1 //===-- AppleGetItemInfoHandler.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 "AppleGetItemInfoHandler.h" 10 11 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h" 12 #include "lldb/Core/Module.h" 13 #include "lldb/Core/Value.h" 14 #include "lldb/Expression/DiagnosticManager.h" 15 #include "lldb/Expression/FunctionCaller.h" 16 #include "lldb/Expression/UtilityFunction.h" 17 #include "lldb/Symbol/Symbol.h" 18 #include "lldb/Target/ExecutionContext.h" 19 #include "lldb/Target/Process.h" 20 #include "lldb/Target/Target.h" 21 #include "lldb/Target/Thread.h" 22 #include "lldb/Utility/ConstString.h" 23 #include "lldb/Utility/LLDBLog.h" 24 #include "lldb/Utility/Log.h" 25 #include "lldb/Utility/StreamString.h" 26 27 using namespace lldb; 28 using namespace lldb_private; 29 30 const char *AppleGetItemInfoHandler::g_get_item_info_function_name = 31 "__lldb_backtrace_recording_get_item_info"; 32 const char *AppleGetItemInfoHandler::g_get_item_info_function_code = 33 " \n\ 34 extern \"C\" \n\ 35 { \n\ 36 /* \n\ 37 * mach defines \n\ 38 */ \n\ 39 \n\ 40 typedef unsigned int uint32_t; \n\ 41 typedef unsigned long long uint64_t; \n\ 42 typedef uint32_t mach_port_t; \n\ 43 typedef mach_port_t vm_map_t; \n\ 44 typedef int kern_return_t; \n\ 45 typedef uint64_t mach_vm_address_t; \n\ 46 typedef uint64_t mach_vm_size_t; \n\ 47 \n\ 48 mach_port_t mach_task_self (); \n\ 49 kern_return_t mach_vm_deallocate (vm_map_t target, mach_vm_address_t address, mach_vm_size_t size); \n\ 50 \n\ 51 /* \n\ 52 * libBacktraceRecording defines \n\ 53 */ \n\ 54 \n\ 55 typedef uint32_t queue_list_scope_t; \n\ 56 typedef void *dispatch_queue_t; \n\ 57 typedef void *introspection_dispatch_queue_info_t; \n\ 58 typedef void *introspection_dispatch_item_info_ref; \n\ 59 \n\ 60 extern uint64_t __introspection_dispatch_queue_item_get_info (introspection_dispatch_item_info_ref item_info_ref, \n\ 61 introspection_dispatch_item_info_ref *returned_queues_buffer, \n\ 62 uint64_t *returned_queues_buffer_size); \n\ 63 extern int printf(const char *format, ...); \n\ 64 \n\ 65 /* \n\ 66 * return type define \n\ 67 */ \n\ 68 \n\ 69 struct get_item_info_return_values \n\ 70 { \n\ 71 uint64_t item_info_buffer_ptr; /* the address of the items buffer from libBacktraceRecording */ \n\ 72 uint64_t item_info_buffer_size; /* the size of the items buffer from libBacktraceRecording */ \n\ 73 }; \n\ 74 \n\ 75 void __lldb_backtrace_recording_get_item_info \n\ 76 (struct get_item_info_return_values *return_buffer, \n\ 77 int debug, \n\ 78 uint64_t /* introspection_dispatch_item_info_ref item_info_ref */ item, \n\ 79 void *page_to_free, \n\ 80 uint64_t page_to_free_size) \n\ 81 { \n\ 82 if (debug) \n\ 83 printf (\"entering get_item_info with args return_buffer == %p, debug == %d, item == 0x%llx, page_to_free == %p, page_to_free_size == 0x%llx\\n\", return_buffer, debug, item, page_to_free, page_to_free_size); \n\ 84 if (page_to_free != 0) \n\ 85 { \n\ 86 mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\ 87 } \n\ 88 \n\ 89 __introspection_dispatch_queue_item_get_info ((void*) item, \n\ 90 (void**)&return_buffer->item_info_buffer_ptr, \n\ 91 &return_buffer->item_info_buffer_size); \n\ 92 } \n\ 93 } \n\ 94 "; 95 96 AppleGetItemInfoHandler::AppleGetItemInfoHandler(Process *process) 97 : m_process(process), m_get_item_info_impl_code(), 98 m_get_item_info_function_mutex(), 99 m_get_item_info_return_buffer_addr(LLDB_INVALID_ADDRESS), 100 m_get_item_info_retbuffer_mutex() {} 101 102 AppleGetItemInfoHandler::~AppleGetItemInfoHandler() = default; 