LLDB  mainline
AppleGetItemInfoHandler.cpp
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1 //===-- AppleGetItemInfoHandler.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 
11 
12 
13 #include "lldb/Core/Module.h"
14 #include "lldb/Core/Value.h"
19 #include "lldb/Symbol/Symbol.h"
21 #include "lldb/Target/Process.h"
22 #include "lldb/Target/Target.h"
23 #include "lldb/Target/Thread.h"
25 #include "lldb/Utility/Log.h"
27 
28 using namespace lldb;
29 using namespace lldb_private;
30 
31 const char *AppleGetItemInfoHandler::g_get_item_info_function_name =
32  "__lldb_backtrace_recording_get_item_info";
33 const char *AppleGetItemInfoHandler::g_get_item_info_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_item_get_info (introspection_dispatch_item_info_ref item_info_ref, \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_item_info_return_values \n\
71  { \n\
72  uint64_t item_info_buffer_ptr; /* the address of the items buffer from libBacktraceRecording */ \n\
73  uint64_t item_info_buffer_size; /* the size of the items buffer from libBacktraceRecording */ \n\
74  }; \n\
75  \n\
76  void __lldb_backtrace_recording_get_item_info \n\
77  (struct get_item_info_return_values *return_buffer, \n\
78  int debug, \n\
79  uint64_t /* introspection_dispatch_item_info_ref item_info_ref */ item, \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_item_info with args return_buffer == %p, debug == %d, item == 0x%llx, page_to_free == %p, page_to_free_size == 0x%llx\\n\", return_buffer, debug, item, 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  __introspection_dispatch_queue_item_get_info ((void*) item, \n\
91  (void**)&return_buffer->item_info_buffer_ptr, \n\
92  &return_buffer->item_info_buffer_size); \n\
93 } \n\
94 } \n\
95 ";
96 
97 AppleGetItemInfoHandler::AppleGetItemInfoHandler(Process *process)
98  : m_process(process), m_get_item_info_impl_code(),
99  m_get_item_info_function_mutex(),
100  m_get_item_info_return_buffer_addr(LLDB_INVALID_ADDRESS),
101  m_get_item_info_retbuffer_mutex() {}
102 
104 
106 
107  if (m_process && m_process->IsAlive() &&
108  m_get_item_info_return_buffer_addr != LLDB_INVALID_ADDRESS) {
109  std::unique_lock<std::mutex> lock(m_get_item_info_retbuffer_mutex,
110  std::defer_lock);
111  lock.try_lock(); // Even if we don't get the lock, deallocate the buffer
112  m_process->DeallocateMemory(m_get_item_info_return_buffer_addr);
113  }
114 }
115 
116 // Compile our __lldb_backtrace_recording_get_item_info() function (from the
117 // source above in g_get_item_info_function_code) if we don't find that
118 // function in the inferior already with USE_BUILTIN_FUNCTION defined. (e.g.
119 // this would be the case for testing.)
120 //
121 // Insert the __lldb_backtrace_recording_get_item_info into the inferior
122 // process if needed.
123 //
124 // Write the get_item_info_arglist into the inferior's memory space to prepare
125 // for the call.
126 //
127 // Returns the address of the arguments written down in the inferior process,
128 // which can be used to make the function call.
129 
130 lldb::addr_t AppleGetItemInfoHandler::SetupGetItemInfoFunction(
131  Thread &thread, ValueList &get_item_info_arglist) {
132  ExecutionContext exe_ctx(thread.shared_from_this());
133  DiagnosticManager diagnostics;
136  FunctionCaller *get_item_info_caller = nullptr;
137 
138  // Scope for mutex locker:
139  {
140  std::lock_guard<std::mutex> guard(m_get_item_info_function_mutex);
141 
142  // First stage is to make the UtilityFunction to hold our injected
143  // function:
144 
145  if (!m_get_item_info_impl_code) {
146  if (g_get_item_info_function_code != NULL) {
147  Status error;
148  m_get_item_info_impl_code.reset(
149  exe_ctx.GetTargetRef().GetUtilityFunctionForLanguage(
150  g_get_item_info_function_code, eLanguageTypeObjC,
151  g_get_item_info_function_name, error));
152  if (error.Fail()) {
153  if (log)
154  log->Printf("Failed to get utility function: %s.",
155  error.AsCString());
156  return args_addr;
157  }
158 
159  if (!m_get_item_info_impl_code->Install(diagnostics, exe_ctx)) {
160  if (log) {
161  log->Printf("Failed to install get-item-info introspection.");
162  diagnostics.Dump(log);
163  }
164  m_get_item_info_impl_code.reset();
165  return args_addr;
166  }
167  } else {
168  if (log)
169  log->Printf("No get-item-info introspection code found.");
170  return LLDB_INVALID_ADDRESS;
171  }
172 
173  // Next make the runner function for our implementation utility function.
