1 //===-- AppleGetPendingItemsHandler.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 "AppleGetPendingItemsHandler.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 *AppleGetPendingItemsHandler::g_get_pending_items_function_name = 31 "__lldb_backtrace_recording_get_pending_items"; 32 const char *AppleGetPendingItemsHandler::g_get_pending_items_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_get_pending_items (dispatch_queue_t queue, \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_pending_items_return_values \n\ 70 { \n\ 71 uint64_t pending_items_buffer_ptr; /* the address of the items buffer from libBacktraceRecording */ \n\ 72 uint64_t pending_items_buffer_size; /* the size of the items buffer from libBacktraceRecording */ \n\ 73 uint64_t count; /* the number of items included in the queues buffer */ \n\ 74 }; \n\ 75 \n\ 76 void __lldb_backtrace_recording_get_pending_items \n\ 77 (struct get_pending_items_return_values *return_buffer, \n\ 78 int debug, \n\ 79 uint64_t /* dispatch_queue_t */ queue, \n\ 80 void *page_to_free, \n\ 81 uint64_t page_to_free_size) \n\ 82 { \n\ 83 if (debug) \n\ 84 printf (\"entering get_pending_items with args return_buffer == %p, debug == %d, queue == 0x%llx, page_to_free == %p, page_to_free_size == 0x%llx\\n\", return_buffer, debug, queue, page_to_free, page_to_free_size); \n\ 85 if (page_to_free != 0) \n\ 86 { \n\ 87 mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\ 88 } \n\ 89 \n\ 90 return_buffer->count = __introspection_dispatch_queue_get_pending_items ( \n\ 91 (void*) queue, \n\ 92 (void**)&return_buffer->pending_items_buffer_ptr, \n\ 93 &return_buffer->pending_items_buffer_size); \n\ 94 if (debug) \n\ 95 printf(\"result was count %lld\\n\", return_buffer->count); \n\ 96 } \n\ 97 } \n\ 98 "; 99 100 AppleGetPendingItemsHandler::AppleGetPendingItemsHandler(Process *process) 101 : m_process(process), m_get_pending_items_impl_code(), 102 m_get_pending_items_function_mutex(), 103 m_get_pending_items_return_buffer_addr(LLDB_INVALID_ADDRESS), 104 m_get_pending_items_retbuffer_mutex() {} 105 106 AppleGetPendingItemsHandler::~AppleGetPendingItemsHandler() = default; 107 108 void AppleGetPendingItemsHandler::Detach() { 109 if (m_process && m_process->IsAlive() && 110 m_get_pending_items_return_buffer_addr != LLDB_INVALID_ADDRESS) { 111 std::unique_lock<std::mutex> lock(m_get_pending_items_retbuffer_mutex, 112 std::defer_lock); 113 (void)lock.try_lock(); // Even if we don't get the lock, deallocate the buffer 114 m_process->DeallocateMemory(m_get_pending_items_return_buffer_addr); 115 } 116 } 117 118 // Compile our __lldb_backtrace_recording_get_pending_items() function (from 119 // the source above in g_get_pending_items_function_code) if we don't find that 120 // function in the inferior already with USE_BUILTIN_FUNCTION defined. (e.g. 121 // this would be the case for testing.) 122 // 123 // Insert the __lldb_backtrace_recording_get_pending_items into the inferior 124 // process if needed. 125 // 126 // Write the get_pending_items_arglist into the inferior's memory space to 127 // prepare for the call. 128 // 129 // Returns the address of the arguments written down in the inferior process, 130 // which can be used to make the function call. 131 132 lldb::addr_t AppleGetPendingItemsHandler::SetupGetPendingItemsFunction( 133 Thread &thread, ValueList &get_pending_items_arglist) { 134 ThreadSP thread_sp(thread.shared_from_this()); 135 ExecutionContext exe_ctx(thread_sp); 136 DiagnosticManager diagnostics; 137 Log *log = GetLog(LLDBLog::SystemRuntime); 138 139 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS; 140 FunctionCaller *get_pending_items_caller = nullptr; 141 142 // Scope for mutex locker: 143 { 144 std::lock_guard<std::mutex> guard(m_get_pending_items_function_mutex); 145 146 // First stage is to make the ClangUtility to hold our injected function: 147 148 if (!m_get_pending_items_impl_code) { 149 if (g_get_pending_items_function_code != nullptr) { 150 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction( 151 g_get_pending_items_function_code, 152 g_get_pending_items_function_name, eLanguageTypeC, exe_ctx); 153 if (!utility_fn_or_error) { 154 LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(), 155 "Failed to create UtilityFunction for pending-items " 156 "introspection: {0}."); 157 return args_addr; 158 } 159 m_get_pending_items_impl_code = std::move(*utility_fn_or_error); 160 } else { 161 LLDB_LOGF(log, "No pending-items introspection code found."); 162 return LLDB_INVALID_ADDRESS; 163 } 164 165 // Next make the runner function for our implementation utility function. 