1 //===-- DynamicLoaderMacOS.cpp --------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "lldb/Breakpoint/StoppointCallbackContext.h" 10 #include "lldb/Core/Debugger.h" 11 #include "lldb/Core/Module.h" 12 #include "lldb/Core/PluginManager.h" 13 #include "lldb/Core/Section.h" 14 #include "lldb/Symbol/ObjectFile.h" 15 #include "lldb/Symbol/SymbolVendor.h" 16 #include "lldb/Target/ABI.h" 17 #include "lldb/Target/StackFrame.h" 18 #include "lldb/Target/Target.h" 19 #include "lldb/Target/Thread.h" 20 #include "lldb/Utility/Log.h" 21 #include "lldb/Utility/State.h" 22 23 #include "DynamicLoaderDarwin.h" 24 #include "DynamicLoaderMacOS.h" 25 26 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h" 27 28 using namespace lldb; 29 using namespace lldb_private; 30 31 // Create an instance of this class. This function is filled into the plugin 32 // info class that gets handed out by the plugin factory and allows the lldb to 33 // instantiate an instance of this class. 34 DynamicLoader *DynamicLoaderMacOS::CreateInstance(Process *process, 35 bool force) { 36 bool create = force; 37 if (!create) { 38 create = true; 39 Module *exe_module = process->GetTarget().GetExecutableModulePointer(); 40 if (exe_module) { 41 ObjectFile *object_file = exe_module->GetObjectFile(); 42 if (object_file) { 43 create = (object_file->GetStrata() == ObjectFile::eStrataUser); 44 } 45 } 46 47 if (create) { 48 const llvm::Triple &triple_ref = 49 process->GetTarget().GetArchitecture().GetTriple(); 50 switch (triple_ref.getOS()) { 51 case llvm::Triple::Darwin: 52 case llvm::Triple::MacOSX: 53 case llvm::Triple::IOS: 54 case llvm::Triple::TvOS: 55 case llvm::Triple::WatchOS: 56 // NEED_BRIDGEOS_TRIPLE case llvm::Triple::BridgeOS: 57 create = triple_ref.getVendor() == llvm::Triple::Apple; 58 break; 59 default: 60 create = false; 61 break; 62 } 63 } 64 } 65 66 if (!UseDYLDSPI(process)) { 67 create = false; 68 } 69 70 if (create) 71 return new DynamicLoaderMacOS(process); 72 return nullptr; 73 } 74 75 // Constructor 76 DynamicLoaderMacOS::DynamicLoaderMacOS(Process *process) 77 : DynamicLoaderDarwin(process), m_image_infos_stop_id(UINT32_MAX), 78 m_break_id(LLDB_INVALID_BREAK_ID), m_mutex(), 79 m_maybe_image_infos_address(LLDB_INVALID_ADDRESS) {} 80 81 // Destructor 82 DynamicLoaderMacOS::~DynamicLoaderMacOS() { 83 if (LLDB_BREAK_ID_IS_VALID(m_break_id)) 84 m_process->GetTarget().RemoveBreakpointByID(m_break_id); 85 } 86 87 bool DynamicLoaderMacOS::ProcessDidExec() { 88 std::lock_guard<std::recursive_mutex> baseclass_guard(GetMutex()); 89 bool did_exec = false; 90 if (m_process) { 91 // If we are stopped after an exec, we will have only one thread... 92 if (m_process->GetThreadList().GetSize() == 1) { 93 // Maybe we still have an image infos address around? If so see 94 // if that has changed, and if so we have exec'ed. 95 if (m_maybe_image_infos_address != LLDB_INVALID_ADDRESS) { 96 lldb::addr_t image_infos_address = m_process->GetImageInfoAddress(); 97 if (image_infos_address != m_maybe_image_infos_address) { 98 // We don't really have to reset this here, since we are going to 99 // call DoInitialImageFetch right away to handle the exec. But in 100 // case anybody looks at it in the meantime, it can't hurt. 101 m_maybe_image_infos_address = image_infos_address; 102 did_exec = true; 103 } 104 } 105 106 if (!did_exec) { 107 // See if we are stopped at '_dyld_start' 108 ThreadSP thread_sp(m_process->GetThreadList().GetThreadAtIndex(0)); 109 if (thread_sp) { 110 lldb::StackFrameSP frame_sp(thread_sp->GetStackFrameAtIndex(0)); 111 if (frame_sp) { 112 const Symbol *symbol = 113 frame_sp->GetSymbolContext(eSymbolContextSymbol).symbol; 114 if (symbol) { 115 if (symbol->GetName() == "_dyld_start") 116 did_exec = true; 117 } 118 } 119 } 120 } 121 } 122 } 123 124 if (did_exec) { 125 m_libpthread_module_wp.reset(); 126 m_pthread_getspecific_addr.Clear(); 127 } 128 return did_exec; 129 } 130 131 // Clear out the state of this class. 