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/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 (void)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 != nullptr) { 162 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction( 163 g_get_current_queues_function_code, 164 g_get_current_queues_function_name, eLanguageTypeC, exe_ctx); 165 if (!utility_fn_or_error) { 166 LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(), 167 "Failed to create UtilityFunction for queues " 168 "introspection: {0}."); 169 return args_addr; 170 } 171 m_get_queues_impl_code_up = std::move(*utility_fn_or_error); 172 } else { 173 if (log) { 174 LLDB_LOGF(log, "No queues introspection code found."); 175 diagnostics.Dump(log); 176 } 177 return LLDB_INVALID_ADDRESS; 178 } 179 } 180 181 // Next make the runner function for our implementation utility function. 182 TypeSystemClang *clang_ast_context = 183 TypeSystemClang::GetScratch(thread.GetProcess()->GetTarget()); 184 CompilerType get_queues_return_type = 185 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 186 Status error; 187 get_queues_caller = m_get_queues_impl_code_up->MakeFunctionCaller( 188 get_queues_return_type, get_queues_arglist, thread_sp, error); 189 if (error.Fail() || get_queues_caller == nullptr) { 190 LLDB_LOGF(log, 191 "Could not get function caller for get-queues function: %s.", 192 error.AsCString()); 193 return args_addr; 194 } 195 } 196 197 diagnostics.Clear(); 198 199 // Now write down the argument values for this particular call. This looks 200 // like it might be a race condition if other threads were calling into here, 201 // but actually it isn't because we allocate a new args structure for this 202 // call by passing args_addr = LLDB_INVALID_ADDRESS... 203 204 if (!get_queues_caller->WriteFunctionArguments( 205 exe_ctx, args_addr, get_queues_arglist, diagnostics)) { 206 if (log) { 207 LLDB_LOGF(log, "Error writing get-queues function arguments."); 208 diagnostics.Dump(log); 209 } 210 return args_addr; 211 } 212 213 return args_addr; 214 } 215 216 AppleGetQueuesHandler::GetQueuesReturnInfo 217 AppleGetQueuesHandler::GetCurrentQueues(Thread &thread, addr_t page_to_free, 218 uint64_t page_to_free_size, 219 Status &error) { 220 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0); 221 ProcessSP process_sp(thread.CalculateProcess()); 222 TargetSP target_sp(thread.CalculateTarget()); 223 TypeSystemClang *clang_ast_context = TypeSystemClang::GetScratch(*target_sp); 224 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME)); 225 226 GetQueuesReturnInfo return_value; 227 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS; 228 return_value.queues_buffer_size = 0; 229 return_value.count = 0; 230 231 error.Clear(); 232 233 if (!thread.SafeToCallFunctions()) { 234 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64, 235 thread.GetID()); 236 error.SetErrorString("Not safe to call functions on this thread."); 237 return return_value; 238 } 239 240 // Set up the arguments for a call to 241 242 // struct get_current_queues_return_values 243 // { 244 // uint64_t queues_buffer_ptr; /* the address of the queues buffer from 245 // libBacktraceRecording */ 246 // uint64_t queues_buffer_size; /* the size of the queues buffer from 247 // libBacktraceRecording */ 248 // uint64_t count; /* the number of queues included in the 249 // queues buffer */ 250 // }; 251 // 252 // void 253 // __lldb_backtrace_recording_get_current_queues 254 // (struct 255 // get_current_queues_return_values 256 // *return_buffer, 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 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 265 Value return_buffer_ptr_value; 266 return_buffer_ptr_value.SetValueType(Value::eValueTypeScalar); 267 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type); 268 269 CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt); 270 Value debug_value; 271 debug_value.SetValueType(Value::eValueTypeScalar); 272 debug_value.SetCompilerType(clang_int_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 CompilerType clang_uint64_type = 279 clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong); 280 Value page_to_free_size_value; 281 page_to_free_size_value.SetValueType(Value::eValueTypeScalar); 282 page_to_free_size_value.SetCompilerType(clang_uint64_type); 283 284 std::lock_guard<std::mutex> guard(m_get_queues_retbuffer_mutex); 285 if (m_get_queues_return_buffer_addr == LLDB_INVALID_ADDRESS) { 286 addr_t bufaddr = process_sp->AllocateMemory( 287 32, ePermissionsReadable | ePermissionsWritable, error); 288 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) { 289 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get " 290 "current queues func call"); 291 return return_value; 292 } 293 m_get_queues_return_buffer_addr = bufaddr; 294 } 295 296 ValueList argument_values; 297 298 return_buffer_ptr_value.GetScalar() = m_get_queues_return_buffer_addr; 299 argument_values.PushValue(return_buffer_ptr_value); 300 301 debug_value.GetScalar() = 0; 302 argument_values.PushValue(debug_value); 303 304 if (page_to_free != LLDB_INVALID_ADDRESS) 305 page_to_free_value.GetScalar() = page_to_free; 306 else 307 page_to_free_value.GetScalar() = 0; 308 argument_values.PushValue(page_to_free_value); 309 310 page_to_free_size_value.GetScalar() = page_to_free_size; 311 argument_values.PushValue(page_to_free_size_value); 312 313 addr_t args_addr = SetupGetQueuesFunction(thread, argument_values); 314 315 if (!m_get_queues_impl_code_up) { 316 error.SetErrorString( 317 "Unable to compile __introspection_dispatch_get_queues."); 318 return return_value; 319 } 320 321 FunctionCaller *get_queues_caller = 322 m_get_queues_impl_code_up->GetFunctionCaller(); 323 324 if (get_queues_caller == nullptr) { 325 error.SetErrorString( 326 "Unable to get caller for call __introspection_dispatch_get_queues"); 327 return return_value; 328 } 329 330 DiagnosticManager diagnostics; 331 ExecutionContext exe_ctx; 332 EvaluateExpressionOptions options; 333 options.SetUnwindOnError(true); 334 options.SetIgnoreBreakpoints(true); 335 options.SetStopOthers(true); 336 #if __has_feature(address_sanitizer) 337 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 338 #else 339 options.SetTimeout(std::chrono::milliseconds(500)); 340 #endif 341 options.SetTryAllThreads(false); 342 options.SetIsForUtilityExpr(true); 343 thread.CalculateExecutionContext(exe_ctx); 344 345 ExpressionResults func_call_ret; 346 Value results; 347 func_call_ret = get_queues_caller->ExecuteFunction( 348 exe_ctx, &args_addr, options, diagnostics, results); 349 if (func_call_ret != eExpressionCompleted || !error.Success()) { 350 LLDB_LOGF(log, 351 "Unable to call introspection_get_dispatch_queues(), got " 352 "ExpressionResults %d, error contains %s", 353 func_call_ret, error.AsCString("")); 354 error.SetErrorString("Unable to call introspection_get_dispatch_queues() " 355 "for list of queues"); 356 return return_value; 357 } 358 359 return_value.queues_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory( 360 m_get_queues_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error); 361 if (!error.Success() || 362 return_value.queues_buffer_ptr == LLDB_INVALID_ADDRESS) { 363 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS; 364 return return_value; 365 } 366 367 return_value.queues_buffer_size = m_process->ReadUnsignedIntegerFromMemory( 368 m_get_queues_return_buffer_addr + 8, 8, 0, error); 369 370 if (!error.Success()) { 371 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS; 372 return return_value; 373 } 374 375 return_value.count = m_process->ReadUnsignedIntegerFromMemory( 376 m_get_queues_return_buffer_addr + 16, 8, 0, error); 377 if (!error.Success()) { 378 return_value.queues_buffer_ptr = LLDB_INVALID_ADDRESS; 379 return return_value; 380 } 381 382 LLDB_LOGF(log, 383 "AppleGetQueuesHandler called " 384 "__introspection_dispatch_get_queues (page_to_free == " 385 "0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64 386 ", size %" PRId64 ", count = %" PRId64, 387 page_to_free, page_to_free_size, return_value.queues_buffer_ptr, 388 return_value.queues_buffer_size, return_value.count); 389 390 return return_value; 391 } 392