1 //===-- AppleGetQueuesHandler.cpp -------------------------------*- C++ -*-===// 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 "lldb/Core/Module.h" 12 #include "lldb/Core/Value.h" 13 #include "lldb/Expression/DiagnosticManager.h" 14 #include "lldb/Expression/FunctionCaller.h" 15 #include "lldb/Expression/UtilityFunction.h" 16 #include "lldb/Symbol/ClangASTContext.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 *AppleGetQueuesHandler::g_get_current_queues_function_name = 30 "__lldb_backtrace_recording_get_current_queues"; 31 const char *AppleGetQueuesHandler::g_get_current_queues_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 *introspection_dispatch_queue_info_t; \n\ 56 \n\ 57 extern uint64_t __introspection_dispatch_get_queues (queue_list_scope_t scope, \n\ 58 introspection_dispatch_queue_info_t *returned_queues_buffer, \n\ 59 uint64_t *returned_queues_buffer_size); \n\ 60 extern int printf(const char *format, ...); \n\ 61 \n\ 62 /* \n\ 63 * return type define \n\ 64 */ \n\ 65 \n\ 66 struct get_current_queues_return_values \n\ 67 { \n\ 68 uint64_t queues_buffer_ptr; /* the address of the queues buffer from libBacktraceRecording */ \n\ 69 uint64_t queues_buffer_size; /* the size of the queues buffer from libBacktraceRecording */ \n\ 70 uint64_t count; /* the number of queues included in the queues buffer */ \n\ 71 }; \n\ 72 \n\ 73 void __lldb_backtrace_recording_get_current_queues \n\ 74 (struct get_current_queues_return_values *return_buffer, \n\ 75 int debug, \n\ 76 void *page_to_free, \n\ 77 uint64_t page_to_free_size) \n\ 78 { \n\ 79 if (debug) \n\ 80 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\ 81 if (page_to_free != 0) \n\ 82 { \n\ 83 mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\ 84 } \n\ 85 \n\ 86 return_buffer->count = __introspection_dispatch_get_queues ( \n\ 87 /* QUEUES_WITH_ANY_ITEMS */ 2, \n\ 88 (void**)&return_buffer->queues_buffer_ptr, \n\ 89 &return_buffer->queues_buffer_size); \n\ 90 if (debug) \n\ 91 printf(\"result was count %lld\\n\", return_buffer->count); \n\ 92 } \n\ 93 } \n\ 94 "; 95 96 AppleGetQueuesHandler::AppleGetQueuesHandler(Process *process) 97 : m_process(process), m_get_queues_impl_code_up(), 98 m_get_queues_function_mutex(), 99 m_get_queues_return_buffer_addr(LLDB_INVALID_ADDRESS), 100 m_get_queues_retbuffer_mutex() {} 101 102 AppleGetQueuesHandler::~AppleGetQueuesHandler() {} 103 104 void AppleGetQueuesHandler::Detach() { 105 106 if (m_process && m_process->IsAlive() && 107 m_get_queues_return_buffer_addr != LLDB_INVALID_ADDRESS) { 108 std::unique_lock<std::mutex> lock(m_get_queues_retbuffer_mutex, 109 std::defer_lock); 110 lock.try_lock(); // Even if we don't get the lock, deallocate the buffer 111 m_process->DeallocateMemory(m_get_queues_return_buffer_addr); 112 } 113 } 114 115 // Construct a CompilerType for the structure that 116 // g_get_current_queues_function_code will return by value so we can extract 117 // the fields after performing the function call. i.e. we are getting this 118 // struct returned to us: 119 // 120 // struct get_current_queues_return_values 121 // { 122 // introspection_dispatch_queue_info_t *queues_buffer; 123 // uint64_t queues_buffer_size; 124 // uint64_t count; 125 // }; 126 127 // Compile our __lldb_backtrace_recording_get_current_queues() function (from 128 // the source above in g_get_current_queues_function_code) if we don't find 129 // that function in the inferior already with USE_BUILTIN_FUNCTION defined. 130 // (e.g. this would be the case for testing.) 131 // 132 // Insert the __lldb_backtrace_recording_get_current_queues into the inferior 133 // process if needed. 134 // 135 // Write the get_queues_arglist into the inferior's memory space to prepare for 136 // the call. 137 // 138 // Returns the address of the arguments written down in the inferior process, 139 // which can be used to make the function call. 140 141 lldb::addr_t 142 AppleGetQueuesHandler::SetupGetQueuesFunction(Thread &thread, 143 ValueList &get_queues_arglist) { 144 ThreadSP thread_sp(thread.shared_from_this()); 145 ExecutionContext exe_ctx(thread_sp); 146 147 Address impl_code_address; 148 DiagnosticManager diagnostics; 149 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME)); 150 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS; 151 152 FunctionCaller *get_queues_caller = nullptr; 153 154 // Scope