LLDB  mainline
AppleGetQueuesHandler.cpp
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1 //===-- AppleGetQueuesHandler.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 
10 
12 #include "lldb/Core/Module.h"
13 #include "lldb/Core/Value.h"
17 #include "lldb/Symbol/Symbol.h"
19 #include "lldb/Target/Process.h"
20 #include "lldb/Target/Target.h"
21 #include "lldb/Target/Thread.h"
23 #include "lldb/Utility/LLDBLog.h"
24 #include "lldb/Utility/Log.h"
26 
27 using namespace lldb;
28 using namespace lldb_private;
29 
30 const char *AppleGetQueuesHandler::g_get_current_queues_function_name =
31  "__lldb_backtrace_recording_get_current_queues";
32 const char *AppleGetQueuesHandler::g_get_current_queues_function_code =
33  " \n\
34 extern \"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 *introspection_dispatch_queue_info_t; \n\
57  \n\
58  extern uint64_t __introspection_dispatch_get_queues (queue_list_scope_t scope, \n\
59  introspection_dispatch_queue_info_t *returned_queues_buffer, \n\
60  uint64_t *returned_queues_buffer_size); \n\
61  extern int printf(const char *format, ...); \n\
62  \n\
63  /* \n\
64  * return type define \n\
65  */ \n\
66  \n\
67  struct get_current_queues_return_values \n\
68  { \n\
69  uint64_t queues_buffer_ptr; /* the address of the queues buffer from libBacktraceRecording */ \n\
70  uint64_t queues_buffer_size; /* the size of the queues buffer from libBacktraceRecording */ \n\
71  uint64_t count; /* the number of queues included in the queues buffer */ \n\
72  }; \n\
73  \n\
74  void __lldb_backtrace_recording_get_current_queues \n\
75  (struct get_current_queues_return_values *return_buffer, \n\
76  int debug, \n\
77  void *page_to_free, \n\
78  uint64_t page_to_free_size) \n\
79 { \n\
80  if (debug) \n\
81  printf (\"entering get_current_queues with args %p, %d, 0x%p, 0x%llx\\n\", return_buffer, debug, page_to_free, page_to_free_size); \n\
82  if (page_to_free != 0) \n\
83  { \n\
84  mach_vm_deallocate (mach_task_self(), (mach_vm_address_t) page_to_free, (mach_vm_size_t) page_to_free_size); \n\
85  } \n\
86  \n\
87  return_buffer->count = __introspection_dispatch_get_queues ( \n\
88  /* QUEUES_WITH_ANY_ITEMS */ 2, \n\
89  (void**)&return_buffer->queues_buffer_ptr, \n\
90  &return_buffer->queues_buffer_size); \n\
91  if (debug) \n\
92  printf(\"result was count %lld\\n\", return_buffer->count); \n\
93 } \n\
94 } \n\
95 ";
96 
97 AppleGetQueuesHandler::AppleGetQueuesHandler(Process *process)
98  : m_process(process), m_get_queues_impl_code_up(),
99  m_get_queues_function_mutex(),
100  m_get_queues_return_buffer_addr(LLDB_INVALID_ADDRESS),
101  m_get_queues_retbuffer_mutex() {}
102 
104 
106 
107  if (m_process && m_process->IsAlive() &&
109  std::unique_lock<std::mutex> lock(m_get_queues_retbuffer_mutex,
110  std::defer_lock);
111  (void)lock.try_lock(); // Even if we don't get the lock, deallocate the buffer
113  }
114 }
115 
116 // Construct a CompilerType for the structure that
117 // g_get_current_queues_function_code will return by value so we can extract
118 // the fields after performing the function call. i.e. we are getting this
119 // struct returned to us:
120 //
121 // struct get_current_queues_return_values
122 // {
123 // introspection_dispatch_queue_info_t *queues_buffer;
124 // uint64_t queues_buffer_size;
125 // uint64_t count;
126 // };
127 
128 // Compile our __lldb_backtrace_recording_get_current_queues() function (from
129 // the source above in g_get_current_queues_function_code) if we don't find
130 // that function in the inferior already with USE_BUILTIN_FUNCTION defined.
131 // (e.g. this would be the case for testing.)
132 //
133 // Insert the __lldb_backtrace_recording_get_current_queues into the inferior
134 // process if needed.
135 //
136 // Write the get_queues_arglist into the inferior's memory space to prepare for
137 // the call.
