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 inserting get-item-info function"); 166 return args_addr; 167 } 168 auto ts = *type_system_or_err; 169 if (!ts) 170 return args_addr; 171 172 CompilerType get_item_info_return_type = 173 ts->GetBasicTypeFromAST(eBasicTypeVoid) 174 .GetPointerType(); 175 176 Status error; 177 get_item_info_caller = m_get_item_info_impl_code->MakeFunctionCaller( 178 get_item_info_return_type, get_item_info_arglist, 179 thread.shared_from_this(), error); 180 if (error.Fail() || get_item_info_caller == nullptr) { 181 LLDB_LOGF(log, "Error inserting get-item-info function: \"%s\".", 182 error.AsCString()); 183 return args_addr; 184 } 185 } else { 186 // If it's already made, then we can just retrieve the caller: 187 get_item_info_caller = m_get_item_info_impl_code->GetFunctionCaller(); 188 if (!get_item_info_caller) { 189 LLDB_LOGF(log, "Failed to get get-item-info introspection caller."); 190 m_get_item_info_impl_code.reset(); 191 return args_addr; 192 } 193 } 194 } 195 196 diagnostics.Clear(); 197 198 // Now write down the argument values for this particular call. This looks 199 // like it might be a race condition if other threads were calling into here, 200 // but actually it isn't because we allocate a new args structure for this 201 // call by passing args_addr = LLDB_INVALID_ADDRESS... 202 203 if (!get_item_info_caller->WriteFunctionArguments( 204 exe_ctx, args_addr, get_item_info_arglist, diagnostics)) { 205 if (log) { 206 LLDB_LOGF(log, "Error writing get-item-info function arguments."); 207 diagnostics.Dump(log); 208 } 209 210 return args_addr; 211 } 212 213 return args_addr; 214 } 215 216 AppleGetItemInfoHandler::GetItemInfoReturnInfo 217 AppleGetItemInfoHandler::GetItemInfo(Thread &thread, uint64_t item, 218 addr_t page_to_free, 219 uint64_t page_to_free_size, 220 Status &error) { 221 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0); 222 ProcessSP process_sp(thread.CalculateProcess()); 223 TargetSP target_sp(thread.CalculateTarget()); 224 TypeSystemClangSP scratch_ts_sp = 225 ScratchTypeSystemClang::GetForTarget(*target_sp); 226 Log *log = GetLog(LLDBLog::SystemRuntime); 227 228 GetItemInfoReturnInfo return_value; 229 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS; 230 return_value.item_buffer_size = 0; 231 232 error.Clear(); 233 234 if (!thread.SafeToCallFunctions()) { 235 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64, 236 thread.GetID()); 237 error.SetErrorString("Not safe to call functions on this thread."); 238 return return_value; 239 } 240 241 // Set up the arguments for a call to 242 243 // struct get_item_info_return_values 244 // { 245 // uint64_t item_info_buffer_ptr; /* the address of the items buffer 246 // from libBacktraceRecording */ 247 // uint64_t item_info_buffer_size; /* the size of the items buffer from 248 // libBacktraceRecording */ 249 // }; 250 // 251 // void __lldb_backtrace_recording_get_item_info 252 // (struct 253 // get_item_info_return_values 254 // *return_buffer, 255 // int debug, 256 // uint64_t item, 257 // void *page_to_free, 258 // uint64_t page_to_free_size) 259 260 // Where the return_buffer argument points to a 24 byte region of memory 261 // already allocated by lldb in the inferior process. 262 263 CompilerType clang_void_ptr_type = 264 scratch_ts_sp->GetBasicType(eBasicTypeVoid).GetPointerType(); 265 Value return_buffer_ptr_value; 266 return_buffer_ptr_value.SetValueType(Value::ValueType::Scalar); 267 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type); 268 269 CompilerType clang_int_type = scratch_ts_sp->GetBasicType(eBasicTypeInt); 270 Value debug_value; 271 debug_value.SetValueType(Value::ValueType::Scalar); 272 debug_value.SetCompilerType(clang_int_type); 273 274 CompilerType clang_uint64_type = 275 scratch_ts_sp->GetBasicType(eBasicTypeUnsignedLongLong); 276 Value item_value; 277 item_value.SetValueType(Value::ValueType::Scalar); 278 item_value.SetCompilerType(clang_uint64_type); 279 280 Value page_to_free_value; 281 page_to_free_value.SetValueType(Value::ValueType::Scalar); 282 page_to_free_value.SetCompilerType(clang_void_ptr_type); 