166 Status error; 167 TypeSystemClangSP scratch_ts_sp = ScratchTypeSystemClang::GetForTarget( 168 thread.GetProcess()->GetTarget()); 169 CompilerType get_pending_items_return_type = 170 scratch_ts_sp->GetBasicType(eBasicTypeVoid).GetPointerType(); 171 get_pending_items_caller = 172 m_get_pending_items_impl_code->MakeFunctionCaller( 173 get_pending_items_return_type, get_pending_items_arglist, 174 thread_sp, error); 175 if (error.Fail() || get_pending_items_caller == nullptr) { 176 LLDB_LOGF(log, 177 "Failed to install pending-items introspection function " 178 "caller: %s.", 179 error.AsCString()); 180 m_get_pending_items_impl_code.reset(); 181 return args_addr; 182 } 183 } 184 } 185 186 diagnostics.Clear(); 187 188 if (get_pending_items_caller == nullptr) { 189 LLDB_LOGF(log, "Failed to get get_pending_items_caller."); 190 return LLDB_INVALID_ADDRESS; 191 } 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_pending_items_caller->WriteFunctionArguments( 199 exe_ctx, args_addr, get_pending_items_arglist, diagnostics)) { 200 if (log) { 201 LLDB_LOGF(log, "Error writing pending-items function arguments."); 202 diagnostics.Dump(log); 203 } 204 205 return args_addr; 206 } 207 208 return args_addr; 209 } 210 211 AppleGetPendingItemsHandler::GetPendingItemsReturnInfo 212 AppleGetPendingItemsHandler::GetPendingItems(Thread &thread, addr_t queue, 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 TypeSystemClangSP scratch_ts_sp = 220 ScratchTypeSystemClang::GetForTarget(*target_sp); 221 Log *log = GetLog(LLDBLog::SystemRuntime); 222 223 GetPendingItemsReturnInfo return_value; 224 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 225 return_value.items_buffer_size = 0; 226 return_value.count = 0; 227 228 error.Clear(); 229 230 if (!thread.SafeToCallFunctions()) { 231 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64, 232 thread.GetID()); 233 error = 234 Status::FromErrorString("Not safe to call functions on this thread."); 235 return return_value; 236 } 237 238 // Set up the arguments for a call to 239 240 // struct get_pending_items_return_values 241 // { 242 // uint64_t pending_items_buffer_ptr; /* the address of the items 243 // buffer from libBacktraceRecording */ 244 // uint64_t pending_items_buffer_size; /* the size of the items buffer 245 // from libBacktraceRecording */ 246 // uint64_t count; /* the number of items included in the 247 // queues buffer */ 248 // }; 249 // 250 // void __lldb_backtrace_recording_get_pending_items 251 // (struct 252 // get_pending_items_return_values 253 // *return_buffer, 254 // int debug, 255 // uint64_t /* dispatch_queue_t */ 256 // queue 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 queue_value; 277 queue_value.SetValueType(Value::ValueType::Scalar); 278 queue_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_pending_items_retbuffer_mutex); 289 if (m_get_pending_items_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_pending_items_return_buffer_addr = bufaddr; 298 } 299 300 ValueList argument_values; 301 302 return_buffer_ptr_value.GetScalar() = m_get_pending_items_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 queue_value.GetScalar() = queue; 309 argument_values.PushValue(queue_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 = SetupGetPendingItemsFunction(thread, argument_values); 321 322 DiagnosticManager diagnostics; 323 ExecutionContext exe_ctx; 324 FunctionCaller *get_pending_items_caller = 325 m_get_pending_items_impl_code->GetFunctionCaller(); 326 327 EvaluateExpressionOptions options; 328 options.SetUnwindOnError(true); 329 options.SetIgnoreBreakpoints(true); 330 options.SetStopOthers(true); 331 #if __has_feature(address_sanitizer) 332 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 333 #else 334 options.SetTimeout(std::chrono::milliseconds(500)); 335 #endif 336 options.SetTryAllThreads(false); 337 options.SetIsForUtilityExpr(true); 338 thread.CalculateExecutionContext(exe_ctx); 339 340 if (get_pending_items_caller == nullptr) { 341 error = Status::FromErrorString( 342 "Unable to compile function to call " 343 "__introspection_dispatch_queue_get_pending_items"); 344 return return_value; 345 } 346 347 ExpressionResults func_call_ret; 348 Value results; 349 func_call_ret = get_pending_items_caller->ExecuteFunction( 350 exe_ctx, &args_addr, options, diagnostics, results); 351 if (func_call_ret != eExpressionCompleted || !error.Success()) { 352 LLDB_LOGF(log, 353 "Unable to call " 354 "__introspection_dispatch_queue_get_pending_items(), got " 355 "ExpressionResults %d, error contains %s", 356 func_call_ret, error.AsCString("")); 357 error = Status::FromErrorString( 358 "Unable to call " 359 "__introspection_dispatch_queue_get_pending_items() " 360 "for list of queues"); 361 return return_value; 362 } 363 364 return_value.items_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory( 365 m_get_pending_items_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error); 366 if (!error.Success() || 367 return_value.items_buffer_ptr == LLDB_INVALID_ADDRESS) { 368 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 369 return return_value; 370 } 371 372 return_value.items_buffer_size = m_process->ReadUnsignedIntegerFromMemory( 373 m_get_pending_items_return_buffer_addr + 8, 8, 0, error); 374 375 if (!error.Success()) { 376 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 377 return return_value; 378 } 379 380 return_value.count = m_process->ReadUnsignedIntegerFromMemory( 381 m_get_pending_items_return_buffer_addr + 16, 8, 0, error); 382 if (!error.Success()) { 383 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 384 return return_value; 385 } 386 387 LLDB_LOGF(log, 388 "AppleGetPendingItemsHandler called " 389 "__introspection_dispatch_queue_get_pending_items " 390 "(page_to_free == 0x%" PRIx64 ", size = %" PRId64 391 "), returned page is at 0x%" PRIx64 ", size %" PRId64 392 ", count = %" PRId64, 393 page_to_free, page_to_free_size, return_value.items_buffer_ptr, 394 return_value.items_buffer_size, return_value.count); 395 396 return return_value; 397 } 398