1 //===-- AppleGetPendingItemsHandler.cpp -------------------------------*- C++ 2 //-*-===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #include "AppleGetPendingItemsHandler.h" 11 12 13 #include "lldb/Core/Module.h" 14 #include "lldb/Core/Value.h" 15 #include "lldb/Expression/DiagnosticManager.h" 16 #include "lldb/Expression/FunctionCaller.h" 17 #include "lldb/Expression/UtilityFunction.h" 18 #include "lldb/Symbol/ClangASTContext.h" 19 #include "lldb/Symbol/Symbol.h" 20 #include "lldb/Target/ExecutionContext.h" 21 #include "lldb/Target/Process.h" 22 #include "lldb/Target/Target.h" 23 #include "lldb/Target/Thread.h" 24 #include "lldb/Utility/ConstString.h" 25 #include "lldb/Utility/Log.h" 26 #include "lldb/Utility/StreamString.h" 27 28 using namespace lldb; 29 using namespace lldb_private; 30 31 const char *AppleGetPendingItemsHandler::g_get_pending_items_function_name = 32 "__lldb_backtrace_recording_get_pending_items"; 33 const char *AppleGetPendingItemsHandler::g_get_pending_items_function_code = 34 " \n\ 35 extern \"C\" \n\ 36 { \n\ 37 /* \n\ 38 * mach defines \n\ 39 */ \n\ 40 \n\ 41 typedef unsigned int uint32_t; \n\ 42 typedef unsigned long long uint64_t; \n\ 43 typedef uint32_t mach_port_t; \n\ 44 typedef mach_port_t vm_map_t; \n\ 45 typedef int kern_return_t; \n\ 46 typedef uint64_t mach_vm_address_t; \n\ 47 typedef uint64_t mach_vm_size_t; \n\ 48 \n\ 49 mach_port_t mach_task_self (); \n\ 50 kern_return_t mach_vm_deallocate (vm_map_t target, mach_vm_address_t address, mach_vm_size_t size); \n\ 51 \n\ 52 /* \n\ 53 * libBacktraceRecording defines \n\ 54 */ \n\ 55 \n\ 56 typedef uint32_t queue_list_scope_t; \n\ 57 typedef void *dispatch_queue_t; \n\ 58 typedef void *introspection_dispatch_queue_info_t; \n\ 59 typedef void *introspection_dispatch_item_info_ref; \n\ 60 \n\ 61 extern uint64_t __introspection_dispatch_queue_get_pending_items (dispatch_queue_t queue, \n\ 62 introspection_dispatch_item_info_ref *returned_queues_buffer, \n\ 63 uint64_t *returned_queues_buffer_size); \n\ 64 extern int printf(const char *format, ...); \n\ 65 \n\ 66 /* \n\ 67 * return type define \n\ 68 */ \n\ 69 \n\ 70 struct get_pending_items_return_values \n\ 71 { \n\ 72 uint64_t pending_items_buffer_ptr; /* the address of the items buffer from libBacktraceRecording */ \n\ 73 uint64_t pending_items_buffer_size; /* the size of the items buffer from libBacktraceRecording */ \n\ 74 uint64_t count; /* the number of items included in the queues buffer */ \n\ 75 }; \n\ 76 \n\ 77 void __lldb_backtrace_recording_get_pending_items \n\ 78 (struct get_pending_items_return_values *return_buffer, \n\ 79 int debug, \n\ 80 uint64_t /* dispatch_queue_t */ queue, \n\ 81 void *page_to_free, \n\ 82 uint64_t page_to_free_size) \n\ 83 { \n\ 84 if (debug) \n\ 85 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\ 86 if (page_to_free != 0) \n\ 87 { \n\ 88 mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\ 89 } \n\ 90 \n\ 91 return_buffer->count = __introspection_dispatch_queue_get_pending_items ( \n\ 92 (void*) queue, \n\ 93 (void**)&return_buffer->pending_items_buffer_ptr, \n\ 94 &return_buffer->pending_items_buffer_size); \n\ 95 if (debug) \n\ 96 printf(\"result was count %lld\\n\", return_buffer->count); \n\ 97 } \n\ 98 } \n\ 99 "; 100 101 AppleGetPendingItemsHandler::AppleGetPendingItemsHandler(Process *process) 102 : m_process(process), m_get_pending_items_impl_code(), 103 m_get_pending_items_function_mutex(), 104 m_get_pending_items_return_buffer_addr(LLDB_INVALID_ADDRESS), 