103 104 void AppleGetItemInfoHandler::Detach() { 105 106 if (m_process && m_process->IsAlive() && 107 m_get_item_info_return_buffer_addr != LLDB_INVALID_ADDRESS) { 108 std::unique_lock<std::mutex> lock(m_get_item_info_retbuffer_mutex, 109 std::defer_lock); 110 (void)lock.try_lock(); // Even if we don't get the lock, deallocate the buffer 111 m_process->DeallocateMemory(m_get_item_info_return_buffer_addr); 112 } 113 } 114 115 // Compile our __lldb_backtrace_recording_get_item_info() function (from the 116 // source above in g_get_item_info_function_code) if we don't find that 117 // function in the inferior already with USE_BUILTIN_FUNCTION defined. (e.g. 118 // this would be the case for testing.) 119 // 120 // Insert the __lldb_backtrace_recording_get_item_info into the inferior 121 // process if needed. 122 // 123 // Write the get_item_info_arglist into the inferior's memory space to prepare 124 // for the call. 125 // 126 // Returns the address of the arguments written down in the inferior process, 127 // which can be used to make the function call. 128 129 lldb::addr_t AppleGetItemInfoHandler::SetupGetItemInfoFunction( 130 Thread &thread, ValueList &get_item_info_arglist) { 131 ExecutionContext exe_ctx(thread.shared_from_this()); 132 DiagnosticManager diagnostics; 133 Log *log = GetLog(LLDBLog::SystemRuntime); 134 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS; 135 FunctionCaller *get_item_info_caller = nullptr; 136 137 // Scope for mutex locker: 138 { 139 std::lock_guard<std::mutex> guard(m_get_item_info_function_mutex); 140 141 // First stage is to make the UtilityFunction to hold our injected 142 // function: 143 144 if (!m_get_item_info_impl_code) { 145 if (g_get_item_info_function_code != nullptr) { 146 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction( 147 g_get_item_info_function_code, g_get_item_info_function_name, 148 eLanguageTypeObjC, exe_ctx); 149 if (!utility_fn_or_error) { 150 LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(), 151 "Failed to create utility function: {0}."); 152 } 153 m_get_item_info_impl_code = std::move(*utility_fn_or_error); 154 } else { 155 LLDB_LOGF(log, "No get-item-info introspection code found."); 156 return LLDB_INVALID_ADDRESS; 157 } 158 159 // Next make the runner function for our implementation utility function. 160 auto type_system_or_err = 161 thread.GetProcess()->GetTarget().GetScratchTypeSystemForLanguage( 162 eLanguageTypeC); 163 if (auto err = type_system_or_err.takeError()) { 164 LLDB_LOG_ERROR(log, std::move(err), 165 "Error inseting get-item-info function"); 166 return args_addr; 167 } 168 CompilerType get_item_info_return_type = 169 type_system_or_err->GetBasicTypeFromAST(eBasicTypeVoid) 170 .GetPointerType(); 171 172 Status error; 173 get_item_info_caller = m_get_item_info_impl_code->MakeFunctionCaller( 174 get_item_info_return_type, get_item_info_arglist, 175 thread.shared_from_this(), error); 176 if (error.Fail() || get_item_info_caller == nullptr) { 177 LLDB_LOGF(log, "Error Inserting get-item-info function: \"%s\".", 178 error.AsCString()); 179 return args_addr; 180 } 181 } else { 182 // If it's already made, then we can just retrieve the caller: 183 get_item_info_caller = m_get_item_info_impl_code->GetFunctionCaller(); 184 if (!get_item_info_caller) { 185 LLDB_LOGF(log, "Failed to get get-item-info introspection caller."); 186 m_get_item_info_impl_code.reset(); 187 return args_addr; 188 } 189 } 190 } 191 192 diagnostics.Clear(); 193 194 // Now write down the argument values for this particular call. This looks 195 // like it might be a race condition if other threads were calling into here, 196 // but actually it isn't because we allocate a new args structure for this 197 // call by passing args_addr = LLDB_INVALID_ADDRESS... 