283 284 Value page_to_free_size_value; 285 page_to_free_size_value.SetValueType(Value::ValueType::Scalar); 286 page_to_free_size_value.SetCompilerType(clang_uint64_type); 287 288 std::lock_guard<std::mutex> guard(m_get_item_info_retbuffer_mutex); 289 if (m_get_item_info_return_buffer_addr == LLDB_INVALID_ADDRESS) { 290 addr_t bufaddr = process_sp->AllocateMemory( 291 32, ePermissionsReadable | ePermissionsWritable, error); 292 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) { 293 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get " 294 "current queues func call"); 295 return return_value; 296 } 297 m_get_item_info_return_buffer_addr = bufaddr; 298 } 299 300 ValueList argument_values; 301 302 return_buffer_ptr_value.GetScalar() = m_get_item_info_return_buffer_addr; 303 argument_values.PushValue(return_buffer_ptr_value); 304 305 debug_value.GetScalar() = 0; 306 argument_values.PushValue(debug_value); 307 308 item_value.GetScalar() = item; 309 argument_values.PushValue(item_value); 310 311 if (page_to_free != LLDB_INVALID_ADDRESS) 312 page_to_free_value.GetScalar() = page_to_free; 313 else 314 page_to_free_value.GetScalar() = 0; 315 argument_values.PushValue(page_to_free_value); 316 317 page_to_free_size_value.GetScalar() = page_to_free_size; 318 argument_values.PushValue(page_to_free_size_value); 319 320 addr_t args_addr = SetupGetItemInfoFunction(thread, argument_values); 321 322 DiagnosticManager diagnostics; 323 ExecutionContext exe_ctx; 324 EvaluateExpressionOptions options; 325 options.SetUnwindOnError(true); 326 options.SetIgnoreBreakpoints(true); 327 options.SetStopOthers(true); 328 #if __has_feature(address_sanitizer) 329 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 330 #else 331 options.SetTimeout(std::chrono::milliseconds(500)); 332 #endif 333 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 334 options.SetTryAllThreads(false); 335 options.SetIsForUtilityExpr(true); 336 thread.CalculateExecutionContext(exe_ctx); 337 338 if (!m_get_item_info_impl_code) { 339 error.SetErrorString("Unable to compile function to call " 340 "__introspection_dispatch_queue_item_get_info"); 341 return return_value; 342 } 343 344 ExpressionResults func_call_ret; 345 Value results; 346 FunctionCaller *func_caller = m_get_item_info_impl_code->GetFunctionCaller(); 347 if (!func_caller) { 348 LLDB_LOGF(log, "Could not retrieve function caller for " 349 "__introspection_dispatch_queue_item_get_info."); 350 error.SetErrorString("Could not retrieve function caller for " 351 "__introspection_dispatch_queue_item_get_info."); 352 return return_value; 353 } 354 355 func_call_ret = func_caller->ExecuteFunction(exe_ctx, &args_addr, options, 356 diagnostics, results); 357 if (func_call_ret != eExpressionCompleted || !error.Success()) { 358 LLDB_LOGF(log, 359 "Unable to call " 360 "__introspection_dispatch_queue_item_get_info(), got " 361 "ExpressionResults %d, error contains %s", 362 func_call_ret, error.AsCString("")); 363 error.SetErrorString("Unable to call " 364 "__introspection_dispatch_queue_get_item_info() for " 365 "list of queues"); 366 return return_value; 367 } 368 369 return_value.item_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory( 370 m_get_item_info_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error); 371 if (!error.Success() || 372 return_value.item_buffer_ptr == LLDB_INVALID_ADDRESS) { 373 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS; 374 return return_value; 375 } 376 377 return_value.item_buffer_size = m_process->ReadUnsignedIntegerFromMemory( 378 m_get_item_info_return_buffer_addr + 8, 8, 0, error); 379 380 if (!error.Success()) { 381 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS; 382 return return_value; 383 } 384 LLDB_LOGF(log, 385 "AppleGetItemInfoHandler called " 386 "__introspection_dispatch_queue_item_get_info (page_to_free == " 387 "0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64 388 ", size %" PRId64, 389 page_to_free, page_to_free_size, return_value.item_buffer_ptr, 390 return_value.item_buffer_size); 391 392 return return_value; 393 } 394