1 //===-- AppleGetQueuesHandler.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 "AppleGetQueuesHandler.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 *AppleGetQueuesHandler::g_get_current_queues_function_name = 31 "__lldb_backtrace_recording_get_current_queues"; 32 const char *AppleGetQueuesHandler::g_get_current_queues_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 *introspection_dispatch_queue_info_t; \n\ 57 \n\ 58 extern uint64_t __introspection_dispatch_get_queues (queue_list_scope_t scope, \n\ 59 introspection_dispatch_queue_info_t *returned_queues_buffer, \n\ 60 uint64_t *returned_queues_buffer_size); \n\ 61 extern int printf(const char *format, ...); \n\ 62 \n\ 63 /* \n\ 64 * return type define \n\ 65 */ \n\ 66 \n\ 67 struct get_current_queues_return_values \n\ 68 { \n\ 69 uint64_t queues_buffer_ptr; /* the address of the queues buffer from libBacktraceRecording */ \n\ 70 uint64_t queues_buffer_size; /* the size of the queues buffer from libBacktraceRecording */ \n\ 71 uint64_t count; /* the number of queues included in the queues buffer */ \n\ 72 }; \n\ 73 \n\ 74 void __lldb_backtrace_recording_get_current_queues \n\ 75 (struct get_current_queues_return_values *return_buffer, \n\ 76 int debug, \n\ 77 void *page_to_free, \n\ 78 uint64_t page_to_free_size) \n\ 79 { \n\ 80 if (debug) \n\ 81 printf (\"entering get_current_queues with args %p, %d, 0x%p, 0x%llx\\n\", return_buffer, debug, page_to_free, page_to_free_size); \n\ 82 if (page_to_free != 0) \n\ 83 { \n\ 84 mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\ 85 } \n\ 86 \n\ 87 return_buffer->count = __introspection_dispatch_get_queues ( \n\ 88 /* QUEUES_WITH_ANY_ITEMS */ 2, \n\ 89 (void**)&return_buffer->queues_buffer_ptr, \n\ 90 &return_buffer->queues_buffer_size); \n\ 91 if (debug) \n\ 92 printf(\"result was count %lld\\n\", return_buffer->count); \n\ 93 } \n\ 94 } \n\ 95 "; 96 97 AppleGetQueuesHandler::AppleGetQueuesHandler(Process *process) 98 : m_process(process), m_get_queues_impl_code_up(), 99 m_get_queues_function_mutex(), 100 m_get_queues_return_buffer_addr(LLDB_INVALID_ADDRESS), 101 m_get_queues_retbuffer_mutex() {} 102 103 AppleGetQueuesHandler::~AppleGetQueuesHandler() = default; 104 105 void AppleGetQueuesHandler::Detach() { 106 107 if (m_process && m_process->IsAlive() && 108 m_get_queues_return_buffer_addr != LLDB_INVALID_ADDRESS) { 109 std::unique_lock<std::mutex> lock(m_get_queues_retbuffer_mutex, 110 std::defer_lock); 111 (void)lock.try_lock(); // Even if we don't get the lock, deallocate the buffer 112 m_process->DeallocateMemory(m_get_queues_return_buffer_addr); 113 } 114 } 115 116 // Construct a CompilerType for the structure that 117 // g_get_current_queues_function_code will return by value so we can extract 118 // the fields after performing the function call. i.e. we are getting this 119 // struct returned to us: 120 // 121 // struct get_current_queues_return_values 122 // { 123 // introspection_dispatch_queue_info_t *queues_buffer; 124 // uint64_t queues_buffer_size; 125 // uint64_t count; 126 // }; 127 128 // Compile our __lldb_backtrace_recording_get_current_queues() function (from 129 // the source above in g_get_current_queues_function_code) if we don't find 130 // that function in the inferior already with USE_BUILTIN_FUNCTION defined. 131 // (e.g. this would be the case for testing.) 132 // 133 // Insert the __lldb_backtrace_recording_get_current_queues into the inferior 134 // process if needed. 