op->machHeader()); else _machHeaderToImageIndex[op->machHeader()] = kBranchIslandDylibIndex; } std::sort(sortedMachHeaders.begin(), sortedMachHeaders.end(), [&](macho_header<P>* lmh, macho_header<P>* rmh) -> bool { if ( _depDAG[lmh]._depth != _depDAG[rmh]._depth ) return (_depDAG[lmh]._depth < _depDAG[rmh]._depth); else return (lmh < rmh); }); // build zeroed array of extra infos dyldCacheImageInfoExtra<E> emptyExtra; emptyExtra.set_exportsTrieAddr(0); emptyExtra.set_weakBindingsAddr(0); emptyExtra.set_exportsTrieSize(0); emptyExtra.set_weakBindingsSize(0); emptyExtra.set_dependentsStartArrayIndex(0); emptyExtra.set_reExportsStartArrayIndex(0); _extraInfo.insert(_extraInfo.begin(), sortedMachHeaders.size(), emptyExtra); //for ( macho_header<P>* mh : sortedMachHeaders ) { // fprintf(stderr, "depth: %3d mh: %p path: %s\n", _depDAG[mh]._depth, mh, _machHeaderToOptimizer[mh]->installName()); //} // build dependency table _dependencyArray.push_back(0xFFFF); // reserve 0 slot to be "no-dependencies" for (macho_header<P>* mh : sortedMachHeaders) { LinkeditOptimizer<P>* op = _machHeaderToOptimizer[mh]; unsigned index = _machHeaderToImageIndex[mh]; auto depPaths = op->getAllDependents(); if ( depPaths.empty() ) { _extraInfo[index].set_dependentsStartArrayIndex(0); } else { _extraInfo[index].set_dependentsStartArrayIndex((uint32_t)_dependencyArray.size()); auto downPaths = op->getDownwardDependents(); for (const char* depPath : depPaths) { macho_header<P>* depMH = _dylibPathToMachHeader[depPath]; uint16_t depIndex = _machHeaderToImageIndex[depMH]; if ( std::find(downPaths.begin(), downPaths.end(), depPath) == downPaths.end()) depIndex |= 0x8000; _dependencyArray.push_back(depIndex); } _dependencyArray.push_back(0xFFFF); // mark end of list } } // build re-exports table _reExportArray.push_back(0xFFFF); // reserve 0 slot to be "no-re-exports" for (macho_header<P>* mh : sortedMachHeaders) { LinkeditOptimizer<P>* op = _machHeaderToOptimizer[mh]; unsigned index = _machHeaderToImageIndex[mh]; auto reExPaths = op->getReExportPaths(); if ( reExPaths.empty() ) { _extraInfo[index].set_reExportsStartArrayIndex(0); } else { _extraInfo[index].set_reExportsStartArrayIndex((uint32_t)_reExportArray.size()); for (const char* reExPath : reExPaths) { macho_header<P>* reExMH = _dylibPathToMachHeader[reExPath]; uint32_t reExIndex = _machHeaderToImageIndex[reExMH]; _reExportArray.push_back(reExIndex); } _reExportArray.push_back(0xFFFF); // mark end of list } } // build ordered list of initializers for (macho_header<P>* mh : sortedMachHeaders) { LinkeditOptimizer<P>* op = _machHeaderToOptimizer[mh]; unsigned index = _machHeaderToImageIndex[mh]; _bottomUpArray.push_back(index); for (uint64_t initializer : op->initializerAddresses()) { //fprintf(stderr, "0x%08llX %s\n", initializer, op->installName()); dyldCacheAcceleratorInitializer<E> entry; entry.set_functionOffset((uint32_t)(initializer-cacheStartAddress)); entry.set_imageIndex(_machHeaderToImageIndex[mh]); _initializers.push_back(entry); } } // build ordered list of DOF sections for (macho_header<P>* mh : sortedMachHeaders) { LinkeditOptimizer<P>* op = _machHeaderToOptimizer[mh]; assert(op != NULL); unsigned imageIndex = _machHeaderToImageIndex[mh]; for (auto& sect : op->dofSections()) { //fprintf(stderr, "0x%08llX %s\n", initializer, op->installName()); dyldCacheAcceleratorDOFEntry<E> entry; entry.set_sectionAddress(sect->addr()); entry.set_sectionSize((uint32_t)sect->size()); entry.set_imageIndex(imageIndex); _dofSections.push_back(entry); } } // register exports trie and weak binding info in each dylib with image extra info for (macho_header<P>* mh : sortedMachHeaders) { LinkeditOptimizer<P>* op = _machHeaderToOptimizer[mh]; unsigned index = _machHeaderToImageIndex[mh]; _extraInfo[index].set_exportsTrieAddr(op->exportsTrieLinkEditOffset() + linkeditStartAddr); _extraInfo[index].set_exportsTrieSize(op->exportsTrieLinkEditSize()); _extraInfo[index].set_weakBindingsAddr(op->weakBindingLinkEditOffset() + linkeditStartAddr); _extraInfo[index].set_weakBindingsSize(op->weakBindingLinkEditSize()); } // record location of __DATA/__dyld section in libdyld.dylib macho_header<P>* libdyldMH = _dylibPathToMachHeader["/usr/lib/system/libdyld.dylib"]; LinkeditOptimizer<P>* libdyldOp = _machHeaderToOptimizer[libdyldMH]; uint64_t