198 199 if (!get_item_info_caller->WriteFunctionArguments( 200 exe_ctx, args_addr, get_item_info_arglist, diagnostics)) { 201 if (log) { 202 LLDB_LOGF(log, "Error writing get-item-info function arguments."); 203 diagnostics.Dump(log); 204 } 205 206 return args_addr; 207 } 208 209 return args_addr; 210 } 211 212 AppleGetItemInfoHandler::GetItemInfoReturnInfo 213 AppleGetItemInfoHandler::GetItemInfo(Thread &thread, uint64_t item, 214 addr_t page_to_free, 215 uint64_t page_to_free_size, 216 Status &error) { 217 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0); 218 ProcessSP process_sp(thread.CalculateProcess()); 219 TargetSP target_sp(thread.CalculateTarget()); 220 TypeSystemClang *clang_ast_context = 221 ScratchTypeSystemClang::GetForTarget(*target_sp); 222 Log *log = GetLog(LLDBLog::SystemRuntime); 223 224 GetItemInfoReturnInfo return_value; 225 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS; 226 return_value.item_buffer_size = 0; 227 228 error.Clear(); 229 230 if (!thread.SafeToCallFunctions()) { 231 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64, 232 thread.GetID()); 233 error.SetErrorString("Not safe to call functions on this thread."); 234 return return_value; 235 } 236 237 // Set up the arguments for a call to 238 239 // struct get_item_info_return_values 240 // { 241 // uint64_t item_info_buffer_ptr; /* the address of the items buffer 242 // from libBacktraceRecording */ 243 // uint64_t item_info_buffer_size; /* the size of the items buffer from 244 // libBacktraceRecording */ 245 // }; 246 // 247 // void __lldb_backtrace_recording_get_item_info 248 // (struct 249 // get_item_info_return_values 250 // *return_buffer, 251 // int debug, 252 // uint64_t item, 253 // void *page_to_free, 254 // uint64_t page_to_free_size) 255 256 // Where the return_buffer argument points to a 24 byte region of memory 257 // already allocated by lldb in the inferior process. 258 259 CompilerType clang_void_ptr_type = 260 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 261 Value return_buffer_ptr_value; 262 return_buffer_ptr_value.SetValueType(Value::ValueType::Scalar); 263 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type); 264 265 CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt); 266 Value debug_value; 267 debug_value.SetValueType(Value::ValueType::Scalar); 268 debug_value.SetCompilerType(clang_int_type); 269 270 CompilerType clang_uint64_type = 271 clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong); 272 Value item_value; 273 item_value.SetValueType(Value::ValueType::Scalar); 274 item_value.SetCompilerType(clang_uint64_type); 275 276 Value page_to_free_value; 277 page_to_free_value.SetValueType(Value::ValueType::Scalar); 278 page_to_free_value.SetCompilerType(clang_void_ptr_type); 279 280 Value page_to_free_size_value; 281 page_to_free_size_value.SetValueType(Value::ValueType::Scalar); 282 page_to_free_size_value.SetCompilerType(clang_uint64_type); 283 284 std::lock_guard<std::mutex> guard(m_get_item_info_retbuffer_mutex); 285 if (m_get_item_info_return_buffer_addr == LLDB_INVALID_ADDRESS) { 286 addr_t bufaddr = process_sp->AllocateMemory( 287 32, ePermissionsReadable | ePermissionsWritable, error); 288 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) { 289 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get " 290 "current queues func call"); 291 return return_value; 292 } 293 m_get_item_info_return_buffer_addr = bufaddr; 294 } 295 296 ValueList argument_values; 297 298 return_buffer_ptr_value.GetScalar() = m_get_item_info_return_buffer_addr; 299 argument_values.PushValue(return_buffer_ptr_value); 300 301 debug_value.GetScalar() = 0; 302 argument_values.PushValue(debug_value); 303 304 item_value.GetScalar() = item; 305 argument_values.PushValue(item_value); 306 307 if (page_to_free != LLDB_INVALID_ADDRESS) 308 page_to_free_value.GetScalar() = page_to_free; 309 else 310 page_to_free_value.GetScalar() = 0; 311 argument_values.PushValue(page_to_free_value); 312 313 page_to_free_size_value.GetScalar() = page_to_free_size; 314 argument_values.PushValue(page_to_free_size_value); 315 316 addr_t args_addr = SetupGetItemInfoFunction(thread, argument_values); 317 318 DiagnosticManager diagnostics; 319 ExecutionContext exe_ctx; 320 EvaluateExpressionOptions options; 321 options.SetUnwindOnError(true); 322 options.SetIgnoreBreakpoints(true); 323 options.SetStopOthers(true); 324 #if __has_feature(address_sanitizer) 325 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 326 #else 327 options.SetTimeout(std::chrono::milliseconds(500)); 328 #endif 329 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 330 options.SetTryAllThreads(false); 331 options.SetIsForUtilityExpr(true); 332 thread.CalculateExecutionContext(exe_ctx); 333 334 if (!m_get_item_info_impl_code) { 335 error.SetErrorString("Unable to compile function to call " 336 "__introspection_dispatch_queue_item_get_info"); 337 return return_value; 338 } 339 340 ExpressionResults func_call_ret; 341 Value results; 342 FunctionCaller *func_caller = m_get_item_info_impl_code->GetFunctionCaller(); 343 if (!func_caller) { 344 LLDB_LOGF(log, "Could not retrieve function caller for " 345 "__introspection_dispatch_queue_item_get_info."); 346 error.SetErrorString("Could not retrieve function caller for " 347 "__introspection_dispatch_queue_item_get_info."); 348 return return_value; 349 } 350 351 func_call_ret = func_caller->ExecuteFunction(exe_ctx, &args_addr, options, 352 diagnostics, results); 353 if (func_call_ret != eExpressionCompleted || !error.Success()) { 354 LLDB_LOGF(log, 355 "Unable to call " 356 "__introspection_dispatch_queue_item_get_info(), got " 357 "ExpressionResults %d, error contains %s", 358 func_call_ret, error.AsCString("")); 359 error.SetErrorString("Unable to call " 360 "__introspection_dispatch_queue_get_item_info() for " 361 "list of queues"); 362 return return_value; 363 } 364 365 return_value.item_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory( 366 m_get_item_info_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error); 367 if (!error.Success() || 368 return_value.item_buffer_ptr == LLDB_INVALID_ADDRESS) { 369 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS; 370 return return_value; 371 } 372 373 return_value.item_buffer_size = m_process->ReadUnsignedIntegerFromMemory( 374 m_get_item_info_return_buffer_addr + 8, 8, 0, error); 375 376 if (!error.Success()) { 377 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS; 378 return return_value; 379 } 380 LLDB_LOGF(log, 381 "AppleGetItemInfoHandler called " 382 "__introspection_dispatch_queue_item_get_info (page_to_free == " 383 "0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64 384 ", size %" PRId64, 385 page_to_free, page_to_free_size, return_value.item_buffer_ptr, 386 return_value.item_buffer_size); 387 388 return return_value; 389 } 390