132 void DynamicLoaderMacOS::DoClear() { 133 std::lock_guard<std::recursive_mutex> guard(m_mutex); 134 135 if (LLDB_BREAK_ID_IS_VALID(m_break_id)) 136 m_process->GetTarget().RemoveBreakpointByID(m_break_id); 137 138 m_break_id = LLDB_INVALID_BREAK_ID; 139 } 140 141 // Check if we have found DYLD yet 142 bool DynamicLoaderMacOS::DidSetNotificationBreakpoint() { 143 return LLDB_BREAK_ID_IS_VALID(m_break_id); 144 } 145 146 void DynamicLoaderMacOS::ClearNotificationBreakpoint() { 147 if (LLDB_BREAK_ID_IS_VALID(m_break_id)) { 148 m_process->GetTarget().RemoveBreakpointByID(m_break_id); 149 m_break_id = LLDB_INVALID_BREAK_ID; 150 } 151 } 152 153 // Try and figure out where dyld is by first asking the Process if it knows 154 // (which currently calls down in the lldb::Process to get the DYLD info 155 // (available on SnowLeopard only). If that fails, then check in the default 156 // addresses. 157 void DynamicLoaderMacOS::DoInitialImageFetch() { 158 Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER)); 159 160 // Remove any binaries we pre-loaded in the Target before 161 // launching/attaching. If the same binaries are present in the process, 162 // we'll get them from the shared module cache, we won't need to re-load them 163 // from disk. 164 UnloadAllImages(); 165 166 StructuredData::ObjectSP all_image_info_json_sp( 167 m_process->GetLoadedDynamicLibrariesInfos()); 168 ImageInfo::collection image_infos; 169 if (all_image_info_json_sp.get() && 170 all_image_info_json_sp->GetAsDictionary() && 171 all_image_info_json_sp->GetAsDictionary()->HasKey("images") && 172 all_image_info_json_sp->GetAsDictionary() 173 ->GetValueForKey("images") 174 ->GetAsArray()) { 175 if (JSONImageInformationIntoImageInfo(all_image_info_json_sp, 176 image_infos)) { 177 LLDB_LOGF(log, "Initial module fetch: Adding %" PRId64 " modules.\n", 178 (uint64_t)image_infos.size()); 179 180 UpdateSpecialBinariesFromNewImageInfos(image_infos); 181 AddModulesUsingImageInfos(image_infos); 182 } 183 } 184 185 m_dyld_image_infos_stop_id = m_process->GetStopID(); 186 m_maybe_image_infos_address = m_process->GetImageInfoAddress(); 187 } 188 189 bool DynamicLoaderMacOS::NeedToDoInitialImageFetch() { return true; } 190 191 // Static callback function that gets called when our DYLD notification 192 // breakpoint gets hit. We update all of our image infos and then let our super 193 // class DynamicLoader class decide if we should stop or not (based on global 194 // preference). 195 bool DynamicLoaderMacOS::NotifyBreakpointHit(void *baton, 196 StoppointCallbackContext *context, 197 lldb::user_id_t break_id, 198 lldb::user_id_t break_loc_id) { 199 // Let the event know that the images have changed 200 // DYLD passes three arguments to the notification breakpoint. 201 // Arg1: enum dyld_notify_mode mode - 0 = adding, 1 = removing, 2 = remove 202 // all Arg2: unsigned long icount - Number of shared libraries 203 // added/removed Arg3: uint64_t mach_headers[] - Array of load addresses 204 // of binaries added/removed 205 206 DynamicLoaderMacOS *dyld_instance = (DynamicLoaderMacOS *)baton; 207 208 ExecutionContext exe_ctx(context->exe_ctx_ref); 209 Process *process = exe_ctx.GetProcessPtr(); 210 211 // This is a sanity check just in case this dyld_instance is an old dyld 212 // plugin's breakpoint still lying around. 