dyldSectionAddr = libdyldOp->dyldSectionAddress(); // build range table for fast address->image lookups for (macho_header<P>* mh : sortedMachHeaders) { LinkeditOptimizer<P>* op = _machHeaderToOptimizer[mh]; unsigned imageIndex = _machHeaderToImageIndex[mh]; for ( const macho_segment_command<P>* segCmd : op->segCmds() ) { if ( strcmp(segCmd->segname(), "__LINKEDIT") == 0 ) continue; dyldCacheAcceleratorRangeEntry<E> entry; entry.set_startAddress(segCmd->vmaddr()); entry.set_size((uint32_t)segCmd->vmsize()); entry.set_imageIndex(imageIndex); _rangeTable.push_back(entry); } } std::sort(_rangeTable.begin(), _rangeTable.end(), [&](const dyldCacheAcceleratorRangeEntry<E>& lRange, const dyldCacheAcceleratorRangeEntry<E>& rRange) -> bool { return (lRange.startAddress() < rRange.startAddress()); }); // build trie that maps install names to image index std::vector<DylibIndexTrie::Entry> dylibEntrys; for (auto &x : _dylibPathToMachHeader) { const std::string& path = x.first; unsigned index = _machHeaderToImageIndex[x.second]; dylibEntrys.push_back(DylibIndexTrie::Entry(path, DylibIndex(index))); } DylibIndexTrie dylibsTrie(dylibEntrys); dylibsTrie.emit(_trieBytes); while ( (_trieBytes.size() % 4) != 0 ) _trieBytes.push_back(0); // fill out header dyldCacheAcceleratorInfo<E>& h = _acceleratorInfoHeader; h.set_version(1); h.set_imageExtrasCount((uint32_t)_extraInfo.size()); h.set_imagesExtrasOffset(ALIGN_AS_TYPE(sizeof(dyld_cache_accelerator_info), dyld_cache_image_info_extra)); h.set_bottomUpListOffset(h.imagesExtrasOffset() + h.imageExtrasCount()*sizeof(dyld_cache_image_info_extra)); h.set_dylibTrieOffset(h.bottomUpListOffset() + h.imageExtrasCount()*sizeof(uint16_t)); h.set_dylibTrieSize((uint32_t)_trieBytes.size()); h.set_initializersOffset(ALIGN_AS_TYPE(h.dylibTrieOffset() + h.dylibTrieSize(), dyld_cache_accelerator_initializer)); h.set_initializersCount((uint32_t)_initializers.size()); h.set_dofSectionsOffset(ALIGN_AS_TYPE(h.initializersOffset() + h.initializersCount()*sizeof(dyld_cache_accelerator_initializer), dyld_cache_accelerator_initializer)); h.set_dofSectionsCount((uint32_t)_dofSections.size()); h.set_reExportListOffset(ALIGN_AS_TYPE(h.dofSectionsOffset() + h.dofSectionsCount()*sizeof(dyld_cache_accelerator_dof), dyld_cache_accelerator_dof)); h.set_reExportCount((uint32_t)_reExportArray.size()); h.set_depListOffset(ALIGN_AS_TYPE(h.reExportListOffset() + h.reExportCount()*sizeof(uint16_t), uint16_t)); h.set_depListCount((uint32_t)_dependencyArray.size()); h.set_rangeTableOffset(ALIGN_AS_TYPE(h.depListOffset() + h.depListCount()*sizeof(uint16_t), dyld_cache_range_entry)); h.set_rangeTableCount((uint32_t)_rangeTable.size()); h.set_dyldSectionAddr(dyldSectionAddr); } template <typename P> void AcceleratorTables<P>::DepNode::computeDepth() { if ( _depth != 0 ) return; _depth = 1; for (DepNode* node : _dependents) { node->computeDepth(); if ( node->_depth >= _depth ) _depth = node->_depth + 1; } } template <typename P> uint32_t AcceleratorTables<P>::totalSize() const { return (uint32_t)align(_acceleratorInfoHeader.rangeTableOffset() + _acceleratorInfoHeader.rangeTableCount()*sizeof(dyld_cache_range_entry), 14); } template <typename P> void AcceleratorTables<P>::copyTo(uint8_t* buffer) { memcpy(buffer, &_acceleratorInfoHeader, sizeof(dyld_cache_accelerator_info)); memcpy(&buffer[_acceleratorInfoHeader.imagesExtrasOffset()], &_extraInfo[0], _extraInfo.size()*sizeof(dyld_cache_image_info_extra)); memcpy(&buffer[_acceleratorInfoHeader.bottomUpListOffset()], &_bottomUpArray[0], _bottomUpArray.size()*sizeof(uint16_t)); memcpy(&buffer[_acceleratorInfoHeader.initializersOffset()], &_initializers[0], _initializers.size()*sizeof(dyld_cache_accelerator_initializer)); memcpy(&buffer[_acceleratorInfoHeader.reExportListOffset()], &_reExportArray[0], _reExportArray.size()*sizeof(uint16_t)); memcpy(&buffer[_acceleratorInfoHeader.dofSectionsOffset()], &_dofSections[0], _dofSections.size()*sizeof(dyld_cache_accelerator_dof)); memcpy(&buffer[_acceleratorInfoHeader.depListOffset()], &_dependencyArray[0], _dependencyArray.size()*sizeof(uint16_t)); memcpy(&buffer[_acceleratorInfoHeader.rangeTableOffset()], &_rangeTable[0], _rangeTable.size()*sizeof(dyld_cache_range_entry)); memcpy(&buffer[_acceleratorInfoHeader.dylibTrieOffset()], &_trieBytes[0], _trieBytes.size()); } template <typename P> LinkeditOptimizer<P>::LinkeditOptimizer(void* cacheBuffer, macho_header<P>* mh) : _mh(mh), _cacheBuffer(cacheBuffer) { _linkeditBias = (uint8_t*)cacheBuffer; const unsigned origLoadCommandsSize = mh->sizeofcmds(); unsigned bytesRemaining = origLoadCommandsSize; unsigned removedCount = 0; const macho_load_command<P>* const cmds = (macho_load_command<P>*)((uint8_t*)mh + sizeof(macho_header<P>)); const uint32_t cmdCount = mh->ncmds(); const macho_load_command<P>* cmd = cmds; const macho_dylib_command<P>* dylibCmd; const macho_routines_command<P>* routinesCmd; macho_segment_command<P>* segCmd; for (uint32_t i = 0; i < cmdCount; ++i) { bool remove = false; switch (cmd->cmd()) { case LC_ID_DYLIB: _installName = ((macho_dylib_command<P>*)cmd)->name(); break; case LC_SYMTAB: _symTabCmd = (macho_symtab_command<P>*)cmd; break; case LC_DYSYMTAB: _dynSymTabCmd = (macho_dysymtab_command<P>*)cmd; break; case LC_DYLD_INFO: case LC_DYLD_INFO_ONLY: _dyldInfo = (macho_dyld_info_command<P>*)cmd; _exportInfoSize = _dyldInfo->export_size(); break; case LC_FUNCTION_STARTS: _functionStartsCmd = (macho_linkedit_data_command<P>*)cmd; break; case LC_DATA_IN_CODE: _dataInCodeCmd = (macho_linkedit_data_command<P>*)cmd; break; case LC_ROUTINES: case LC_ROUTINES_64: routinesCmd = (macho_routines_command<P>*)cmd; _initializerAddresses.push_back(routinesCmd->init_address()); break; case LC_REEXPORT_DYLIB: case LC_LOAD_DYLIB: case LC_LOAD_WEAK_DYLIB: case LC_LOAD_UPWARD_DYLIB: dylibCmd = (macho_dylib_command<P>*)cmd; _allDependentPaths.push_back(dylibCmd->name()); if ( cmd->cmd() != LC_LOAD_UPWARD_DYLIB ) _downDependentPaths.push_back(dylibCmd->name()); if ( cmd->cmd() == LC_REEXPORT_DYLIB ) _reExportPaths.push_back(dylibCmd->name()); break; case macho_segment_command<P>::CMD: segCmd = (macho_segment_command<P>*)cmd; _segCmds.push_back(segCmd); if ( strcmp(segCmd->segname(), "__LINKEDIT") == 0 ) { _linkeditSize = (uint32_t)segCmd->vmsize(); _linkeditCacheOffset = (uint32_t)segCmd->fileoff(); _linkeditAddr = segCmd->vmaddr(); } else if ( segCmd->nsects() > 0 ) { macho_section<P>* const sectionsStart = (macho_section<P>*)((uint8_t*)segCmd + sizeof(macho_segment_command<P>)); macho_section<P>* const sectionsEnd = §ionsStart[segCmd->nsects()]; for (macho_section<P>* sect=sectionsStart; sect < sectionsEnd; ++sect) { const uint8_t type = sect->flags() & SECTION_TYPE; if ( type == S_MOD_INIT_FUNC_POINTERS ) { const pint_t* inits = (pint_t*)((char*)cacheBuffer + sect->offset()); const size_t count = sect->size() / sizeof(pint_t); for (size_t j=0; j < count; ++j) { uint64_t func = P::getP(inits[j]); _initializerAddresses.push_back(func); } } else if ( type == S_DTRACE_DOF ) { _dofSections.push_back(sect); } else if ( (strcmp(sect->sectname(), "__dyld") == 0) && (strncmp(sect->segname(), "__DATA", 6) == 0) ) { _dyldSectionAddr = sect->addr(); } } } break; case LC_SEGMENT_SPLIT_INFO: remove = true; break; } uint32_t cmdSize = cmd->cmdsize(); macho_load_command<P>* nextCmd = (macho_load_command<P>*)(((uint8_t*)cmd)+cmdSize); if ( remove ) { ::memmove((void*)cmd, (void*)nextCmd, bytesRemaining); ++removedCount; } else { bytesRemaining -= cmdSize; cmd = nextCmd; } } // zero out stuff removed ::bzero((void*)cmd, bytesRemaining); // update header mh->set_ncmds(cmdCount - removedCount); mh->set_sizeofcmds(origLoadCommandsSize - bytesRemaining); } /* static void dumpLoadCommands(const uint8_t* mheader) { const mach_header* const mh = (mach_header*)mheader; const uint32_t cmd_count = mh->ncmds; bool is64 = (mh->magic == MH_MAGIC_64); const load_command* cmds = (load_command*)(mheader + (is64 ? sizeof(mach_header_64) : sizeof(mach_header))); const load_command* cmd = cmds; const segment_command* segCmd; const segment_command_64* seg64Cmd; const symtab_command* symTab; const linkedit_data_command* leData; const uint8_t* linkEditBias = NULL; for (uint32_t i = 0; i < cmd_count; ++i) { switch (cmd->cmd) { case LC_SEGMENT: segCmd = (const segment_command*)cmd; printf("LC_SEGMENT\n"); printf(" segname = %s\n", segCmd->segname); printf(" vmaddr = 0x%08X\n", segCmd->vmaddr); printf(" vmsize = 0x%08X\n", segCmd->vmsize); printf(" fileoff = 0x%08X\n", segCmd->fileoff); printf(" filesize = 0x%08X\n", segCmd->filesize); if ( strcmp(segCmd->segname, "__TEXT") == 0 ) { linkEditBias = mheader - segCmd->fileoff; } break; case LC_SEGMENT_64: seg64Cmd = (const segment_command_64*)cmd; printf("LC_SEGMENT_64\n"); printf(" segname = %s\n", seg64Cmd->segname); printf(" vmaddr = 0x%09llX\n", seg64Cmd->vmaddr); printf(" vmsize = 0x%09llX\n", seg64Cmd->vmsize); printf(" fileoff = 0x%09llX\n", seg64Cmd->fileoff); printf(" filesize = 0x%09llX\n", seg64Cmd->filesize); if ( strcmp(seg64Cmd->segname, "__TEXT") == 0 ) { linkEditBias = mheader - seg64Cmd->fileoff; } break; case LC_SYMTAB: symTab = (const symtab_command*)cmd; printf("LC_SYMTAB\n"); printf(" symoff = 0x%08X\n", symTab->symoff); printf(" nsyms = 0x%08X\n", symTab->nsyms); printf(" stroff = 0x%08X\n", symTab->stroff); printf(" strsize = 0x%08X\n", symTab->strsize); { const char* strPool = (char*)&linkEditBias[symTab->stroff]; const nlist_64* sym0 = (nlist_64*)(&linkEditBias[symTab->symoff]); printf(" sym[0].n_strx = 0x%08X (%s)\n", sym0->n_un.n_strx, &strPool[sym0->n_un.n_strx]); printf(" sym[0].n_type = 0x%02X\n", sym0->n_type); printf(" sym[0].n_sect = 0x%02X\n", sym0->n_sect); printf(" sym[0].n_desc = 0x%04X\n", sym0->n_desc); printf(" sym[0].n_value = 0x%llX\n", sym0->n_value); const nlist_64* sym1 = (nlist_64*)(&linkEditBias[symTab->symoff+16]); printf(" sym[1].n_strx = 0x%08X (%s)\n", sym1->n_un.n_strx, &strPool[sym1->n_un.n_strx]); printf(" sym[1].n_type = 0x%02X\n", sym1->n_type); printf(" sym[1].n_sect = 0x%02X\n", sym1->n_sect); printf(" sym[1].n_desc = 0x%04X\n", sym1->n_desc); printf(" sym[1].n_value = 0x%llX\n", sym1->n_value); } break; case LC_FUNCTION_STARTS: leData = (const linkedit_data_command*)cmd; printf("LC_FUNCTION_STARTS\n"); printf(" dataoff = 0x%08X\n", leData->dataoff); printf(" datasize = 0x%08X\n", leData->datasize); default: //printf("0x%08X\n", cmd->cmd); break; } cmd = (const load_command*)(((uint8_t*)cmd)+cmd->cmdsize); } } */ template <typename P> void LinkeditOptimizer<P>::updateLoadCommands(uint32_t mergedLinkeditStartOffset, uint64_t mergedLinkeditAddr, uint64_t newLinkeditSize, uint32_t sharedSymbolTableStartOffset, uint32_t sharedSymbolTableCount, uint32_t sharedSymbolStringsOffset, uint32_t sharedSymbolStringsSize) { // update __LINKEDIT segment in all dylibs to overlap the same shared region for (macho_segment_command<P>* segCmd : _segCmds) { if ( strcmp(segCmd->segname(), "__LINKEDIT") == 0 ) { segCmd->set_vmaddr(mergedLinkeditAddr); segCmd->set_vmsize(newLinkeditSize); segCmd->set_fileoff(mergedLinkeditStartOffset); segCmd->set_filesize(newLinkeditSize); } else if ( strcmp(segCmd->segname(), "__TEXT") == 0 ) { // HACK until lldb fixed in: <rdar://problem/20357466> DynamicLoaderMacOSXDYLD fixes for Monarch dyld shared cache segCmd->set_fileoff(0); } } // update symbol table to point to shared symbol table _symTabCmd->set_symoff(mergedLinkeditStartOffset + sharedSymbolTableStartOffset + _newLocalSymbolsStartIndex*sizeof(macho_nlist<P>)); _symTabCmd->set_nsyms(_newLocalSymbolCount+_newExportedSymbolCount+_newImportedSymbolCount); _symTabCmd->set_stroff(mergedLinkeditStartOffset + sharedSymbolStringsOffset); _symTabCmd->set_strsize(sharedSymbolStringsSize); // update dynamic symbol table to have proper offsets into shared symbol table _dynSymTabCmd->set_ilocalsym(0); _dynSymTabCmd->set_nlocalsym(_newLocalSymbolCount); _dynSymTabCmd->set_iextdefsym(_newExportedSymbolsStartIndex-_newLocalSymbolsStartIndex); _dynSymTabCmd->set_nextdefsym(_newExportedSymbolCount); _dynSymTabCmd->set_iundefsym(_newImportedSymbolsStartIndex-_newLocalSymbolsStartIndex); _dynSymTabCmd->set_nundefsym(_newImportedSymbolCount); _dynSymTabCmd->set_tocoff(0); _dynSymTabCmd->set_ntoc(0); _dynSymTabCmd->set_modtaboff(0); _dynSymTabCmd->set_nmodtab(0); _dynSymTabCmd->set_indirectsymoff(mergedLinkeditStartOffset + _newIndirectSymbolTableOffset); _dynSymTabCmd->set_extreloff(0); _dynSymTabCmd->set_locreloff(0); _dynSymTabCmd->set_nlocrel(0); // update dyld info if ( _dyldInfo != nullptr ) { _dyldInfo->set_rebase_off(0); _dyldInfo->set_rebase_size(0); _dyldInfo->set_bind_off(_dyldInfo->bind_size() ? mergedLinkeditStartOffset + _newBindingInfoOffset : 0); _dyldInfo->set_weak_bind_off(_dyldInfo->weak_bind_size() ? mergedLinkeditStartOffset + _newWeakBindingInfoOffset : 0 ); _dyldInfo->set_lazy_bind_off(_dyldInfo->lazy_bind_size() ? mergedLinkeditStartOffset + _newLazyBindingInfoOffset : 0 ); _dyldInfo->set_export_off(mergedLinkeditStartOffset + _newExportInfoOffset); } // update function-starts if ( _functionStartsCmd != nullptr ) _functionStartsCmd->set_dataoff(mergedLinkeditStartOffset+_newFunctionStartsOffset); // update data-in-code if ( _dataInCodeCmd != nullptr ) _dataInCodeCmd->set_dataoff(mergedLinkeditStartOffset+_newDataInCodeOffset); } template <typename P> void LinkeditOptimizer<P>::copyWeakBindingInfo(uint8_t* newLinkEditContent, uint32_t& offset) { if ( _dyldInfo == nullptr ) return; unsigned size = _dyldInfo->weak_bind_size(); if ( size != 0 ) { ::memcpy(&newLinkEditContent[offset], &_linkeditBias[_dyldInfo->weak_bind_off()], size); _newWeakBindingInfoOffset = offset; _newWeakBindingSize = size; offset += size; } } template <typename P> void LinkeditOptimizer<P>::copyLazyBindingInfo(uint8_t* newLinkEditContent, uint32_t& offset) { if ( _dyldInfo == nullptr ) return; unsigned size = _dyldInfo->lazy_bind_size(); if ( size != 0 ) { ::memcpy(&newLinkEditContent[offset], &_linkeditBias[_dyldInfo->lazy_bind_off()], size); _newLazyBindingInfoOffset = offset; offset += size; } } template <typename P> void LinkeditOptimizer<P>::copyBindingInfo(uint8_t* newLinkEditContent, uint32_t& offset) { if ( _dyldInfo == nullptr ) return; unsigned size = _dyldInfo->bind_size(); if ( size != 0 ) { ::memcpy(&newLinkEditContent[offset], &_linkeditBias[_dyldInfo->bind_off()], size); _newBindingInfoOffset = offset; offset += size; } } template <typename P> void LinkeditOptimizer<P>::copyExportInfo(uint8_t* newLinkEditContent, uint32_t& offset) { if ( _dyldInfo == nullptr ) return; unsigned size = _dyldInfo->export_size(); if ( size != 0 ) { ::memcpy(&newLinkEditContent[offset], &_linkeditBias[_dyldInfo->export_off()], size); _newExportInfoOffset = offset; offset += size; } } template <typename P> void LinkeditOptimizer<P>::copyFunctionStarts(uint8_t* newLinkEditContent, uint32_t& offset) { if ( _functionStartsCmd == nullptr ) return; unsigned size = _functionStartsCmd->datasize(); ::memcpy(&newLinkEditContent[offset], &_linkeditBias[_functionStartsCmd->dataoff()], size); _newFunctionStartsOffset = offset; offset += size; } template <typename P> void LinkeditOptimizer<P>::copyDataInCode(uint8_t* newLinkEditContent, uint32_t& offset) { if ( _dataInCodeCmd == nullptr ) return; unsigned size = _dataInCodeCmd->datasize(); ::memcpy(&newLinkEditContent[offset], &_linkeditBias[_dataInCodeCmd->dataoff()], size); _newDataInCodeOffset = offset; offset += size; } template <typename P> void LinkeditOptimizer<P>::copyLocalSymbols(uint8_t* newLinkEditContent, SortedStringPool<P>& stringPool, uint32_t& offset, uint32_t& symbolIndex, bool redact, std::vector<LocalSymbolInfo>& localSymbolInfos, std::vector<macho_nlist<P>>& unmappedLocalSymbols, SortedStringPool<P>& localSymbolsStringPool) { LocalSymbolInfo localInfo; localInfo.dylibOffset = (uint32_t)(((uint8_t*)_mh) - (uint8_t*)_cacheBuffer); localInfo.nlistStartIndex = (uint32_t)unmappedLocalSymbols.size(); localInfo.nlistCount = 0; _newLocalSymbolsStartIndex = symbolIndex; const char* strings = (char*)&_linkeditBias[_symTabCmd->stroff()]; const macho_nlist<P>* const symbolTable = (macho_nlist<P>*)(&_linkeditBias[_symTabCmd->symoff()]); const macho_nlist<P>* const firstExport = &symbolTable[_dynSymTabCmd->ilocalsym()]; const macho_nlist<P>* const lastExport = &symbolTable[_dynSymTabCmd->ilocalsym()+_dynSymTabCmd->nlocalsym()]; for (const macho_nlist<P>* entry = firstExport; entry < lastExport; ++entry) { if ( (entry->n_type() & N_TYPE) != N_SECT) continue; if ( (entry->n_type() & N_STAB) != 0) continue; const char* name = &strings[entry->n_strx()]; macho_nlist<P>* newSymbolEntry = (macho_nlist<P>*)&newLinkEditContent[offset]; *newSymbolEntry = *entry; if ( redact ) { // if removing local symbols, change __text symbols to "<redacted>" so backtraces don't have bogus names if ( entry->n_sect() == 1 ) { stringPool.add(symbolIndex, "<redacted>"); ++symbolIndex; offset += sizeof(macho_nlist<P>); } // copy local symbol to unmmapped locals area localSymbolsStringPool.add((uint32_t)unmappedLocalSymbols.size(), name); unmappedLocalSymbols.push_back(*entry); unmappedLocalSymbols.back().set_n_strx(0); } else { stringPool.add(symbolIndex, name); ++symbolIndex; offset += sizeof(macho_nlist<P>); } } _newLocalSymbolCount = symbolIndex - _newLocalSymbolsStartIndex; localInfo.nlistCount = (uint32_t)unmappedLocalSymbols.size() - localInfo.nlistStartIndex; localSymbolInfos.push_back(localInfo); } template <typename P> void LinkeditOptimizer<P>::copyExportedSymbols(uint8_t* newLinkEditContent, SortedStringPool<P>& stringPool, uint32_t& offset, uint32_t& symbolIndex) { _newExportedSymbolsStartIndex = symbolIndex; const char* strings = (char*)&_linkeditBias[_symTabCmd->stroff()]; const macho_nlist<P>* const symbolTable = (macho_nlist<P>*)(&_linkeditBias[_symTabCmd->symoff()]); const macho_nlist<P>* const firstExport = &symbolTable[_dynSymTabCmd->iextdefsym()]; const macho_nlist<P>* const lastExport = &symbolTable[_dynSymTabCmd->iextdefsym()+_dynSymTabCmd->nextdefsym()]; uint32_t oldSymbolIndex = _dynSymTabCmd->iextdefsym(); for (const macho_nlist<P>* entry = firstExport; entry < lastExport; ++entry, ++oldSymbolIndex) { if ( (entry->n_type() & N_TYPE) != N_SECT) continue; const char* name = &strings[entry->n_strx()]; if ( strncmp(name, ".objc_", 6) == 0 ) continue; if ( strncmp(name, "$ld$", 4) == 0 ) continue; macho_nlist<P>* newSymbolEntry = (macho_nlist<P>*)&newLinkEditContent[offset]; *newSymbolEntry = *entry; newSymbolEntry->set_n_strx(0); stringPool.add(symbolIndex, name); _oldToNewSymbolIndexes[oldSymbolIndex] = symbolIndex - _newLocalSymbolsStartIndex; ++symbolIndex; offset += sizeof(macho_nlist<P>); } _newExportedSymbolCount = symbolIndex - _newExportedSymbolsStartIndex; } template <typename P> void LinkeditOptimizer<P>::copyImportedSymbols(uint8_t* newLinkEditContent, SortedStringPool<P>& stringPool, uint32_t& offset, uint32_t& symbolIndex) { _newImportedSymbolsStartIndex = symbolIndex; const char* strings = (char*)&_linkeditBias[_symTabCmd->stroff()]; const macho_nlist<P>* const symbolTable = (macho_nlist<P>*)(&_linkeditBias[_symTabCmd->symoff()]); const macho_nlist<P>* const firstImport = &symbolTable[_dynSymTabCmd->iundefsym()]; const macho_nlist<P>* const lastImport = &symbolTable[_dynSymTabCmd->iundefsym()+_dynSymTabCmd->nundefsym()]; uint32_t oldSymbolIndex = _dynSymTabCmd->iundefsym(); for (const macho_nlist<P>* entry = firstImport; entry < lastImport; ++entry, ++oldSymbolIndex) { if ( (entry->n_type() & N_TYPE) != N_UNDF) continue; const char* name = &strings[entry->n_strx()]; macho_nlist<P>* newSymbolEntry = (macho_nlist<P>*)&newLinkEditContent[offset]; *newSymbolEntry = *entry; newSymbolEntry->set_n_strx(0); stringPool.add(symbolIndex, name); _oldToNewSymbolIndexes[oldSymbolIndex] = symbolIndex - _newLocalSymbolsStartIndex; ++symbolIndex; offset += sizeof(macho_nlist<P>); } _newImportedSymbolCount = symbolIndex - _newImportedSymbolsStartIndex; } template <typename P> void LinkeditOptimizer<P>::copyIndirectSymbolTable(uint8_t* newLinkEditContent, uint32_t& offset) { _newIndirectSymbolTableOffset = offset; const uint32_t* const indirectTable = (uint32_t*)&_linkeditBias[_dynSymTabCmd->indirectsymoff()]; uint32_t* newIndirectTable = (uint32_t*)&newLinkEditContent[offset]; for (int i=0; i < _dynSymTabCmd->nindirectsyms(); ++i) { uint32_t symbolIndex = E::get32(indirectTable[i]); if ( (symbolIndex == INDIRECT_SYMBOL_ABS) || (symbolIndex == INDIRECT_SYMBOL_LOCAL) ) E::set32(newIndirectTable[i], symbolIndex); else E::set32(newIndirectTable[i], _oldToNewSymbolIndexes[symbolIndex]); offset += sizeof(uint32_t); } } template <typename P> uint64_t mergeLinkedits(SharedCache& cache, bool dontMapLocalSymbols, bool addAcceleratorTables, std::vector<LinkeditOptimizer<P>*>& optimizers) { // allocate space for new linkedit data uint32_t linkeditStartOffset = 0xFFFFFFFF; uint32_t linkeditEndOffset = 0; uint64_t linkeditStartAddr = 0; for (LinkeditOptimizer<P>* op : optimizers) { uint32_t leOffset = op->linkeditOffset(); if ( leOffset < linkeditStartOffset ) { linkeditStartOffset = leOffset; linkeditStartAddr = op->linkeditAddr(); } uint32_t leEndOffset = op->linkeditOffset() + op->linkeditSize(); if ( leEndOffset > linkeditEndOffset ) linkeditEndOffset = leEndOffset; } uint64_t totalUnoptLinkeditsSize = linkeditEndOffset - linkeditStartOffset; uint8_t* newLinkEdit = (uint8_t*)calloc(totalUnoptLinkeditsSize, 1); SortedStringPool<P> stringPool; uint32_t offset = 0; verboseLog("Merged LINKEDIT:"); // copy weak binding info uint32_t startWeakBindInfosOffset = offset; for (LinkeditOptimizer<P>* op : optimizers) { op->copyWeakBindingInfo(newLinkEdit, offset); } verboseLog(" weak bindings size: %5uKB", (offset-startWeakBindInfosOffset)/1024); // copy export info uint32_t startExportInfosOffset = offset; for (LinkeditOptimizer<P>* op : optimizers) { op->copyExportInfo(newLinkEdit, offset); } verboseLog(" exports info size: %5uKB", (offset-startExportInfosOffset)/1024); // in theory, an optimized cache can drop the binding info if ( true ) { // copy binding info uint32_t startBindingsInfosOffset = offset; for (LinkeditOptimizer<P>* op : optimizers) { op->copyBindingInfo(newLinkEdit, offset); } verboseLog(" bindings size: %5uKB", (offset-startBindingsInfosOffset)/1024); // copy lazy binding info uint32_t startLazyBindingsInfosOffset = offset; for (LinkeditOptimizer<P>* op : optimizers) { op->copyLazyBindingInfo(newLinkEdit, offset); } verboseLog(" lazy bindings size: %5uKB", (offset-startLazyBindingsInfosOffset)/1024); } // copy symbol table entries std::vector<macho_nlist<P>> unmappedLocalSymbols; if ( dontMapLocalSymbols ) unmappedLocalSymbols.reserve(0x01000000); std::vector<LocalSymbolInfo> localSymbolInfos; localSymbolInfos.reserve(optimizers.size()); SortedStringPool<P> localSymbolsStringPool; uint32_t symbolIndex = 0; const uint32_t sharedSymbolTableStartOffset = offset; uint32_t sharedSymbolTableExportsCount = 0; uint32_t sharedSymbolTableImportsCount = 0; for (LinkeditOptimizer<P>* op : optimizers) { op->copyLocalSymbols(newLinkEdit, stringPool, offset, symbolIndex, dontMapLocalSymbols, localSymbolInfos, unmappedLocalSymbols, localSymbolsStringPool); uint32_t x = symbolIndex; op->copyExportedSymbols(newLinkEdit, stringPool, offset, symbolIndex); sharedSymbolTableExportsCount += (symbolIndex-x); uint32_t y = symbolIndex; op->copyImportedSymbols(newLinkEdit, stringPool, offset, symbolIndex); sharedSymbolTableImportsCount += (symbolIndex-y); } uint32_t sharedSymbolTableCount = symbolIndex; const uint32_t sharedSymbolTableEndOffset = offset; // copy function starts uint32_t startFunctionStartsOffset = offset; for (LinkeditOptimizer<P>* op : optimizers) { op->copyFunctionStarts(newLinkEdit, offset); } verboseLog(" function starts size: %5uKB", (offset-startFunctionStartsOffset)/1024); // copy data-in-code info uint32_t startDataInCodeOffset = offset; for (LinkeditOptimizer<P>* op : optimizers) { op->copyDataInCode(newLinkEdit, offset); } verboseLog(" data in code size: %5uB", offset-startDataInCodeOffset); // copy indirect symbol tables for (LinkeditOptimizer<P>* op : optimizers) { op->copyIndirectSymbolTable(newLinkEdit, offset); } // if indirect table has odd number of entries, end will not be 8-byte aligned if ( (offset % sizeof(typename P::uint_t)) != 0 ) offset += 4; // copy string pool uint32_t sharedSymbolStringsOffset = offset; uint32_t sharedSymbolStringsSize = stringPool.copyPoolAndUpdateOffsets((char*)&newLinkEdit[sharedSymbolStringsOffset], (macho_nlist<P>*)&newLinkEdit[sharedSymbolTableStartOffset]); offset += sharedSymbolStringsSize; uint32_t newLinkeditUnalignedSize = offset; uint64_t newLinkeditEnd = align(linkeditStartOffset+newLinkeditUnalignedSize, 14); verboseLog(" symbol table size: %5uKB (%d exports, %d imports)", (sharedSymbolTableEndOffset-sharedSymbolTableStartOffset)/1024, sharedSymbolTableExportsCount, sharedSymbolTableImportsCount); verboseLog(" symbol string pool size: %5uKB", sharedSymbolStringsSize/1024); // overwrite mapped LINKEDIT area in cache with new merged LINKEDIT content verboseLog("LINKEDITS optimized from %uMB to %uMB", (uint32_t)totalUnoptLinkeditsSize/(1024*1024), (uint32_t)newLinkeditUnalignedSize/(1024*1024)); ::memcpy((char*)cache.buffer().get()+linkeditStartOffset, newLinkEdit, newLinkeditUnalignedSize); ::bzero((char*)cache.buffer().get()+linkeditStartOffset+newLinkeditUnalignedSize, totalUnoptLinkeditsSize-newLinkeditUnalignedSize); ::free(newLinkEdit); // If making cache for customers, add extra accelerator tables for dyld if ( addAcceleratorTables ) { AcceleratorTables<P> tables(cache.buffer().get(), linkeditStartAddr, optimizers); uint32_t tablesSize = tables.totalSize(); if ( tablesSize < (totalUnoptLinkeditsSize-newLinkeditUnalignedSize) ) { tables.copyTo((uint8_t*)cache.buffer().get()+newLinkeditEnd); newLinkeditEnd += tablesSize; uint64_t accelInfoAddr = align(linkeditStartAddr + newLinkeditUnalignedSize, 14); cache.setAcceleratorInfoRange(accelInfoAddr, tablesSize); } else { warning("not enough room to add dyld accelerator tables"); } } // update mapping to reduce linkedit size cache.setLinkeditsMappingEndFileOffset(newLinkeditEnd); // overwrite end of un-opt linkedits to create a new unmapped region for local symbols uint64_t newFileSize = newLinkeditEnd; if ( dontMapLocalSymbols ) { typedef typename P::E E; uint32_t localSymbolsOffset = (uint32_t)align(newFileSize, 14); uint32_t spaceAtEnd = linkeditEndOffset - (uint32_t)newLinkeditEnd; dyldCacheLocalSymbolsInfo<E>* infoHeader = (dyldCacheLocalSymbolsInfo<E>*)((uint8_t*)cache.buffer().get()+localSymbolsOffset); const uint32_t entriesOffset = sizeof(dyldCacheLocalSymbolsInfo<E>); const uint32_t entriesCount = (uint32_t)localSymbolInfos.size(); const uint32_t nlistOffset = (uint32_t)align(entriesOffset + entriesCount * sizeof(dyldCacheLocalSymbolEntry<E>), 4); // 16-byte align start const uint32_t nlistCount = (uint32_t)unmappedLocalSymbols.size(); const uint32_t stringsOffset = nlistOffset + nlistCount * sizeof(macho_nlist<P>); // copy info for each dylib dyldCacheLocalSymbolEntry<E>* entries = (dyldCacheLocalSymbolEntry<E>*)(((uint8_t*)infoHeader)+entriesOffset); for (int i=0; i < entriesCount; ++i) { entries[i].set_dylibOffset(localSymbolInfos[i].dylibOffset); entries[i].set_nlistStartIndex(localSymbolInfos[i].nlistStartIndex); entries[i].set_nlistCount(localSymbolInfos[i].nlistCount); } // copy nlists macho_nlist<P>* newLocalsSymbolTable = (macho_nlist<P>*)(((uint8_t*)infoHeader)+nlistOffset); ::memcpy(newLocalsSymbolTable, &unmappedLocalSymbols[0], nlistCount*sizeof(macho_nlist<P>)); // copy string pool const uint32_t stringsSize = localSymbolsStringPool.copyPoolAndUpdateOffsets(((char*)infoHeader)+stringsOffset, newLocalsSymbolTable); const uint32_t localsRegionSize = (uint32_t)align(stringsOffset+stringsSize, 14); if ( localsRegionSize > spaceAtEnd ) terminate("not enough room to store local symbols"); // fill in local symbols info infoHeader->set_nlistOffset(nlistOffset); infoHeader->set_nlistCount(nlistCount); infoHeader->set_stringsOffset(stringsOffset); infoHeader->set_stringsSize(stringsSize); infoHeader->set_entriesOffset(entriesOffset); infoHeader->set_entriesCount(entriesCount); // update cache size newFileSize += localsRegionSize; verboseLog("Unmapped local symbol info: %uMB", localsRegionSize/(1024*1024)); cache.setUnmappedLocalsRange(localSymbolsOffset, localsRegionSize); } // update all load commands to new merged layout for (LinkeditOptimizer<P>* op : optimizers) { op->updateLoadCommands(linkeditStartOffset, linkeditStartAddr, newLinkeditEnd-linkeditStartOffset, sharedSymbolTableStartOffset, sharedSymbolTableCount, sharedSymbolStringsOffset, sharedSymbolStringsSize); } return newFileSize; } } // anonymous namespace template <typename P> void SharedCache::optimizeLinkedit(bool dontMapLocalSymbols, bool addAcceleratorTables, const std::vector<uint64_t>& branchPoolOffsets) { // construct a LinkeditOptimizer for each image std::vector<LinkeditOptimizer<P>*> optimizers; forEachImage([&](const void* mh, const char*, time_t, ino_t, const std::vector<MachOProxy::Segment>&) { optimizers.push_back(new LinkeditOptimizer<P>(_buffer.get(), (macho_header<P>*)mh)); }); // add optimizer for each branch pool for (uint64_t poolOffset : branchPoolOffsets) { macho_header<P>* mh = (macho_header<P>*)((char*)_buffer.get() + poolOffset); optimizers.push_back(new LinkeditOptimizer<P>(_buffer.get(), mh)); } // merge linkedit info _fileSize = mergeLinkedits(*this, dontMapLocalSymbols, addAcceleratorTables, optimizers); // delete optimizers for (LinkeditOptimizer<P>* op : optimizers) delete op; } void SharedCache::optimizeLinkedit(bool dontMapLocalSymbols, bool addAcceleratorTables, const std::vector<uint64_t>& branchPoolOffsets) { switch ( _arch.arch ) { case CPU_TYPE_ARM: case CPU_TYPE_I386: optimizeLinkedit<Pointer32<LittleEndian>>(dontMapLocalSymbols, addAcceleratorTables, branchPoolOffsets); break; case CPU_TYPE_X86_64: case CPU_TYPE_ARM64: optimizeLinkedit<Pointer64<LittleEndian>>(dontMapLocalSymbols, addAcceleratorTables, branchPoolOffsets); break; default: terminate("unsupported arch 0x%08X", _arch.arch); } } |