for mutex locker: 155 { 156 std::lock_guard<std::mutex> guard(m_get_queues_function_mutex); 157 158 // First stage is to make the ClangUtility to hold our injected function: 159 160 if (!m_get_queues_impl_code_up) { 161 if (g_get_current_queues_function_code != NULL) { 162 Status error; 163 m_get_queues_impl_code_up.reset( 164 exe_ctx.GetTargetRef().GetUtilityFunctionForLanguage( 165 g_get_current_queues_function_code, eLanguageTypeC, 166 g_get_current_queues_function_name, error)); 167 if (error.Fail()) { 168 if (log) 169 log->Printf( 170 "Failed to get UtilityFunction for queues introspection: %s.", 171 error.AsCString()); 172 return args_addr; 173 } 174 175 if (!m_get_queues_impl_code_up->Install(diagnostics, exe_ctx)) { 176 if (log) { 177 log->Printf("Failed to install queues introspection"); 178 diagnostics.Dump(log); 179 } 180 m_get_queues_impl_code_up.reset(); 181 return args_addr; 182 } 183 } else { 184 if (log) { 185 log->Printf("No queues introspection code found."); 186 diagnostics.Dump(log); 187 } 188 return LLDB_INVALID_ADDRESS; 189 } 190 } 191 192 // Next make the runner function for our implementation utility function. 193 ClangASTContext *clang_ast_context = 194 thread.GetProcess()->GetTarget().GetScratchClangASTContext(); 195 CompilerType get_queues_return_type = 196 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 197 Status error; 198 get_queues_caller = m_get_queues_impl_code_up->MakeFunctionCaller( 199 get_queues_return_type, get_queues_arglist, thread_sp, error); 200 if (error.Fail() || get_queues_caller == nullptr) { 201 if (log) 202 log->Printf( 203 "Could not get function caller for get-queues function: %s.", 204 error.AsCString()); 205 return args_addr; 206 } 207 } 208 209 diagnostics.Clear(); 210 211 // Now write down the argument values for this particular call. This looks 212 // like it might be a race condition if other threads were calling into here, 213 // but actually it isn't because we allocate a new args structure for this 214 // call by passing args_addr = LLDB_INVALID_ADDRESS... 215 216 if (!get_queues_caller->WriteFunctionArguments( 217 exe_ctx, args_addr, get_queues_arglist, diagnostics)) { 218 if (log) { 219 log->Printf("Error writing get-queues function arguments."); 220 diagnostics.Dump(log); 221 } 222 return args_addr; 223 } 224 225 return args_addr; 226 } 227 228 AppleGetQueuesHandler::GetQueuesReturnInfo 229 AppleGetQueuesHandler::GetCurrentQueues(Thread &thread, addr_t page_to_free, 230 uint64_t page_to_free_size, 231 Status &error) { 232 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0); 233 ProcessSP process_sp(thread.CalculateProcess()); 234 TargetSP target_sp(thread.CalculateTarget()); 235 ClangASTContext *clang_ast_context = target_sp->GetScratchClangASTContext(); 236 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME)); 237 238 GetQueuesReturnInfo return_value; 239 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS; 240 return_value.queues_buffer_size = 0; 241 return_value.count = 0; 242 243 error.Clear(); 244 245 if (!thread.SafeToCallFunctions()) { 246 if (log) 247 log->Printf("Not safe to call functions on thread 0x%" PRIx64, 248 thread.GetID()); 249 error.SetErrorString("Not safe to call functions on this thread."); 250 return return_value; 251 } 252 253 // Set up the arguments for a call to 254 255 // struct get_current_queues_return_values 256 // { 257 // uint64_t queues_buffer_ptr; /* the address of the queues buffer from 258 // libBacktraceRecording */ 259 // uint64_t queues_buffer_size; /* the size of the queues buffer from 260 // libBacktraceRecording */ 261 // uint64_t count; /* the number of queues included in the 262 // queues buffer */ 263 // }; 264 // 265 // void 266 // __lldb_backtrace_recording_get_current_queues 267 // (struct 268 // get_current_queues_return_values 269 // *return_buffer, 270 // void *page_to_free, 271 // uint64_t page_to_free_size); 272 273 // Where the return_buffer argument points to a 24 byte region of memory 274 // already allocated by lldb in the inferior process. 