213 if (process != dyld_instance->m_process) 214 return false; 215 216 if (dyld_instance->m_image_infos_stop_id != UINT32_MAX && 217 process->GetStopID() < dyld_instance->m_image_infos_stop_id) { 218 return false; 219 } 220 221 const lldb::ABISP &abi = process->GetABI(); 222 if (abi) { 223 // Build up the value array to store the three arguments given above, then 224 // get the values from the ABI: 225 226 TypeSystemClang *clang_ast_context = 227 ScratchTypeSystemClang::GetForTarget(process->GetTarget()); 228 if (!clang_ast_context) 229 return false; 230 231 ValueList argument_values; 232 233 Value mode_value; // enum dyld_notify_mode { dyld_notify_adding=0, 234 // dyld_notify_removing=1, dyld_notify_remove_all=2 }; 235 Value count_value; // unsigned long count 236 Value headers_value; // uint64_t machHeaders[] (aka void*) 237 238 CompilerType clang_void_ptr_type = 239 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 240 CompilerType clang_uint32_type = 241 clang_ast_context->GetBuiltinTypeForEncodingAndBitSize( 242 lldb::eEncodingUint, 32); 243 CompilerType clang_uint64_type = 244 clang_ast_context->GetBuiltinTypeForEncodingAndBitSize( 245 lldb::eEncodingUint, 32); 246 247 mode_value.SetValueType(Value::ValueType::Scalar); 248 mode_value.SetCompilerType(clang_uint32_type); 249 250 if (process->GetTarget().GetArchitecture().GetAddressByteSize() == 4) { 251 count_value.SetValueType(Value::ValueType::Scalar); 252 count_value.SetCompilerType(clang_uint32_type); 253 } else { 254 count_value.SetValueType(Value::ValueType::Scalar); 255 count_value.SetCompilerType(clang_uint64_type); 256 } 257 258 headers_value.SetValueType(Value::ValueType::Scalar); 259 headers_value.SetCompilerType(clang_void_ptr_type); 260 261 argument_values.PushValue(mode_value); 262 argument_values.PushValue(count_value); 263 argument_values.PushValue(headers_value); 264 265 if (abi->GetArgumentValues(exe_ctx.GetThreadRef(), argument_values)) { 266 uint32_t dyld_mode = 267 argument_values.GetValueAtIndex(0)->GetScalar().UInt(-1); 268 if (dyld_mode != static_cast<uint32_t>(-1)) { 269 // Okay the mode was right, now get the number of elements, and the 270 // array of new elements... 271 uint32_t image_infos_count = 272 argument_values.GetValueAtIndex(1)->GetScalar().UInt(-1); 273 if (image_infos_count != static_cast<uint32_t>(-1)) { 274 addr_t header_array = 275 argument_values.GetValueAtIndex(2)->GetScalar().ULongLong(-1); 276 if (header_array != static_cast<uint64_t>(-1)) { 277 std::vector<addr_t> image_load_addresses; 278 for (uint64_t i = 0; i < image_infos_count; i++) { 279 Status error; 280 addr_t addr = process->ReadUnsignedIntegerFromMemory( 281 header_array + (8 * i), 8, LLDB_INVALID_ADDRESS, error); 282 if (addr != LLDB_INVALID_ADDRESS) { 283 image_load_addresses.push_back(addr); 284 } 285 } 286 if (dyld_mode == 0) { 287 // dyld_notify_adding 288 dyld_instance->AddBinaries(image_load_addresses); 289 } else if (dyld_mode == 1) { 290 // dyld_notify_removing 291 dyld_instance->UnloadImages(image_load_addresses); 292 } else if (dyld_mode == 2) { 293 // dyld_notify_remove_all 294 dyld_instance->UnloadAllImages(); 295 } 296 } 297 } 298 } 299 } 300 } else { 301 process->GetTarget().GetDebugger().GetAsyncErrorStream()->Printf( 302 "No ABI plugin located for triple %s -- shared libraries will not be " 303 "registered!