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 auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction( 150 g_get_pending_items_function_code, 151 g_get_pending_items_function_name, eLanguageTypeC, exe_ctx); 152 if (!utility_fn_or_error) { 153 LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(), 154 "Failed to create UtilityFunction for pending-items " 155 "introspection: {0}."); 156 return args_addr; 157 } 158 m_get_pending_items_impl_code = std::move(*utility_fn_or_error); 159 } else { 160 LLDB_LOGF(log, "No pending-items introspection code found."); 161 return LLDB_INVALID_ADDRESS; 162 } 163 164 // Next make the runner function for our implementation utility function. 165 Status error; 166 TypeSystemClang *clang_ast_context = 167 TypeSystemClang::GetScratch(thread.GetProcess()->GetTarget()); 168 CompilerType get_pending_items_return_type = 169 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 170 get_pending_items_caller = 171 m_get_pending_items_impl_code->MakeFunctionCaller( 172 get_pending_items_return_type, get_pending_items_arglist, 173 thread_sp, error); 174 if (error.Fail() || get_pending_items_caller == nullptr) { 175 LLDB_LOGF(log, 176 "Failed to install pending-items introspection function " 177 "caller: %s.", 178 error.AsCString()); 179 m_get_pending_items_impl_code.reset(); 180 return args_addr; 181 } 182 } 183 } 184 185 diagnostics.Clear(); 186 187 if (get_pending_items_caller == nullptr) { 188 LLDB_LOGF(log, "Failed to get get_pending_items_caller."); 189 return LLDB_INVALID_ADDRESS; 190 } 191 192 // Now write down the argument values for this particular call. This looks 193 // like it might be a race condition if other threads were calling into here, 194 // but actually it isn't because we allocate a new args structure for this 195 // call by passing args_addr = LLDB_INVALID_ADDRESS... 196 197 if (!get_pending_items_caller->WriteFunctionArguments( 198 exe_ctx, args_addr, get_pending_items_arglist, diagnostics)) { 199 if (log) { 200 LLDB_LOGF(log, "Error writing pending-items function arguments."); 201 diagnostics.Dump(log); 202 } 203 204 return args_addr; 205 } 206 207 return args_addr; 208 } 209 210 AppleGetPendingItemsHandler::GetPendingItemsReturnInfo 211 AppleGetPendingItemsHandler::GetPendingItems(Thread &thread, addr_t queue, 212 addr_t page_to_free, 213 uint64_t page_to_free_size, 214 Status &error) { 215 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0); 216 ProcessSP process_sp(thread.CalculateProcess()); 217 TargetSP target_sp(thread.CalculateTarget()); 218 TypeSystemClang *clang_ast_context = TypeSystemClang::GetScratch(*target_sp); 219 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME)); 220 221 GetPendingItemsReturnInfo return_value; 222 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 223 return_value.items_buffer_size = 0; 224 return_value.count = 0; 225 226 error.Clear(); 227 228 if (!thread.SafeToCallFunctions()) { 229 LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64, 230 thread.GetID()); 231 error.SetErrorString("Not safe to call functions on this thread."); 232 return return_value; 233 } 234 235 // Set up the arguments for a call to 236 237 // struct get_pending_items_return_values 238 // { 239 // uint64_t pending_items_buffer_ptr; /* the address of the items 240 // buffer from libBacktraceRecording */ 241 // uint64_t pending_items_buffer_size; /* the size of the items buffer 242 // from libBacktraceRecording */ 243 // uint64_t count; /* the number of items included in the 244 // queues buffer */ 245 // }; 246 // 247 // void __lldb_backtrace_recording_get_pending_items 248 // (struct 249 // get_pending_items_return_values 250 // *return_buffer, 251 // int debug, 252 // uint64_t /* dispatch_queue_t */ 253 // queue 254 // void *page_to_free, 255 // uint64_t page_to_free_size) 256 257 // Where the return_buffer argument points to a 24 byte region of memory 258 // already allocated by lldb in the inferior process. 