275 276 CompilerType clang_void_ptr_type = 277 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 278 Value return_buffer_ptr_value; 279 return_buffer_ptr_value.SetValueType(Value::eValueTypeScalar); 280 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type); 281 282 CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt); 283 Value debug_value; 284 debug_value.SetValueType(Value::eValueTypeScalar); 285 debug_value.SetCompilerType(clang_int_type); 286 287 Value page_to_free_value; 288 page_to_free_value.SetValueType(Value::eValueTypeScalar); 289 page_to_free_value.SetCompilerType(clang_void_ptr_type); 290 291 CompilerType clang_uint64_type = 292 clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong); 293 Value page_to_free_size_value; 294 page_to_free_size_value.SetValueType(Value::eValueTypeScalar); 295 page_to_free_size_value.SetCompilerType(clang_uint64_type); 296 297 std::lock_guard<std::mutex> guard(m_get_queues_retbuffer_mutex); 298 if (m_get_queues_return_buffer_addr == LLDB_INVALID_ADDRESS) { 299 addr_t bufaddr = process_sp->AllocateMemory( 300 32, ePermissionsReadable | ePermissionsWritable, error); 301 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) { 302 if (log) 303 log->Printf("Failed to allocate memory for return buffer for get " 304 "current queues func call"); 305 return return_value; 306 } 307 m_get_queues_return_buffer_addr = bufaddr; 308 } 309 310 ValueList argument_values; 311 312 return_buffer_ptr_value.GetScalar() = m_get_queues_return_buffer_addr; 313 argument_values.PushValue(return_buffer_ptr_value); 314 315 debug_value.GetScalar() = 0; 316 argument_values.PushValue(debug_value); 317 318 if (page_to_free != LLDB_INVALID_ADDRESS) 319 page_to_free_value.GetScalar() = page_to_free; 320 else 321 page_to_free_value.GetScalar() = 0; 322 argument_values.PushValue(page_to_free_value); 323 324 page_to_free_size_value.GetScalar() = page_to_free_size; 325 argument_values.PushValue(page_to_free_size_value); 326 327 addr_t args_addr = SetupGetQueuesFunction(thread, argument_values); 328 329 if (!m_get_queues_impl_code_up) { 330 error.SetErrorString( 331 "Unable to compile __introspection_dispatch_get_queues."); 332 return return_value; 333 } 334 335 FunctionCaller *get_queues_caller = 336 m_get_queues_impl_code_up->GetFunctionCaller(); 337 338 if (get_queues_caller == NULL) { 339 error.SetErrorString( 340 "Unable to get caller for call __introspection_dispatch_get_queues"); 341 return return_value; 342 } 343 344 DiagnosticManager diagnostics; 345 ExecutionContext exe_ctx; 346 EvaluateExpressionOptions options; 347 options.SetUnwindOnError(true); 348 options.SetIgnoreBreakpoints(true); 349 options.SetStopOthers(true); 350 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 351 options.SetTryAllThreads(false); 352 options.SetIsForUtilityExpr(true); 353 thread.CalculateExecutionContext(exe_ctx); 354 355 ExpressionResults func_call_ret; 356 Value results; 357 func_call_ret = get_queues_caller->ExecuteFunction( 358 exe_ctx, &args_addr, options, diagnostics, results); 359 if (func_call_ret != eExpressionCompleted || !error.Success()) { 360 if (log) 361 log->Printf("Unable to call introspection_get_dispatch_queues(), got " 362 "ExpressionResults %d, error contains %s", 363 func_call_ret, error.AsCString("")); 364 error.SetErrorString("Unable to call introspection_get_dispatch_queues() " 365 "for list of queues"); 366 return return_value; 367 } 368 369 return_value.queues_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory( 370 m_get_queues_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error); 371 if (!error.Success() || 372 return_value.queues_buffer_ptr == LLDB_INVALID_ADDRESS) { 373 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS; 374 return return_value; 375 } 376 377 return_value.queues_buffer_size = m_process->ReadUnsignedIntegerFromMemory( 378 m_get_queues_return_buffer_addr + 8, 8, 0, error); 379 380 if (!error.Success()) { 381 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS; 382 return return_value; 383 } 384 385 return_value.count = m_process->ReadUnsignedIntegerFromMemory( 386 m_get_queues_return_buffer_addr + 16, 8, 0, error); 387 if (!error.Success()) { 388 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS; 389 return return_value; 390 } 391 392 if (log) 393 log->Printf("AppleGetQueuesHandler called " 394 "__introspection_dispatch_get_queues (page_to_free == " 395 "0x%" PRIx64 ", size = %" PRId64 396 "), returned page is at 0x%" PRIx64 ", size %" PRId64 397 ", count = %" PRId64, 398 page_to_free, page_to_free_size, return_value.queues_buffer_ptr, 399 return_value.queues_buffer_size, return_value.count); 400 401 return return_value; 402 } 403