105 m_get_pending_items_retbuffer_mutex() {} 106 107 AppleGetPendingItemsHandler::~AppleGetPendingItemsHandler() {} 108 109 void AppleGetPendingItemsHandler::Detach() { 110 if (m_process && m_process->IsAlive() && 111 m_get_pending_items_return_buffer_addr != LLDB_INVALID_ADDRESS) { 112 std::unique_lock<std::mutex> lock(m_get_pending_items_retbuffer_mutex, 113 std::defer_lock); 114 lock.try_lock(); // Even if we don't get the lock, deallocate the buffer 115 m_process->DeallocateMemory(m_get_pending_items_return_buffer_addr); 116 } 117 } 118 119 // Compile our __lldb_backtrace_recording_get_pending_items() function (from 120 // the source above in g_get_pending_items_function_code) if we don't find that 121 // function in the inferior already with USE_BUILTIN_FUNCTION defined. (e.g. 122 // this would be the case for testing.) 123 // 124 // Insert the __lldb_backtrace_recording_get_pending_items into the inferior 125 // process if needed. 126 // 127 // Write the get_pending_items_arglist into the inferior's memory space to 128 // prepare for the call. 129 // 130 // Returns the address of the arguments written down in the inferior process, 131 // which can be used to make the function call. 132 133 lldb::addr_t AppleGetPendingItemsHandler::SetupGetPendingItemsFunction( 134 Thread &thread, ValueList &get_pending_items_arglist) { 135 ThreadSP thread_sp(thread.shared_from_this()); 136 ExecutionContext exe_ctx(thread_sp); 137 DiagnosticManager diagnostics; 138 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME)); 139 140 lldb::addr_t args_addr = LLDB_INVALID_ADDRESS; 141 FunctionCaller *get_pending_items_caller = nullptr; 142 143 // Scope for mutex locker: 144 { 145 std::lock_guard<std::mutex> guard(m_get_pending_items_function_mutex); 146 147 // First stage is to make the ClangUtility to hold our injected function: 148 149 if (!m_get_pending_items_impl_code) { 150 if (g_get_pending_items_function_code != NULL) { 151 Status error; 152 m_get_pending_items_impl_code.reset( 153 exe_ctx.GetTargetRef().GetUtilityFunctionForLanguage( 154 g_get_pending_items_function_code, eLanguageTypeObjC, 155 g_get_pending_items_function_name, error)); 156 if (error.Fail()) { 157 if (log) 158 log->Printf("Failed to get UtilityFunction for pending-items " 159 "introspection: %s.", 160 error.AsCString()); 161 return args_addr; 162 } 163 164 if (!m_get_pending_items_impl_code->Install(diagnostics, exe_ctx)) { 165 if (log) { 166 log->Printf("Failed to install pending-items introspection."); 167 diagnostics.Dump(log); 168 } 169 m_get_pending_items_impl_code.reset(); 170 return args_addr; 171 } 172 } else { 173 if (log) 174 log->Printf("No pending-items introspection code found."); 175 return LLDB_INVALID_ADDRESS; 176 } 177 178 // Next make the runner function for our implementation utility function. 179 Status error; 180 ClangASTContext *clang_ast_context = 181 thread.GetProcess()->GetTarget().GetScratchClangASTContext(); 182 CompilerType get_pending_items_return_type = 183 clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType(); 184 get_pending_items_caller = 185 m_get_pending_items_impl_code->MakeFunctionCaller( 186 get_pending_items_return_type, get_pending_items_arglist, 187 thread_sp, error); 188 if (error.Fail() || get_pending_items_caller == nullptr) { 189 if (log) 190 log->Printf("Failed to install pending-items introspection function " 191 "caller: %s.", 192 error.AsCString()); 193 m_get_pending_items_impl_code.reset(); 