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/Log.h" 24 #include "lldb/Utility/StreamString.h" 25 26 using namespace lldb; 27 using namespace lldb_private; 28 29 const char *AppleGetPendingItemsHandler::g_get_pending_items_function_name = 30 "__lldb_backtrace_recording_get_pending_items"; 31 const char *AppleGetPendingItemsHandler::g_get_pending_items_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_get_pending_items (dispatch_queue_t queue, \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_pending_items_return_values \n\ 69 { \n\ 70 uint64_t pending_items_buffer_ptr; /* the address of the items buffer from libBacktraceRecording */ \n\ 71 uint64_t pending_items_buffer_size; /* the size of the items buffer from libBacktraceRecording */ \n\ 72 uint64_t count; /* the number of items included in the queues buffer */ \n\ 73 }; \n\ 74 \n\ 75 void __lldb_backtrace_recording_get_pending_items \n\ 76 (struct get_pending_items_return_values *return_buffer, \n\ 77 int debug, \n\ 78 uint64_t /* dispatch_queue_t */ queue, \n\ 79 void *page_to_free, \n\ 80 uint64_t page_to_free_size) \n\ 81 { \n\ 82 if (debug) \n\ 83 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\ 84 if (page_to_free != 0) \n\ 85 { \n\ 86 mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\ 87 } \n\ 88 \n\ 89 return_buffer->count = __introspection_dispatch_queue_get_pending_items ( \n\ 90 (void*) queue, \n\ 91 (void**)&return_buffer->pending_items_buffer_ptr, \n\ 92 &return_buffer->pending_items_buffer_size); \n\ 93 if (debug) \n\ 94 printf(\"result was count %lld\\n\", return_buffer->count); \n\ 95 } \n\ 96 } \n\ 97 "; 98 99 AppleGetPendingItemsHandler::AppleGetPendingItemsHandler(Process *process) 100 : m_process(process), m_get_pending_items_impl_code(), 101 m_get_pending_items_function_mutex(), 102 m_get_pending_items_return_buffer_addr(LLDB_INVALID_ADDRESS), 103 m_get_pending_items_retbuffer_mutex() {} 104 105 AppleGetPendingItemsHandler::~AppleGetPendingItemsHandler() {} 106 107 void AppleGetPendingItemsHandler::Detach() { 108 if (m_process && m_process->IsAlive() && 109 m_get_pending_items_return_buffer_addr != LLDB_INVALID_ADDRESS) { 110 std::unique_lock<std::mutex> lock(m_get_pending_items_retbuffer_mutex, 111 std::defer_lock); 112 (void)lock.try_lock(); // Even if we don't get the lock, deallocate the buffer 113 m_process->DeallocateMemory(m_get_pending_items_return_buffer_addr); 114 } 115 } 116 117 // Compile our __lldb_backtrace_recording_get_pending_items() function (from 118 // the source above in g_get_pending_items_function_code) if we don't find that 119 // function in the inferior already with USE_BUILTIN_FUNCTION defined. (e.g. 120 // this would be the case for testing.) 121 // 122 // Insert the __lldb_backtrace_recording_get_pending_items into the inferior 123 // process if needed. 124 // 125 // Write the get_pending_items_arglist into the inferior's memory space to 126 // prepare for the call. 127 // 128 // Returns the address of the arguments written down in the inferior process, 129 // which can be used to make the function call. 130 131 lldb::addr_t AppleGetPendingItemsHandler::SetupGetPendingItemsFunction( 132 Thread &thread, ValueList &get_pending_items_arglist) { 133 ThreadSP thread_sp(thread.shared_from_this()); 134 ExecutionContext exe_ctx(thread_sp); 135 DiagnosticManager diagnostics; 136 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME)); 137 138 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS; 139 FunctionCaller *get_pending_items_caller = nullptr; 140 141 // Scope for mutex locker: 142 { 143 std::lock_guard<std::mutex> guard(m_get_pending_items_function_mutex); 144 145 // First stage is to make the ClangUtility to hold our injected function: 146 147 if (!m_get_pending_items_impl_code) { 148 if (g_get_pending_items_function_code != nullptr) { 149 Status error; 150 m_get_pending_items_impl_code.reset( 151 exe_ctx.GetTargetRef().GetUtilityFunctionForLanguage( 152 g_get_pending_items_function_code, eLanguageTypeObjC, 153 g_get_pending_items_function_name, error)); 154 if (error.Fail()) { 155 LLDB_LOGF(log, 156 "Failed to get UtilityFunction for pending-items " 157 "introspection: %s.", 158 error.AsCString()); 159 return args_addr; 160 } 161 162 if (!m_get_pending_items_impl_code->Install(diagnostics, exe_ctx)) { 163 if (log) { 164 LLDB_LOGF(log, "Failed to install pending-items introspection."); 165 diagnostics.Dump(log); 166 } 167 m_get_pending_items_impl_code.reset(); 168 return args_addr; 169 } 170 } else { 171 LLDB_LOGF(log, "No pending-items introspection code found."); 172 return LLDB_INVALID_ADDRESS; 173 } 174 175 // Next make the runner function for our implementation utility function. 