174  Status error;
175 
176  TypeSystem *type_system =
177  thread.GetProcess()->GetTarget().GetScratchTypeSystemForLanguage(
178  nullptr, eLanguageTypeC);
179  CompilerType get_item_info_return_type =
181 
182  get_item_info_caller = m_get_item_info_impl_code->MakeFunctionCaller(
183  get_item_info_return_type, get_item_info_arglist,
184  thread.shared_from_this(), error);
185  if (error.Fail() || get_item_info_caller == nullptr) {
186  if (log)
187  log->Printf("Error Inserting get-item-info function: \"%s\".",
188  error.AsCString());
189  return args_addr;
190  }
191  } else {
192  // If it's already made, then we can just retrieve the caller:
193  get_item_info_caller = m_get_item_info_impl_code->GetFunctionCaller();
194  if (!get_item_info_caller) {
195  if (log)
196  log->Printf("Failed to get get-item-info introspection caller.");
197  m_get_item_info_impl_code.reset();
198  return args_addr;
199  }
200  }
201  }
202 
203  diagnostics.Clear();
204 
205  // Now write down the argument values for this particular call. This looks
206  // like it might be a race condition if other threads were calling into here,
207  // but actually it isn't because we allocate a new args structure for this
208  // call by passing args_addr = LLDB_INVALID_ADDRESS...
209 
210  if (!get_item_info_caller->WriteFunctionArguments(
211  exe_ctx, args_addr, get_item_info_arglist, diagnostics)) {
212  if (log) {
213  log->Printf("Error writing get-item-info function arguments.");
214  diagnostics.Dump(log);
215  }
216 
217  return args_addr;
218  }
219 
220  return args_addr;
221 }
222 
225  addr_t page_to_free,
226  uint64_t page_to_free_size,
227  Status &error) {
228  lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
229  ProcessSP process_sp(thread.CalculateProcess());
230  TargetSP target_sp(thread.CalculateTarget());
231  ClangASTContext *clang_ast_context = target_sp->GetScratchClangASTContext();
233 
234  GetItemInfoReturnInfo return_value;
235  return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
236  return_value.item_buffer_size = 0;
237 
238  error.Clear();
239 
240  if (!thread.SafeToCallFunctions()) {
241  if (log)
242  log->Printf("Not safe to call functions on thread 0x%" PRIx64,
243  thread.GetID());
244  error.SetErrorString("Not safe to call functions on this thread.");
245  return return_value;
246  }
247 
248  // Set up the arguments for a call to
249 
250  // struct get_item_info_return_values
251  // {
252  // uint64_t item_info_buffer_ptr; /* the address of the items buffer
253  // from libBacktraceRecording */
254  // uint64_t item_info_buffer_size; /* the size of the items buffer from
255  // libBacktraceRecording */
256  // };
257  //
258  // void __lldb_backtrace_recording_get_item_info
259  // (struct
260  // get_item_info_return_values
261  // *return_buffer,
262  // int debug,
263  // uint64_t item,
264  // void *page_to_free,
265  // uint64_t page_to_free_size)
266 
267  // Where the return_buffer argument points to a 24 byte region of memory
268  // already allocated by lldb in the inferior process.