194 return args_addr; 195 } 196 } 197 } 198 199 diagnostics.Clear(); 200 201 if (get_pending_items_caller == nullptr) { 202 if (log) 203 log->Printf("Failed to get get_pending_items_caller."); 204 return LLDB_INVALID_ADDRESS; 205 } 206 207 // Now write down the argument values for this particular call. This looks 208 // like it might be a race condition if other threads were calling into here, 209 // but actually it isn't because we allocate a new args structure for this 210 // call by passing args_addr = LLDB_INVALID_ADDRESS... 211 212 if (!get_pending_items_caller->WriteFunctionArguments( 213 exe_ctx, args_addr, get_pending_items_arglist, diagnostics)) { 214 if (log) { 215 log->Printf("Error writing pending-items function arguments."); 216 diagnostics.Dump(log); 217 } 218 219 return args_addr; 220 } 221 222 return args_addr; 223 } 224 225 AppleGetPendingItemsHandler::GetPendingItemsReturnInfo 226 AppleGetPendingItemsHandler::GetPendingItems(Thread &thread, addr_t queue, 227 addr_t page_to_free, 228 uint64_t page_to_free_size, 229 Status &error) { 230 lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0); 231 ProcessSP process_sp(thread.CalculateProcess()); 232 TargetSP target_sp(thread.CalculateTarget()); 233 ClangASTContext *clang_ast_context = target_sp->GetScratchClangASTContext(); 234 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME)); 235 236 GetPendingItemsReturnInfo return_value; 237 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 238 return_value.items_buffer_size = 0; 239 return_value.count = 0; 240 241 error.Clear(); 242 243 if (!thread.SafeToCallFunctions()) { 244 if (log) 245 log->Printf("Not safe to call functions on thread 0x%" PRIx64, 246 thread.GetID()); 247 error.SetErrorString("Not safe to call functions on this thread."); 248 return return_value; 249 } 250 251 // Set up the arguments for a call to 252 253 // struct get_pending_items_return_values 254 // { 255 // uint64_t pending_items_buffer_ptr; /* the address of the items 256 // buffer from libBacktraceRecording */ 257 // uint64_t pending_items_buffer_size; /* the size of the items buffer 258 // from libBacktraceRecording */ 259 // uint64_t count; /* the number of items included in the 260 // queues buffer */ 261 // }; 262 // 263 // void __lldb_backtrace_recording_get_pending_items 264 // (struct 265 // get_pending_items_return_values 266 // *return_buffer, 267 // int debug, 268 // uint64_t /* dispatch_queue_t */ 269 // queue 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 CompilerType clang_uint64_type = 288 clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong); 289 Value queue_value; 290 queue_value.SetValueType(Value::eValueTypeScalar); 291 queue_value.SetCompilerType(clang_uint64_type); 292 293 Value page_to_free_value; 294 page_to_free_value.SetValueType(Value::eValueTypeScalar); 295 page_to_free_value.SetCompilerType(clang_void_ptr_type); 296 297 Value page_to_free_size_value; 298 page_to_free_size_value.SetValueType(Value::eValueTypeScalar); 299 page_to_free_size_value.SetCompilerType(clang_uint64_type); 300 301 std::lock_guard<std::mutex> guard(m_get_pending_items_retbuffer_mutex); 302 if (m_get_pending_items_return_buffer_addr == LLDB_INVALID_ADDRESS) { 303 addr_t bufaddr = process_sp->AllocateMemory( 304 32, ePermissionsReadable | ePermissionsWritable, error); 305 if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) { 306 if (log) 307 log->Printf("Failed to allocate memory for return buffer for