176 Status error; 177 TypeSystemClang *clang_ast_context = 178 TypeSystemClang::GetScratch(thread.GetProcess()->GetTarget()); 179 CompilerType get_pending_items_return_type = 180 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 181 get_pending_items_caller = 182 m_get_pending_items_impl_code->MakeFunctionCaller( 183 get_pending_items_return_type, get_pending_items_arglist, 184 thread_sp, error); 185 if (error.Fail() || get_pending_items_caller == nullptr) { 186 LLDB_LOGF(log, 187 "Failed to install pending-items introspection function " 188 "caller: %s.", 189 error.AsCString()); 190 m_get_pending_items_impl_code.reset(); 191 return args_addr; 192 } 193 } 194 } 195 196 diagnostics.Clear(); 197 198 if (get_pending_items_caller == nullptr) { 199 LLDB_LOGF(log, "Failed to get get_pending_items_caller."); 200 return LLDB_INVALID_ADDRESS; 201 } 202 203 // Now write down the argument values for this particular call. This looks 204 // like it might be a race condition if other threads were calling into here, 205 // but actually it isn't because we allocate a new args structure for this 206 // call by passing args_addr = LLDB_INVALID_ADDRESS... 207 208 if (!get_pending_items_caller->WriteFunctionArguments( 209 exe_ctx, args_addr, get_pending_items_arglist, diagnostics)) { 210 if (log) { 211 LLDB_LOGF(log, "Error writing pending-items function arguments."); 212 diagnostics.Dump(log); 213 } 214 215 return args_addr; 216 } 217 218 return args_addr; 219 } 220 221 AppleGetPendingItemsHandler::GetPendingItemsReturnInfo 222 AppleGetPendingItemsHandler::GetPendingItems(Thread &thread, addr_t queue, 223 addr_t page_to_free, 224 uint64_t page_to_free_size, 225 Status &error) { 226 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0); 227 ProcessSP process_sp(thread.CalculateProcess()); 228 TargetSP target_sp(thread.CalculateTarget()); 229 TypeSystemClang *clang_ast_context = TypeSystemClang::GetScratch(*target_sp); 230 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME)); 231 232 GetPendingItemsReturnInfo return_value; 233 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 234 return_value.items_buffer_size = 0; 235 return_value.count = 0; 236 237 error.Clear(); 238 239 if (!thread.SafeToCallFunctions()) { 240 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64, 241 thread.GetID()); 242 error.SetErrorString("Not safe to call functions on this thread."); 243 return return_value; 244 } 245 246 // Set up the arguments for a call to 247 248 // struct get_pending_items_return_values 249 // { 250 // uint64_t pending_items_buffer_ptr; /* the address of the items 251 // buffer from libBacktraceRecording */ 252 // uint64_t pending_items_buffer_size; /* the size of the items buffer 253 // from libBacktraceRecording */ 254 // uint64_t count; /* the number of items included in the 255 // queues buffer */ 256 // }; 257 // 258 // void __lldb_backtrace_recording_get_pending_items 259 // (struct 260 // get_pending_items_return_values 261 // *return_buffer, 262 // int debug, 263 // uint64_t /* dispatch_queue_t */ 264 // queue 265 // void *page_to_free, 266 // uint64_t page_to_free_size) 267 268 // Where the return_buffer argument points to a 24 byte region of memory 269 // already allocated by lldb in the inferior process. 