\n", 304 process->GetTarget().GetArchitecture().GetTriple().getTriple().c_str()); 305 } 306 307 // Return true to stop the target, false to just let the target run 308 return dyld_instance->GetStopWhenImagesChange(); 309 } 310 311 void DynamicLoaderMacOS::AddBinaries( 312 const std::vector<lldb::addr_t> &load_addresses) { 313 Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER)); 314 ImageInfo::collection image_infos; 315 316 LLDB_LOGF(log, "Adding %" PRId64 " modules.", 317 (uint64_t)load_addresses.size()); 318 StructuredData::ObjectSP binaries_info_sp = 319 m_process->GetLoadedDynamicLibrariesInfos(load_addresses); 320 if (binaries_info_sp.get() && binaries_info_sp->GetAsDictionary() && 321 binaries_info_sp->GetAsDictionary()->HasKey("images") && 322 binaries_info_sp->GetAsDictionary() 323 ->GetValueForKey("images") 324 ->GetAsArray() && 325 binaries_info_sp->GetAsDictionary() 326 ->GetValueForKey("images") 327 ->GetAsArray() 328 ->GetSize() == load_addresses.size()) { 329 if (JSONImageInformationIntoImageInfo(binaries_info_sp, image_infos)) { 330 UpdateSpecialBinariesFromNewImageInfos(image_infos); 331 AddModulesUsingImageInfos(image_infos); 332 } 333 m_dyld_image_infos_stop_id = m_process->GetStopID(); 334 } 335 } 336 337 // Dump the _dyld_all_image_infos members and all current image infos that we 338 // have parsed to the file handle provided. 339 void DynamicLoaderMacOS::PutToLog(Log *log) const { 340 if (log == nullptr) 341 return; 342 } 343 344 bool DynamicLoaderMacOS::SetNotificationBreakpoint() { 345 if (m_break_id == LLDB_INVALID_BREAK_ID) { 346 ModuleSP dyld_sp(GetDYLDModule()); 347 if (dyld_sp) { 348 bool internal = true; 349 bool hardware = false; 350 LazyBool skip_prologue = eLazyBoolNo; 351 FileSpecList *source_files = nullptr; 352 FileSpecList dyld_filelist; 353 dyld_filelist.Append(dyld_sp->GetObjectFile()->GetFileSpec()); 354 355 Breakpoint *breakpoint = 356 m_process->GetTarget() 357 .CreateBreakpoint(&dyld_filelist, source_files, 358 "_dyld_debugger_notification", 359 eFunctionNameTypeFull, eLanguageTypeC, 0, 360 skip_prologue, internal, hardware) 361 .get(); 362 breakpoint->SetCallback(DynamicLoaderMacOS::NotifyBreakpointHit, this, 363 true); 364 breakpoint->SetBreakpointKind("shared-library-event"); 365 m_break_id = breakpoint->GetID(); 366 } 367 } 368 return m_break_id != LLDB_INVALID_BREAK_ID; 369 } 370 371 addr_t 372 DynamicLoaderMacOS::GetDyldLockVariableAddressFromModule(Module *module) { 373 SymbolContext sc; 374 Target &target = m_process->GetTarget(); 375 if (Symtab *symtab = module->GetSymtab()) { 376 std::vector<uint32_t> match_indexes; 377 ConstString g_symbol_name("_dyld_global_lock_held"); 378 uint32_t num_matches = 0; 379 num_matches = 380 symtab->AppendSymbolIndexesWithName(g_symbol_name, match_indexes); 381 if (num_matches == 1) { 382 Symbol *symbol = symtab->SymbolAtIndex(match_indexes[0]); 383 if (symbol && 384 (symbol->ValueIsAddress() || symbol->GetAddressRef().IsValid())) { 385 return symbol->GetAddressRef().GetOpcodeLoadAddress(&target); 386 } 387 } 388 } 389 return LLDB_INVALID_ADDRESS; 390 } 391 392 // Look for this symbol: 393 // 394 // int __attribute__((visibility("hidden"))) _dyld_global_lock_held = 395 // 0; 396 // 397 // in libdyld.dylib. 398 Status DynamicLoaderMacOS::CanLoadImage() { 399 Status error; 400 addr_t symbol_address = LLDB_INVALID_ADDRESS; 401 ConstString g_libdyld_name("libdyld.dylib"); 402 Target &target = m_process->GetTarget(); 403 const ModuleList &target_modules = target.GetImages(); 404 std::lock_guard<std::recursive_mutex> guard(target_modules.GetMutex()); 405 406 // Find any modules named "libdyld.dylib" and look for the symbol there first 407 for (ModuleSP module_sp : target.GetImages().ModulesNoLocking()) { 408 if (module_sp) { 409 if (module_sp->GetFileSpec().GetFilename() == g_libdyld_name) { 410 symbol_address = GetDyldLockVariableAddressFromModule(module_sp.get()); 411 if (symbol_address != LLDB_INVALID_ADDRESS) 412 break; 413 } 414 } 415 } 416 417 // Search through all modules looking for the symbol in them 418 if (symbol_address == LLDB_INVALID_ADDRESS) { 419 for (ModuleSP module_sp : target.GetImages().Modules()) { 420 if (module_sp) { 421 addr_t symbol_address = 422 GetDyldLockVariableAddressFromModule(module_sp.get()); 423 if (symbol_address != LLDB_INVALID_ADDRESS) 424 break; 425 } 426 } 427 } 428 429 // Default assumption is that it is OK to load images. Only say that we 430 // cannot load images if we find the symbol in libdyld and it indicates that 431 // we cannot. 