269 
270  CompilerType clang_void_ptr_type =
271  clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
272  Value return_buffer_ptr_value;
273  return_buffer_ptr_value.SetValueType(Value::eValueTypeScalar);
274  return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type);
275 
276  CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt);
277  Value debug_value;
279  debug_value.SetCompilerType(clang_int_type);
280 
281  CompilerType clang_uint64_type =
282  clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong);
283  Value item_value;
285  item_value.SetCompilerType(clang_uint64_type);
286 
287  Value page_to_free_value;
288  page_to_free_value.SetValueType(Value::eValueTypeScalar);
289  page_to_free_value.SetCompilerType(clang_void_ptr_type);
290 
291  Value page_to_free_size_value;
292  page_to_free_size_value.SetValueType(Value::eValueTypeScalar);
293  page_to_free_size_value.SetCompilerType(clang_uint64_type);
294 
295  std::lock_guard<std::mutex> guard(m_get_item_info_retbuffer_mutex);
296  if (m_get_item_info_return_buffer_addr == LLDB_INVALID_ADDRESS) {
297  addr_t bufaddr = process_sp->AllocateMemory(
298  32, ePermissionsReadable | ePermissionsWritable, error);
299  if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) {
300  if (log)
301  log->Printf("Failed to allocate memory for return buffer for get "
302  "current queues func call");
303  return return_value;
304  }
305  m_get_item_info_return_buffer_addr = bufaddr;
306  }
307 
308  ValueList argument_values;
309 
310  return_buffer_ptr_value.GetScalar() = m_get_item_info_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  item_value.GetScalar() = item;
317  argument_values.PushValue(item_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 = SetupGetItemInfoFunction(thread, argument_values);
329 
330  DiagnosticManager diagnostics;
331  ExecutionContext exe_ctx;
333  options.SetUnwindOnError(true);
334  options.SetIgnoreBreakpoints(true);
335  options.SetStopOthers(true);
336  options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
337  options.SetTryAllThreads(false);
338  options.SetIsForUtilityExpr(true);
339  thread.CalculateExecutionContext(exe_ctx);
340 
341  if (!m_get_item_info_impl_code) {
342  error.SetErrorString("Unable to compile function to call "
343  "__introspection_dispatch_queue_item_get_info");
344  return return_value;
345  }
346 
347  ExpressionResults func_call_ret;
348  Value results;
349  FunctionCaller *func_caller = m_get_item_info_impl_code->GetFunctionCaller();
350  if (!func_caller) {
351  if (log)
352  log->Printf("Could not retrieve function caller for "
353  "__introspection_dispatch_queue_item_get_info.");
354  error.SetErrorString("Could not retrieve function caller for "
355  "__introspection_dispatch_queue_item_get_info.");
356  return return_value;
357  }
358 
359  func_call_ret = func_caller->ExecuteFunction(exe_ctx, &args_addr, options,
360  diagnostics, results);
361  if (func_call_ret != eExpressionCompleted || !error.Success()) {
362  if (log)
363  log->Printf("Unable to call "
364  "__introspection_dispatch_queue_item_get_info(), got "
365  "ExpressionResults %d, error contains %s",
366  func_call_ret, error.AsCString(""));
367  error.SetErrorString("Unable to call "
368  "__introspection_dispatch_queue_get_item_info() for "
369  "list of queues");
370  return return_value;
371  }
372 
373  return_value.item_buffer_ptr = m_process->ReadUnsignedIntegerFromMemory(
374  m_get_item_info_return_buffer_addr, 8, LLDB_INVALID_ADDRESS, error);
375  if (!error.Success() ||
376  return_value.item_buffer_ptr == LLDB_INVALID_ADDRESS) {
377  return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
378  return return_value;
379  }
380 
381  return_value.item_buffer_size = m_process->ReadUnsignedIntegerFromMemory(
382  m_get_item_info_return_buffer_addr + 8, 8, 0, error);
383 
384  if (!error.Success()) {
385  return_value.item_buffer_ptr = LLDB_INVALID_ADDRESS;
386  return return_value;
387  }
388  if (log)
389  log->Printf("AppleGetItemInfoHandler called "
390  "__introspection_dispatch_queue_item_get_info (page_to_free == "
391  "0x%" PRIx64 ", size = %" PRId64
392  "), returned page is at 0x%" PRIx64 ", size %" PRId64,
393  page_to_free, page_to_free_size, return_value.item_buffer_ptr,
394  return_value.item_buffer_size);
395 
396  return return_value;
397 }
lldb::ExpressionResults ExecuteFunction(ExecutionContext &exe_ctx, lldb::addr_t *args_addr_ptr, const EvaluateExpressionOptions &options, DiagnosticManager &diagnostic_manager, Value &results)
Run the function this FunctionCaller was created with.
