398 lines · cpp
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-exception6//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 27using namespace lldb;28using namespace lldb_private;29 30const char *AppleGetPendingItemsHandler::g_get_pending_items_function_name =31 "__lldb_backtrace_recording_get_pending_items";32const char *AppleGetPendingItemsHandler::g_get_pending_items_function_code =33 " \n\34extern \"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 100AppleGetPendingItemsHandler::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 106AppleGetPendingItemsHandler::~AppleGetPendingItemsHandler() = default;107 108void 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 buffer114 m_process->DeallocateMemory(m_get_pending_items_return_buffer_addr);115 }116}117 118// Compile our __lldb_backtrace_recording_get_pending_items() function (from119// the source above in g_get_pending_items_function_code) if we don't find that120// 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 inferior124// process if needed.125//126// Write the get_pending_items_arglist into the inferior's memory space to127// 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 132lldb::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 looks194 // 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 this196 // 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 211AppleGetPendingItemsHandler::GetPendingItemsReturnInfo212AppleGetPendingItemsHandler::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 to239 240 // struct get_pending_items_return_values241 // {242 // uint64_t pending_items_buffer_ptr; /* the address of the items243 // buffer from libBacktraceRecording */244 // uint64_t pending_items_buffer_size; /* the size of the items buffer245 // from libBacktraceRecording */246 // uint64_t count; /* the number of items included in the247 // queues buffer */248 // };249 //250 // void __lldb_backtrace_recording_get_pending_items251 // (struct252 // get_pending_items_return_values253 // *return_buffer,254 // int debug,255 // uint64_t /* dispatch_queue_t */256 // queue257 // 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 memory261 // 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 else314 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#else334 options.SetTimeout(std::chrono::milliseconds(500));335#endif336 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 = %" PRId64391 "), returned page is at 0x%" PRIx64 ", size %" PRId64392 ", 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