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