void SetIgnoreBreakpoints(bool ignore=false)
Definition: Target.h:289
#define LIBLLDB_LOG_SYSTEM_RUNTIME
Definition: Logging.h:40
Enumerations for broadcasting.
Definition: SBLaunchInfo.h:14
void SetUnwindOnError(bool unwind=false)
Definition: Target.h:285
lldb::user_id_t GetID() const
Get accessor for the user ID.
Definition: UserID.h:49
void CalculateExecutionContext(ExecutionContext &exe_ctx) override
Reconstruct the object&#39;s execution context into sc.
Definition: Thread.cpp:1598
void SetValueType(ValueType value_type)
Definition: Value.h:154
"lldb/Target/ExecutionContext.h" A class that contains an execution context.
bool WriteFunctionArguments(ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref, DiagnosticManager &diagnostic_manager)
Insert the default function argument struct.
#define LLDB_INVALID_ADDRESS
Invalid value definitions.
Definition: lldb-defines.h:85
void SetTimeout(const Timeout< std::micro > &timeout)
Definition: Target.h:306
Log * GetLogIfAllCategoriesSet(uint32_t mask)
Definition: Logging.cpp:57
lldb::TargetSP CalculateTarget() override
Definition: Thread.cpp:1584
Status DeallocateMemory(lldb::addr_t ptr)
The public interface to deallocating memory in the process.
Definition: Process.cpp:2415
void Clear()
Clear the object state.
Definition: Status.cpp:167
virtual CompilerType GetBasicTypeFromAST(lldb::BasicType basic_type)=0
Encapsulates a function that can be called.
void SetErrorString(llvm::StringRef err_str)
Set the current error string to err_str.
Definition: Status.cpp:241
A plug-in interface definition class for debugging a process.
Definition: Process.h:353
lldb::ProcessSP CalculateProcess() override
Definition: Thread.cpp:1592
bool Success() const
Test for success condition.
Definition: Status.cpp:287
CompilerType GetPointerType() const
GetItemInfoReturnInfo GetItemInfo(Thread &thread, lldb::addr_t item, lldb::addr_t page_to_free, uint64_t page_to_free_size, lldb_private::Status &error)
Get the information about a work item by calling __introspection_dispatch_queue_item_get_info.
lldb::ProcessSP GetProcess() const
Definition: Thread.h:154
void SetStopOthers(bool stop_others=true)
Definition: Target.h:322
uint64_t addr_t
Definition: lldb-types.h:83
bool Fail() const
Test for error condition.
Definition: Status.cpp:181
virtual bool IsAlive()
Check if a process is still alive.
Definition: Process.cpp:1182
Non-standardized C, such as K&R.
Definition: SBAddress.h:15
void SetTryAllThreads(bool try_others=true)
Definition: Target.h:318
virtual bool SafeToCallFunctions()
Check whether this thread is safe to run functions.
Definition: Thread.cpp:1844
void SetCompilerType(const CompilerType &compiler_type)
Definition: Value.cpp:268
const Scalar & GetScalar() const
Definition: Value.h:178
const char * AsCString(const char *default_error_str="unknown error") const
Get the error string associated with the current error.
Definition: Status.cpp:130
virtual lldb::StackFrameSP GetStackFrameAtIndex(uint32_t idx)
Definition: Thread.h:395
uint64_t ReadUnsignedIntegerFromMemory(lldb::addr_t load_addr, size_t byte_size, uint64_t fail_value, Status &error)
Reads an unsigned integer of the specified byte size from process memory.
Definition: Process.cpp:2150
void Printf(const char *format,...) __attribute__((format(printf
Definition: Log.cpp:113
An error handling class.
Definition: Status.h:44
void PushValue(const Value &value)
Definition: Value.cpp:697