135 // 136 // Write the get_queues_arglist into the inferior's memory space to prepare for 137 // the call. 138 // 139 // Returns the address of the arguments written down in the inferior process, 140 // which can be used to make the function call. 141 142 lldb::addr_t 143 AppleGetQueuesHandler::SetupGetQueuesFunction(Thread &thread, 144 ValueList &get_queues_arglist) { 145 ThreadSP thread_sp(thread.shared_from_this()); 146 ExecutionContext exe_ctx(thread_sp); 147 148 Address impl_code_address; 149 DiagnosticManager diagnostics; 150 Log *log = GetLog(LLDBLog::SystemRuntime); 151 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS; 152 153 FunctionCaller *get_queues_caller = nullptr; 154 155 // Scope for mutex locker: 156 { 157 std::lock_guard<std::mutex> guard(m_get_queues_function_mutex); 158 159 // First stage is to make the ClangUtility to hold our injected function: 160 161 if (!m_get_queues_impl_code_up) { 162 if (g_get_current_queues_function_code != nullptr) { 163 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction( 164 g_get_current_queues_function_code, 165 g_get_current_queues_function_name, eLanguageTypeC, exe_ctx); 166 if (!utility_fn_or_error) { 167 LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(), 168 "Failed to create UtilityFunction for queues " 169 "introspection: {0}."); 170 return args_addr; 171 } 172 m_get_queues_impl_code_up = std::move(*utility_fn_or_error); 173 } else { 174 if (log) { 175 LLDB_LOGF(log, "No queues introspection code found."); 176 diagnostics.Dump(log); 177 } 178 return LLDB_INVALID_ADDRESS; 179 } 180 } 181 182 // Next make the runner function for our implementation utility function. 183 TypeSystemClangSP scratch_ts_sp = 184 ScratchTypeSystemClang::GetForTarget(thread.GetProcess()->GetTarget()); 185 CompilerType get_queues_return_type = 186 scratch_ts_sp->GetBasicType(eBasicTypeVoid).GetPointerType(); 187 Status error; 188 get_queues_caller = m_get_queues_impl_code_up->MakeFunctionCaller( 189 get_queues_return_type, get_queues_arglist, thread_sp, error); 190 if (error.Fail() || get_queues_caller == nullptr) { 191 LLDB_LOGF(log, 192 "Could not get function caller for get-queues function: %s.", 193 error.AsCString()); 194 return args_addr; 195 } 196 } 197 198 diagnostics.Clear(); 199 200 // Now write down the argument values for this particular call. This looks 201 // like it might be a race condition if other threads were calling into here, 202 // but actually it isn't because we allocate a new args structure for this 203 // call by passing args_addr = LLDB_INVALID_ADDRESS... 204 205 if (!get_queues_caller->WriteFunctionArguments( 206 exe_ctx, args_addr, get_queues_arglist, diagnostics)) { 207 if (log) { 208 LLDB_LOGF(log, "Error writing get-queues function arguments."); 209 diagnostics.Dump(log); 210 } 211 return args_addr; 212 } 213 214 return args_addr; 215 } 216 217 AppleGetQueuesHandler::GetQueuesReturnInfo 218 AppleGetQueuesHandler::GetCurrentQueues(Thread &thread, 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 GetQueuesReturnInfo return_value; 229 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS; 230 return_value.queues_buffer_size = 0; 231 return_value.count = 0; 232 233 error.Clear(); 234 235 if (!thread.SafeToCallFunctions()) { 236 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64, 237 thread.GetID()); 238 error = 239 Status::FromErrorString("Not safe to call functions on this thread."); 240 return return_value; 241 } 242 243 // Set up the arguments for a call to 244 245 // struct get_current_queues_return_values 246 // { 247 // uint64_t queues_buffer_ptr; /* the address of the queues buffer from 248 // libBacktraceRecording */ 249 // uint64_t queues_buffer_size; /* the size of the queues buffer from 250 // libBacktraceRecording */ 251 // uint64_t count; /* the number of queues included in the 252 // queues buffer */ 253 // }; 254 // 255 // void 256 // __lldb_backtrace_recording_get_current_queues 257 // (struct 258 // get_current_queues_return_values 259 // *return_buffer, 260 // void *page_to_free, 261 // uint64_t page_to_free_size); 262 263 // Where the return_buffer argument points to a 24 byte region of memory 264 // already allocated by lldb in the inferior process. 