138 //
139 // Returns the address of the arguments written down in the inferior process,
140 // which can be used to make the function call.
141 
144  ValueList &get_queues_arglist) {
145  ThreadSP thread_sp(thread.shared_from_this());
146  ExecutionContext exe_ctx(thread_sp);
147 
148  Address impl_code_address;
149  DiagnosticManager diagnostics;
152 
153  FunctionCaller *get_queues_caller = nullptr;
154 
155  // Scope for mutex locker:
156  {
157  std::lock_guard<std::mutex> guard(m_get_queues_function_mutex);
158 
159  // First stage is to make the ClangUtility to hold our injected function:
160 
162  if (g_get_current_queues_function_code != nullptr) {
163  auto utility_fn_or_error = exe_ctx.GetTargetRef().CreateUtilityFunction(
166  if (!utility_fn_or_error) {
167  LLDB_LOG_ERROR(log, utility_fn_or_error.takeError(),
168  "Failed to create UtilityFunction for queues "
169  "introspection: {0}.");
170  return args_addr;
171  }
172  m_get_queues_impl_code_up = std::move(*utility_fn_or_error);
173  } else {
174  if (log) {
175  LLDB_LOGF(log, "No queues introspection code found.");
176  diagnostics.Dump(log);
177  }
178  return LLDB_INVALID_ADDRESS;
179  }
180  }
181 
182  // Next make the runner function for our implementation utility function.
183  TypeSystemClang *clang_ast_context =
184  ScratchTypeSystemClang::GetForTarget(thread.GetProcess()->GetTarget());
185  CompilerType get_queues_return_type =
186  clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
187  Status error;
188  get_queues_caller = m_get_queues_impl_code_up->MakeFunctionCaller(
189  get_queues_return_type, get_queues_arglist, thread_sp, error);
190  if (error.Fail() || get_queues_caller == nullptr) {
191  LLDB_LOGF(log,
192  "Could not get function caller for get-queues function: %s.",
193  error.AsCString());
194  return args_addr;
195  }
196  }
197 
198  diagnostics.Clear();
199 
200  // Now write down the argument values for this particular call. This looks
201  // like it might be a race condition if other threads were calling into here,
202  // but actually it isn't because we allocate a new args structure for this
203  // call by passing args_addr = LLDB_INVALID_ADDRESS...
204 
205  if (!get_queues_caller->WriteFunctionArguments(
206  exe_ctx, args_addr, get_queues_arglist, diagnostics)) {
207  if (log) {
208  LLDB_LOGF(log, "Error writing get-queues function arguments.");
209  diagnostics.Dump(log);
210  }
211  return args_addr;
212  }
213 
214  return args_addr;
215 }
216 
219  uint64_t page_to_free_size,
220  Status &error) {
221  lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
222  ProcessSP process_sp(thread.CalculateProcess());
223  TargetSP target_sp(thread.CalculateTarget());
224  TypeSystemClang *clang_ast_context =
227 
228  GetQueuesReturnInfo return_value;
230  return_value.queues_buffer_size = 0;
231  return_value.count = 0;
232 
233  error.Clear();
234 
235  if (!thread.SafeToCallFunctions()) {
236  LLDB_LOGF(log, "Not safe to call functions on thread 0x%" PRIx64,
237  thread.GetID());
238  error.SetErrorString("Not safe to call functions on this thread.");
239  return return_value;
240  }
241 
242  // Set up the arguments for a call to
243 
244  // struct get_current_queues_return_values
245  // {
246  // uint64_t queues_buffer_ptr; /* the address of the queues buffer from
247  // libBacktraceRecording */
248  // uint64_t queues_buffer_size; /* the size of the queues buffer from
249  // libBacktraceRecording */
250  // uint64_t count; /* the number of queues included in the
251  // queues buffer */
252  // };
253  //
254  // void
255  // __lldb_backtrace_recording_get_current_queues
256  // (struct
257  // get_current_queues_return_values
258  // *return_buffer,
259  // void *page_to_free,
260  // uint64_t page_to_free_size);
261 
262  // Where the return_buffer argument points to a 24 byte region of memory
263  // already allocated by lldb in the inferior process.