432 433 if (symbol_address != LLDB_INVALID_ADDRESS) { 434 { 435 int lock_held = 436 m_process->ReadUnsignedIntegerFromMemory(symbol_address, 4, 0, error); 437 if (lock_held != 0) { 438 error.SetErrorString("dyld lock held - unsafe to load images."); 439 } 440 } 441 } else { 442 // If we were unable to find _dyld_global_lock_held in any modules, or it 443 // is not loaded into memory yet, we may be at process startup (sitting at 444 // _dyld_start) - so we should not allow dlopen calls. But if we found more 445 // than one module then we are clearly past _dyld_start so in that case 446 // we'll default to "it's safe". 447 if (target.GetImages().GetSize() <= 1) 448 error.SetErrorString("could not find the dyld library or " 449 "the dyld lock symbol"); 450 } 451 return error; 452 } 453 454 bool DynamicLoaderMacOS::GetSharedCacheInformation( 455 lldb::addr_t &base_address, UUID &uuid, LazyBool &using_shared_cache, 456 LazyBool &private_shared_cache) { 457 base_address = LLDB_INVALID_ADDRESS; 458 uuid.Clear(); 459 using_shared_cache = eLazyBoolCalculate; 460 private_shared_cache = eLazyBoolCalculate; 461 462 if (m_process) { 463 StructuredData::ObjectSP info = m_process->GetSharedCacheInfo(); 464 StructuredData::Dictionary *info_dict = nullptr; 465 if (info.get() && info->GetAsDictionary()) { 466 info_dict = info->GetAsDictionary(); 467 } 468 469 // {"shared_cache_base_address":140735683125248,"shared_cache_uuid 470 // ":"DDB8D70C- 471 // C9A2-3561-B2C8-BE48A4F33F96","no_shared_cache":false,"shared_cache_private_cache":false} 472 473 if (info_dict && info_dict->HasKey("shared_cache_uuid") && 474 info_dict->HasKey("no_shared_cache") && 475 info_dict->HasKey("shared_cache_base_address")) { 476 base_address = info_dict->GetValueForKey("shared_cache_base_address") 477 ->GetIntegerValue(LLDB_INVALID_ADDRESS); 478 std::string uuid_str = std::string( 479 info_dict->GetValueForKey("shared_cache_uuid")->GetStringValue()); 480 if (!uuid_str.empty()) 481 uuid.SetFromStringRef(uuid_str); 482 if (!info_dict->GetValueForKey("no_shared_cache")->GetBooleanValue()) 483 using_shared_cache = eLazyBoolYes; 484 else 485 using_shared_cache = eLazyBoolNo; 486 if (info_dict->GetValueForKey("shared_cache_private_cache") 487 ->GetBooleanValue()) 488 private_shared_cache = eLazyBoolYes; 489 else 490 private_shared_cache = eLazyBoolNo; 491 492 return true; 493 } 494 } 495 return false; 496 } 497 498 void DynamicLoaderMacOS::Initialize() { 499 PluginManager::RegisterPlugin(GetPluginNameStatic(), 500 GetPluginDescriptionStatic(), CreateInstance); 501 } 502 503 void DynamicLoaderMacOS::Terminate() { 504 PluginManager::UnregisterPlugin(CreateInstance); 505 } 506 507 lldb_private::ConstString DynamicLoaderMacOS::GetPluginNameStatic() { 508 static ConstString g_name("macos-dyld"); 509 return g_name; 510 } 511 512 const char *DynamicLoaderMacOS::GetPluginDescriptionStatic() { 513 return "Dynamic loader plug-in that watches for shared library loads/unloads " 514 "in MacOSX user processes."; 515 } 516 517 // PluginInterface protocol 518 lldb_private::ConstString DynamicLoaderMacOS::GetPluginName() { 519 return GetPluginNameStatic(); 520 } 521 522 uint32_t DynamicLoaderMacOS::GetPluginVersion() { return 1; } 523