get " 308 "current queues func call"); 309 return return_value; 310 } 311 m_get_pending_items_return_buffer_addr = bufaddr; 312 } 313 314 ValueList argument_values; 315 316 return_buffer_ptr_value.GetScalar() = m_get_pending_items_return_buffer_addr; 317 argument_values.PushValue(return_buffer_ptr_value); 318 319 debug_value.GetScalar() = 0; 320 argument_values.PushValue(debug_value); 321 322 queue_value.GetScalar() = queue; 323 argument_values.PushValue(queue_value); 324 325 if (page_to_free != LLDB_INVALID_ADDRESS) 326 page_to_free_value.GetScalar() = page_to_free; 327 else 328 page_to_free_value.GetScalar() = 0; 329 argument_values.PushValue(page_to_free_value); 330 331 page_to_free_size_value.GetScalar() = page_to_free_size; 332 argument_values.PushValue(page_to_free_size_value); 333 334 addr_t args_addr = SetupGetPendingItemsFunction(thread, argument_values); 335 336 DiagnosticManager diagnostics; 337 ExecutionContext exe_ctx; 338 FunctionCaller *get_pending_items_caller = 339 m_get_pending_items_impl_code->GetFunctionCaller(); 340 341 EvaluateExpressionOptions options; 342 options.SetUnwindOnError(true); 343 options.SetIgnoreBreakpoints(true); 344 options.SetStopOthers(true); 345 options.SetTimeout(process_sp->GetUtilityExpressionTimeout()); 346 options.SetTryAllThreads(false); 347 options.SetIsForUtilityExpr(true); 348 thread.CalculateExecutionContext(exe_ctx); 349 350 if (get_pending_items_caller == NULL) { 351 error.SetErrorString("Unable to compile function to call " 352 "__introspection_dispatch_queue_get_pending_items"); 353 return return_value; 354 } 355 356 ExpressionResults func_call_ret; 357 Value results; 358 func_call_ret = get_pending_items_caller->ExecuteFunction( 359 exe_ctx, &args_addr, options, diagnostics, results); 360 if (func_call_ret != eExpressionCompleted || !error.Success()) { 361 if (log) 362 log->Printf("Unable to call " 363 "__introspection_dispatch_queue_get_pending_items(), got " 364 "ExpressionResults %d, error contains %s", 365 func_call_ret, error.AsCString("")); 366 error.SetErrorString("Unable to call " 367 "__introspection_dispatch_queue_get_pending_items() " 368 "for list of queues"); 369 return return_value; 370 } 371 372 return_value.items_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory( 373 m_get_pending_items_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error); 374 if (!error.Success() || 375 return_value.items_buffer_ptr == LLDB_INVALID_ADDRESS) { 376 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 377 return return_value; 378 } 379 380 return_value.items_buffer_size = m_process->ReadUnsignedIntegerFromMemory( 381 m_get_pending_items_return_buffer_addr + 8, 8, 0, error); 382 383 if (!error.Success()) { 384 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 385 return return_value; 386 } 387 388 return_value.count = m_process->ReadUnsignedIntegerFromMemory( 389 m_get_pending_items_return_buffer_addr + 16, 8, 0, error); 390 if (!error.Success()) { 391 return_value.items_buffer_ptr = LLDB_INVALID_ADDRESS; 392 return return_value; 393 } 394 395 if (log) 396 log->Printf("AppleGetPendingItemsHandler called " 397 "__introspection_dispatch_queue_get_pending_items " 398 "(page_to_free == 0x%" PRIx64 ", size = %" PRId64 399 "), returned page is at 0x%" PRIx64 ", size %" PRId64 400 ", count = %" PRId64, 401 page_to_free, page_to_free_size, return_value.items_buffer_ptr, 402 return_value.items_buffer_size, return_value.count); 403 404 return return_value; 405 } 406