264 
265  CompilerType clang_void_ptr_type =
266  clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
267  Value return_buffer_ptr_value;
268  return_buffer_ptr_value.SetValueType(Value::ValueType::Scalar);
269  return_buffer_ptr_value.SetCompilerType(clang_void_ptr_type);
270 
271  CompilerType clang_int_type = clang_ast_context->GetBasicType(eBasicTypeInt);
272  Value debug_value;
274  debug_value.SetCompilerType(clang_int_type);
275 
276  Value page_to_free_value;
277  page_to_free_value.SetValueType(Value::ValueType::Scalar);
278  page_to_free_value.SetCompilerType(clang_void_ptr_type);
279 
280  CompilerType clang_uint64_type =
281  clang_ast_context->GetBasicType(eBasicTypeUnsignedLongLong);
282  Value page_to_free_size_value;
283  page_to_free_size_value.SetValueType(Value::ValueType::Scalar);
284  page_to_free_size_value.SetCompilerType(clang_uint64_type);
285 
286  std::lock_guard<std::mutex> guard(m_get_queues_retbuffer_mutex);
288  addr_t bufaddr = process_sp->AllocateMemory(
289  32, ePermissionsReadable | ePermissionsWritable, error);
290  if (!error.Success() || bufaddr == LLDB_INVALID_ADDRESS) {
291  LLDB_LOGF(log, "Failed to allocate memory for return buffer for get "
292  "current queues func call");
293  return return_value;
294  }
296  }
297 
298  ValueList argument_values;
299 
300  return_buffer_ptr_value.GetScalar() = m_get_queues_return_buffer_addr;
301  argument_values.PushValue(return_buffer_ptr_value);
302 
303  debug_value.GetScalar() = 0;
304  argument_values.PushValue(debug_value);
305 
306  if (page_to_free != LLDB_INVALID_ADDRESS)
307  page_to_free_value.GetScalar() = page_to_free;
308  else
309  page_to_free_value.GetScalar() = 0;
310  argument_values.PushValue(page_to_free_value);
311 
312  page_to_free_size_value.GetScalar() = page_to_free_size;
313  argument_values.PushValue(page_to_free_size_value);
314 
315  addr_t args_addr = SetupGetQueuesFunction(thread, argument_values);
316 
318  error.SetErrorString(
319  "Unable to compile __introspection_dispatch_get_queues.");
320  return return_value;
321  }
322 
323  FunctionCaller *get_queues_caller =
324  m_get_queues_impl_code_up->GetFunctionCaller();
325 
326  if (get_queues_caller == nullptr) {
327  error.SetErrorString(
328  "Unable to get caller for call __introspection_dispatch_get_queues");
329  return return_value;
330  }
331 
332  DiagnosticManager diagnostics;
333  ExecutionContext exe_ctx;
335  options.SetUnwindOnError(true);
336  options.SetIgnoreBreakpoints(true);
337  options.SetStopOthers(true);
338 #if __has_feature(address_sanitizer)
339  options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
340 #else
341  options.SetTimeout(std::chrono::milliseconds(500));
342 #endif
343  options.SetTryAllThreads(false);
344  options.SetIsForUtilityExpr(true);
345  thread.CalculateExecutionContext(exe_ctx);
346 
347  ExpressionResults func_call_ret;
348  Value results;
349  func_call_ret = get_queues_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 introspection_get_dispatch_queues(), got "
354  "ExpressionResults %d, error contains %s",
355  func_call_ret, error.AsCString(""));
356  error.SetErrorString("Unable to call introspection_get_dispatch_queues() "
357  "for list of queues");
358  return return_value;
359  }
360 
363  if (!error.Success() ||
364  return_value.queues_buffer_ptr == LLDB_INVALID_ADDRESS) {
366  return return_value;
367  }
368 
371 
372  if (!error.Success()) {
374  return return_value;
375  }
376 
379  if (!error.Success()) {
381  return return_value;
382  }
383 
384  LLDB_LOGF(log,
385  "AppleGetQueuesHandler called "
386  "__introspection_dispatch_get_queues (page_to_free == "
387  "0x%" PRIx64 ", size = %" PRId64 "), returned page is at 0x%" PRIx64
388  ", size %" PRId64 ", count = %" PRId64,
389  page_to_free, page_to_free_size, return_value.queues_buffer_ptr,
390  return_value.queues_buffer_size, return_value.count);
391 
392  return return_value;
393 }
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A raw scalar value.
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Definition: Process.cpp:2333
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Get the list of queues that exist (with any active or pending items) via a call to introspection_get_...
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