259 260 CompilerType clang_void_ptr_type = 261 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 262 Value return_buffer_ptr_value; 263 return_buffer_ptr_value.SetValueType(Value::eValueTypeScalar); 264 return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type); 265 266 CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt); 267 Value debug_value; 268 debug_value.SetValueType(Value::eValueTypeScalar); 269 debug_value.SetCompilerType(clang_int_type); 270 271 CompilerType clang_uint64_type = 272 clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong); 273 Value queue_value; 274 queue_value.SetValueType(Value::eValueTypeScalar); 275 queue_value.SetCompilerType(clang_uint64_type); 276 277 Value page_to_free_value; 278 page_to_free_value.SetValueType(Value::eValueTypeScalar); 279 page_to_free_value.SetCompilerType(clang_void_ptr_type); 280 281 Value page_to_free_size_value; 282 page_to_free_size_value.SetValueType(Value::eValueTypeScalar); 283 page_to_free_size_value.SetCompilerType(clang_uint64_type); 284 285 std::lock_guard<std::mutex> guard(m_get_pending_items_retbuffer_mutex); 286 if (m_get_pending_items_return_buffer_addr == LLDB_INVALID_ADDRESS) { 287 addr_t bufaddr = process_sp->AllocateMemory( 288 32, ePermissionsReadable | ePermissionsWritable, error); 289 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) { 290 LLDB_LOGF(log, "Failed to allocate memory for return buffer for get " 291 "current queues func call"); 292 return return_value; 293 } 294 m_get_pending_items_return_buffer_addr = bufaddr; 295 } 296 297 ValueList argument_values; 298 299 return_buffer_ptr_value.GetScalar() = m_get_pending_items_return_buffer_addr; 300 argument_values.PushValue(return_buffer_ptr_value); 301 302 debug_value.GetScalar() = 0; 303 argument_values.PushValue(debug_value); 304 305 queue_value.GetScalar() = queue; 306 argument_values.PushValue(queue_value); 307 308 if (page_to_free != LLDB_INVALID_ADDRESS) 309 page_to_free_value.GetScalar() = page_to_free; 310 else 311 page_to_free_value.GetScalar() = 0; 312 argument_values.PushValue(page_to_free_value); 313 314 page_to_free_size_value.GetScalar() = page_to_free_size; 315 argument_values.PushValue(page_to_free_size_value); 316 317 addr_t args_addr = SetupGetPendingItemsFunction(thread, argument_values); 318 319 DiagnosticManager diagnostics; 320 ExecutionContext exe_ctx; 321 FunctionCaller *get_pending_items_caller = 322 m_get_pending_items_impl_code->GetFunctionCaller(); 323 324 EvaluateExpressionOptions options; 325 options.SetUnwindOnError(true); 326 options.SetIgnoreBreakpoints(true); 327 options.SetStopOthers(true); 328 #if __has_feature(address_sanitizer) 329 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 330 #else 331 options.SetTimeout(std::chrono::milliseconds(500)); 332 #endif 333 options.SetTryAllThreads(false); 334 options.SetIsForUtilityExpr(true); 335 thread.CalculateExecutionContext(exe_ctx); 336 337 if (get_pending_items_caller == nullptr) { 338 error.SetErrorString("Unable to compile function to call " 339 "__introspection_dispatch_queue_get_pending_items"); 340 return return_value; 341 } 342 343 ExpressionResults func_call_ret; 344 Value results; 345 func_call_ret = get_pending_items_caller->ExecuteFunction( 346 exe_ctx, &args_addr, options, diagnostics, results); 347 if (func_call_ret != eExpressionCompleted || !error.Success()) { 348 LLDB_LOGF(log, 349 "Unable to call " 350 "__introspection_dispatch_queue_get_pending_items(), got " 351 "ExpressionResults %d, error contains %s", 352 func_call_ret, error.AsCString("")); 353 error.SetErrorString("Unable to call " 354 "__introspection_dispatch_queue_get_pending_items() " 355 "for list of queues"); 356 return return_value; 357 } 358 359 return_value.items_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory( 360 m_get_pending_items_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error); 361 if (!error.Success() || 362 return_value.items_buffer_ptr == LLDB_INVALID_ADDRESS) { 363 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 364 return return_value; 365 } 366 367 return_value.items_buffer_size = m_process->ReadUnsignedIntegerFromMemory( 368 m_get_pending_items_return_buffer_addr + 8, 8, 0, error); 369 370 if (!error.Success()) { 371 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 372 return return_value; 373 } 374 375 return_value.count = m_process->ReadUnsignedIntegerFromMemory( 376 m_get_pending_items_return_buffer_addr + 16, 8, 0, error); 377 if (!error.Success()) { 378 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 379 return return_value; 380 } 381 382 LLDB_LOGF(log, 383 "AppleGetPendingItemsHandler called " 384 "__introspection_dispatch_queue_get_pending_items " 385 "(page_to_free == 0x%" PRIx64 ", size = %" PRId64 386 "), returned page is at 0x%" PRIx64 ", size %" PRId64 387 ", count = %" PRId64, 388 page_to_free, page_to_free_size, return_value.items_buffer_ptr, 389 return_value.items_buffer_size, return_value.count); 390 391 return return_value; 392 } 393