270 271 CompilerType clang_void_ptr_type = 272 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 273 Value return_buffer_ptr_value; 274 return_buffer_ptr_value.SetValueType(Value::eValueTypeScalar); 275 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type); 276 277 CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt); 278 Value debug_value; 279 debug_value.SetValueType(Value::eValueTypeScalar); 280 debug_value.SetCompilerType(clang_int_type); 281 282 CompilerType clang_uint64_type = 283 clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong); 284 Value queue_value; 285 queue_value.SetValueType(Value::eValueTypeScalar); 286 queue_value.SetCompilerType(clang_uint64_type); 287 288 Value page_to_free_value; 289 page_to_free_value.SetValueType(Value::eValueTypeScalar); 290 page_to_free_value.SetCompilerType(clang_void_ptr_type); 291 292 Value page_to_free_size_value; 293 page_to_free_size_value.SetValueType(Value::eValueTypeScalar); 294 page_to_free_size_value.SetCompilerType(clang_uint64_type); 295 296 std::lock_guard<std::mutex> guard(m_get_pending_items_retbuffer_mutex); 297 if (m_get_pending_items_return_buffer_addr == LLDB_INVALID_ADDRESS) { 298 addr_t bufaddr = process_sp->AllocateMemory( 299 32, ePermissionsReadable | ePermissionsWritable, error); 300 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) { 301 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get " 302 "current queues func call"); 303 return return_value; 304 } 305 m_get_pending_items_return_buffer_addr = bufaddr; 306 } 307 308 ValueList argument_values; 309 310 return_buffer_ptr_value.GetScalar() = m_get_pending_items_return_buffer_addr; 311 argument_values.PushValue(return_buffer_ptr_value); 312 313 debug_value.GetScalar() = 0; 314 argument_values.PushValue(debug_value); 315 316 queue_value.GetScalar() = queue; 317 argument_values.PushValue(queue_value); 318 319 if (page_to_free != LLDB_INVALID_ADDRESS) 320 page_to_free_value.GetScalar() = page_to_free; 321 else 322 page_to_free_value.GetScalar() = 0; 323 argument_values.PushValue(page_to_free_value); 324 325 page_to_free_size_value.GetScalar() = page_to_free_size; 326 argument_values.PushValue(page_to_free_size_value); 327 328 addr_t args_addr = SetupGetPendingItemsFunction(thread, argument_values); 329 330 DiagnosticManager diagnostics; 331 ExecutionContext exe_ctx; 332 FunctionCaller *get_pending_items_caller = 333 m_get_pending_items_impl_code->GetFunctionCaller(); 334 335 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 if (get_pending_items_caller == nullptr) { 349 error.SetErrorString("Unable to compile function to call " 350 "__introspection_dispatch_queue_get_pending_items"); 351 return return_value; 352 } 353 354 ExpressionResults func_call_ret; 355 Value results; 356 func_call_ret = get_pending_items_caller->ExecuteFunction( 357 exe_ctx, &args_addr, options, diagnostics, results); 358 if (func_call_ret != eExpressionCompleted || !error.Success()) { 359 LLDB_LOGF(log, 360 "Unable to call " 361 "__introspection_dispatch_queue_get_pending_items(), got " 362 "ExpressionResults %d, error contains %s", 363 func_call_ret, error.AsCString("")); 364 error.SetErrorString("Unable to call " 365 "__introspection_dispatch_queue_get_pending_items() " 366 "for list of queues"); 367 return return_value; 368 } 369 370 return_value.items_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory( 371 m_get_pending_items_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error); 372 if (!error.Success() || 373 return_value.items_buffer_ptr == LLDB_INVALID_ADDRESS) { 374 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 375 return return_value; 376 } 377 378 return_value.items_buffer_size = m_process->ReadUnsignedIntegerFromMemory( 379 m_get_pending_items_return_buffer_addr + 8, 8, 0, error); 380 381 if (!error.Success()) { 382 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 383 return return_value; 384 } 385 386 return_value.count = m_process->ReadUnsignedIntegerFromMemory( 387 m_get_pending_items_return_buffer_addr + 16, 8, 0, error); 388 if (!error.Success()) { 389 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 390 return return_value; 391 } 392 393 LLDB_LOGF(log, 394 "AppleGetPendingItemsHandler called " 395 "__introspection_dispatch_queue_get_pending_items " 396 "(page_to_free == 0x%" PRIx64 ", size = %" PRId64 397 "), returned page is at 0x%" PRIx64 ", size %" PRId64 398 ", count = %" PRId64, 399 page_to_free, page_to_free_size, return_value.items_buffer_ptr, 400 return_value.items_buffer_size, return_value.count); 401 402 return return_value; 403 } 404