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() {} 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 = TypeSystemClang::GetScratch(*target_sp); 220 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME)); 221 222 GetItemInfoReturnInfo return_value; 223 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS; 224 return_value.item_buffer_size = 0; 225 226 error.Clear(); 227 228 if (!thread.SafeToCallFunctions()) { 229 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64, 230 thread.GetID()); 231 error.SetErrorString("Not safe to call functions on this thread."); 232 return return_value; 233 } 234 235 // Set up the arguments for a call to 236 237 // struct get_item_info_return_values 238 // { 239 // uint64_t item_info_buffer_ptr; /* the address of the items buffer 240 // from libBacktraceRecording */ 241 // uint64_t item_info_buffer_size; /* the size of the items buffer from 242 // libBacktraceRecording */ 243 // }; 244 // 245 // void __lldb_backtrace_recording_get_item_info 246 // (struct 247 // get_item_info_return_values 248 // *return_buffer, 249 // int debug, 250 // uint64_t item, 251 // void *page_to_free, 252 // uint64_t page_to_free_size) 253 254 // Where the return_buffer argument points to a 24 byte region of memory 255 // already allocated by lldb in the inferior process. 256 257 CompilerType clang_void_ptr_type = 258 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 259 Value return_buffer_ptr_value; 260 return_buffer_ptr_value.SetValueType(Value::eValueTypeScalar); 261 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type); 262 263 CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt); 264 Value debug_value; 265 debug_value.SetValueType(Value::eValueTypeScalar); 266 debug_value.SetCompilerType(clang_int_type); 267 268 CompilerType clang_uint64_type = 269 clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong); 270 Value item_value; 271 item_value.SetValueType(Value::eValueTypeScalar); 272 item_value.SetCompilerType(clang_uint64_type); 273 274 Value page_to_free_value; 275 page_to_free_value.SetValueType(Value::eValueTypeScalar); 276 page_to_free_value.SetCompilerType(clang_void_ptr_type); 277 278 Value page_to_free_size_value; 279 page_to_free_size_value.SetValueType(Value::eValueTypeScalar); 280 page_to_free_size_value.SetCompilerType(clang_uint64_type); 281 282 std::lock_guard<std::mutex> guard(m_get_item_info_retbuffer_mutex); 283 if (m_get_item_info_return_buffer_addr == LLDB_INVALID_ADDRESS) { 284 addr_t bufaddr = process_sp->AllocateMemory( 285 32, ePermissionsReadable | ePermissionsWritable, error); 286 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) { 287 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get " 288 "current queues func call"); 289 return return_value; 290 } 291 m_get_item_info_return_buffer_addr = bufaddr; 292 } 293 294 ValueList argument_values; 295 296 return_buffer_ptr_value.GetScalar() = m_get_item_info_return_buffer_addr; 297 argument_values.PushValue(return_buffer_ptr_value); 298 299 debug_value.GetScalar() = 0; 300 argument_values.PushValue(debug_value); 301 302 item_value.GetScalar() = item; 303 argument_values.PushValue(item_value); 304 305 if (page_to_free != LLDB_INVALID_ADDRESS) 306 page_to_free_value.GetScalar() = page_to_free; 307 else 308 page_to_free_value.GetScalar() = 0; 309 argument_values.PushValue(page_to_free_value); 310 311 page_to_free_size_value.GetScalar() = page_to_free_size; 312 argument_values.PushValue(page_to_free_size_value); 313 314 addr_t args_addr = SetupGetItemInfoFunction(thread, argument_values); 315 316 DiagnosticManager diagnostics; 317 ExecutionContext exe_ctx; 318 EvaluateExpressionOptions options; 319 options.SetUnwindOnError(true); 320 options.SetIgnoreBreakpoints(true); 321 options.SetStopOthers(true); 322 #if __has_feature(address_sanitizer) 323 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 324 #else 325 options.SetTimeout(std::chrono::milliseconds(500)); 326 #endif 327 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 328 options.SetTryAllThreads(false); 329 options.SetIsForUtilityExpr(true); 330 thread.CalculateExecutionContext(exe_ctx); 331 332 if (!m_get_item_info_impl_code) { 333 error.SetErrorString("Unable to compile function to call " 334 "__introspection_dispatch_queue_item_get_info"); 335 return return_value; 336 } 337 338 ExpressionResults func_call_ret; 339 Value results; 340 FunctionCaller *func_caller = m_get_item_info_impl_code->GetFunctionCaller(); 341 if (!func_caller) { 342 LLDB_LOGF(log, "Could not retrieve function caller for " 343 "__introspection_dispatch_queue_item_get_info."); 344 error.SetErrorString("Could not retrieve function caller for " 345 "__introspection_dispatch_queue_item_get_info."); 346 return return_value; 347 } 348 349 func_call_ret = func_caller->ExecuteFunction(exe_ctx, &args_addr, options, 350 diagnostics, results); 351 if (func_call_ret != eExpressionCompleted || !error.Success()) { 352 LLDB_LOGF(log, 353 "Unable to call " 354 "__introspection_dispatch_queue_item_get_info(), got " 355 "ExpressionResults %d, error contains %s", 356 func_call_ret, error.AsCString("")); 357 error.SetErrorString("Unable to call " 358 "__introspection_dispatch_queue_get_item_info() for " 359 "list of queues"); 360 return return_value; 361 } 362 363 return_value.item_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory( 364 m_get_item_info_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error); 365 if (!error.Success() || 366 return_value.item_buffer_ptr == LLDB_INVALID_ADDRESS) { 367 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS; 368 return return_value; 369 } 370 371 return_value.item_buffer_size = m_process->ReadUnsignedIntegerFromMemory( 372 m_get_item_info_return_buffer_addr + 8, 8, 0, error); 373 374 if (!error.Success()) { 375 return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS; 376 return return_value; 377 } 378 LLDB_LOGF(log, 379 "AppleGetItemInfoHandler called " 380 "__introspection_dispatch_queue_item_get_info (page_to_free == " 381 "0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64 382 ", size %" PRId64, 383 page_to_free, page_to_free_size, return_value.item_buffer_ptr, 384 return_value.item_buffer_size); 385 386 return return_value; 387 } 388