265 266 CompilerType clang_void_ptr_type = 267 scratch_ts_sp->GetBasicType(eBasicTypeVoid).GetPointerType(); 268 Value return_buffer_ptr_value; 269 return_buffer_ptr_value.SetValueType(Value::ValueType::Scalar); 270 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type); 271 272 CompilerType clang_int_type = scratch_ts_sp->GetBasicType(eBasicTypeInt); 273 Value debug_value; 274 debug_value.SetValueType(Value::ValueType::Scalar); 275 debug_value.SetCompilerType(clang_int_type); 276 277 Value page_to_free_value; 278 page_to_free_value.SetValueType(Value::ValueType::Scalar); 279 page_to_free_value.SetCompilerType(clang_void_ptr_type); 280 281 CompilerType clang_uint64_type = 282 scratch_ts_sp->GetBasicType(eBasicTypeUnsignedLongLong); 283 Value page_to_free_size_value; 284 page_to_free_size_value.SetValueType(Value::ValueType::Scalar); 285 page_to_free_size_value.SetCompilerType(clang_uint64_type); 286 287 std::lock_guard<std::mutex> guard(m_get_queues_retbuffer_mutex); 288 if (m_get_queues_return_buffer_addr == LLDB_INVALID_ADDRESS) { 289 addr_t bufaddr = process_sp->AllocateMemory( 290 32, ePermissionsReadable | ePermissionsWritable, error); 291 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) { 292 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get " 293 "current queues func call"); 294 return return_value; 295 } 296 m_get_queues_return_buffer_addr = bufaddr; 297 } 298 299 ValueList argument_values; 300 301 return_buffer_ptr_value.GetScalar() = m_get_queues_return_buffer_addr; 302 argument_values.PushValue(return_buffer_ptr_value); 303 304 debug_value.GetScalar() = 0; 305 argument_values.PushValue(debug_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 = SetupGetQueuesFunction(thread, argument_values); 317 318 if (!m_get_queues_impl_code_up) { 319 error = Status::FromErrorString( 320 "Unable to compile __introspection_dispatch_get_queues."); 321 return return_value; 322 } 323 324 FunctionCaller *get_queues_caller = 325 m_get_queues_impl_code_up->GetFunctionCaller(); 326 327 if (get_queues_caller == nullptr) { 328 error = Status::FromErrorString( 329 "Unable to get caller for call __introspection_dispatch_get_queues"); 330 return return_value; 331 } 332 333 DiagnosticManager diagnostics; 334 ExecutionContext exe_ctx; 335 EvaluateExpressionOptions options; 336 options.SetUnwindOnError(true); 337 options.SetIgnoreBreakpoints(true); 338 options.SetStopOthers(true); 339 #if __has_feature(address_sanitizer) 340 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 341 #else 342 options.SetTimeout(std::chrono::milliseconds(500)); 343 #endif 344 options.SetTryAllThreads(false); 345 options.SetIsForUtilityExpr(true); 346 thread.CalculateExecutionContext(exe_ctx); 347 348 ExpressionResults func_call_ret; 349 Value results; 350 func_call_ret = get_queues_caller->ExecuteFunction( 351 exe_ctx, &args_addr, options, diagnostics, results); 352 if (func_call_ret != eExpressionCompleted || !error.Success()) { 353 LLDB_LOGF(log, 354 "Unable to call introspection_get_dispatch_queues(), got " 355 "ExpressionResults %d, error contains %s", 356 func_call_ret, error.AsCString("")); 357 error = Status::FromErrorString( 358 "Unable to call introspection_get_dispatch_queues() " 359 "for list of queues"); 360 return return_value; 361 } 362 363 return_value.queues_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory( 364 m_get_queues_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error); 365 if (!error.Success() || 366 return_value.queues_buffer_ptr == LLDB_INVALID_ADDRESS) { 367 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS; 368 return return_value; 369 } 370 371 return_value.queues_buffer_size = m_process->ReadUnsignedIntegerFromMemory( 372 m_get_queues_return_buffer_addr + 8, 8, 0, error); 373 374 if (!error.Success()) { 375 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS; 376 return return_value; 377 } 378 379 return_value.count = m_process->ReadUnsignedIntegerFromMemory( 380 m_get_queues_return_buffer_addr + 16, 8, 0, error); 381 if (!error.Success()) { 382 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS; 383 return return_value; 384 } 385 386 LLDB_LOGF(log, 387 "AppleGetQueuesHandler called " 388 "__introspection_dispatch_get_queues (page_to_free == " 389 "0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64 390 ", size %" PRId64 ", count = %" PRId64, 391 page_to_free, page_to_free_size, return_value.queues_buffer_ptr, 392 return_value.queues_buffer_size, return_value.count); 393 394 return return_value; 395 } 396